Re: [PATCH v4 3/3] Documentation: of: Document graph bindings

From: Grant Likely
Date: Sat Mar 08 2014 - 00:38:39 EST


On Wed, 26 Feb 2014 16:50:52 +0200, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
> On 26/02/14 16:57, Philipp Zabel wrote:
> > Hi Tomi,
> >
> > Am Mittwoch, den 26.02.2014, 15:14 +0200 schrieb Tomi Valkeinen:
> >> On 25/02/14 16:58, Philipp Zabel wrote:
> >>
> >>> +Optional endpoint properties
> >>> +----------------------------
> >>> +
> >>> +- remote-endpoint: phandle to an 'endpoint' subnode of a remote device node.
> >>
> >> Why is that optional? What use is an endpoint, if it's not connected to
> >> something?
> >
> > This allows to include the an empty endpoint template in a SoC dtsi for
> > the convenience of board dts writers. Also, the same property is
> > currently listed as optional in video-interfaces.txt.
> >
> > soc.dtsi:
> > display-controller {
> > port {
> > disp0: endpoint { };
> > };
> > };
> >
> > board.dts:
> > #include "soc.dtsi"
> > &disp0 {
> > remote-endpoint = <&panel_input>;
> > };
> > panel {
> > port {
> > panel_in: endpoint {
> > remote-endpoint = <&disp0>;
> > };
> > };
> > };
> >
> > Any board not using that port can just leave the endpoint disconnected.
>
> Hmm I see. I'm against that.
>
> I think the SoC dtsi should not contain endpoint node, or even port node
> (at least usually). It doesn't know how many endpoints, if any, a
> particular board has. That part should be up to the board dts.

Why? We have established precedence for unused devices still being in
the tree. I really see no issue with it.

g.

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