linux/drivers/pwm/core.c

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// SPDX-License-Identifier: GPL-2.0-or-later
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
/*
* Generic pwmlib implementation
*
* Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
* Copyright (C) 2011-2012 Avionic Design GmbH
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
#include <linux/acpi.h>
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
#include <linux/module.h>
#include <linux/pwm.h>
#include <linux/radix-tree.h>
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
#include <dt-bindings/pwm/pwm.h>
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
#define MAX_PWMS 1024
static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
static DEFINE_MUTEX(pwm_lock);
static LIST_HEAD(pwm_chips);
static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
static RADIX_TREE(pwm_tree, GFP_KERNEL);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
static struct pwm_device *pwm_to_device(unsigned int pwm)
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
{
return radix_tree_lookup(&pwm_tree, pwm);
}
static int alloc_pwms(int pwm, unsigned int count)
{
unsigned int from = 0;
unsigned int start;
if (pwm >= MAX_PWMS)
return -EINVAL;
if (pwm >= 0)
from = pwm;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
count, 0);
if (pwm >= 0 && start != pwm)
return -EEXIST;
if (start + count > MAX_PWMS)
return -ENOSPC;
return start;
}
static void free_pwms(struct pwm_chip *chip)
{
unsigned int i;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
radix_tree_delete(&pwm_tree, pwm->pwm);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
}
bitmap_clear(allocated_pwms, chip->base, chip->npwm);
kfree(chip->pwms);
chip->pwms = NULL;
}
static struct pwm_chip *pwmchip_find_by_name(const char *name)
{
struct pwm_chip *chip;
if (!name)
return NULL;
mutex_lock(&pwm_lock);
list_for_each_entry(chip, &pwm_chips, list) {
const char *chip_name = dev_name(chip->dev);
if (chip_name && strcmp(chip_name, name) == 0) {
mutex_unlock(&pwm_lock);
return chip;
}
}
mutex_unlock(&pwm_lock);
return NULL;
}
static int pwm_device_request(struct pwm_device *pwm, const char *label)
{
int err;
if (test_bit(PWMF_REQUESTED, &pwm->flags))
return -EBUSY;
if (!try_module_get(pwm->chip->ops->owner))
return -ENODEV;
if (pwm->chip->ops->request) {
err = pwm->chip->ops->request(pwm->chip, pwm);
if (err) {
module_put(pwm->chip->ops->owner);
return err;
}
}
set_bit(PWMF_REQUESTED, &pwm->flags);
pwm->label = label;
return 0;
}
struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
/* check, whether the driver supports a third cell for flags */
if (pc->of_pwm_n_cells < 3)
return ERR_PTR(-EINVAL);
/* flags in the third cell are optional */
if (args->args_count < 2)
return ERR_PTR(-EINVAL);
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);
pwm = pwm_request_from_chip(pc, args->args[0], NULL);
if (IS_ERR(pwm))
return pwm;
pwm->args.period = args->args[1];
pwm->args.polarity = PWM_POLARITY_NORMAL;
if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
pwm->args.polarity = PWM_POLARITY_INVERSED;
return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
static struct pwm_device *
of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
/* sanity check driver support */
if (pc->of_pwm_n_cells < 2)
return ERR_PTR(-EINVAL);
/* all cells are required */
if (args->args_count != pc->of_pwm_n_cells)
return ERR_PTR(-EINVAL);
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);
pwm = pwm_request_from_chip(pc, args->args[0], NULL);
if (IS_ERR(pwm))
return pwm;
pwm->args.period = args->args[1];
return pwm;
}
static void of_pwmchip_add(struct pwm_chip *chip)
{
if (!chip->dev || !chip->dev->of_node)
return;
if (!chip->of_xlate) {
chip->of_xlate = of_pwm_simple_xlate;
chip->of_pwm_n_cells = 2;
}
of_node_get(chip->dev->of_node);
}
static void of_pwmchip_remove(struct pwm_chip *chip)
{
if (chip->dev)
of_node_put(chip->dev->of_node);
}
/**
* pwm_set_chip_data() - set private chip data for a PWM
* @pwm: PWM device
* @data: pointer to chip-specific data
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwm_set_chip_data(struct pwm_device *pwm, void *data)
{
if (!pwm)
return -EINVAL;
pwm->chip_data = data;
return 0;
}
EXPORT_SYMBOL_GPL(pwm_set_chip_data);
/**
* pwm_get_chip_data() - get private chip data for a PWM
* @pwm: PWM device
*
* Returns: A pointer to the chip-private data for the PWM device.
*/
void *pwm_get_chip_data(struct pwm_device *pwm)
{
return pwm ? pwm->chip_data : NULL;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
}
EXPORT_SYMBOL_GPL(pwm_get_chip_data);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
static bool pwm_ops_check(const struct pwm_ops *ops)
{
/* driver supports legacy, non-atomic operation */
if (ops->config && ops->enable && ops->disable)
return true;
/* driver supports atomic operation */
if (ops->apply)
return true;
return false;
}
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
/**
* pwmchip_add_with_polarity() - register a new PWM chip
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
* @chip: the PWM chip to add
* @polarity: initial polarity of PWM channels
*
* Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
* will be used. The initial polarity for all channels is specified by the
* @polarity parameter.
