Re: [PATCH 2/5] Documentation: leds: Add description of brightness setting API

From: Sakari Ailus
Date: Tue Sep 22 2015 - 06:26:16 EST


Hi Jacek,

Jacek Anaszewski wrote:
> This patch adds description of the LED subsystem API for
> setting an LED brightness.
>
> Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
> ---
> Documentation/leds/leds-class.txt | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt
> index 62261c0..2cc38fa 100644
> --- a/Documentation/leds/leds-class.txt
> +++ b/Documentation/leds/leds-class.txt
> @@ -52,6 +52,27 @@ above leaves scope for further attributes should they be needed. If sections
> of the name don't apply, just leave that section blank.
>
>
> +Brightness setting API
> +======================
> +
> +LED subsystem core exposes following API for setting brightness:
> +
> + - led_set_brightness : if necessary, cancels the software blink timer that
> + implements blinking when the hardware doesn't; it is guaranteed
> + not to sleep, which implies the possibility of delegating the
> + job to a work queue task (uses led_set_brightness_nosleep
> + underneath - see below),
> + - led_set_brightness_sync : for use cases when immediate effect is desired;
> + it can block the caller for the time required for accessing
> + device registers and can sleep,
> + - led_set_brightness_nosleep : sets an LEDs brightness using either
> + brightness_set op, which is guaranteed not to sleep, or, if only
> + brightness_set_blocking op is available, delegates it to a work
> + queue task; this API is inteded for use by LED core and
> + led-triggers, as they can be called from atomic context, and thus
> + cannot sleep.

led_set_brightness_nosleep() isn't part of the API intended to be used
outside the LED framework --- I wouldn't document it here, only the part
relevant for users outside the LED class and triggers frameworks.

> +
> +
> Hardware accelerated blink of LEDs
> ==================================
>
>


--
Kind regards,

Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx
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