On Tue, Nov 29, 2016 at 2:27 AM, Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > Hi Rob, > > On Tuesday 22 Nov 2016 11:36:55 Laurent Pinchart wrote: >> On Monday 21 Nov 2016 10:48:15 Rob Herring wrote: >> > On Sat, Nov 19, 2016 at 05:28:01AM +0200, Laurent Pinchart wrote: >> >> Document properties common to several display panels in a central >> >> location that can be referenced by the panel device tree bindings. >> > >> > Looks good. Just one comment... >> > >> > [...] >> > >> >> +Connectivity >> >> +------------ >> >> + >> >> +- ports: Panels receive video data through one or multiple connections. >> >> While >> >> + the nature of those connections is specific to the panel type, the >> >> + connectivity is expressed in a standard fashion using ports as >> >> specified in >> >> + the device graph bindings defined in >> >> + Documentation/devicetree/bindings/graph.txt. >> > >> > We allow panels to either use graph binding or be a child of the display >> > controller. >> >> I knew that some display controllers use a phandle to the panel (see the >> fsl,panel and nvidia,panel properties), but I didn't know we had panels as >> children of display controller nodes. I don't think we should allow that for >> anything but DSI panels, as the DT hierarchy is based on control buses. Are >> you sure we have other panels instantiated through that mechanism ? Some panels have no control bus, so were do we place them? I would say the hierarchy is based on buses with a preference for the control bus when there are multiple buses. I'm not a fan of just sticking things are the top level. > Ping ? > > Please note that this file documents properties common to multiple panel DT > bindings, but in no way makes it mandatory to use the OF graph bindings for > panels. The decision is left to individual bindings. It is mandatory in the sense that we don't want more cases of "fsl,panel". Rob
