pwm: lpss: Add support for runtime PM

To be able to save some power when PWM is not in use, add support for
runtime PM for this driver. This also allows the platform to transition to
low power S0ix states when the system is idle.

Signed-off-by: Huiquan Zhong <huiquan.zhong@intel.com>
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index df03b50f20dd..25044104003b 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 
 #include "pwm-lpss.h"
 
@@ -105,6 +106,8 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
                 duty_ns = 1;
         on_time_div = 255 - (255 * duty_ns / period_ns);
 
+        pm_runtime_get_sync(chip->dev);
+
         ctrl = pwm_lpss_read(pwm);
         ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
         ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
@@ -113,11 +116,14 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
         ctrl |= PWM_SW_UPDATE;
         pwm_lpss_write(pwm, ctrl);
 
+        pm_runtime_put(chip->dev);
+
         return 0;
 }
 
 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
+        pm_runtime_get_sync(chip->dev);
         pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
         return 0;
 }
@@ -125,6 +131,7 @@ static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 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 = {