Re: [PATCH 5/5] leds: core: Use set_brightness_work for the blocking op

From: Sakari Ailus
Date: Tue Sep 22 2015 - 04:04:11 EST


Hi Jacek,

Jacek Anaszewski wrote:
> This patch makes LED core capable of setting brightness for drivers
> that implement brightness_set_blocking op. It removes from LED class
> drivers responsibility for using work queues on their own.
>
> In order to achieve this set_brightness_delayed callback is being
> modified to call newly added __led_set_brightness helper instead of
> led_set_brightness_async.
>
> led_set_brightness_async function didn't set brightness in an
> asynchronous way in all cases. It was mistakenly assuming that all
> LED subsystem drivers used work queue in their brightness_set op,
> whereas only half of them did that. Since it has no users now,
> it is being removed.
>
> Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
> ---
> drivers/leds/led-core.c | 22 +++++++++++++++++++++-
> drivers/leds/leds.h | 10 ----------
> include/linux/leds.h | 2 +-
> 3 files changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index fe6c2df..d8649f1 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -25,6 +25,22 @@ EXPORT_SYMBOL_GPL(leds_list_lock);
> LIST_HEAD(leds_list);
> EXPORT_SYMBOL_GPL(leds_list);
>
> +static int __led_set_brightness(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + int ret = 0;
> +
> + if (led_cdev->brightness_set)
> + led_cdev->brightness_set(led_cdev, led_cdev->brightness);
> + else if (led_cdev->brightness_set_blocking)
> + ret = led_cdev->brightness_set_blocking(led_cdev,

You can return here, and drop ret.

> + led_cdev->brightness);
> + else
> + return -EINVAL;
> +
> + return ret;
> +}
> +
> static void led_timer_function(unsigned long data)
> {
> struct led_classdev *led_cdev = (void *)data;
> @@ -83,6 +99,7 @@ static void set_brightness_delayed(struct work_struct *ws)
> {
> struct led_classdev *led_cdev =
> container_of(ws, struct led_classdev, set_brightness_work);
> + int ret;
>
> if (led_cdev->flags & LED_BLINK_DISABLE) {
> led_cdev->delayed_set_value = LED_OFF;
> @@ -90,7 +107,10 @@ static void set_brightness_delayed(struct work_struct *ws)
> led_cdev->flags &= ~LED_BLINK_DISABLE;
> }
>
> - led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
> + ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);

As __led_set_brightness() isn't used elsewhere and both are rather
simple functions, I'd just move the contents of that function here.

> + if (ret < 0)
> + dev_err(led_cdev->dev,
> + "Setting an LED's brightness failed (%d)\n", ret);
> }
>
> static void led_set_software_blink(struct led_classdev *led_cdev,
> diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
> index 11520eb..04b8e41 100644
> --- a/drivers/leds/leds.h
> +++ b/drivers/leds/leds.h
> @@ -16,16 +16,6 @@
> #include <linux/rwsem.h>
> #include <linux/leds.h>
>
> -static inline void led_set_brightness_async(struct led_classdev *led_cdev,
> - enum led_brightness value)
> -{
> - value = min(value, led_cdev->max_brightness);
> - led_cdev->brightness = value;
> -
> - if (!(led_cdev->flags & LED_SUSPENDED))
> - led_cdev->brightness_set(led_cdev, value);
> -}
> -
> static inline int led_set_brightness_sync(struct led_classdev *led_cdev,
> enum led_brightness value)
> {
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 9f850e6..ae3c178 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -155,7 +155,7 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev,
> *
> * Set an LED's brightness, and, if necessary, cancel the
> * software blink timer that implements blinking when the
> - * hardware doesn't.
> + * hardware doesn't. This function is guaranteed not to sleep.
> */
> extern void led_set_brightness(struct led_classdev *led_cdev,
> enum led_brightness brightness);
>

--
Kind regards,

Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx
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