Commit 9c5f91cc authored Mar 28, 2018 by Enric Balletbo i Serra Committed by Greg Kroah-Hartman Mar 27, 2019

pwm-backlight: Enable/disable the PWM before/after LCD enable toggle.



commit 5fb5caee92ba35a4a3baa61d45a78eb057e2c031 upstream.

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>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 423f2c97

drivers/video/backlight/pwm_bl.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -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)
		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;
		}