[v6] Enable Remote GPIO over RPMSG on i.MX Platform

[PATCH v6 1/5] dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support

Posted by Shenwei Wang 1 month, 3 weeks ago

Remote processors may announce multiple devices (e.g., I2C, GPIO) over
an RPMSG channel. These devices 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  | 49 +++++++++++++++++
 .../bindings/remoteproc/fsl,imx-rproc.yaml    | 54 +++++++++++++++++++
 2 files changed, 103 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..b3e1a5dbf731
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
@@ -0,0 +1,49 @@
+# 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 GPIO driver over RPMSG
+
+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.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - fsl,rpmsg-gpio
+          - const: rpmsg-gpio
+      - const: rpmsg-gpio
+
+  reg:
+    maxItems: 1
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-controller: true
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - "#gpio-cells"
+  - "#interrupt-cells"
+
+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 57d75acb0b5e..fd8e5a61a459 100644
--- a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
+++ b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
@@ -84,6 +84,33 @@ properties:
       This property is to specify the resource id of the remote processor in SoC
       which supports SCFW
 
+  rpmsg:
+    type: object
+    additionalProperties: false
+    description:
+      Present a group of RPMSG channel devices.
+
+    properties:
+      rpmsg-io-channel:
+        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
 
@@ -146,5 +173,32 @@ examples:
                 &mu 3 1>;
       memory-region = <&vdev0buffer>, <&vdev0vring0>, <&vdev0vring1>, <&rsc_table>;
       syscon = <&src>;
+
+      rpmsg {
+        rpmsg-io-channel {
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          gpio@0 {
+            compatible = "rpmsg-gpio";
+            reg = <0>;
+            gpio-controller;
+            #gpio-cells = <2>;
+            #interrupt-cells = <2>;
+            interrupt-controller;
+            interrupt-parent = <&rpmsg_gpioa>;
+          };
+
+          gpio@1 {
+            compatible = "rpmsg-gpio";
+            reg = <1>;
+            gpio-controller;
+            #gpio-cells = <2>;
+            #interrupt-cells = <2>;
+            interrupt-controller;
+            interrupt-parent = <&rpmsg_gpiob>;
+          };
+        };
+      };
     };
 ...
-- 
2.43.0

Re: [PATCH v6 1/5] dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support

Posted by Arnaud POULIQUEN 1 month, 2 weeks ago

Hello Shenwei,


On 12/12/25 20:43, Shenwei Wang wrote:
> Remote processors may announce multiple devices (e.g., I2C, GPIO) over
> an RPMSG channel. These devices 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  | 49 +++++++++++++++++
>   .../bindings/remoteproc/fsl,imx-rproc.yaml    | 54 +++++++++++++++++++
>   2 files changed, 103 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..b3e1a5dbf731
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
> @@ -0,0 +1,49 @@
> +# 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 GPIO driver over RPMSG
> +
> +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.
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - fsl,rpmsg-gpio
> +          - const: rpmsg-gpio
> +      - const: rpmsg-gpio
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#gpio-cells":
> +    const: 2
> +
> +  gpio-controller: true
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 2
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#gpio-cells"
> +  - "#interrupt-cells"
> +
> +allOf:
> +  - $ref: /schemas/gpio/gpio.yaml#
> +
> +unevaluatedProperties: false
> diff --git a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> index 57d75acb0b5e..fd8e5a61a459 100644
> --- a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> @@ -84,6 +84,33 @@ properties:
>         This property is to specify the resource id of the remote processor in SoC
>         which supports SCFW
>   
> +  rpmsg:
> +    type: object
> +    additionalProperties: false
> +    description:
> +      Present a group of RPMSG channel devices.
> +
> +    properties:
> +      rpmsg-io-channel:
> +        type: object
> +        additionalProperties: false
> +        properties:
> +          '#address-cells':
> +            const: 1
> +
> +          '#size-cells':
> +            const: 0
> +
> +        patternProperties:
> +          "gpio@[0-9a-f]+$":
> +            type: object
> +            $ref: /schemas/gpio/gpio-rpmsg.yaml#
> +            unevaluatedProperties: false
> +
> +        required:
> +          - '#address-cells'
> +          - '#size-cells'
> +
>   required:
>     - compatible
>   
> @@ -146,5 +173,32 @@ examples:
>                   &mu 3 1>;
>         memory-region = <&vdev0buffer>, <&vdev0vring0>, <&vdev0vring1>, <&rsc_table>;
>         syscon = <&src>;
> +
> +      rpmsg {
> +        rpmsg-io-channel {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          gpio@0 {
> +            compatible = "rpmsg-gpio";
> +            reg = <0>;
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +            #interrupt-cells = <2>;
> +            interrupt-controller;
> +            interrupt-parent = <&rpmsg_gpioa>;


"rpmsg_gpioa" seems not defined, or I missed something?

