Re: [PATCH v15 2/5] dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support

[Mathieu Poirier]

On Tue, 21 Jul 2026 at 14:48, Shenwei Wang <shenwei.wang@xxxxxxxxxxx> wrote:
>
> From: Shenwei Wang <shenwei.wang@xxxxxxx>
>
> 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@xxxxxxx>
> ---
>  .../devicetree/bindings/gpio/gpio-rpmsg.yaml  | 55 +++++++++++++++++++
>  .../bindings/remoteproc/fsl,imx-rproc.yaml    | 53 ++++++++++++++++++
>  2 files changed, 108 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@xxxxxxx>
> +
> +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
> +          - const: rpmsg-gpio
> +      - const: rpmsg-gpio
> +
> +  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:
> +  - $ref: /schemas/gpio/gpio.yaml#
> +
> +unevaluatedProperties: false
> diff --git a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> index c18f71b64889..b9b559b186af 100644
> --- a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> @@ -88,6 +88,34 @@ properties:
>        This property is to specify the resource id of the remote processor in SoC
>        which supports SCFW
>
> +  rpmsg:
> +    type: object
> +    additionalProperties: false
> +    description:
> +      Represents the RPMSG bus between Linux and the remote system. Contains
> +      a group of RPMSG channel devices running on the bus.
> +
> +    properties:
> +      rpmsg-io:
> +        type: object
> +        additionalProperties: false
> +        properties:
> +          '#address-cells':
> +            const: 1
> +
> +          '#size-cells':
> +            const: 0
> +
> +        patternProperties:
> +          "^gpio@[0-9a-f]+$":
> +            type: object
> +            $ref: /schemas/gpio/gpio-rpmsg.yaml#
> +            unevaluatedProperties: false
> +
> +        required:
> +          - '#address-cells'
> +          - '#size-cells'
> +
>  required:
>    - compatible
>
> @@ -150,5 +178,30 @@ examples:
>                  &mu 3 1>;
>        memory-region = <&vdev0buffer>, <&vdev0vring0>, <&vdev0vring1>, <&rsc_table>;
>        syscon = <&src>;
> +
> +      rpmsg {
> +        rpmsg-io {
> +          #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;
> +          };
> +        };

As I (and Arnaud) have stated before, I don't think this is the best
way to lay out bindings for rpmsg-gpio nodes.  I am currently thinking
about a representation that aligns better with other virtio devices.

> +      };
>      };
>  ...
> --
> 2.43.0
>