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>

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 0fa7d2bd0e4811c6c404663451c67f6ecea6afee..155153ecb894074ac76f7d5fbecd91377eb16a3e 100644 (file)
--- 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)
                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;
 }