*
* Returns: 0 on success or a negative error code on failure.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
int pwmchip_add_with_polarity(struct pwm_chip *chip,
enum pwm_polarity polarity)
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
{
struct pwm_device *pwm;
unsigned int i;
int ret;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
if (!chip || !chip->dev || !chip->ops || !chip->npwm)
return -EINVAL;
if (!pwm_ops_check(chip->ops))
return -EINVAL;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
mutex_lock(&pwm_lock);
ret = alloc_pwms(chip->base, chip->npwm);
if (ret < 0)
goto out;
chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
if (!chip->pwms) {
ret = -ENOMEM;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
goto out;
}
chip->base = ret;
for (i = 0; i < chip->npwm; i++) {
pwm = &chip->pwms[i];
pwm->chip = chip;
pwm->pwm = chip->base + i;
pwm->hwpwm = i;
pwm->state.polarity = polarity;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
if (chip->ops->get_state)
chip->ops->get_state(chip, pwm, &pwm->state);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
}
bitmap_set(allocated_pwms, chip->base, chip->npwm);
INIT_LIST_HEAD(&chip->list);
list_add(&chip->list, &pwm_chips);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
ret = 0;
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_add(chip);
out:
mutex_unlock(&pwm_lock);
pwm: Fix deadlock warning when removing PWM device This patch fixes deadlock warning if removing PWM device when CONFIG_PROVE_LOCKING is enabled. This issue can be reproceduced by the following steps on the R-Car H3 Salvator-X board if the backlight is disabled: # cd /sys/class/pwm/pwmchip0 # echo 0 > export # ls device export npwm power pwm0 subsystem uevent unexport # cd device/driver # ls bind e6e31000.pwm uevent unbind # echo e6e31000.pwm > unbind [ 87.659974] ====================================================== [ 87.666149] WARNING: possible circular locking dependency detected [ 87.672327] 5.0.0 #7 Not tainted [ 87.675549] ------------------------------------------------------ [ 87.681723] bash/2986 is trying to acquire lock: [ 87.686337] 000000005ea0e178 (kn->count#58){++++}, at: kernfs_remove_by_name_ns+0x50/0xa0 [ 87.694528] [ 87.694528] but task is already holding lock: [ 87.700353] 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c [ 87.707405] [ 87.707405] which lock already depends on the new lock. [ 87.707405] [ 87.715574] [ 87.715574] the existing dependency chain (in reverse order) is: [ 87.723048] [ 87.723048] -> #1 (pwm_lock){+.+.}: [ 87.728017] __mutex_lock+0x70/0x7e4 [ 87.732108] mutex_lock_nested+0x1c/0x24 [ 87.736547] pwm_request_from_chip.part.6+0x34/0x74 [ 87.741940] pwm_request_from_chip+0x20/0x40 [ 87.746725] export_store+0x6c/0x1f4 [ 87.750820] dev_attr_store+0x18/0x28 [ 87.754998] sysfs_kf_write+0x54/0x64 [ 87.759175] kernfs_fop_write+0xe4/0x1e8 [ 87.763615] __vfs_write+0x40/0x184 [ 87.767619] vfs_write+0xa8/0x19c [ 87.771448] ksys_write+0x58/0xbc [ 87.775278] __arm64_sys_write+0x18/0x20 [ 87.779721] el0_svc_common+0xd0/0x124 [ 87.783986] el0_svc_compat_handler+0x1c/0x24 [ 87.788858] el0_svc_compat+0x8/0x18 [ 87.792947] [ 87.792947] -> #0 (kn->count#58){++++}: [ 87.798260] lock_acquire+0xc4/0x22c [ 87.802353] __kernfs_remove+0x258/0x2c4 [ 87.806790] kernfs_remove_by_name_ns+0x50/0xa0 [ 87.811836] remove_files.isra.1+0x38/0x78 [ 87.816447] sysfs_remove_group+0x48/0x98 [ 87.820971] sysfs_remove_groups+0x34/0x4c [ 87.825583] device_remove_attrs+0x6c/0x7c [ 87.830197] device_del+0x11c/0x33c [ 87.834201] device_unregister+0x14/0x2c [ 87.838638] pwmchip_sysfs_unexport+0x40/0x4c [ 87.843509] pwmchip_remove+0xf4/0x13c [ 87.847773] rcar_pwm_remove+0x28/0x34 [ 87.852039] platform_drv_remove+0x24/0x64 [ 87.856651] device_release_driver_internal+0x18c/0x21c [ 87.862391] device_release_driver+0x14/0x1c [ 87.867175] unbind_store+0xe0/0x124 [ 87.871265] drv_attr_store+0x20/0x30 [ 87.875442] sysfs_kf_write+0x54/0x64 [ 87.879618] kernfs_fop_write+0xe4/0x1e8 [ 87.884055] __vfs_write+0x40/0x184 [ 87.888057] vfs_write+0xa8/0x19c [ 87.891887] ksys_write+0x58/0xbc [ 87.895716] __arm64_sys_write+0x18/0x20 [ 87.900154] el0_svc_common+0xd0/0x124 [ 87.904417] el0_svc_compat_handler+0x1c/0x24 [ 87.909289] el0_svc_compat+0x8/0x18 [ 87.913378] [ 87.913378] other info that might help us debug this: [ 87.913378] [ 87.921374] Possible unsafe locking scenario: [ 87.921374] [ 87.927286] CPU0 CPU1 [ 87.931808] ---- ---- [ 87.936331] lock(pwm_lock); [ 87.939293] lock(kn->count#58); [ 87.945120] lock(pwm_lock); [ 87.950599] lock(kn->count#58); [ 87.953908] [ 87.953908] *** DEADLOCK *** [ 87.953908] [ 87.959821] 4 locks held by bash/2986: [ 87.963563] #0: 00000000ace7bc30 (sb_writers#6){.