Re: [Linux-fbdev-devel] [PATCH] Backlight driver for omap3evm

[Hiremath, V. <hva...@ti...>]

Thanks,
Vaibhav Hiremath

> -----Original Message-----
> From: lin...@vg... [mailto:linux-omap-
> ow...@vg...] On Behalf Of Premi, Sanjeev
> Sent: Wednesday, January 07, 2009 8:52 PM
> To: Richard Purdie
> Cc: lin...@vg...
> Subject: RE: [PATCH] Backlight driver for omap3evm
> 
> 
> > -----Original Message-----
> > From: Richard Purdie [mailto:rp...@rp...]
> > Sent: Wednesday, January 07, 2009 8:37 PM
> > To: Premi, Sanjeev
> > Cc: lin...@vg...
> > Subject: Re: [PATCH] Backlight driver for omap3evm
> >
> > On Wed, 2009-01-07 at 20:25 +0530, Sanjeev Premi wrote:
> > should be done in the platform code for the board, not in the
> > general driver. If you do that, you should be able to reuse
> > most of the generic-bl device code.
> 
> I tried so, but wasn't able to get the Kconfig dependencies right to
> get 'generic-bl' into my build. Hence, removed the code that I
> believed to be generic (since yesterday's mail) and created the
> patch.
> 
> Will give another try.
> 
[Hiremath, Vaibhav] Now I will be following up for OMAP3EVM backlight driver patch initiated/posted by Sanjeev. I was just referring to the backlight drives currently available under Linux tree, and observed that almost all drivers have been implemented in different way. I could not able to get one driver to which I can refer to for adding support for OMAP3EVM backlight driver.

Can anybody tell me the expected way of implementation for backlight driver is?

I have some questions here,

	- If I understand correctly (and as mentioned and pointed out by Richard in the mail-chain), platform_device should get added in platform file where it registers the pointer to the structure "struct generic_bl_info". 
This I believe should be standard way everybody should follow, which is not the case.
Am I missing something here?

	- The below question may sound foolish, but to is important for me to understand the framework.

If I have simple and straight control of backlight, do I really required to have separate backlight driver for my platform? Can I make use of generic-bl driver?
The only difference (atleast to my platform) would be the SYSFS entry, the entry will get created something like
/sys/class/backlight/generic-bl/

Is it required to make driver, Power aware and differentiate from generic driver?

Do we have any document on backlight driver framework?

> >
> > Regards,
> >
> > Richard
> >
> >
> > --
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