Re: [RFR 2/2] drm/panel: Add simple panel support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

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Hi Tomi,

On Thursday 17 October 2013 14:35:49 Tomi Valkeinen wrote:
> On 17/10/13 14:02, Laurent Pinchart wrote:
> >> Okay, so if I understand correctly, translating those bindings to panel
> >> 
> >> nodes would look somewhat like this:
> >> 	dc: display-controller {
> >> 		ports {
> >> 			port@0 {
> >> 				remote-endpoint = <&panel>;
> >> 			};
> >> 		};
> >> 	};
> >> 	
> >> 	panel: panel {
> >> 		ports {
> >> 			port@0 {
> >> 				remote-endpoint = <&dc>;
> >> 			};
> >> 		};
> >> 	};
> >> 
> >> The above leaves out any of the other, non-relevant properties. Does
> >> that sound about right?
> > 
> > Yes it does.
> 
> It does?
> 
> Shouldn't it be something like:
> 
> panel {
> 	ports {
> 		port@0 {
> 			endpoint@0 {
> 				remote = <&dc>;
> 			};
> 		};
> 	};
> };
> 
> And simplified:
> 
> panel {
> 	port {
> 		endpoint@0 {
> 			remote = <&dc>;
> 		};
> 	};
> };
> 
> You do need a node for the endpoint, a remote-endpoint property is not
> enough.

My bad, you'r absolutely right. More sleep is needed.

(And while we're at it, the remote-endpoint properties must point to an 
endpoint, not the device DT node.

> > Please note that, when a device has as single port, the ports node can be
> > omitted, and the port doesn't need to be numbered. You would then end up
> > with> 
> >  	dc: display-controller {
> > 		port {
> > 			remote-endpoint = <&panel>;
> >  		};
> >  	};
> >  	
> >  	panel: panel {
> >  		port {
> >  			remote-endpoint = <&dc>;
> >  		};
> >  	};
> > 
> > I don't think there's a way to simplify it further.
> 
> I'm not sure if there's a specific need for the port or endpoint nodes
> in cases like the above. Even if we have common properties describing
> the endpoint, I guess they could just be in the parent node.
> 
> panel {
> 	remote = <&dc>;
> 	common-video-property = <asd>;
> };
> 
> The above would imply one port and one endpoint. Would that work? If we
> had a function like parse_endpoint(node), we could just point it to
> either a real endpoint node, or to the device's node.

You reference the display controller here, not a specific display controller 
output. Don't most display controllers have several outputs ?

-- 
Regards,

Laurent Pinchart

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