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Commit 87770780 authored by Philipp Zabel's avatar Philipp Zabel Committed by Lee Jones
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backlight: pwm_bl: Fix broken PWM backlight for non-dt platforms 



Commit ee65ad0e2a9e ("backlight: pwm_bl: Avoid backlight flicker when
probed from DT") tries to dereference the device of_node pointer
unconditionally, causing a NULL pointer dereference on non-dt platforms.
Fix it by replacing the phandle variable with a node variable and
by checking that for NULL before dereferencing it.

Reported-by: default avatarRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Acked-by: default avatarThierry Reding <thierry.reding@gmail.com>
Tested-by: default avatarRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent fcf13f0b

drivers/video/backlight/pwm_bl.c

+4 −5
Original line number Diff line number Diff line
@@ -198,8 +198,8 @@ static int pwm_backlight_probe(struct platform_device *pdev) 
	struct platform_pwm_backlight_data defdata;

	struct backlight_properties props;

	struct backlight_device *bl;

	struct device_node *node = pdev->dev.of_node;

	struct pwm_bl_data *pb;

	phandle phandle = pdev->dev.of_node->phandle;

	int initial_blank = FB_BLANK_UNBLANK;

	int ret;
@@ -273,7 +273,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) 
		 * assume that another driver will enable the backlight at the

		 * appropriate time. Therefore, if it is disabled, keep it so.

		 */

		if (phandle &&

		if (node && node->phandle &&

		    gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT &&

		    gpiod_get_value(pb->enable_gpio) == 0)

			initial_blank = FB_BLANK_POWERDOWN;
@@ -287,12 +287,11 @@ static int pwm_backlight_probe(struct platform_device *pdev) 
		goto err_alloc;

	}



	if (phandle && !regulator_is_enabled(pb->power_supply))

	if (node && node->phandle && !regulator_is_enabled(pb->power_supply))

		initial_blank = FB_BLANK_POWERDOWN;



	pb->pwm = devm_pwm_get(&pdev->dev, NULL);

	if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER

	    && !pdev->dev.of_node) {

	if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {

		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");

		pb->legacy = true;

		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");