|author||Geert Uytterhoeven <firstname.lastname@example.org>||2017-04-04 12:54:35 +0200|
|committer||Daniel Thompson <email@example.com>||2017-04-19 19:59:44 +0100|
backlight: pwm_bl: Fix GPIO out for unimplemented .get_direction()backlight-for-v4.11backlight-for-v4.11
Commit 7613c922315e308a ("backlight: pwm_bl: Move the checks for initial power state to a separate function") not just moved some code, but made slight changes in semantics. If a gpiochip doesn't implement the optional .get_direction() callback, gpiod_get_direction always returns -EINVAL, which is never equal to GPIOF_DIR_IN, leading to the GPIO not being configured for output. To avoid this, invert the test and check for not GPIOF_DIR_OUT instead, like the original code did. This restores the display on r8a7740/armadillo. Fixes: 7613c922315e308a ("backlight: pwm_bl: Move the checks for initial power state to a separate function") Signed-off-by: Geert Uytterhoeven <firstname.lastname@example.org> Reviewed-by: Peter Ujfalusi <email@example.com> Acked-by: Philipp Zabel <firstname.lastname@example.org> Acked-by: Daniel Thompson <email@example.com> Signed-off-by: Daniel Thompson <firstname.lastname@example.org>
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index d7efcb63..002f1ce 100644
@@ -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)
pb->power_supply = devm_regulator_get(&pdev->dev, "power");