+.+}, at: vfs_write+0x188/0x19c [ 87.971044] #1: 00000000287991b2 (&of->mutex){+.+.}, at: kernfs_fop_write+0xb4/0x1e8 [ 87.978872] #2: 00000000f739d016 (&dev->mutex){....}, at: device_release_driver_internal+0x40/0x21c [ 87.988001] #3: 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c [ 87.995481] [ 87.995481] stack backtrace: [ 87.999836] CPU: 0 PID: 2986 Comm: bash Not tainted 5.0.0 #7 [ 88.005489] Hardware name: Renesas Salvator-X board based on r8a7795 ES1.x (DT) [ 88.012791] Call trace: [ 88.015235] dump_backtrace+0x0/0x190 [ 88.018891] show_stack+0x14/0x1c [ 88.022204] dump_stack+0xb0/0xec [ 88.025514] print_circular_bug.isra.32+0x1d0/0x2e0 [ 88.030385] __lock_acquire+0x1318/0x1864 [ 88.034388] lock_acquire+0xc4/0x22c [ 88.037958] __kernfs_remove+0x258/0x2c4 [ 88.041874] kernfs_remove_by_name_ns+0x50/0xa0 [ 88.046398] remove_files.isra.1+0x38/0x78 [ 88.050487] sysfs_remove_group+0x48/0x98 [ 88.054490] sysfs_remove_groups+0x34/0x4c [ 88.058580] device_remove_attrs+0x6c/0x7c [ 88.062671] device_del+0x11c/0x33c [ 88.066154] device_unregister+0x14/0x2c [ 88.070070] pwmchip_sysfs_unexport+0x40/0x4c [ 88.074421] pwmchip_remove+0xf4/0x13c [ 88.078163] rcar_pwm_remove+0x28/0x34 [ 88.081906] platform_drv_remove+0x24/0x64 [ 88.085996] device_release_driver_internal+0x18c/0x21c [ 88.091215] device_release_driver+0x14/0x1c [ 88.095478] unbind_store+0xe0/0x124 [ 88.099048] drv_attr_store+0x20/0x30 [ 88.102704] sysfs_kf_write+0x54/0x64 [ 88.106359] kernfs_fop_write+0xe4/0x1e8 [ 88.110275] __vfs_write+0x40/0x184 [ 88.113757] vfs_write+0xa8/0x19c [ 88.117065] ksys_write+0x58/0xbc [ 88.120374] __arm64_sys_write+0x18/0x20 [ 88.124291] el0_svc_common+0xd0/0x124 [ 88.128034] el0_svc_compat_handler+0x1c/0x24 [ 88.132384] el0_svc_compat+0x8/0x18 The sysfs unexport in pwmchip_remove() is completely asymmetric to what we do in pwmchip_add_with_polarity() and commit 0733424c9ba9 ("pwm: Unexport children before chip removal") is a strong indication that this was wrong to begin with. We should just move pwmchip_sysfs_unexport() where it belongs, which is right after pwmchip_sysfs_unexport_children(). In that case, we do not need separate functions anymore either. We also really want to remove sysfs irrespective of whether or not the chip will be removed as a result of pwmchip_remove(). We can only assume that the driver will be gone after that, so we shouldn't leave any dangling sysfs files around. This warning disappears if we move pwmchip_sysfs_unexport() to the top of pwmchip_remove(), pwmchip_sysfs_unexport_children(). That way it is also outside of the pwm_lock section, which indeed doesn't seem to be needed. Moving the pwmchip_sysfs_export() call outside of that section also seems fine and it'd be perfectly symmetric with pwmchip_remove() again. So, this patch fixes them. Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com> [shimoda: revise the commit log and code] Fixes: 76abbdde2d95 ("pwm: Add sysfs interface") Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal") Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Tested-by: Hoan Nguyen An <na-hoan@jinso.co.jp> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-19 18:40:08 +08:00
if (!ret)
pwmchip_sysfs_export(chip);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
return ret;
}
EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
/**
* pwmchip_add() - register a new PWM chip
* @chip: the PWM chip to add
*
* Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
* will be used. The initial polarity for all channels is normal.
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwmchip_add(struct pwm_chip *chip)
{
return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
}
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
EXPORT_SYMBOL_GPL(pwmchip_add);
/**
* pwmchip_remove() - remove a PWM chip
* @chip: the PWM chip to remove
*
* Removes a PWM chip. This function may return busy if the PWM chip provides
* a PWM device that is still requested.
