On 24/03/17 16:42, Daniel Thompson wrote:
On 22/03/17 17:21, Geert Uytterhoeven wrote: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 <geert+renesas@xxxxxxxxx>Acked-by: Daniel Thommpson <daniel.thompson@xxxxxxxxxx>
Actually, it would be better if there only one m... Acked-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Daniel.
--- drivers/video/backlight/pwm_bl.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index d7efcb632f7d9dde..002f1ce22bd02032 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");
