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Commit c971ff18 authored by Florian Vaussard's avatar Florian Vaussard Committed by Bryan Wu
Browse files

leds: leds-pwm: Defer led_pwm_set() if PWM can sleep 



Call to led_pwm_set() can happen inside atomic context, like triggers.
If the PWM call can sleep, defer using a worker.

Signed-off-by: default avatarFlorian Vaussard <florian.vaussard@epfl.ch>
Reviewed-by: default avatarPeter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: default avatarBryan Wu <cooloney@gmail.com>
parent 24d32128

drivers/leds/leds-pwm.c

+42 −8
Original line number Diff line number Diff line
@@ -23,12 +23,16 @@ 
#include <linux/pwm.h>

#include <linux/leds_pwm.h>

#include <linux/slab.h>

#include <linux/workqueue.h>



struct led_pwm_data {

	struct led_classdev	cdev;

	struct pwm_device	*pwm;

	struct work_struct	work;

	unsigned int		active_low;

	unsigned int		period;

	int			duty;

	bool			can_sleep;

};



struct led_pwm_priv {
@@ -36,6 +40,26 @@ struct led_pwm_priv { 
	struct led_pwm_data leds[0];

};



static void __led_pwm_set(struct led_pwm_data *led_dat)

{

	int new_duty = led_dat->duty;



	pwm_config(led_dat->pwm, new_duty, led_dat->period);



	if (new_duty == 0)

		pwm_disable(led_dat->pwm);

	else

		pwm_enable(led_dat->pwm);

}



static void led_pwm_work(struct work_struct *work)

{

	struct led_pwm_data *led_dat =

		container_of(work, struct led_pwm_data, work);



	__led_pwm_set(led_dat);

}



static void led_pwm_set(struct led_classdev *led_cdev,

	enum led_brightness brightness)

{
@@ -44,13 +68,12 @@ static void led_pwm_set(struct led_classdev *led_cdev, 
	unsigned int max = led_dat->cdev.max_brightness;

	unsigned int period =  led_dat->period;



	if (brightness == 0) {

		pwm_config(led_dat->pwm, 0, period);

		pwm_disable(led_dat->pwm);

	} else {

		pwm_config(led_dat->pwm, brightness * period / max, period);

		pwm_enable(led_dat->pwm);

	}

	led_dat->duty = brightness * period / max;



	if (led_dat->can_sleep)

		schedule_work(&led_dat->work);

	else

		__led_pwm_set(led_dat);

}



static inline size_t sizeof_pwm_leds_priv(int num_leds)
@@ -100,6 +123,10 @@ static struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev) 
		led_dat->cdev.brightness = LED_OFF;

		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;



		led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);

		if (led_dat->can_sleep)

			INIT_WORK(&led_dat->work, led_pwm_work);



		ret = led_classdev_register(&pdev->dev, &led_dat->cdev);

		if (ret < 0) {

			dev_err(&pdev->dev, "failed to register for %s\n",
@@ -153,6 +180,10 @@ static int led_pwm_probe(struct platform_device *pdev) 
			led_dat->cdev.max_brightness = cur_led->max_brightness;

			led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;



			led_dat->can_sleep = pwm_can_sleep(led_dat->pwm);

			if (led_dat->can_sleep)

				INIT_WORK(&led_dat->work, led_pwm_work);



			ret = led_classdev_register(&pdev->dev, &led_dat->cdev);

			if (ret < 0)

				goto err;
@@ -180,8 +211,11 @@ static int led_pwm_remove(struct platform_device *pdev) 
	struct led_pwm_priv *priv = platform_get_drvdata(pdev);

	int i;



	for (i = 0; i < priv->num_leds; i++)

	for (i = 0; i < priv->num_leds; i++) {

		led_classdev_unregister(&priv->leds[i].cdev);

		if (priv->leds[i].can_sleep)

			cancel_work_sync(&priv->leds[i].work);

	}



	return 0;

}