*
* Returns: 0 on success or a negative error code on failure.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
int pwmchip_remove(struct pwm_chip *chip)
{
unsigned int i;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
int ret = 0;
pwm: Fix deadlock warning when removing PWM device This patch fixes deadlock warning if removing PWM device when CONFIG_PROVE_LOCKING is enabled. This issue can be reproceduced by the following steps on the R-Car H3 Salvator-X board if the backlight is disabled: # cd /sys/class/pwm/pwmchip0 # echo 0 > export # ls device export npwm power pwm0 subsystem uevent unexport # cd device/driver # ls bind e6e31000.pwm uevent unbind # echo e6e31000.pwm > unbind [ 87.659974] ====================================================== [ 87.666149] WARNING: possible circular locking dependency detected [ 87.672327] 5.0.0 #7 Not tainted [ 87.675549] ------------------------------------------------------ [ 87.681723] bash/2986 is trying to acquire lock: [ 87.686337] 000000005ea0e178 (kn->count#58){++++}, at: kernfs_remove_by_name_ns+0x50/0xa0 [ 87.694528] [ 87.694528] but task is already holding lock: [ 87.700353] 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c [ 87.707405] [ 87.707405] which lock already depends on the new lock. [ 87.707405] [ 87.715574] [ 87.715574] the existing dependency chain (in reverse order) is: [ 87.723048] [ 87.723048] -> #1 (pwm_lock){+.+.}: [ 87.728017] __mutex_lock+0x70/0x7e4 [ 87.732108] mutex_lock_nested+0x1c/0x24 [ 87.736547] pwm_request_from_chip.part.6+0x34/0x74 [ 87.741940] pwm_request_from_chip+0x20/0x40 [ 87.746725] export_store+0x6c/0x1f4 [ 87.750820] dev_attr_store+0x18/0x28 [ 87.754998] sysfs_kf_write+0x54/0x64 [ 87.759175] kernfs_fop_write+0xe4/0x1e8 [ 87.763615] __vfs_write+0x40/0x184 [ 87.767619] vfs_write+0xa8/0x19c [ 87.771448] ksys_write+0x58/0xbc [ 87.775278] __arm64_sys_write+0x18/0x20 [ 87.779721] el0_svc_common+0xd0/0x124 [ 87.783986] el0_svc_compat_handler+0x1c/0x24 [ 87.788858] el0_svc_compat+0x8/0x18 [ 87.792947] [ 87.792947] -> #0 (kn->count#58){++++}: [ 87.798260] lock_acquire+0xc4/0x22c [ 87.802353] __kernfs_remove+0x258/0x2c4 [ 87.806790] kernfs_remove_by_name_ns+0x50/0xa0 [ 87.811836] remove_files.isra.1+0x38/0x78 [ 87.816447] sysfs_remove_group+0x48/0x98 [ 87.820971] sysfs_remove_groups+0x34/0x4c [ 87.825583] device_remove_attrs+0x6c/0x7c [ 87.830197] device_del+0x11c/0x33c [ 87.834201] device_unregister+0x14/0x2c [ 87.838638] pwmchip_sysfs_unexport+0x40/0x4c [ 87.843509] pwmchip_remove+0xf4/0x13c [ 87.847773] rcar_pwm_remove+0x28/0x34 [ 87.852039] platform_drv_remove+0x24/0x64 [ 87.856651] device_release_driver_internal+0x18c/0x21c [ 87.862391] device_release_driver+0x14/0x1c [ 87.867175] unbind_store+0xe0/0x124 [ 87.871265] drv_attr_store+0x20/0x30 [ 87.875442] sysfs_kf_write+0x54/0x64 [ 87.879618] kernfs_fop_write+0xe4/0x1e8 [ 87.884055] __vfs_write+0x40/0x184 [ 87.888057] vfs_write+0xa8/0x19c [ 87.891887] ksys_write+0x58/0xbc [ 87.895716] __arm64_sys_write+0x18/0x20 [ 87.900154] el0_svc_common+0xd0/0x124 [ 87.904417] el0_svc_compat_handler+0x1c/0x24 [ 87.909289] el0_svc_compat+0x8/0x18 [ 87.913378] [ 87.913378] other info that might help us debug this: [ 87.913378] [ 87.921374] Possible unsafe locking scenario: [ 87.921374] [ 87.927286] CPU0 CPU1 [ 87.931808] ---- ---- [ 87.936331] lock(pwm_lock); [ 87.939293] lock(kn->count#58); [ 87.945120] lock(pwm_lock); [ 87.950599] lock(kn->count#58); [ 87.953908] [ 87.953908] *** DEADLOCK *** [ 87.953908] [ 87.959821] 4 locks held by bash/2986: [ 87.963563] #0: 00000000ace7bc30 (sb_writers#6){.+.+}, at: vfs_write+0x188/0x19c [ 87.971044] #1: 00000000287991b2 (&of->mutex){+.+.}, at: kernfs_fop_write+0xb4/0x1e8 [ 87.978872] #2: 00000000f739d016 (&dev->mutex){....}, at: device_release_driver_internal+0x40/0x21c [ 87.988001] #3: 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c [ 87.995481] [ 87.995481] stack backtrace: [ 87.999836] CPU: 0 PID: 2986 Comm: bash Not tainted 5.0.0 #7 [ 88.005489] Hardware name: Renesas Salvator-X board based on r8a7795 ES1.x (DT) [ 88.012791] Call trace: [ 88.015235] dump_backtrace+0x0/0x190 [ 88.018891] show_stack+0x14/0x1c [ 88.022204] dump_stack+0xb0/0xec [ 88.025514] print_circular_bug.isra.32+0x1d0/0x2e0 [ 88.030385] __lock_acquire+0x1318/0x1864 [ 88.034388] lock_acquire+0xc4/0x22c [ 88.037958] __kernfs_remove+0x258/0x2c4 [ 88.041874] kernfs_remove_by_name_ns+0x50/0xa0 [ 88.046398] remove_files.isra.1+0x38/0x78 [ 88.050487] sysfs_remove_group+0x48/0x98 [ 88.054490] sysfs_remove_groups+0x34/0x4c [ 88.058580] device_remove_attrs+0x6c/0x7c [ 88.062671] device_del+0x11c/0x33c [ 88.066154] device_unregister+0x14/0x2c [ 88.070070] pwmchip_sysfs_unexport+0x40/0x4c [ 88.074421] pwmchip_remove+0xf4/0x13c [ 88.078163] rcar_pwm_remove+0x28/0x34 [ 88.081906] platform_drv_remove+0x24/0x64 [ 88.085996] device_release_driver_internal+0x18c/0x21c [ 88.091215] device_release_driver+0x14/0x1c [ 88.095478] unbind_store+0xe0/0x124 [ 88.099048] drv_attr_store+0x20/0x30 [ 88.102704] sysfs_kf_write+0x54/0x64 [ 88.106359] kernfs_fop_write+0xe4/0x1e8 [ 88.110275] __vfs_write+0x40/0x184 [ 88.113757] vfs_write+0xa8/0x19c [ 88.117065] ksys_write+0x58/0xbc [ 88.120374] __arm64_sys_write+0x18/0x20 [ 88.124291] el0_svc_common+0xd0/0x124 [ 