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Message-ID: <20150624084421.GB17732@amd> Date: Wed, 24 Jun 2015 10:44:21 +0200 From: Pavel Machek <pavel@....cz> To: Stas Sergeev <stsp@...t.ru> Cc: linux-leds@...r.kernel.org, Linux kernel <linux-kernel@...r.kernel.org>, Bryan Wu <cooloney@...il.com>, Richard Purdie <rpurdie@...ys.net>, Jacek Anaszewski <j.anaszewski@...sung.com>, Kyungmin Park <kyungmin.park@...sung.com>, Stas Sergeev <stsp@...rs.sourceforge.net> Subject: Re: [PATCH v2] leds: fix brightness changing when software blinking is active On Tue 2015-06-23 19:59:27, Stas Sergeev wrote: > 02.05.2015 17:59, Pavel Machek пишет: > > On Thu 2015-05-14 18:24:02, Stas Sergeev wrote: > >> > >> The following sequence: > >> echo timer >/sys/class/leds/<name>/trigger > >> echo 1 >/sys/class/leds/<name>/brightness > >> should change the ON brightness for blinking. > >> The function led_set_brightness() was mistakenly initiating the > >> delayed blink stop procedure, which resulted in no blinking with > >> the timer trigger still active. > >> > >> This patch fixes the problem by changing led_set_brightness() > >> to not initiate the delayed blink stop when brightness is not 0. > > > > Could we get this part of API documented? It is quite non-obvious... 0 clears the trigger, > > other values do not, I thought it is a bug when I saw it... > I guess the thinking was that if ON brightness differs > from OFF brightness, you should not clear the trigger. > But if you put ON brightness similar to OFF brightness, > then you can as well stop blinking at all. And none of this is documented. So what about this? diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led index 3646ec8..b734d7f 100644 --- a/Documentation/ABI/testing/sysfs-class-led +++ b/Documentation/ABI/testing/sysfs-class-led @@ -4,16 +4,25 @@ KernelVersion: 2.6.17 Contact: Richard Purdie <rpurdie@...ys.net> Description: Set the brightness of the LED. Most LEDs don't - have hardware brightness support so will just be turned on for + have hardware brightness support, so will just be turned on for non-zero brightness settings. The value is between 0 and /sys/class/leds/<led>/max_brightness. + Writing 0 to this file clears active trigger. + + Writing non-zero to this file while trigger is active changes the + top brightness trigger is going to use. + + What: /sys/class/leds/<led>/max_brightness Date: March 2006 KernelVersion: 2.6.17 Contact: Richard Purdie <rpurdie@...ys.net> Description: - Maximum brightness level for this led, default is 255 (LED_FULL). + Maximum brightness level for this LED, default is 255 (LED_FULL). + + If the LED does not support different brightness levels, this + should be 1. What: /sys/class/leds/<led>/trigger Date: March 2006 @@ -21,7 +30,7 @@ KernelVersion: 2.6.17 Contact: Richard Purdie <rpurdie@...ys.net> Description: Set the trigger for this LED. A trigger is a kernel based source - of led events. + of LED events. You can change triggers in a similar manner to the way an IO scheduler is chosen. Trigger specific parameters can appear in /sys/class/leds/<led> once a given trigger is selected. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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