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pwm: jz4740: Use clocks from TCU driver 

The ingenic-timer "TCU" driver provides us with clocks, that can be
(un)gated, reparented or reclocked from devicetree, instead of having
these settings hardcoded in this driver.

The new code now uses a clk pointer per PWM (instead of a clk per
pwm-chip before). So the pointer is stored in per-pwm data now.
The calls to arch-specific timer code is replaced with standard
clock API calls to start and stop each channel's clock.

While this driver is devicetree-compatible, it is never (as of now)
probed from devicetree, so this change does not introduce a ABI problem
with current devicetree files.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Paul Cercueil 2020-03-23 15:24:18 +01:00 committed by Thierry Reding
parent d3817a6470
commit ce1f9cece0
2 changed files with 41 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/pwm/Kconfig
View File

@ -235,6 +235,7 @@ config PWM_IMX_TPM
config PWM_JZ4740
tristate "Ingenic JZ47xx PWM support"
depends on MACH_INGENIC
depends on COMMON_CLK
help
Generic PWM framework driver for Ingenic JZ47xx based
machines.

54
drivers/pwm/pwm-jz4740.c
View File

@ -24,7 +24,6 @@
struct jz4740_pwm_chip {
struct pwm_chip chip;
struct clk *clk;
};
static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
@ -34,6 +33,11 @@ static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct jz4740_pwm_chip *jz = to_jz4740(chip);
struct clk *clk;
char name[16];
int err;
/*
* Timers 0 and 1 are used for system tasks, so they are unavailable
* for use as PWMs.
@ -41,16 +45,33 @@ static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
if (pwm->hwpwm < 2)
return -EBUSY;
jz4740_timer_start(pwm->hwpwm);
snprintf(name, sizeof(name), "timer%u", pwm->hwpwm);
clk = clk_get(chip->dev, name);
if (IS_ERR(clk)) {
if (PTR_ERR(clk) != -EPROBE_DEFER)
dev_err(chip->dev, "Failed to get clock: %pe", clk);
return PTR_ERR(clk);
}
err = clk_prepare_enable(clk);
if (err < 0) {
clk_put(clk);
return err;
}
pwm_set_chip_data(pwm, clk);
return 0;
}
static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
jz4740_timer_set_ctrl(pwm->hwpwm, 0);
struct clk *clk = pwm_get_chip_data(pwm);
jz4740_timer_stop(pwm->hwpwm);
clk_disable_unprepare(clk);
clk_put(clk);
}
static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
@ -91,17 +112,22 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
struct clk *clk = pwm_get_chip_data(pwm),
*parent_clk = clk_get_parent(clk);
unsigned long rate, period, duty;
unsigned long long tmp;
unsigned long period, duty;
unsigned int prescaler = 0;
uint16_t ctrl;
int err;
tmp = (unsigned long long)clk_get_rate(jz4740->clk) * state->period;
rate = clk_get_rate(parent_clk);
tmp = (unsigned long long)rate * state->period;
do_div(tmp, 1000000000);
period = tmp;
while (period > 0xffff && prescaler < 6) {
period >>= 2;
rate >>= 2;
++prescaler;
}
@ -117,14 +143,18 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
jz4740_pwm_disable(chip, pwm);
err = clk_set_rate(clk, rate);
if (err) {
dev_err(chip->dev, "Unable to set rate: %d", err);
return err;
}
jz4740_timer_set_count(pwm->hwpwm, 0);
jz4740_timer_set_duty(pwm->hwpwm, duty);
jz4740_timer_set_period(pwm->hwpwm, period);
ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
ctrl |= JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
switch (state->polarity) {
case PWM_POLARITY_NORMAL:
@ -158,10 +188,6 @@ static int jz4740_pwm_probe(struct platform_device *pdev)
if (!jz4740)
return -ENOMEM;
jz4740->clk = devm_clk_get(&pdev->dev, "ext");
if (IS_ERR(jz4740->clk))
return PTR_ERR(jz4740->clk);
jz4740->chip.dev = &pdev->dev;
jz4740->chip.ops = &jz4740_pwm_ops;
jz4740->chip.npwm = NUM_PWM;