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Commit edf387b6 authored by Vladimir Zapolskiy's avatar Vladimir Zapolskiy Committed by Lee Jones
Browse files

backlight: pwm: Clean-up pwm requested using legacy API 



If PWM device is requested by means of legacy API pwm_request(), its
resources are not freed on module unbind, which may cause an oops on
access, e.g. by reading /sys/kernel/debug/pwm.

Reported-by: default avatarDmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
Signed-off-by: default avatarVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 0df1f248

drivers/video/backlight/pwm_bl.c

+4 −1
Original line number Original line Diff line number Diff line
@@ -34,6 +34,7 @@ struct pwm_bl_data { 
	struct regulator	*power_supply;

	struct regulator	*power_supply;

	struct gpio_desc	*enable_gpio;

	struct gpio_desc	*enable_gpio;

	unsigned int		scale;

	unsigned int		scale;

	bool			legacy;

	int			(*notify)(struct device *,

	int			(*notify)(struct device *,

					  int brightness);

					  int brightness);

	void			(*notify_after)(struct device *,

	void			(*notify_after)(struct device *,
@@ -274,7 +275,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) 
	pb->pwm = devm_pwm_get(&pdev->dev, NULL);

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

	if (IS_ERR(pb->pwm)) {

	if (IS_ERR(pb->pwm)) {

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

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



		pb->legacy = true;

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

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

		if (IS_ERR(pb->pwm)) {

		if (IS_ERR(pb->pwm)) {

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

			dev_err(&pdev->dev, "unable to request legacy PWM\n");
@@ -339,6 +340,8 @@ static int pwm_backlight_remove(struct platform_device *pdev) 




	if (pb->exit)

	if (pb->exit)

		pb->exit(&pdev->dev);

		pb->exit(&pdev->dev);

	if (pb->legacy)

		pwm_free(pb->pwm);





	return 0;

	return 0;

}

}