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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2017-01-28 17:10:41 +0200
committerThierry Reding <thierry.reding@gmail.com>2017-01-30 08:13:55 +0100
commitb14e8ceff03404cce4d9b85204246d3ed1259ec7 (patch)
treec4a10333148f00eb20e12e6bdb9565c878173bf9 /drivers/pwm
parentb5c050c719922901891bdd8580d224e2a0035db5 (diff)
downloadlinux-b14e8ceff03404cce4d9b85204246d3ed1259ec7.tar.bz2
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>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/pwm-lpss.c64
1 files changed, 29 insertions, 35 deletions
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index ffa01ab907a6..09869f91d2d0 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -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);
- /*
- * 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;
-}
+ 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);
+ }
-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);
+ return 0;
}
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,
};