Messages in this thread | | | Date | Tue, 7 Oct 2008 17:20:32 +0200 | From | Rodolfo Giometti <> | Subject | Re: [PATCH V3] led: Backlight trigger for led subsystem |
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On Tue, Oct 07, 2008 at 03:54:20PM +0200, Pavel Machek wrote: > Hi! > > > This patch set adds a new led trigger which emulates the backlight > > behaviour: the leds are turned off and on each time the display blanks > > and unblacks. > > > > Since backlights are usually implemented with leds this patch set is > > useful for those drivers whose manage leds controller used as > > backlight controller. > > > > The driver simply registers itself into the led subsystem and then the > > user may get backlight emulation by setting the "backlight" > > trigger. Moreover a driver, which usually manages more than one led, > > can use some leds as "led" and the others as "backlights" at user > > request. > > We already have backlight subsystem, it can also handle display > brightness. Why not use that?
Just to use a led as "led" or as "backlight" at user request. You can do it by using:
echo none > /sys/class/leds/lcd/trigger echo backlight > /sys/class/leds/lcd/trigger
and the led will work accordingly.
Also a led used as "backlight" is just a normal led (you can set the brightness as a normal led) but it switchs off automatically when the LCD blanks.
Ciao,
Rodolfo
--
GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@linux.it Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti
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