88.128034] el0_svc_compat_handler+0x1c/0x24 [ 88.132384] el0_svc_compat+0x8/0x18 The sysfs unexport in pwmchip_remove() is completely asymmetric to what we do in pwmchip_add_with_polarity() and commit 0733424c9ba9 ("pwm: Unexport children before chip removal") is a strong indication that this was wrong to begin with. We should just move pwmchip_sysfs_unexport() where it belongs, which is right after pwmchip_sysfs_unexport_children(). In that case, we do not need separate functions anymore either. We also really want to remove sysfs irrespective of whether or not the chip will be removed as a result of pwmchip_remove(). We can only assume that the driver will be gone after that, so we shouldn't leave any dangling sysfs files around. This warning disappears if we move pwmchip_sysfs_unexport() to the top of pwmchip_remove(), pwmchip_sysfs_unexport_children(). That way it is also outside of the pwm_lock section, which indeed doesn't seem to be needed. Moving the pwmchip_sysfs_export() call outside of that section also seems fine and it'd be perfectly symmetric with pwmchip_remove() again. So, this patch fixes them. Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com> [shimoda: revise the commit log and code] Fixes: 76abbdde2d95 ("pwm: Add sysfs interface") Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal") Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Tested-by: Hoan Nguyen An <na-hoan@jinso.co.jp> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-19 18:40:08 +08:00
pwmchip_sysfs_unexport(chip);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
mutex_lock(&pwm_lock);
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
ret = -EBUSY;
goto out;
}
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
}
list_del_init(&chip->list);
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_remove(chip);
free_pwms(chip);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
out:
mutex_unlock(&pwm_lock);
return ret;
}
EXPORT_SYMBOL_GPL(pwmchip_remove);
/**
* pwm_request() - request a PWM device
* @pwm: global PWM device index
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
* @label: PWM device label
*
* This function is deprecated, use pwm_get() instead.
*
* Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
* failure.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
struct pwm_device *pwm_request(int pwm, const char *label)
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
{
struct pwm_device *dev;
int err;
if (pwm < 0 || pwm >= MAX_PWMS)
return ERR_PTR(-EINVAL);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
mutex_lock(&pwm_lock);
dev = pwm_to_device(pwm);
if (!dev) {
dev = ERR_PTR(-EPROBE_DEFER);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
goto out;
}
err = pwm_device_request(dev, label);
if (err < 0)
dev = ERR_PTR(err);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
out:
mutex_unlock(&pwm_lock);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
return dev;
}
EXPORT_SYMBOL_GPL(pwm_request);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
/**
* pwm_request_from_chip() - request a PWM device relative to a PWM chip
* @chip: PWM chip
* @index: per-chip index of the PWM to request
* @label: a literal description string of this PWM
*
* Returns: A pointer to the PWM device at the given index of the given PWM
* chip. A negative error code is returned if the index is not valid for the
* specified PWM chip or if the PWM device cannot be requested.
*/
struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
unsigned int index,
const char *label)
{
struct pwm_device *pwm;
int err;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
if (!chip || index >= chip->npwm)
return ERR_PTR(-EINVAL);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
mutex_lock(&pwm_lock);
pwm = &chip->pwms[index];
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
err = pwm_device_request(pwm, label);
if (err < 0)
pwm = ERR_PTR(err);
mutex_unlock(&pwm_lock);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_request_from_chip);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
/**
* pwm_free() - free a PWM device
* @pwm: PWM device
*
* This function is deprecated, use pwm_put() instead.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
void pwm_free(struct pwm_device *pwm)
{
pwm_put(pwm);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
}
EXPORT_SYMBOL_GPL(pwm_free);
/**
* pwm_apply_state() - atomically apply a new state to a PWM device
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
* @pwm: PWM device
* @state: new state to apply. This can be adjusted by the PWM driver
* if the requested config is not achievable, for example,
* ->duty_cycle and ->period might be approximated.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
{
int err;
if (!pwm || !state || !state->period ||
state->duty_cycle > state->period)
return -EINVAL;
if (state->period == pwm->state.period &&
state->duty_cycle == pwm->state.duty_cycle &&
state->polarity == pwm->state.polarity &&
state->enabled == pwm->state.enabled)
return 0;
if (pwm->chip->ops->apply) {
err = pwm->chip->ops->apply(pwm->chip, pwm, state);
if (err)
return err;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
pwm->state = *state;
} else {
/*
* FIXME: restore the initial state in case of error.
