Re: [Gumstix-users] How does the u-boot default display select an LCD driver?

[Steve S. <sa...@gm...>]

On Wed, Jan 27, 2010 at 1:55 PM, Doug Gibbs <dg...@te...> wrote:
> I have a Gumstix Overo on a custom board based off of the Palo43 and
> Beagleboard. It includes the DVI driver chip like the Beagleboard, TI
> TFP410. I have the DVI output working.
>
> The LCD is a 7 inch screen. I believe it is the same LCD as they ship with
> the DevKit8000 (a Beagle clone).
>
> I have created a new driver in /drivers/video/omap2/displays/panel_7_inch.c,
> included it in the Kconfig and Makefile. It builds with the correct
> parameters for my display.
>
> How can I set a parameter in u-boot or for kernel startup to use my driver?
> I would like to do "setenv defaultdisply lcd7in" from u-boot and have my
> display driver used. I can not figure out how the u-boot environment
> parameter is used by the kernel at startup.

You'll need to modify the overo board file and rebuild the kernel.
For an example, see how the other two LCD's are handled in the current
source:

http://www.sakoman.com/cgi-bin/gitweb.cgi?p=linux-omap-2.6.git;a=blob;f=arch/arm/mach-omap2/board-overo.c;h=b90b14089d655eb390a278582b842db209e77c72;hb=refs/heads/omap3-2.6.32

Steve


> I would guess this is a generic thing, not just for displays. I have
> searched though the rootfs for lcd43, but must have missed it. If you can
> point me to where the environment variable is read from nand, I can probably
> find my way from there.
> Thanks,
> Doug
>
>
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