Re: [PATCH] dt-bindings: display: bridge: Drop requirement on input port for DSI devices

Rob Herring
2022-04-01T17:35:03Z

On Fri, Apr 01, 2022 at 03:22:19AM +0200, Marek Vasut wrote:
> On 4/1/22 01:52, Rob Herring wrote:
> > On Wed, 23 Mar 2022 16:48:23 +0100, Maxime Ripard wrote:
> > > MIPI-DSI devices, if they are controlled through the bus itself, have to
> > > be described as a child node of the controller they are attached to.
> > >
> > > Thus, there's no requirement on the controller having an OF-Graph output
> > > port to model the data stream: it's assumed that it would go from the
> > > parent to the child.
> > >
> > > However, some bridges controlled through the DSI bus still require an
> > > input OF-Graph port, thus requiring a controller with an OF-Graph output
> > > port. This prevents those bridges from being used with the controllers
> > > that do not have one without any particular reason to.
> > >
> > > Let's drop that requirement.
> > >
> > > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > > ---
> > > .../devicetree/bindings/display/bridge/chipone,icn6211.yaml | 1 -
> > > .../devicetree/bindings/display/bridge/toshiba,tc358762.yaml | 1 -
> > > 2 files changed, 2 deletions(-)
> > >
> >
> > I tend to agree with port@0 not being needed and really like
> > consistency.
>
> The consistent thing to do would be to always use port@0 and OF graph, no ?

I guess it depends how wide our scope for consistency is. Just DSI bus
controlled bridges? DSI panels? All bridges and panels? Any panel
without a control interface has the same dilemma as those can be a child
of the display controller (or bridge) and not even use OF graph.

All simple panels don't require 'port' either. That's presumably only
consistent because we made a single schema. I'd assume 'non-simple'
panels with their own schema are not consistent.

Rob