*/
if (state->polarity != pwm->state.polarity) {
if (!pwm->chip->ops->set_polarity)
return -ENOTSUPP;
/*
* Changing the polarity of a running PWM is
* only allowed when the PWM driver implements
* ->apply().
*/
if (pwm->state.enabled) {
pwm->chip->ops->disable(pwm->chip, pwm);
pwm->state.enabled = false;
}
err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
state->polarity);
if (err)
return err;
pwm->state.polarity = state->polarity;
}
if (state->period != pwm->state.period ||
state->duty_cycle != pwm->state.duty_cycle) {
err = pwm->chip->ops->config(pwm->chip, pwm,
state->duty_cycle,
state->period);
if (err)
return err;
pwm->state.duty_cycle = state->duty_cycle;
pwm->state.period = state->period;
}
if (state->enabled != pwm->state.enabled) {
if (state->enabled) {
err = pwm->chip->ops->enable(pwm->chip, pwm);
if (err)
return err;
} else {
pwm->chip->ops->disable(pwm->chip, pwm);
}
pwm->state.enabled = state->enabled;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(pwm_apply_state);
/**
* pwm_capture() - capture and report a PWM signal
* @pwm: PWM device
* @result: structure to fill with capture result
* @timeout: time to wait, in milliseconds, before giving up on capture
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
unsigned long timeout)
{
int err;
if (!pwm || !pwm->chip->ops)
return -EINVAL;
if (!pwm->chip->ops->capture)
return -ENOSYS;
mutex_lock(&pwm_lock);
err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
mutex_unlock(&pwm_lock);
return err;
}
EXPORT_SYMBOL_GPL(pwm_capture);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
/**
* pwm_adjust_config() - adjust the current PWM config to the PWM arguments
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
* @pwm: PWM device
*
* This function will adjust the PWM config to the PWM arguments provided
* by the DT or PWM lookup table. This is particularly useful to adapt
* the bootloader config to the Linux one.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
*/
int pwm_adjust_config(struct pwm_device *pwm)
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
{
struct pwm_state state;
struct pwm_args pargs;
pwm_get_args(pwm, &pargs);
pwm_get_state(pwm, &state);
/*
* If the current period is zero it means that either the PWM driver
* does not support initial state retrieval or the PWM has not yet
* been configured.
*
* In either case, we setup the new period and polarity, and assign a
* duty cycle of 0.
*/
if (!state.period) {
state.duty_cycle = 0;
state.period = pargs.period;
state.polarity = pargs.polarity;
return pwm_apply_state(pwm, &state);
}
/*
* Adjust the PWM duty cycle/period based on the period value provided
* in PWM args.
*/
if (pargs.period != state.period) {
u64 dutycycle = (u64)state.duty_cycle * pargs.period;
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
do_div(dutycycle, state.period);
state.duty_cycle = dutycycle;
state.period = pargs.period;
}
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
/*
* If the polarity changed, we should also change the duty cycle.
*/
if (pargs.polarity != state.polarity) {
state.polarity = pargs.polarity;
state.duty_cycle = state.period - state.duty_cycle;
}
return pwm_apply_state(pwm, &state);
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 16:40:40 +08:00
}
EXPORT_SYMBOL_GPL(pwm_adjust_config);
static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
{
struct pwm_chip *chip;
mutex_lock(&pwm_lock);
list_for_each_entry(chip, &pwm_chips, list)
if (chip->dev && chip->dev->of_node == np) {
mutex_unlock(&pwm_lock);
return chip;
}
mutex_unlock(&pwm_lock);
return ERR_PTR(-EPROBE_DEFER);
}
static struct device_link *pwm_device_link_add(struct device *dev,
struct pwm_device *pwm)
{
struct device_link *dl;
if (!dev) {
/*
* No device for the PWM consumer has been provided. It may
* impact the PM sequence ordering: the PWM supplier may get
* suspended before the consumer.
*/
dev_warn(pwm->chip->dev,
"No consumer device specified to create a link to\n");
return NULL;
}
dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
if (!dl) {
dev_err(dev, "failed to create device link to %s\n",
dev_name(pwm->chip->dev));
return ERR_PTR(-EINVAL);
}
return dl;
}
/**
* of_pwm_get() - request a PWM via the PWM framework
* @dev: device for PWM consumer
* @np: device node to get the PWM from
* @con_id: consumer name
*
* Returns the PWM device parsed from the phandle and index specified in the
* "pwms" property of a device tree node or a negative error-code on failure.
* Values parsed from the device tree are stored in the returned PWM device
* object.
*
* If con_id is NULL, the first PWM device listed in the "pwms" property will
* be requested. Otherwise the "pwm-names" property is used to do a reverse
* lookup of the PWM index. This also means that the "pwm-names" property
* becomes mandatory for devices that look up the PWM device via the con_id
* parameter.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
const char *con_id)
{
struct pwm_device *pwm = NULL;
struct of_phandle_args args;
struct device_link *dl;
struct pwm_chip *pc;
int index = 0;
int err;
if (con_id) {
index = of_property_match_string(np, "pwm-names", con_id);
if (index < 0)
return ERR_PTR(index);
}
err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
&args);
if (err) {
pr_err("%s(): can't parse \"pwms\" property\n", __func__);
return ERR_PTR(err);
}
pc = of_node_to_pwmchip(args.np);
if (IS_ERR(pc)) {
if (PTR_ERR(pc) != -EPROBE_DEFER)
pr_err("%s(): PWM chip not found\n", __func__);
pwm = ERR_CAST(pc);
goto put;
}
pwm = pc->of_xlate(pc, &args);
if (IS_ERR(pwm))
goto put;
dl = pwm_device_link_add(dev, pwm);
if (IS_ERR(dl)) {
/* of_xlate ended up calling pwm_request_from_chip() */
pwm_free(pwm);
pwm = ERR_CAST(dl);
goto put;
}
/*
* If a consumer name was not given, try to look it up from the
* "pwm-names" property if it exists. Otherwise use the name of
* the user device node.
