linux-kernel - [PATCH] backlight: pwm_bl: Fix condition to set enable gpio as output

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Date:   Sun, 16 Apr 2017 12:35:46 +0200
From:   Paul Kocialkowski <contact@...lk.fr>
To:     linux-kernel@...r.kernel.org
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
        linux-tegra@...r.kernel.org, Paul Kocialkowski <contact@...lk.fr>
Subject: [PATCH] backlight: pwm_bl: Fix condition to set enable gpio as output

The move to a dedicated pwm_backlight_initial_power_state function in
commit 7613c922315e308a6486d802abed2eb74443dffd modified the condition
to set the enable gpio as output. This breaks specific use cases using
that GPIO, such as tegra124-based nyan Chromebooks where backlight
stopped working.

This puts the condition back to the way it was before the move.

Signed-off-by: Paul Kocialkowski <contact@...lk.fr>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index d7efcb632f7d..e81b2b55be2b 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -304,7 +304,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	 * 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_IN ||
+	    gpiod_get_value(pb->enable_gpio) != 0))
 		gpiod_direction_output(pb->enable_gpio, 1);
 
 	pb->power_supply = devm_regulator_get(&pdev->dev, "power");
-- 
2.12.2