linux-kernel - Re: [PATCH V3] led: Backlight trigger for led subsystem

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Date:	Tue, 7 Oct 2008 23:19:17 +0200
From:	Pavel Machek <pavel@...e.cz>
To:	Mark Brown <broonie@...ena.org.uk>
Cc:	Rodolfo Giometti <giometti@...eenne.com>,
	linux-kernel@...r.kernel.org, Richard Purdie <rpurdie@...ys.net>
Subject: Re: [PATCH V3] led: Backlight trigger for led subsystem

On Tue 2008-10-07 21:39:46, Mark Brown wrote:
> On Tue, Oct 07, 2008 at 10:19:54PM +0200, Rodolfo Giometti wrote:
> > On Tue, Oct 07, 2008 at 09:56:48PM +0200, Pavel Machek wrote:
> 
> > > Hmm, what's "your board"?
> 
> > Sorry, I meant "my custom board". :) It's PXA270 based but it's not
> > into Linux main tree.
> 
> Another example, support for which should be coming shortly, is the LED
> driver provided by the WM8350: this is a PMIC capable of producing outputs
> to drive LEDs, potentially strings of very bright LEDs.  This is frequently
> used to illuminate displays but the actual function depends entirely on how
> the system has been wired up.
> 
> The implementation is identical no matter what the LEDs are doing but the
> current out of tree drivers have two drivers for this bit of the hardware,
> one for use in the normal LED case and one for when used as a backlight,
> which is redundnant.  With the driver Rodolfo has written this should no
> longer be required and the backlight trigger can be used to share the
> hardware interface code.

Well, Rodolfo's patch will not allow you to set backlight brightness,
only on/off, right?

So if your leds are really a backlight, you still should use backlight
class directly...
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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