[PATCH v1 1/3] dt-bindings: drm/bridge: Document Cadence MHDP bridge bindings in yaml format

[Jyri Sarha]

On 03/12/2019 12:16, Yuti Amonkar wrote:
> Document the bindings used for the Cadence MHDP DPI/DP bridge in
> yaml format.
> 
> Signed-off-by: Yuti Amonkar <yamonkar at cadence.com>

Couple of comments bellow.

> ---
>  .../bindings/display/bridge/cdns,mhdp.yaml         | 101 +++++++++++++++++++++
>  1 file changed, 101 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/cdns,mhdp.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,mhdp.yaml b/Documentation/devicetree/bindings/display/bridge/cdns,mhdp.yaml
> new file mode 100644
> index 0000000..1739f2e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/cdns,mhdp.yaml
> @@ -0,0 +1,101 @@
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/display/bridge/cdns,mhdp.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Cadence MHDP bridge
> +
> +maintainers:
> +  - Swapnil Jakhade <sjakhade at cadence.com>
> +  - Yuti Amonkar <yamonkar at cadence.com>
> +
> +properties:
> +  compatible:
> +    items:
> +      - const: ti,j721e-mhdp8546
> +      - const: cdns,mhdp8546
> +
> +  clocks:
> +    items:
       ^^^^^^
No need for this, but "maxItems: 1" would probably make sense.

> +      descrption:

Typo in the key word. Please try "make dt_binding_check" (see
Documentation/devicetree/writing-schema.rst) to run a formal check on
your binding.

> +        DP bridge clock, it's used by the IP to know how to translate a number of
> +        clock cycles into a time (which is used to comply with DP standard timings
> +        and delays).
> +
> +  reg:

Add these here to make it explicit that there can be either 1 or 2 items.
    maxItems: 2
    minItems: 1


> +    items:       ^^^^^^
This could probably be removed too.

> +      - description:
> +          Register block of mhdptx abp registers upto PHY mapped area(AUX_CONFIG_P).
> +          The AUX and PMA registers are mapped to associated phy driver.
> +      - description:
> +          Register block for DSS_EDP0_INTG_CFG_VP registers in case of TI J7 SoCs.

It looks like the dt_binding_check accepts two descriptions, but I
wonder how easy it is to understand that they are referring to the two
reg items. Maybe we should add reg-names property to make things more
explicit. For instance "mhdptx" and "j721e-intg".

> +
> +  phys:
> +    description: see the Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml
> +
> +  phy-names:
> +    const: dpphy
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  power-domains:
> +    maxItems: 1
> +    description: phandle to the associated power domain
> +
> +  ports:
> +    type: object
> +    description:
> +      Ports as described in Documentation/devictree/bindings/graph.txt
> +    properties:
I think you need

      "#address-cells":
        const: 1

      "#size-cells":
        const: 0

here, and you should make them "requred".

> +       port at 0:
> +         description:
> +           input port representing the DP bridge input
> +
> +       port at 1:
> +         description:
> +           output port representing the DP bridge output
> +    required:
> +      - port at 0
> +      - port at 1
> +
> +required:
> +  - compatible
> +  - clocks
> +  - reg
> +  - phys
> +  - phy-names
> +  - ports
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    mhdp: dp-bridge at f0fb000000 {
> +        compatible = "ti,j721e-mhdp8546", "cdns,mhdp8546";
> +        reg = <0xf0 0xfb000000 0x0 0x1000000>,
> +              <0xf0 0xfc000000 0x0 0x2000000>;
> +        clocks = <&mhdp_clock>;
> +        phys = <&dp_phy>;
> +        phy-names = "dpphy";
> +
> +        ports {
> +              #address-cells = <1>;
> +              #size-cells = <0>;
> +
> +              port at 0 {
> +                     reg = <0>;
> +                     dp_bridge_input: endpoint {
> +                                               remote-endpoint = <&xxx_dpi_output>;
> +                     };
> +              };
> +
> +              port at 1 {
> +                     reg = <1>;
> +                     dp_bridge_output: endpoint {
> +                                     remote-endpoint = <&xxx_dp_connector_input>;
> +                     };
> +              };
> +      };
> +    };
> +...
> 


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