[PATCH v6 6/7] dt/bindings: drm/bridge: it6505: Add mode-switch support

[Pin-yen Lin]

Hi Krzysztof,

On Mon, Nov 28, 2022 at 5:02 AM Krzysztof Kozlowski
<krzysztof.kozlowski at linaro.org> wrote:
>
> On 24/11/2022 11:20, 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 v6:
> > - Remove switches node and use endpoints and data-lanes property to
> >   describe the connections.
> >
> >  .../bindings/display/bridge/ite,it6505.yaml   | 94 ++++++++++++++++++-
> >  1 file changed, 90 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > index 833d11b2303a..b4b9881c7759 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > +++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > @@ -52,9 +52,53 @@ properties:
> >      maxItems: 1
> >      description: extcon specifier for the Power Delivery
> >
> > -  port:
> > -    $ref: /schemas/graph.yaml#/properties/port
> > -    description: A port node pointing to DPI host port node
> > +  data-lanes:
> > +    maxItems: 1
> > +    description: restrict the dp output data-lanes with value of 1-4
>
> Hm, where is the definition of this type? For example it comes with
> video-interfaces, which you did not reference here.
>
Actually I messed up here with another accepted patch:
https://lore.kernel.org/all/20221103091243.96036-2-allen.chen@ite.com.tw/

This and the next new property have been added in that patch.
> > +
> > +  max-pixel-clock-khz:
>
> There is no such unit accepted:
> https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml
>
> > +    maxItems: 1
>
> maxItems of what type? What is this?
>
> > +    description: restrict max pixel clock
> > +
> > +  ports:
> > +    $ref: /schemas/graph.yaml#/properties/ports
>
> This is incompatible change... how do you handle now ABI break?
>
This is also added in another patch, and currently we don't have any
upstream it6505 users now.
> > +
> > +    properties:
> > +      port at 0:
> > +        $ref: /schemas/graph.yaml#/$defs/port-base
>
> Why changing the ref?

The `unevaluatedProperties: false` in
`/schemas/graph.yaml#/properties/port` does not allow me to add new
properties here.
>
> > +        unevaluatedProperties: false
> > +        description: A port node pointing to DPI host port node
> > +
> > +      port at 1:
> > +        $ref: /schemas/graph.yaml#/properties/port-base
> > +        description:
> > +          Video port for panel or connector.
> > +
> > +        patternProperties:
> > +          "^endpoint@[01]$":
> > +            $ref: /schemas/media/video-interfaces.yaml#
> > +            type: object
> > +            unevaluatedProperties: false
> > +
> > +            properties:
> > +              reg:
> > +                maxItems: 1
> > +
> > +              remote-endpoint: true
> > +
> > +              data-lanes:
> > +                minItems: 1
> > +                uniqueItems: true
> > +                items:
> > +                  - enum: [ 0, 1, 2, 3]
>
> Same problem as your previouspatch.
>
> > +
> > +              mode-switch:
> > +                type: boolean
> > +                description: Register this node as a Type-C mode switch or not.
> > +
> > +         required:
> > +        - reg
> > +           - remote-endpoint
> >
> >  required:
> >    - compatible
> > @@ -62,7 +106,7 @@ required:
> >    - pwr18-supply
> >    - interrupts
> >    - reset-gpios
> > -  - extcon
> > +  - ports
> >
> >  additionalProperties: false
> >
> > @@ -92,3 +136,45 @@ examples:
> >              };
> >          };
> >      };
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +
> > +    &i2c3 {
> > +        clock-frequency = <100000>;
> > +
> > +        it6505dptx: it6505dptx at 5c {
>
> Node names should be generic.
> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
>
I'll fix this in v7.
> > +            compatible = "ite,it6505";
> > +            interrupts = <8 IRQ_TYPE_LEVEL_LOW 8 0>;
> > +            reg = <0x5c>;
> > +            pinctrl-names = "default";
> > +            pinctrl-0 = <&it6505_pins>;
> > +            ovdd-supply = <&mt6366_vsim2_reg>;
> > +            pwr18-supply = <&pp1800_dpbrdg_dx>;
> > +            reset-gpios = <&pio 177 0>;
> > +            hpd-gpios = <&pio 10 0>;
> > +
> > +            ports {
> > +                #address-cells = <1>;
> > +                #size-cells = <0>;
> > +                port at 0 {
> > +                    reg = <0>;
> > +                    it6505_in: endpoint {
> > +                        remote-endpoint = <&dpi_out>;
> > +                    };
> > +                };
> > +                port at 1 {
> > +                    reg = <1>;
> > +                    ite_typec0: endpoint at 0 {
> > +                        mode-switch;
> > +                        data-lanes = <0 1>;
>
> Does not look like you tested the bindings. Please run `make
> dt_binding_check` (see
> Documentation/devicetree/bindings/writing-schema.rst for instructions).
Sorry for not checking the documentation and testing the patches
before submitting this.

I'll fix the errors in v7.

Best regards,
Pin-yen
>
> Best regards,
> Krzysztof
>