[PATCH 3/4] dt-bindings: display: imx: add binding for i.MX8MP HDMI PAI

[Liu Ying]

Hi Shengjiu,

On 07/18/2025, Shengjiu Wang wrote:
> Add binding for the i.MX8MP HDMI parallel Audio interface block.
> As this port is linked to imx8mp-hdmi-tx, add port at 2 in
> fsl,imx8mp-hdmi-tx.yaml document.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
> ---
>  .../display/bridge/fsl,imx8mp-hdmi-tx.yaml    | 13 ++++
>  .../display/imx/fsl,imx8mp-hdmi-pai.yaml      | 61 +++++++++++++++++++
>  2 files changed, 74 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/imx/fsl,imx8mp-hdmi-pai.yaml

Usually, to add a new driver, a DT binding patch comes first.

> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/fsl,imx8mp-hdmi-tx.yaml b/Documentation/devicetree/bindings/display/bridge/fsl,imx8mp-hdmi-tx.yaml
> index 05442d437755..cf810b277557 100644
> --- a/Documentation/devicetree/bindings/display/bridge/fsl,imx8mp-hdmi-tx.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/fsl,imx8mp-hdmi-tx.yaml
> @@ -49,9 +49,14 @@ properties:
>          $ref: /schemas/graph.yaml#/properties/port
>          description: HDMI output port
>  
> +      port at 2:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: Parallel audio input port
> +
>      required:
>        - port at 0
>        - port at 1
> +      - port at 2

Can port at 2 be optional?
Note that video output can work with only port at 0 and port at 1.

>  
>  required:
>    - compatible
> @@ -98,5 +103,13 @@ examples:
>                      remote-endpoint = <&hdmi0_con>;
>                  };
>              };
> +
> +            port at 2 {
> +                reg = <2>;
> +
> +                endpoint {
> +                    remote-endpoint = <&pai_to_hdmi_tx>;
> +                };
> +            };
>          };
>      };
> diff --git a/Documentation/devicetree/bindings/display/imx/fsl,imx8mp-hdmi-pai.yaml b/Documentation/devicetree/bindings/display/imx/fsl,imx8mp-hdmi-pai.yaml
> new file mode 100644
> index 000000000000..d2d723935032
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/imx/fsl,imx8mp-hdmi-pai.yaml
> @@ -0,0 +1,61 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/imx/fsl,imx8mp-hdmi-pai.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Freescale i.MX8MP HDMI Parallel Audio Interface
> +
> +maintainers:
> +  - Shengjiu Wang <shengjiu.wang at nxp.com>
> +
> +description:
> +  The HDMI TX Parallel Audio Interface (HTX_PAI) is a digital module that acts as the
> +  bridge between the Audio Subsystem to the HDMI TX Controller.
> +
> +properties:

In i.MX8MP TRM, HTX_PAI block diagram mentions an APB interface.
Does it mean a clock is needed?

> +  compatible:
> +    const: fsl,imx8mp-hdmi-pai
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  power-domains:
> +    maxItems: 1
> +
> +  port:
> +    $ref: /schemas/graph.yaml#/properties/port
> +    description: Output to the HDMI TX controller.
> +    unevaluatedProperties: false

Why do you need this line?

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - power-domains
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>

Unused. Drop.

> +    #include <dt-bindings/power/imx8mp-power.h>
> +
> +    hdmi at 32fc4800 {
> +        compatible = "fsl,imx8mp-hdmi-pai";
> +        reg = <0x32fc4800 0x800>;
> +        interrupt-parent = <&irqsteer_hdmi>;
> +        interrupts = <14>;
> +        power-domains = <&hdmi_blk_ctrl IMX8MP_HDMIBLK_PD_PAI>;
> +
> +        port {
> +

Drop this blank line.

> +            pai_to_hdmi_tx: endpoint {
> +                remote-endpoint = <&hdmi_tx_from_pai>;
> +            };
> +        };
> +    };

-- 
Regards,
Liu Ying