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authorGeert Uytterhoeven <geert+renesas@glider.be>2017-04-04 12:54:35 +0200
committerDaniel Thompson <daniel.thompson@linaro.org>2017-04-19 19:59:44 +0100
commit892c7788c72480e8282b8aafe0783a244cc9f47f (patch)
tree09b6d7d6dd83d7c746c2984c63d9afbaefe6922c
parent4f7d029b9bf009fbee76bb10c0c4351a1870d2f3 (diff)
downloadlinux-backlight-for-v4.11.tar.gz
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 <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>
-rw-r--r--drivers/video/backlight/pwm_bl.c7
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
--- 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");