[UPSTREAM] Move backlight handling out of pcf50633 driver

[Balaji Rao]

On Sun, Oct 19, 2008 at 09:01:25AM -0700, Sean McNeil wrote:
> Hi Balaji,
> 
> Balaji Rao wrote:
> > On Sun, Oct 19, 2008 at 10:24:22AM +0100, Andy Green wrote:
> >   
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> >> Somebody in the thread at some point said:
> >>
> >> Nice work Balaji.
> >>
> >>     
> > Andy,
> >
> > Thank you.
> >   
> >> | Can you make the max brightness a #define where it can be an arbitrary
> >> | value such as 100 or 255? I'm also curious about suspend/resume ordering
> >>
> >> This will be more important than it sounds.  How about we ourselves
> >> change to 255 as the logical max brightness.  Existing code can find our
> >> actual max brightness down /sys and scale accordingly.
> >>     
> >
> > Hmmm.. Are we sure we need to do this ? I'm mildly interested in it
> > because the max_brightness is exported as well and any good userspace code
> > that tries to control the backlight must read the max_brightness value.
> >   
> 
> It is unfortunate, but there are still some very high profile software
> stacks that assume brightness ranges from 0-255. A smaller amount that
> expects 0-100. These will get fixed over time, but it is nice to be able
> to specify an arbitrary max value in the kernel and have it scale
> appropriately. I can live with just making it a max of 255, though, as
> that is what I'm dealing with here.
> 

Ah, ok. Making it take 256 values hurts none but helps many. If no one 
objects to this, I'll go ahead and do it.

Thank you,

	- Balaji