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backlight: pwm_bl: Fix GPIO out for unimplemented .get_direction() 

Commit 7613c92231 ("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: 7613c92231 ("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>
zero-colors
Geert Uytterhoeven 2017-04-04 12:54:35 +02:00 committed by Daniel Thompson
parent 4f7d029b9b
commit 892c7788c7
1 changed files with 4 additions and 3 deletions
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7
drivers/video/backlight/pwm_bl.c
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@ -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");