linux-kernel - Re: [PATCH v17 3/8] dt-bindings: display: bridge: Add Cadence MHDP8501

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Message-ID: <w72m4bxymngdadhp4x3mxyvv4j6k3mgtoqg3tcw4p3xdmhfpmx@wbkmfj3zmwcv>
Date: Tue, 24 Sep 2024 11:55:17 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Sandor Yu <Sandor.yu@....com>
Cc: andrzej.hajda@...el.com, neil.armstrong@...aro.org, 
	Laurent.pinchart@...asonboard.com, jonas@...boo.se, jernej.skrabec@...il.com, airlied@...il.com, 
	daniel@...ll.ch, robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, 
	shawnguo@...nel.org, s.hauer@...gutronix.de, festevam@...il.com, vkoul@...nel.org, 
	dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, linux-phy@...ts.infradead.org, mripard@...nel.org, 
	kernel@...gutronix.de, linux-imx@....com, oliver.brown@....com, 
	alexander.stein@...tq-group.com, sam@...nborg.org, 
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: Re: [PATCH v17 3/8] dt-bindings: display: bridge: Add Cadence
 MHDP8501

On Tue, Sep 24, 2024 at 03:36:48PM GMT, Sandor Yu wrote:
> Add bindings for Cadence MHDP8501 DisplayPort/HDMI bridge.
> 
> Signed-off-by: Sandor Yu <Sandor.yu@....com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> ---
> v16->v17:
> - Add lane-mapping property
> 
> v9->v16:
>  *No change
> 
> .../display/bridge/cdns,mhdp8501.yaml         | 109 ++++++++++++++++++
>  1 file changed, 109 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/cdns,mhdp8501.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,mhdp8501.yaml b/Documentation/devicetree/bindings/display/bridge/cdns,mhdp8501.yaml
> new file mode 100644
> index 0000000000000..3f79f328c7425
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/cdns,mhdp8501.yaml
> @@ -0,0 +1,109 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/cdns,mhdp8501.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Cadence MHDP8501 DP/HDMI bridge
> +
> +maintainers:
> +  - Sandor Yu <Sandor.yu@....com>
> +
> +description:
> +  Cadence MHDP8501 DisplayPort/HDMI interface.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - fsl,imx8mq-mhdp8501
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +    description: MHDP8501 DP/HDMI APB clock.
> +
> +  phys:
> +    maxItems: 1
> +    description:
> +      phandle to the DP/HDMI PHY
> +
> +  interrupts:
> +    items:
> +      - description: Hotplug cable plugin.
> +      - description: Hotplug cable plugout.
> +
> +  interrupt-names:
> +    items:
> +      - const: plug_in
> +      - const: plug_out
> +
> +  lane-mapping:
> +    description: lane mapping for HDMI or DisplayPort interface.
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description:
> +          Input port from display controller output.
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description:
> +          Output port to DisplayPort or HDMI connector.
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - interrupts
> +  - interrupt-names
> +  - phys
> +  - lane-mapping
> +  - ports
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/imx8mq-clock.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    mhdp: display-bridge@...00000 {
> +        compatible = "fsl,imx8mq-mhdp8501";
> +        reg = <0x32c00000 0x100000>;
> +        interrupts = <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>,
> +                     <GIC_SPI 25 IRQ_TYPE_LEVEL_HIGH>;
> +        interrupt-names = "plug_in", "plug_out";
> +        clocks = <&clk IMX8MQ_CLK_DISP_APB_ROOT>;
> +        phys = <&mdhp_phy>;
> +        lane-mapping = <0xe4>;

What does this value mean? The DT should be describing the hardware, not
the register values. Can it be expressed as the data-lanes property of
the corresponding port?

> +
> +        ports {
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            port@0 {
> +                reg = <0>;
> +
> +                mhdp_in: endpoint {
> +                    remote-endpoint = <&dcss_out>;
> +                };
> +            };
> +
> +            port@1 {
> +                reg = <1>;
> +
> +                mhdp_out: endpoint {
> +                    remote-endpoint = <&dp_connector>;
> +                };
> +            };
> +        };
> +    };
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry