pwm: Clear chip_data in pwm_put()

After a PWM is disposed by its user the per chip data becomes invalid.
Clear the data in common code instead of the device drivers to get
consistent behaviour. Before this patch only three of nine drivers
cleaned up here.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/core.c

@@ -877,6 +877,7 @@ void pwm_put(struct pwm_device *pwm)
 	if (pwm->chip->ops->free)
 		pwm->chip->ops->free(pwm->chip, pwm);
 
+	pwm_set_chip_data(pwm, NULL);
 	pwm->label = NULL;
 
 	module_put(pwm->chip->ops->owner);

drivers/pwm/pwm-berlin.c

@@ -84,7 +84,6 @@ static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm);
 
-	pwm_set_chip_data(pwm, NULL);
 	kfree(channel);
 }
 

drivers/pwm/pwm-pca9685.c

@@ -176,7 +176,6 @@ static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
 	pm_runtime_put(pca->chip.dev);
 	mutex_lock(&pca->lock);
 	pwm = &pca->chip.pwms[offset];
-	pwm_set_chip_data(pwm, NULL);
 	mutex_unlock(&pca->lock);
 }
 

drivers/pwm/pwm-samsung.c

@@ -238,7 +238,6 @@ static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm)
 static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	devm_kfree(chip->dev, pwm_get_chip_data(pwm));
-	pwm_set_chip_data(pwm, NULL);
 }
 
 static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)