diff mbox series

[BACKPORT,4.14.y,7/8] pwm-backlight: Enable/disable the PWM before/after LCD enable toggle.

Message ID 20190322161727.1153278-8-arnd@arndb.de
State Accepted
Commit 9c5f91cc9b2e8d4637182e9b43124af31803abbe
Headers show
Series candidates from spreadtrum 4.14 product kernel | expand

Commit Message

Arnd Bergmann March 22, 2019, 4:17 p.m. UTC
From: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Before this patch the enable signal was set before the PWM signal and
vice-versa on power off. This sequence is wrong, at least, it is on
the different panels datasheets that I checked, so I inverted the sequence
to follow the specs.

For reference the following panels have the mentioned sequence:
  - N133HSE-EA1 (Innolux)
  - N116BGE (Innolux)
  - N156BGE-L21 (Innolux)
  - B101EAN0 (Auo)
  - B101AW03 (Auo)
  - LTN101NT05 (Samsung)
  - CLAA101WA01A (Chunghwa)

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
(cherry picked from commit 5fb5caee92ba35a4a3baa61d45a78eb057e2c031)
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
 drivers/video/backlight/pwm_bl.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
diff mbox series


diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 0fa7d2bd0e48..155153ecb894 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -54,10 +54,11 @@  static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
 	if (err < 0)
 		dev_err(pb->dev, "failed to enable power supply\n");
+	pwm_enable(pb->pwm);
 	if (pb->enable_gpio)
 		gpiod_set_value_cansleep(pb->enable_gpio, 1);
-	pwm_enable(pb->pwm);
 	pb->enabled = true;
@@ -66,12 +67,12 @@  static void pwm_backlight_power_off(struct pwm_bl_data *pb)
 	if (!pb->enabled)
-	pwm_config(pb->pwm, 0, pb->period);
-	pwm_disable(pb->pwm);
 	if (pb->enable_gpio)
 		gpiod_set_value_cansleep(pb->enable_gpio, 0);
+	pwm_config(pb->pwm, 0, pb->period);
+	pwm_disable(pb->pwm);
 	pb->enabled = false;