releases/4.14.109/pwm-backlight-enable-disable-the-pwm-before-after-lcd-enable-toggle.patch

   1 From 5fb5caee92ba35a4a3baa61d45a78eb057e2c031 Mon Sep 17 00:00:00 2001
   2 From: Enric Balletbo i Serra <enric.balletbo@collabora.com>
   3 Date: Wed, 28 Mar 2018 19:03:23 +0200
   4 Subject: pwm-backlight: Enable/disable the PWM before/after LCD enable toggle.
   5
   6 From: Enric Balletbo i Serra <enric.balletbo@collabora.com>
   7
   8 commit 5fb5caee92ba35a4a3baa61d45a78eb057e2c031 upstream.
   9
  10 Before this patch the enable signal was set before the PWM signal and
  11 vice-versa on power off. This sequence is wrong, at least, it is on
  12 the different panels datasheets that I checked, so I inverted the sequence
  13 to follow the specs.
  14
  15 For reference the following panels have the mentioned sequence:
  16   - N133HSE-EA1 (Innolux)
  17   - N116BGE (Innolux)
  18   - N156BGE-L21 (Innolux)
  19   - B101EAN0 (Auo)
  20   - B101AW03 (Auo)
  21   - LTN101NT05 (Samsung)
  22   - CLAA101WA01A (Chunghwa)
  23
  24 Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
  25 Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
  26 Acked-by: Jingoo Han <jingoohan1@gmail.com>
  27 Acked-by: Thierry Reding <thierry.reding@gmail.com>
  28 Signed-off-by: Lee Jones <lee.jones@linaro.org>
  29 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
  30 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  31
  32 ---
  33  drivers/video/backlight/pwm_bl.c |    9 +++++----
  34  1 file changed, 5 insertions(+), 4 deletions(-)
  35
  36 --- a/drivers/video/backlight/pwm_bl.c
  37 +++ b/drivers/video/backlight/pwm_bl.c
  38 @@ -54,10 +54,11 @@ static void pwm_backlight_power_on(struc
  39         if (err < 0)
  40                 dev_err(pb->dev, "failed to enable power supply\n");
  41
  42 +       pwm_enable(pb->pwm);
  43 +
  44         if (pb->enable_gpio)
  45                 gpiod_set_value_cansleep(pb->enable_gpio, 1);
  46
  47 -       pwm_enable(pb->pwm);
  48         pb->enabled = true;
  49  }
  50
  51 @@ -66,12 +67,12 @@ static void pwm_backlight_power_off(stru
  52         if (!pb->enabled)
  53                 return;
  54
  55 -       pwm_config(pb->pwm, 0, pb->period);
  56 -       pwm_disable(pb->pwm);
  57 -
  58         if (pb->enable_gpio)
  59                 gpiod_set_value_cansleep(pb->enable_gpio, 0);
  60
  61 +       pwm_config(pb->pwm, 0, pb->period);
  62 +       pwm_disable(pb->pwm);
  63 +
  64         regulator_disable(pb->power_supply);
  65         pb->enabled = false;
  66  }