On Wed, May 19, 2021 at 4:06 PM Doug Anderson <dianders@xxxxxxxxxxxx> wrote: > > Hi, > > On Wed, May 19, 2021 at 1:02 PM Rob Herring <robh@xxxxxxxxxx> wrote: > > > > On Mon, May 17, 2021 at 01:09:00PM -0700, Douglas Anderson wrote: > > > We want to be able to list an eDP panel as a child of a ti-sn65dsi86 > > > node to represent the fact that the panel is connected to the bridge's > > > DP AUX bus. Though the panel and the bridge chip are connected in > > > several ways, the DP AUX bus is the primary control interface between > > > the two and thus makes the most sense to model in device tree > > > hierarchy. > > > > > > Listing a panel in this way makes it possible for the panel driver to > > > easily get access to the DP AUX bus that it resides on, which can be > > > useful to help in auto-detecting the panel and for turning on various > > > bits. > > > > > > NOTE: it's still possible to continue using the bridge chip and point > > > to a panel that _isn't_ listed as a child of the bridge chip (since > > > it's worked that way previously), but that should be deprecated since > > > there is no downside to listing the panel under the bridge chip. > > > > > > The idea for this bus's design was hashed out over IRC [1]. > > > > > > [1] https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&date=2021-05-11 > > > > > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > > > --- > > > Possibly we might want something fancier that could be included by > > > other eDP controller bindings. If we want to do this, I'd love to be > > > pointed at a good example to follow. > > > > > > Changes in v7: > > > - ti-sn65dsi86: Add aux-bus child patch new for v7. > > > > > > .../bindings/display/bridge/ti,sn65dsi86.yaml | 22 ++++++++++++++++++- > > > 1 file changed, 21 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml > > > index 26932d2e86ab..51f5a29e216c 100644 > > > --- a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml > > > +++ b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml > > > @@ -70,6 +70,11 @@ properties: > > > const: 1 > > > description: See ../../pwm/pwm.yaml for description of the cell formats. > > > > > > + aux-bus: > > > > As this is a node: > > > > type: object > > > > > + description: > > > + It is recommended that you place your panel under the aux-bus node > > > + here to represent the control hierarchy. > > > + > > > ports: > > > $ref: /schemas/graph.yaml#/properties/ports > > > > > > @@ -201,11 +206,26 @@ examples: > > > > > > port@1 { > > > reg = <1>; > > > - endpoint { > > > + sn65dsi86_out: endpoint { > > > remote-endpoint = <&panel_in_edp>; > > > }; > > > }; > > > }; > > > + > > > + aux-bus { > > > + panel { > > > > We should perhaps have a separate aux-bus schema. > > Yeah. Before spending lots of time digging into how to do this I > wanted to see if anyone was going to give me a big-old NAK on the > whole approach. ;-) > > I guess I'd make a file called "dp-aux-bus.yaml" (maybe right under > bindings/display?) and then I'd include it like this: > > aux-bus: > $ref: "../dp-aux-bus.yaml#" Right. > > Something should > > define the child node is 'panel' and nothing else. > > At the moment the code also requires that the node name is 'aux-bus'. > Any objections to that? No. There's 2 ways to do that. The above does and adding $nodename in dp-aux-bus.yaml will. The latter also means the schema will be applied automatically to any node named 'aux-bus'. That means the schema will be applied twice unless you have 'select: false'. The main advantage of the latter case is it gets applied even without all the users converted to schema. > > Though perhaps > > connectors are valid too? > > They might be. We could always add it later? Sure. Rob
