Re: [PATCH v8 1/3] dt-bindings: display: mediatek: Add OF graph support for board path

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

Hi, Angelo:

On Tue, 2024-06-18 at 12:17 +0200, AngeloGioacchino Del Regno wrote:
> The display IPs in MediaTek SoCs support being interconnected with
> different instances of DDP IPs (for example, merge0 or merge1) and/or
> with different DDP IPs (for example, rdma can be connected with either
> color, dpi, dsi, merge, etc), forming a full Display Data Path that
> ends with an actual display.
> 
> The final display pipeline is effectively board specific, as it does
> depend on the display that is attached to it, and eventually on the
> sensors supported by the board (for example, Adaptive Ambient Light
> would need an Ambient Light Sensor, otherwise it's pointless!), other
> than the output type.
> 
> Add support for OF graphs to most of the MediaTek DDP (display) bindings
> to add flexibility to build custom hardware paths, hence enabling board
> specific configuration of the display pipeline and allowing to finally
> migrate away from using hardcoded paths.
> 
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
> Tested-by: Alexandre Mergnat <amergnat@baylibre.com>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---

[snip]

>  
> diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,ethdr.yaml b/Documentation/devicetree/bindings/display/mediatek/mediatek,ethdr.yaml
> index 677882348ede..98db47894eeb 100644
> --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,ethdr.yaml
> +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,ethdr.yaml
> @@ -110,6 +110,28 @@ properties:
>        include/dt-bindings/gce/<chip>-gce.h, mapping to the register of display
>        function block.
>  
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +    description:
> +      Input and output ports can have multiple endpoints, each of those
> +      connects to either the primary, secondary, etc, display pipeline.
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: ETHDR input, usually from one of the MERGE blocks.

Sorry, I find one question now.
I think ETHDR may have multiple input, and ETHDR receive data from all input at the same time.
Why here has only one input port?

MERGE -->+-----------------+
         |                 |
MERGE -->|                 |
         |      ETHDR      |
MERGE -->|                 |
         |                 |
MERGE -->+-----------------+

Regards,
CK

> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description:
> +          ETHDR output to the input of the next desired component in the
> +          display pipeline, for example one of the available MERGE blocks,
> +          or others.
> +
> +    required:
> +      - port@0
> +      - port@1
> +
>  required:
>    - compatible
>    - reg
>