Merge tag 'backlight-for-v4.11' of git://git.linaro.org/people/daniel.thompson/linux

Pull backlight fix from Daniel Thompson:
 "Normally pull requests for backlight come from Lee Jones (and will
  continue to do so) but the bug fixed here is annoying for few people
  so I'm providing a little holiday cover.

  Fix a single bug in the PWM backlight driver and make it play nice
  with a wider range of GPIO devices. This bug is a regression and was
  independently discovered by Geert Uytterhoevan and Paul Kocialkowski
  (and is tested by both)"

* tag 'backlight-for-v4.11' of git://git.linaro.org/people/daniel.thompson/linux:
  backlight: pwm_bl: Fix GPIO out for unimplemented .get_direction()

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index d7efcb632f7d..002f1ce22bd0 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -297,14 +297,15 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	}
 
 	/*
-	 * If the GPIO is configured as input, change the direction to output
-	 * and set the GPIO as active.
+	 * If the GPIO is not known to be already configured as output, that
+	 * is, if gpiod_get_direction returns either GPIOF_DIR_IN or -EINVAL,
+	 * change the direction to output and set the GPIO as active.
 	 * Do not force the GPIO to active when it was already output as it
 	 * could cause backlight flickering or we would enable the backlight too
 	 * early. Leave the decision of the initial backlight state for later.
 	 */
 	if (pb->enable_gpio &&
-	    gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_IN)
+	    gpiod_get_direction(pb->enable_gpio) != GPIOF_DIR_OUT)
 		gpiod_direction_output(pb->enable_gpio, 1);
 
 	pb->power_supply = devm_regulator_get(&pdev->dev, "power");