| Message ID | 1509022186-19636-3-git-send-email-LW@KARO-electronics.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | backlight: pwm_bl: prevent backlight flicker when switching PWM on | expand |
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 002f1ce..921f322 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -50,6 +50,8 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) if (pb->enabled) return; + pwm_enable(pb->pwm); + err = regulator_enable(pb->power_supply); if (err < 0) dev_err(pb->dev, "failed to enable power supply\n"); @@ -57,7 +59,6 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) if (pb->enable_gpio) gpiod_set_value_cansleep(pb->enable_gpio, 1); - pwm_enable(pb->pwm); pb->enabled = true; }
When the PWM is re-enabled after being switched off, the backlight may flicker due to the backlight power being switched on while the PWM is still unconfigured. This is especially true if the PWM output is active low (assuming that the PWM output is low when the PWM is not enabled). Configure the PWM before switching backlight power on to prevent this. Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de> --- drivers/video/backlight/pwm_bl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)