*/
if (!con_id) {
err = of_property_read_string_index(np, "pwm-names", index,
&con_id);
if (err < 0)
con_id = np->name;
}
pwm->label = con_id;
put:
of_node_put(args.np);
return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_get);
#if IS_ENABLED(CONFIG_ACPI)
static struct pwm_chip *device_to_pwmchip(struct device *dev)
{
struct pwm_chip *chip;
mutex_lock(&pwm_lock);
list_for_each_entry(chip, &pwm_chips, list) {
struct acpi_device *adev = ACPI_COMPANION(chip->dev);
if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
mutex_unlock(&pwm_lock);
return chip;
}
}
mutex_unlock(&pwm_lock);
return ERR_PTR(-EPROBE_DEFER);
}
#endif
/**
* acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
* @fwnode: firmware node to get the "pwm" property from
*
* Returns the PWM device parsed from the fwnode and index specified in the
* "pwms" property or a negative error-code on failure.
* Values parsed from the device tree are stored in the returned PWM device
* object.
*
* This is analogous to of_pwm_get() except con_id is not yet supported.
* ACPI entries must look like
* Package () {"pwms", Package ()
* { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
{
struct pwm_device *pwm = ERR_PTR(-ENODEV);
#if IS_ENABLED(CONFIG_ACPI)
struct fwnode_reference_args args;
struct acpi_device *acpi;
struct pwm_chip *chip;
int ret;
memset(&args, 0, sizeof(args));
ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
if (ret < 0)
return ERR_PTR(ret);
acpi = to_acpi_device_node(args.fwnode);
if (!acpi)
return ERR_PTR(-EINVAL);
if (args.nargs < 2)
return ERR_PTR(-EPROTO);
chip = device_to_pwmchip(&acpi->dev);
if (IS_ERR(chip))
return ERR_CAST(chip);
pwm = pwm_request_from_chip(chip, args.args[0], NULL);
if (IS_ERR(pwm))
return pwm;
pwm->args.period = args.args[1];
pwm->args.polarity = PWM_POLARITY_NORMAL;
if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
pwm->args.polarity = PWM_POLARITY_INVERSED;
#endif
return pwm;
}
/**
* pwm_add_table() - register PWM device consumers
* @table: array of consumers to register
* @num: number of consumers in table
*/
void pwm_add_table(struct pwm_lookup *table, size_t num)
{
mutex_lock(&pwm_lookup_lock);
while (num--) {
list_add_tail(&table->list, &pwm_lookup_list);
table++;
}
mutex_unlock(&pwm_lookup_lock);
}
/**
* pwm_remove_table() - unregister PWM device consumers
* @table: array of consumers to unregister
* @num: number of consumers in table
*/
void pwm_remove_table(struct pwm_lookup *table, size_t num)
{
mutex_lock(&pwm_lookup_lock);
while (num--) {
list_del(&table->list);
table++;
}
mutex_unlock(&pwm_lookup_lock);
}
/**
* pwm_get() - look up and request a PWM device
* @dev: device for PWM consumer
* @con_id: consumer name
*
* Lookup is first attempted using DT. If the device was not instantiated from
* a device tree, a PWM chip and a relative index is looked up via a table
* supplied by board setup code (see pwm_add_table()).
*
* Once a PWM chip has been found the specified PWM device will be requested
* and is ready to be used.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
{
const char *dev_id = dev ? dev_name(dev) : NULL;
struct pwm_device *pwm;
struct pwm_chip *chip;
struct device_link *dl;
unsigned int best = 0;
struct pwm_lookup *p, *chosen = NULL;
unsigned int match;
int err;
/* look up via DT first */
if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
return of_pwm_get(dev, dev->of_node, con_id);
/* then lookup via ACPI */
if (dev && is_acpi_node(dev->fwnode)) {
pwm = acpi_pwm_get(dev->fwnode);
if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
return pwm;
}
/*
* We look up the provider in the static table typically provided by
* board setup code. We first try to lookup the consumer device by
* name. If the consumer device was passed in as NULL or if no match
* was found, we try to find the consumer by directly looking it up
* by name.
*
* If a match is found, the provider PWM chip is looked up by name
* and a PWM device is requested using the PWM device per-chip index.
*
* The lookup algorithm was shamelessly taken from the clock
* framework:
*
* We do slightly fuzzy matching here:
* An entry with a NULL ID is assumed to be a wildcard.
* If an entry has a device ID, it must match
* If an entry has a connection ID, it must match
* Then we take the most specific entry - with the following order
* of precedence: dev+con > dev only > con only.
*/
mutex_lock(&pwm_lookup_lock);
list_for_each_entry(p, &pwm_lookup_list, list) {
match = 0;
if (p->dev_id) {
if (!dev_id || strcmp(p->dev_id, dev_id))
continue;
match += 2;
}
if (p->con_id) {
if (!con_id || strcmp(p->con_id, con_id))
continue;
match += 1;
}
if (match > best) {
chosen = p;
if (match != 3)
best = match;
else
break;
}
}
mutex_unlock(&pwm_lookup_lock);
if (!chosen)
return ERR_PTR(-ENODEV);
chip = pwmchip_find_by_name(chosen->provider);
/*
* If the lookup entry specifies a module, load the module and retry
* the PWM chip lookup. This can be used to work around driver load
* ordering issues if driver's can't be made to properly support the
* deferred probe mechanism.
