Messages in this thread | | | Subject | Re: [PATCH v4 3/3] Documentation: of: Document graph bindings | From | Philipp Zabel <> | Date | Wed, 26 Feb 2014 15:57:03 +0100 |
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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.
On the other hand, the same could be achieved with Heiko Stübner's conditional nodes dtc patch:
soc.dtsi: display-controller { port { /delete-unreferenced/ disp0: endpoint { }; }; };
> Also, if this is being worked on, I'd like to propose the addition of > simpler single-endpoint cases which I've been using with OMAP DSS. So if > there's just a single endpoint for the device, which is very common, you > can have just: > > device { > ... > endpoint { ... }; > }; > > However, I guess that the patch just keeps growing and growing, so maybe > it's better to add such things later =).
Yes, that looks good. I'd be happy if we could add this in a second step as a backwards compatible simplification.
regards Philipp
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