backlight: pwm_bl: Disable PWM on shutdown, suspend and remove

[platform/kernel/linux-starfive.git] / drivers / video / backlight / pwm_bl.c

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index fce4122..289bd9c 100644 (file)
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -54,8 +54,7 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb)
        if (pb->post_pwm_on_delay)
                msleep(pb->post_pwm_on_delay);
 
-       if (pb->enable_gpio)
-               gpiod_set_value_cansleep(pb->enable_gpio, 1);
+       gpiod_set_value_cansleep(pb->enable_gpio, 1);
 
        pb->enabled = true;
 }
@@ -65,8 +64,7 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
        if (!pb->enabled)
                return;
 
-       if (pb->enable_gpio)
-               gpiod_set_value_cansleep(pb->enable_gpio, 0);
+       gpiod_set_value_cansleep(pb->enable_gpio, 0);
 
        if (pb->pwm_off_delay)
                msleep(pb->pwm_off_delay);
@@ -429,8 +427,7 @@ static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb)
         * Synchronize the enable_gpio with the observed state of the
         * hardware.
         */
-       if (pb->enable_gpio)
-               gpiod_direction_output(pb->enable_gpio, active);
+       gpiod_direction_output(pb->enable_gpio, active);
 
        /*
         * Do not change pb->enabled here! pb->enabled essentially
@@ -629,9 +626,14 @@ static void pwm_backlight_remove(struct platform_device *pdev)
 {
        struct backlight_device *bl = platform_get_drvdata(pdev);
        struct pwm_bl_data *pb = bl_get_data(bl);
+       struct pwm_state state;
 
        backlight_device_unregister(bl);
        pwm_backlight_power_off(pb);
+       pwm_get_state(pb->pwm, &state);
+       state.duty_cycle = 0;
+       state.enabled = false;
+       pwm_apply_state(pb->pwm, &state);
 
        if (pb->exit)
                pb->exit(&pdev->dev);
@@ -641,8 +643,13 @@ static void pwm_backlight_shutdown(struct platform_device *pdev)
 {
        struct backlight_device *bl = platform_get_drvdata(pdev);
        struct pwm_bl_data *pb = bl_get_data(bl);
+       struct pwm_state state;
 
        pwm_backlight_power_off(pb);
+       pwm_get_state(pb->pwm, &state);
+       state.duty_cycle = 0;
+       state.enabled = false;
+       pwm_apply_state(pb->pwm, &state);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -650,12 +657,24 @@ static int pwm_backlight_suspend(struct device *dev)
 {
        struct backlight_device *bl = dev_get_drvdata(dev);
        struct pwm_bl_data *pb = bl_get_data(bl);
+       struct pwm_state state;
 
        if (pb->notify)
                pb->notify(pb->dev, 0);
 
        pwm_backlight_power_off(pb);
 
+       /*
+        * Note that disabling the PWM doesn't guarantee that the output stays
+        * at its inactive state. However without the PWM disabled, the PWM
+        * driver refuses to suspend. So disable here even though this might
+        * enable the backlight on poorly designed boards.
+        */
+       pwm_get_state(pb->pwm, &state);
+       state.duty_cycle = 0;
+       state.enabled = false;
+       pwm_apply_state(pb->pwm, &state);
+
        if (pb->notify_after)
                pb->notify_after(pb->dev, 0);