Re: [PATCH 3/4] OMAPDSS: panel-sharp-ls037v7dw01: add device tree support

[Tony Lindgren <tony@atomide.com>]

* Tomi Valkeinen <tomi.valkeinen@ti.com> [140507 09:03]:
> On 07/05/14 18:03, Tony Lindgren wrote:
> 
> >>> +	lcd0: display {
> >>> +		compatible = "sharp,ls037v7dw01";
> >>> +		power-supply = <&lcd_3v3>;
> >>> +		reset-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>;	/* gpio155, lcd RESB */
> >>> +		enable-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH	/* gpio154, lcd MO */
> >>> +				&gpio1 2 GPIO_ACTIVE_HIGH	/* gpio2, lcd LR */
> >>> +				&gpio1 3 GPIO_ACTIVE_HIGH	/* gpio3, lcd UD */
> >>> +				&gpio5 24 GPIO_ACTIVE_HIGH>;	/* gpio152, lcd INI */
> >>
> >> Why are most of the gpios in 'enable-gpios'? MO, LR and UD don't really
> >> have anything to do with enabling the panel. Why not just have one
> >> 'gpios' array with all the gpios, as they are quite a mixed bunch?
> > 
> > Yeah that's what I had initially, but reading simple-panel.txt noticed
> > there are some standardized GPIOs for reset and enable.
> 
> I'm not sure if it's worth to try to make it compatible with
> simple-panel. simple-panel bindings do not work with omapdss anyway, and
> simple-panel doesn't have the support for input ports/endpoints.
> 
> Can the panel be used with only one gpio (I guess that would be INI or
> RESB)? If not, simple-panel doesn't work.

I guess in theory yes.
 
> > How about we set up one reset-gpios, one enable-gpios and an array of
> > three unlabelled GPIOs?
> > 
> > Or if we want to add something generic, we could add new mode-gpios
> > property that other panels might be able to use too?
> > 
> > BTW, I'm also personally fine with all five gpios showing in a single
> > gpios property, I'm not too exited about naming anything in DT..
> 
> I don't have a strong opinion here. I don't have much experience with
> DT, especially with making bindings compatible with other ones.
> 
> I'd just forget the simple-panel, and have single gpio array.

Well if it's a don't care flag for both of us, let's try to use
the existing standard for simple-panel.txt and add mode-gpios
property. I'll post a patch for that.

Regards,

Tony