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pwm: lpss: Switch to new atomic API 

Instead of doing things separately, which is not so reliable on some platforms,
switch the driver to use new atomic API, i.e. ->apply() callback.

The change has been tested on Intel platforms such as Broxton, BayTrail, and
Merrifield.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Andy Shevchenko 2017-01-28 17:10:41 +02:00 committed by Thierry Reding
parent b5c050c719
commit b14e8ceff0
1 changed files with 29 additions and 35 deletions
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64
drivers/pwm/pwm-lpss.c
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@ -82,15 +82,20 @@ static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
static void pwm_lpss_update(struct pwm_device *pwm)
{
/*
* Set a limit for busyloop since not all implementations correctly
* clear PWM_SW_UPDATE bit (at least it's not visible on OS side).
*/
unsigned int count = 10;
pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
/* Give it some time to propagate */
usleep_range(10, 50);
while (pwm_lpss_read(pwm) & PWM_SW_UPDATE && --count)
usleep_range(10, 20);
}
static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
static void pwm_lpss_prepare(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
unsigned long long on_time_div;
unsigned long c = lpwm->info->clk_rate, base_unit_range;
unsigned long long base_unit, freq = NSEC_PER_SEC;
@ -111,8 +116,6 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
do_div(on_time_div, period_ns);
on_time_div = 255ULL - on_time_div;
pm_runtime_get_sync(chip->dev);
ctrl = pwm_lpss_read(pwm);
ctrl &= ~PWM_ON_TIME_DIV_MASK;
ctrl &= ~(base_unit_range << PWM_BASE_UNIT_SHIFT);
@ -120,42 +123,33 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
ctrl |= on_time_div;
pwm_lpss_write(pwm, ctrl);
/*
* If the PWM is already enabled we need to notify the hardware
* about the change by setting PWM_SW_UPDATE.
*/
if (pwm_is_enabled(pwm))
pwm_lpss_update(pwm);
pm_runtime_put(chip->dev);
return 0;
}
static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
pm_runtime_get_sync(chip->dev);
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
if (state->enabled) {
if (!pwm_is_enabled(pwm)) {
pm_runtime_get_sync(chip->dev);
pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
pwm_lpss_update(pwm);
pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
} else {
pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
pwm_lpss_update(pwm);
}
} else if (pwm_is_enabled(pwm)) {
pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
pm_runtime_put(chip->dev);
}
/*
* Hardware must first see PWM_SW_UPDATE before the PWM can be
* enabled.
*/
pwm_lpss_update(pwm);
pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
return 0;
}
static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
pm_runtime_put(chip->dev);
}
static const struct pwm_ops pwm_lpss_ops = {
.config = pwm_lpss_config,
.enable = pwm_lpss_enable,
.disable = pwm_lpss_disable,
.apply = pwm_lpss_apply,
.owner = THIS_MODULE,
};