linux/drivers/input/misc/rotary_encoder.c

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/*
* rotary_encoder.c
*
* (c) 2009 Daniel Mack <daniel@caiaq.de>
* Copyright (C) 2011 Johan Hovold <jhovold@gmail.com>
*
* state machine code inspired by code from Tim Ruetz
*
* A generic driver for rotary encoders connected to GPIO lines.
* See file:Documentation/input/rotary-encoder.txt for more information
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/rotary_encoder.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#define DRV_NAME "rotary-encoder"
struct rotary_encoder {
struct input_dev *input;
const struct rotary_encoder_platform_data *pdata;
unsigned int axis;
unsigned int pos;
unsigned int irq_a;
unsigned int irq_b;
bool armed;
unsigned char dir; /* 0 - clockwise, 1 - CCW */
char last_stable;
};
static int rotary_encoder_get_state(const struct rotary_encoder_platform_data *pdata)
{
int a = !!gpio_get_value(pdata->gpio_a);
int b = !!gpio_get_value(pdata->gpio_b);
a ^= pdata->inverted_a;
b ^= pdata->inverted_b;
return ((a << 1) | b);
}
static void rotary_encoder_report_event(struct rotary_encoder *encoder)
{
const struct rotary_encoder_platform_data *pdata = encoder->pdata;
if (pdata->relative_axis) {
input_report_rel(encoder->input,
pdata->axis, encoder->dir ? -1 : 1);
} else {
unsigned int pos = encoder->pos;
if (encoder->dir) {
/* turning counter-clockwise */
if (pdata->rollover)
pos += pdata->steps;
if (pos)
pos--;
} else {
/* turning clockwise */
if (pdata->rollover || pos < pdata->steps)
pos++;
}
if (pdata->rollover)
pos %= pdata->steps;
encoder->pos = pos;
input_report_abs(encoder->input, pdata->axis, encoder->pos);
}
input_sync(encoder->input);
}
static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
{
struct rotary_encoder *encoder = dev_id;
int state;
state = rotary_encoder_get_state(encoder->pdata);
switch (state) {
case 0x0:
if (encoder->armed) {
rotary_encoder_report_event(encoder);
encoder->armed = false;
}
break;
case 0x1:
case 0x2:
if (encoder->armed)
encoder->dir = state - 1;
break;
case 0x3:
encoder->armed = true;
break;
}
return IRQ_HANDLED;
}
static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
{
struct rotary_encoder *encoder = dev_id;
int state;
state = rotary_encoder_get_state(encoder->pdata);
switch (state) {
case 0x00:
case 0x03:
if (state != encoder->last_stable) {
rotary_encoder_report_event(encoder);
encoder->last_stable = state;
}
break;
case 0x01:
case 0x02:
encoder->dir = (encoder->last_stable + state) & 0x01;
break;
}
return IRQ_HANDLED;
}
#ifdef CONFIG_OF
static struct of_device_id rotary_encoder_of_match[] = {
{ .compatible = "rotary-encoder", },
{ },
};
MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
static struct rotary_encoder_platform_data * __devinit
rotary_encoder_parse_dt(struct device *dev)
{
const struct of_device_id *of_id =
of_match_device(rotary_encoder_of_match, dev);
struct device_node *np = dev->of_node;
struct rotary_encoder_platform_data *pdata;
enum of_gpio_flags flags;
if (!of_id || !np)
return NULL;
pdata = kzalloc(sizeof(struct rotary_encoder_platform_data),
GFP_KERNEL);
if (!pdata)
return ERR_PTR(-ENOMEM);
of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps);
of_property_read_u32(np, "linux,axis", &pdata->axis);
pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
pdata->relative_axis = !!of_get_property(np,
"rotary-encoder,relative-axis", NULL);
pdata->rollover = !!of_get_property(np,
"rotary-encoder,rollover", NULL);
pdata->half_period = !!of_get_property(np,
"rotary-encoder,half-period", NULL);
return pdata;
}
#else
static inline struct rotary_encoder_platform_data *
rotary_encoder_parse_dt(struct device *dev)
{
return NULL;
}
#endif
static int __devinit rotary_encoder_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct rotary_encoder_platform_data *pdata = dev_get_platdata(dev);
struct rotary_encoder *encoder;
struct input_dev *input;
irq_handler_t handler;
int err;
if (!pdata) {
pdata = rotary_encoder_parse_dt(dev);
if (IS_ERR(pdata))
return PTR_ERR(pdata);
if (!pdata) {
dev_err(dev, "missing platform data\n");
return -EINVAL;
}
}
encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
input = input_allocate_device();
if (!encoder || !input) {
err = -ENOMEM;
goto exit_free_mem;
}
encoder->input = input;
encoder->pdata = pdata;
input->name = pdev->name;
input->id.bustype = BUS_HOST;
input->dev.parent = dev;
if (pdata->relative_axis) {
input->evbit[0] = BIT_MASK(EV_REL);
input->relbit[0] = BIT_MASK(pdata->axis);
} else {
input->evbit[0] = BIT_MASK(EV_ABS);
input_set_abs_params(encoder->input,
pdata->axis, 0, pdata->steps, 0, 1);
}
/* request the GPIOs */
err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev));
if (err) {
dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
goto exit_free_mem;
}
err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
if (err) {
dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_b);
goto exit_free_gpio_a;
}
encoder->irq_a = gpio_to_irq(pdata->gpio_a);
encoder->irq_b = gpio_to_irq(pdata->gpio_b);
/* request the IRQs */
if (pdata->half_period) {
handler = &rotary_encoder_half_period_irq;
encoder->last_stable = rotary_encoder_get_state(pdata);
} else {
handler = &rotary_encoder_irq;
}
err = request_irq(encoder->irq_a, handler,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
DRV_NAME, encoder);
if (err) {
dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a);
goto exit_free_gpio_b;
}
err = request_irq(encoder->irq_b, handler,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
DRV_NAME, encoder);
if (err) {
dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b);
goto exit_free_irq_a;
}
err = input_register_device(input);
if (err) {
dev_err(dev, "failed to register input device\n");
goto exit_free_irq_b;
}
platform_set_drvdata(pdev, encoder);
return 0;
exit_free_irq_b:
free_irq(encoder->irq_b, encoder);
exit_free_irq_a:
free_irq(encoder->irq_a, encoder);
exit_free_gpio_b:
gpio_free(pdata->gpio_b);
exit_free_gpio_a:
gpio_free(pdata->gpio_a);
exit_free_mem:
input_free_device(input);
kfree(encoder);
if (!dev_get_platdata(&pdev->dev))
kfree(pdata);
return err;
}
static int __devexit rotary_encoder_remove(struct platform_device *pdev)
{
struct rotary_encoder *encoder = platform_get_drvdata(pdev);
const struct rotary_encoder_platform_data *pdata = encoder->pdata;
free_irq(encoder->irq_a, encoder);
free_irq(encoder->irq_b, encoder);
gpio_free(pdata->gpio_a);
gpio_free(pdata->gpio_b);
input_unregister_device(encoder->input);
kfree(encoder);
if (!dev_get_platdata(&pdev->dev))
kfree(pdata);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver rotary_encoder_driver = {
.probe = rotary_encoder_probe,
.remove = __devexit_p(rotary_encoder_remove),
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(rotary_encoder_of_match),
}
};
module_platform_driver(rotary_encoder_driver);
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DESCRIPTION("GPIO rotary encoder driver");
MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold");
MODULE_LICENSE("GPL v2");