Regards,
Arnaud

> +          };
> +
> +          gpio@1 {
> +            compatible = "rpmsg-gpio";
> +            reg = <1>;
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +            #interrupt-cells = <2>;
> +            interrupt-controller;
> +            interrupt-parent = <&rpmsg_gpiob>;
> +          };
> +        };
> +      };
>       };
>   ...

Re: [PATCH v6 1/5] dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support

Posted by Rob Herring 1 month, 3 weeks ago

On Fri, Dec 12, 2025 at 01:43:37PM -0600, Shenwei Wang wrote:
> Remote processors may announce multiple devices (e.g., I2C, GPIO) over
> an RPMSG channel. 

Which channel does that happen on?

> These devices 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  | 49 +++++++++++++++++
>  .../bindings/remoteproc/fsl,imx-rproc.yaml    | 54 +++++++++++++++++++
>  2 files changed, 103 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..b3e1a5dbf731
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
> @@ -0,0 +1,49 @@
> +# 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 GPIO driver over RPMSG

The driver doesn't go over RPMSG. It's a GPIO provider or protocol.

> +
> +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.

Got a reference to where any of this is defined?

> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - fsl,rpmsg-gpio
> +          - const: rpmsg-gpio
> +      - const: rpmsg-gpio
> +
> +  reg:
> +    maxItems: 1

I still don't understand how 'reg' is determined. You may have explained 
it previously, but *this* patch needs to make me understand.

> +
> +  "#gpio-cells":
> +    const: 2
> +
> +  gpio-controller: true
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 2
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#gpio-cells"
> +  - "#interrupt-cells"
> +
> +allOf:
> +  - $ref: /schemas/gpio/gpio.yaml#
> +
> +unevaluatedProperties: false
> diff --git a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> index 57d75acb0b5e..fd8e5a61a459 100644
> --- a/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml
> @@ -84,6 +84,33 @@ properties:
>        This property is to specify the resource id of the remote processor in SoC
>        which supports SCFW
>  
> +  rpmsg:
> +    type: object
> +    additionalProperties: false
> +    description:
> +      Present a group of RPMSG channel devices.
> +
> +    properties:
> +      rpmsg-io-channel:
> +        type: object
> +        additionalProperties: false
> +        properties:
> +          '#address-cells':
> +            const: 1
> +
> +          '#size-cells':
> +            const: 0
> +
> +        patternProperties:
> +          "gpio@[0-9a-f]+$":
> +            type: object
> +            $ref: /schemas/gpio/gpio-rpmsg.yaml#
> +            unevaluatedProperties: false
> +
> +        required:
> +          - '#address-cells'
> +          - '#size-cells'
> +
>  required:
>    - compatible
>  
> @@ -146,5 +173,32 @@ examples:
>                  &mu 3 1>;
>        memory-region = <&vdev0buffer>, <&vdev0vring0>, <&vdev0vring1>, <&rsc_table>;
>        syscon = <&src>;
> +
> +      rpmsg {

What's the purpose of this node? Is it going to contain things other 
than "rpmsg io channels"?

> +        rpmsg-io-channel {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          gpio@0 {
> +            compatible = "rpmsg-gpio";
> +            reg = <0>;
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +            #interrupt-cells = <2>;
> +            interrupt-controller;
> +            interrupt-parent = <&rpmsg_gpioa>;
> +          };
> +
> +          gpio@1 {
> +            compatible = "rpmsg-gpio";
> +            reg = <1>;
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +            #interrupt-cells = <2>;
> +            interrupt-controller;
> +            interrupt-parent = <&rpmsg_gpiob>;
> +          };
> +        };
> +      };
>      };
>  ...
> -- 
> 2.43.0
>

[PATCH v6 1/5] dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support
[PATCH v6 2/5] remoteproc: imx_rproc: Populate devices under "rpmsg" subnode
[PATCH v6 3/5] docs: driver-api: gpio: generic gpio driver over rpmsg bus
[PATCH v6 4/5] gpio: rpmsg: add generic rpmsg GPIO driver
[PATCH v6 5/5] arm64: dts: imx8ulp: Add rpmsg node under imx_rproc