Merge tag 'media/v4.5-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...

[karo-tx-linux.git] / drivers / pwm / pwm-lpss.c

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index ebf8450a2a09cc21046bca6481c2175f465918f0..295b963dbddb7bdf59b159c6de03ba701d4efc9e 100644 (file)
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -13,6 +13,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -80,6 +81,13 @@ static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
        writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
 }
 
+static void pwm_lpss_update(struct pwm_device *pwm)
+{
+       pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
+       /* Give it some time to propagate */
+       usleep_range(10, 50);
+}
+
 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
                           int duty_ns, int period_ns)
 {
@@ -117,10 +125,15 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
        base_unit &= (base_unit_range - 1);
        ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
        ctrl |= on_time_div;
-       /* request PWM to update on next cycle */
-       ctrl |= PWM_SW_UPDATE;
        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;
@@ -129,6 +142,12 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
        pm_runtime_get_sync(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;
 }