[PATCH v11 7/9] dt-bindings: display: bridge: it6505: Add mode-switch support

[Pin-yen Lin]

Hi Rob,

Thanks for the review.

On Wed, Feb 8, 2023 at 4:52 AM Rob Herring <robh at kernel.org> wrote:
>
> On Sat, Feb 04, 2023 at 09:30:38PM +0800, Pin-yen Lin wrote:
> > ITE IT6505 can be used in systems to switch the DP traffic between
> > two downstreams, which can be USB Type-C DisplayPort alternate mode
> > lane or regular DisplayPort output ports.
> >
> > Update the binding to accommodate this usage by introducing a
> > data-lanes and a mode-switch property on endpoints.
> >
> > Signed-off-by: Pin-yen Lin <treapking at chromium.org>
> >
> > ---
> >
> > Changes in v11:
> > - Updated the description of the endpoints in the bindings
> > - Referenced video-interfaces.yaml instead for the endpoints binding
> > - Removed duplicated definitions from inherited schema
> >
> > Changes in v9:
> > - Fixed subject prefix again
> > - Changed the naming of the example node for it6505
> >
> > Changes in v8:
> > - Updated bindings for data-lanes property
> > - Fixed subject prefix
> >
> > Changes in v7:
> > - Fixed issues reported by dt_binding_check.
> > - Updated the schema and the example dts for data-lanes.
> > - Changed to generic naming for the example dts node.
> >
> > Changes in v6:
> > - Remove switches node and use endpoints and data-lanes property to
> >   describe the connections.
> >
> >  .../bindings/display/bridge/ite,it6505.yaml   | 101 +++++++++++++++---
> >  1 file changed, 88 insertions(+), 13 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > index b16a9d9127dd..8ae9c5cba22c 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > +++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > @@ -75,22 +75,49 @@ properties:
> >        port at 1:
> >          $ref: /schemas/graph.yaml#/$defs/port-base
> >          unevaluatedProperties: false
> > -        description: Video port for DP output
> > +        description:
> > +          Video port for DP output. Each endpoint connects to a video output
> > +          downstream, and the "data-lanes" property is used to describe the pin
> > +          connections. 0, 1, 2, 3 in "data-lanes" maps to TX0, TX1, TX2, TX3,
> > +          respectively.
> >
> > -        properties:
> > -          endpoint:
> > -            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> > +
> > +        patternProperties:
> > +          "^endpoint@[01]$":
> > +            $ref: /schemas/media/video-interfaces.yaml#
> >              unevaluatedProperties: false
> >
> >              properties:
> > +              reg: true
> > +
> > +              remote-endpoint: true
> > +
> >                data-lanes:
> > -                minItems: 1
> > -                uniqueItems: true
> > -                items:
> > -                  - enum: [ 0, 1 ]
> > -                  - const: 1
> > -                  - const: 2
> > -                  - const: 3
> > +                oneOf:
> > +                  - items:
> > +                      - enum: [0, 1, 2, 3]
> > +
> > +                  - items:
> > +                      - const: 0
> > +                      - const: 1
> > +
> > +                  - items:
> > +                      - const: 2
> > +                      - const: 3
> > +
> > +                  - items:
> > +                      - const: 0
> > +                      - const: 1
> > +                      - const: 2
> > +                      - const: 3
> > +
> > +              mode-switch:
> > +                type: boolean
> > +                description: Register this node as a Type-C mode switch or not.
>
> Existing users put this property in the device's node, not the endpoint.
> That seems more like a property of the device, than the DP link.

In our use case, we want to register two mode switches for the same
device. That's why we put the "mode-switch" property in the endpoints
instead of the device node.

>
> You are using fwnode_typec_mux_get(), right?

Yes. This is called by cros_ec_typec.c[1] in our use case.

[1]: https://elixir.bootlin.com/linux/latest/source/drivers/platform/chrome/cros_ec_typec.c#L148

Regards,
Pin-yen
>
> Rob