colibri-pxa300: LCD_LDD / LCD_CS gpio conflict

pieterg pieterg at gmx.com
Tue Sep 7 03:20:33 EDT 2010


On Tuesday 07 September 2010 04:43:31 Eric Miao wrote:
> On Mon, Sep 6, 2010 at 9:12 PM, pieterg <pieterg at gmx.com> wrote:
> > In colibri-pxa300.c, line 132, gpio config GPIO62_LCD_CS_N is
> > overriding the GPIO62_LCD_LDD_8 configuration, earlier in the pin
> > config table.
> >
> > As a result, one pixel data line is missing, obviously causing wrong
> > pixel data on passive lcd panels.
> >
> > Not sure what the best workaround should be.
> > LDD_CS is not available on the colibri evalboard as far as I can see,
> > so we might just define GPIO127_LCD_CS_N instead? (till the soc/carrier
> > board configs have been split)
> >
> > Or for now just put GPIO62_LCD_CS_N between
> > #ifdef ?
>
> Possibly define two groups of LCD pin configurations and select them
> when the appropriate LCD expansion card is plugged. If it can be
> detected at run-time, that will be perfect, otherwise have to come
> up with ugly #ifdef .. #else then.

I don't think you can detect whether an active or passive lcd panel is used.
And since the LCD_CS_N is only used for active panels, we can be sure that 
we only need it when CONFIG_FB_PXA_SMARTPANEL is defined.
So though it's ugly, it is already there, and we can use it.

Rgds, Pieter



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