From: peter.ujfalusi@ti•com (Peter Ujfalusi)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3 3/3] leds: leds-pwm: Defer led_pwm_set() if PWM can sleep
Date: Tue, 29 Jan 2013 09:20:31 +0100 [thread overview]
Message-ID: <5107864F.6060807@ti.com> (raw)
In-Reply-To: <1359381659-24454-4-git-send-email-florian.vaussard@epfl.ch>
On 01/28/2013 03:00 PM, Florian Vaussard wrote:
> Call to led_pwm_set() can happen inside atomic context, like triggers.
> If the PWM call can sleep, defer using a worker.
>
> Cc: Peter Ujfalusi <peter.ujfalusi@ti•com>
> Signed-off-by: Florian Vaussard <florian.vaussard@epfl•ch>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti•com>
> ---
> drivers/leds/leds-pwm.c | 50 +++++++++++++++++++++++++++++++++++++++-------
> 1 files changed, 42 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
> index a1ea5f6..faf52c0 100644
> --- a/drivers/leds/leds-pwm.c
> +++ b/drivers/leds/leds-pwm.c
> @@ -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;
> }
>
--
P?ter
next prev parent reply other threads:[~2013-01-29 8:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-28 14:00 [PATCH v3 0/3] leds-pwm: Defer PWM calls if PWM can sleep Florian Vaussard
2013-01-28 14:00 ` [PATCH v3 1/3] pwm: Add pwm_can_sleep() as exported API to users Florian Vaussard
2013-01-29 8:20 ` Peter Ujfalusi
2013-01-30 8:14 ` Thierry Reding
2013-01-28 14:00 ` [PATCH v3 2/3] pwm: Add can_sleep property to drivers Florian Vaussard
2013-01-30 8:15 ` Thierry Reding
2013-01-28 14:00 ` [PATCH v3 3/3] leds: leds-pwm: Defer led_pwm_set() if PWM can sleep Florian Vaussard
2013-01-29 8:20 ` Peter Ujfalusi [this message]
2013-01-30 8:17 ` Thierry Reding
2013-02-04 8:53 ` Florian Vaussard
2013-02-27 16:08 ` Florian Vaussard
2013-03-04 10:44 ` Florian Vaussard
2013-03-04 10:58 ` Thierry Reding
2013-03-05 15:39 ` Florian Vaussard
2013-03-12 10:06 ` Florian Vaussard
2013-03-15 17:08 ` Bryan Wu
2013-03-15 18:59 ` Thierry Reding
2013-03-15 20:09 ` Florian Vaussard
2013-03-15 21:02 ` Bryan Wu
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