Messages in this thread | | | Subject | Re: [PATCH] backlight: pwm_bl: Fix GPIO out for unimplemented .get_direction() | From | Daniel Thompson <> | Date | Fri, 24 Mar 2017 16:43:44 +0000 |
| |
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@glider.be> > > Acked-by: Daniel Thommpson <daniel.thompson@linaro.org>
Actually, it would be better if there only one m...
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
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"); >> >
| |