Re: [PATCH v4 1/5] pwm-backlight: enable/disable the PWM before/after LCD enable toggle.

On Monday, July 24, 2017 11:14 AM, Daniel Thompson wrote:

On 21/07/17 11:48, Enric Balletbo i Serra wrote:

quoted

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

quoted

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 <redacted>

Acked-by: Daniel Thompson <redacted>

Acked-by: Jingoo Han <jingoohan1@gmail.com>

Best regards,
Jingoo Han

quoted

---
Changes since v3:
  - List the part numbers for the panel checked (Daniel Thompson)
Changes since v2:
  - Add this as a separate patch (Thierry Reding)
Changes since v1:
  - None

  drivers/video/backlight/pwm_bl.c | 9 +++++----
  1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c

b/drivers/video/backlight/pwm_bl.c

quoted

index 002f1ce..909a686 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)

quoted

  	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)

quoted

  	if (!pb->enabled)
  		return;

-	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);
+
  	regulator_disable(pb->power_supply);
  	pb->enabled = false;
  }