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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: Florian Vaussard <florian.vaussard@epfl.ch>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
hifive-unleashed-5.1
Florian Vaussard 2013-01-28 06:00:59 -08:00 committed by Bryan Wu
parent 24d3212847
commit c971ff185f
1 changed files with 42 additions and 8 deletions
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50
drivers/leds/leds-pwm.c
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@ -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;
}