*/
if (!chip && chosen->module) {
err = request_module(chosen->module);
if (err == 0)
chip = pwmchip_find_by_name(chosen->provider);
}
if (!chip)
return ERR_PTR(-EPROBE_DEFER);
pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm))
return pwm;
dl = pwm_device_link_add(dev, pwm);
if (IS_ERR(dl)) {
pwm_free(pwm);
return ERR_CAST(dl);
}
pwm->args.period = chosen->period;
pwm->args.polarity = chosen->polarity;
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_get);
/**
* pwm_put() - release a PWM device
* @pwm: PWM device
*/
void pwm_put(struct pwm_device *pwm)
{
if (!pwm)
return;
mutex_lock(&pwm_lock);
if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
pr_warn("PWM device already freed\n");
goto out;
}
if (pwm->chip->ops->free)
pwm->chip->ops->free(pwm->chip, pwm);
pwm_set_chip_data(pwm, NULL);
pwm->label = NULL;
module_put(pwm->chip->ops->owner);
out:
mutex_unlock(&pwm_lock);
}
EXPORT_SYMBOL_GPL(pwm_put);
static void devm_pwm_release(struct device *dev, void *res)
{
pwm_put(*(struct pwm_device **)res);
}
/**
* devm_pwm_get() - resource managed pwm_get()
* @dev: device for PWM consumer
* @con_id: consumer name
*
* This function performs like pwm_get() but the acquired PWM device will
* automatically be released on driver detach.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
{
struct pwm_device **ptr, *pwm;
ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
pwm = pwm_get(dev, con_id);
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return pwm;
}
EXPORT_SYMBOL_GPL(devm_pwm_get);
/**
* devm_of_pwm_get() - resource managed of_pwm_get()
* @dev: device for PWM consumer
* @np: device node to get the PWM from
* @con_id: consumer name
*
* This function performs like of_pwm_get() but the acquired PWM device will
* automatically be released on driver detach.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
const char *con_id)
{
struct pwm_device **ptr, *pwm;
ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
pwm = of_pwm_get(dev, np, con_id);
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return pwm;
}
EXPORT_SYMBOL_GPL(devm_of_pwm_get);
/**
* devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
* @dev: device for PWM consumer
* @fwnode: firmware node to get the PWM from
* @con_id: consumer name
*
* Returns the PWM device parsed from the firmware node. See of_pwm_get() and
* acpi_pwm_get() for a detailed description.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
struct fwnode_handle *fwnode,
const char *con_id)
{
struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
if (is_of_node(fwnode))
pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
else if (is_acpi_node(fwnode))
pwm = acpi_pwm_get(fwnode);
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return pwm;
}
EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
static int devm_pwm_match(struct device *dev, void *res, void *data)
{
struct pwm_device **p = res;
if (WARN_ON(!p || !*p))
return 0;
return *p == data;
}
/**
* devm_pwm_put() - resource managed pwm_put()
* @dev: device for PWM consumer
* @pwm: PWM device
*
* Release a PWM previously allocated using devm_pwm_get(). Calling this
* function is usually not needed because devm-allocated resources are
* automatically released on driver detach.
*/
void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
{
WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
}
EXPORT_SYMBOL_GPL(devm_pwm_put);
#ifdef CONFIG_DEBUG_FS
static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
{
unsigned int i;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
struct pwm_state state;
pwm_get_state(pwm, &state);
seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
if (test_bit(PWMF_REQUESTED, &pwm->flags))
seq_puts(s, " requested");
if (state.enabled)
seq_puts(s, " enabled");
seq_printf(s, " period: %u ns", state.period);
seq_printf(s, " duty: %u ns", state.duty_cycle);
seq_printf(s, " polarity: %s",
state.polarity ? "inverse" : "normal");
seq_puts(s, "\n");
}
}
static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
{
mutex_lock(&pwm_lock);
s->private = "";
return seq_list_start(&pwm_chips, *pos);
}
static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
s->private = "\n";
return seq_list_next(v, &pwm_chips, pos);
}
static void pwm_seq_stop(struct seq_file *s, void *v)
{
mutex_unlock(&pwm_lock);
}
static int pwm_seq_show(struct seq_file *s, void *v)
{
struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
chip->dev->bus ? chip->dev->bus->name : "no-bus",
dev_name(chip->dev), chip->npwm,
(chip->npwm != 1) ? "s" : "");
pwm_dbg_show(chip, s);
return 0;
}
static const struct seq_operations pwm_seq_ops = {
.start = pwm_seq_start,
.next = pwm_seq_next,
.stop = pwm_seq_stop,
.show = pwm_seq_show,
};
static int pwm_seq_open(struct inode *inode, struct file *file)
{
return seq_open(file, &pwm_seq_ops);
}
static const struct file_operations pwm_debugfs_ops = {
.owner = THIS_MODULE,
.open = pwm_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init pwm_debugfs_init(void)
{
debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
&pwm_debugfs_ops);
return 0;
}
subsys_initcall(pwm_debugfs_init);
#endif /* CONFIG_DEBUG_FS */