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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: Dmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Vladimir Zapolskiy 2014-10-11 16:46:26 +03:00 committed by Lee Jones
parent 0df1f2487d
commit edf387b6d1
1 changed files with 4 additions and 1 deletions
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5
drivers/video/backlight/pwm_bl.c
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@ -34,6 +34,7 @@ struct pwm_bl_data {
struct regulator *power_supply;
struct gpio_desc *enable_gpio;
unsigned int scale;
bool legacy;
int (*notify)(struct device *,
int brightness);
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);
if (IS_ERR(pb->pwm)) {
dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
pb->legacy = true;
pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
if (IS_ERR(pb->pwm)) {
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)
pb->exit(&pdev->dev);
if (pb->legacy)
pwm_free(pb->pwm);
return 0;
}