Re: [PATCH v16 2/5] dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support

[Conor Dooley <conor@kernel.org>]

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On Wed, Sep 23, 2026 at 01:42:29PM -0500, Shenwei Wang wrote:
> From: Shenwei Wang <shenwei.wang@nxp.com>
> 
> Remote processors may announce multiple GPIO controllers over an RPMSG
> channel. These GPIO controllers may require corresponding device tree
> nodes, especially when acting as providers, to supply phandles for their
> consumers.
> 
> Define an RPMSG node to work as a container for a group of RPMSG channels
> under the imx_rproc node. Each subnode within "rpmsg" represents an
> individual RPMSG channel. The name of each subnode corresponds to the
> channel name as defined by the remote processor.
> 
> All remote devices associated with a given channel are defined as child
> nodes under the corresponding channel node.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
> ---
>  .../devicetree/bindings/gpio/gpio-rpmsg.yaml  | 55 +++++++++++++++++++
>  .../bindings/remoteproc/fsl,imx-rproc.yaml    | 46 ++++++++++++++++
>  2 files changed, 101 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml b/Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
> new file mode 100644
> index 000000000000..41eb2e149942
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/gpio-rpmsg.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic RPMSG GPIO Controller
> +
> +maintainers:
> +  - Shenwei Wang <shenwei.wang@nxp.com>
> +
> +description:
> +  On an AMP platform, some GPIO controllers are exposed by the remote processor
> +  through the RPMSG bus. The RPMSG GPIO transport protocol defines the packet
> +  structure and communication flow between Linux and the remote firmware. Those
> +  controllers are managed via this transport protocol. For more details of the
> +  protocol, check the document below.
> +  Documentation/driver-api/gpio/gpio-rpmsg.rst
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - fsl,rpmsg-gpio

Is this even used? Your dts patch doesn't have it.

> +          - const: rpmsg-gpio
> +      - const: rpmsg-gpio

Sounds like, if linux are the arbiters of what this protocol is,
"linux," should be used as a vendor prefix.

> +
> +  reg:
> +    description:
> +      The reg property represents the index of the GPIO controllers. Since
> +      the driver manages controllers on a remote system, this index tells
> +      the remote system which controller to operate.
> +    maxItems: 1
> +
> +  "#gpio-cells":
> +    const: 2
> +
> +  gpio-controller: true
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 2
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#gpio-cells"
> +  - gpio-controller
> +
> +allOf:
> +  - $ref: /schemas/gpio/gpio.yaml#
> +
> +unevaluatedProperties: false
> diff --git a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> index c18f71b64889..5c82255b92a5 100644
> --- a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> @@ -88,6 +88,29 @@ properties:
>        This property is to specify the resource id of the remote processor in SoC
>        which supports SCFW
>  
> +  rpmsg:
> +    type: object
> +    additionalProperties: false
> +    description:
> +      Represents the RPMSG bus between Linux and the remote system. Contains
> +      a group of RPMSG devices running on the bus.
> +    properties:
> +      '#address-cells':
> +        const: 1
> +
> +      '#size-cells':
> +        const: 0
> +
> +    patternProperties:
> +      "^gpio@[0-9a-f]+$":
> +        type: object
> +        $ref: /schemas/gpio/gpio-rpmsg.yaml#
> +        unevaluatedProperties: false
> +
> +    required:
> +      - '#address-cells'
> +      - '#size-cells'
> +
>  required:
>    - compatible
>  
> @@ -150,5 +173,28 @@ examples:
>                  &mu 3 1>;
>        memory-region = <&vdev0buffer>, <&vdev0vring0>, <&vdev0vring1>, <&rsc_table>;
>        syscon = <&src>;
> +
> +      rpmsg {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        gpio@0 {
> +          compatible = "rpmsg-gpio";
> +          reg = <0>;
> +          gpio-controller;
> +          #gpio-cells = <2>;
> +          #interrupt-cells = <2>;
> +          interrupt-controller;
> +        };
> +
> +        gpio@1 {
> +          compatible = "rpmsg-gpio";
> +          reg = <1>;
> +          gpio-controller;
> +          #gpio-cells = <2>;
> +          #interrupt-cells = <2>;
> +          interrupt-controller;
> +        };
> +      };
>      };
>  ...
> -- 
> 2.43.0
> 

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