Re: [PATCH V2 1/2] ARM: dts: Add DT changes for display on snow

[Mark Rutland <mark.rutland@arm.com>]

On Thu, Aug 28, 2014 at 02:10:18PM +0100, Thierry Reding wrote:
> On Thu, Aug 28, 2014 at 03:04:32PM +0530, Ajay kumar wrote:
> > On Thu, Aug 28, 2014 at 2:45 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> > > On Thu, Aug 28, 2014 at 06:34:33AM +0100, Ajay kumar wrote:
> > >> On Wed, Aug 27, 2014 at 8:31 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> > >> > On Wed, Aug 27, 2014 at 03:48:27PM +0100, Ajay Kumar wrote:
> > >> >> Add DT nodes for ptn3460 bridge chip and panel.
> > >> >> Add backlight enable pin and backlight power supply for pwm-backlight.
> > >> >> Also add bridge phandle needed by dp to enable display on snow.
> > >> >>
> > >> >> Note that, snow doesn't support "chunghwa,claa101wb01" panel,
> > >> >> but still we choose to reuse the binding since "chunghwa,claa101wb01"
> > >> >> has similar LCD timings.
> > >> >
> > >> > What does it actually have?
> > >> >
> > >> > It's fine to have "chunghwa,claa101wb01" as a fallback but we should
> > >> > have an identifier for the actual display, too.
> > >> Actual display used is "AUO,B116XTN0", for which no data currently exists
> > >> in panel file. Instead of adding a new panel_desc for B116XTN0,
> > >> why not we reuse existing ones? what is the "identifier" you are talking about?
> > >
> > > The compatible string.
> > >
> > > So in the dts we'd have compatible = "au0,b116xtn0", "chunghwa,claa101wb01";
> > Sorry, hardware engineer says actual LCD name is "auo,b116xw03".
> > 
> > > That way if we need specific data we can add it later.
> > I think we can add a new panel_desc for "auo,b116xw03".
> > Because its actual LCD dimension is 256x144, but "chungwa, claa101wb01" has
> > LCD dimension 223x125.
> > What is Thierry's opinion on adding this new LCD?
> 
> I think you should simply add a new panel_desc for the panel. It may use
> similar timings, but it's likely not "compatible" in the way required by
> device tree. As you say, dimensions are different and those may have an
> influence on the DPI setting. There's really no reason why this should
> share the panel_desc with another panel.
> 
> Thierry

This sounds sane to me.

Mark.