Hi Sakari,
On 09/22/2015 12:26 PM, Sakari Ailus wrote:
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.
OK, I'll move this description to drivers/leds/leds.h, next to the
function declaration.
+
+
Hardware accelerated blink of LEDs
==================================
--
Best Regards,
Jacek Anaszewski
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