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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2017-04-04 12:54:35 +0200 |
|---|---|---|
| committer | Daniel Thompson <daniel.thompson@linaro.org> | 2017-04-19 19:59:44 +0100 |
| commit | 892c7788c72480e8282b8aafe0783a244cc9f47f (patch) | |
| tree | 09b6d7d6dd83d7c746c2984c63d9afbaefe6922c /drivers/video/backlight | |
| parent | 4f7d029b9bf009fbee76bb10c0c4351a1870d2f3 (diff) | |
| download | linux-stable-892c7788c72480e8282b8aafe0783a244cc9f47f.tar.gz linux-stable-892c7788c72480e8282b8aafe0783a244cc9f47f.tar.bz2 linux-stable-892c7788c72480e8282b8aafe0783a244cc9f47f.zip | |
backlight: pwm_bl: Fix GPIO out for unimplemented .get_direction()
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>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Diffstat (limited to 'drivers/video/backlight')
| -rw-r--r-- | drivers/video/backlight/pwm_bl.c | 7 |
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"); |