[PATCH v6 0/5] Enable Remote GPIO over RPMSG on i.MX Platform

[PATCH v6 0/5] Enable Remote GPIO over RPMSG on i.MX Platform

[Shenwei Wang]

Support the remote devices on the remote processor via the RPMSG bus on
i.MX platform.

Changes in v6:
 - make the driver more generic with the actions below:
     rename the driver file to gpio-rpmsg.c
     remove the imx related info in the function and variable names
     rename the imx_rpmsg.h to rpdev_info.h
     create a gpio-rpmsg.yaml and refer it in imx_rproc.yaml
 - update the gpio-rpmsg.rst according to the feedback from Andrew and
   move the source file to driver-api/gpio
 - fix the bug reported by Zhongqiu Han
 - remove the I2C related info

Changes in v5:
 - move the gpio-rpmsg.rst from admin-guide to staging directory after
   discussion with Randy Dunlap.
 - add include files with some code improvements per Bartosz's comments.

Changes in v4:
 - add a documentation to describe the transport protocol per Andrew's
   comments.
 - add a new handler to get the gpio direction.

Changes in v3:
 - fix various format issue and return value check per Peng 's review
   comments.
 - add the logic to also populate the subnodes which are not in the
   device map per Arnaud's request. (in imx_rproc.c)
 - update the yaml per Frank's review comments.

Changes in v2:
 - re-implemented the gpio driver per Linus Walleij's feedback by using
   GPIOLIB_IRQCHIP helper library.
 - fix various format issue per Mathieu/Peng 's review comments.
 - update the yaml doc per Rob's feedback

Shenwei Wang (5):
  dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support
  remoteproc: imx_rproc: Populate devices under "rpmsg" subnode
  docs: driver-api: gpio: generic gpio driver over rpmsg bus
  gpio: rpmsg: add generic rpmsg GPIO driver
  arm64: dts: imx8ulp: Add rpmsg node under imx_rproc

 .../devicetree/bindings/gpio/gpio-rpmsg.yaml  |  49 ++
 .../bindings/remoteproc/fsl,imx-rproc.yaml    |  54 ++
 Documentation/driver-api/gpio/gpio-rpmsg.rst  | 232 +++++++++
 Documentation/driver-api/gpio/index.rst       |   1 +
 arch/arm64/boot/dts/freescale/imx8ulp.dtsi    |  27 +
 drivers/gpio/Kconfig                          |  16 +
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-rpmsg.c                     | 490 ++++++++++++++++++
 drivers/remoteproc/imx_rproc.c                | 143 +++++
 include/linux/rpmsg/rpdev_info.h              |  33 ++
 10 files changed, 1046 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
 create mode 100644 Documentation/driver-api/gpio/gpio-rpmsg.rst
 create mode 100644 drivers/gpio/gpio-rpmsg.c
 create mode 100644 include/linux/rpmsg/rpdev_info.h

--
2.43.0

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

[Shenwei Wang]

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

[PATCH v6 2/5] remoteproc: imx_rproc: Populate devices under "rpmsg" subnode

[Shenwei Wang]

Register the RPMsg channel driver and populate remote devices defined
under the "rpmsg" subnode upon receiving their notification messages.

The following illustrates the expected DTS layout structure:

	cm33: remoteproc-cm33 {
		compatible = "fsl,imx8ulp-cm33";

		rpmsg {
			rpmsg-io-channel {
				gpio@0 {
					compatible = "fsl,imx-rpmsg-gpio";
					reg = <0>;
				};

				gpio@1 {
					compatible = "fsl,imx-rpmsg-gpio";
					reg = <1>;
				};

				...
			};

			...
		};
	};

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 drivers/remoteproc/imx_rproc.c   | 143 +++++++++++++++++++++++++++++++
 include/linux/rpmsg/rpdev_info.h |  33 +++++++
 2 files changed, 176 insertions(+)
 create mode 100644 include/linux/rpmsg/rpdev_info.h

diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 33f21ab24c92..65ee16fd66d1 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -15,6 +15,8 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
@@ -22,6 +24,8 @@
 #include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/remoteproc.h>
+#include <linux/rpmsg.h>
+#include <linux/rpmsg/rpdev_info.h>
 #include <linux/workqueue.h>
 
 #include "imx_rproc.h"
@@ -1016,6 +1020,141 @@ static void imx_rproc_destroy_workqueue(void *data)
 	destroy_workqueue(workqueue);
 }
 
+struct imx_rpmsg_driver {
+	struct rpmsg_driver rpdrv;
+	const char *compat;
+	void *driver_data;
+};
+
+static const char *channel_device_map[][2] = {
+	{"rpmsg-io-channel", "rpmsg-gpio"},
+};
+
+static int imx_rpmsg_endpoint_cb(struct rpmsg_device *rpdev, void *data,
+				 int len, void *priv, u32 src)
+{
+	struct rpdev_platform_info *drvdata;
+
+	drvdata = dev_get_drvdata(&rpdev->dev);
+	if (drvdata && drvdata->rx_callback)
+		return drvdata->rx_callback(rpdev, data, len, priv, src);
+
+	return 0;
+}
+
+static void imx_rpmsg_endpoint_remove(struct rpmsg_device *rpdev)
+{
+	of_platform_depopulate(&rpdev->dev);
+}
+
+static int imx_rpmsg_endpoint_probe(struct rpmsg_device *rpdev)
+{
+	struct rpdev_platform_info *drvdata;
+	struct imx_rpmsg_driver *imx_rpdrv;
+	struct device *dev = &rpdev->dev;
+	struct of_dev_auxdata *auxdata;
+	struct rpmsg_driver *rpdrv;
+
+	rpdrv = container_of(dev->driver, struct rpmsg_driver, drv);
+	imx_rpdrv = container_of(rpdrv, struct imx_rpmsg_driver, rpdrv);
+
+	if (!imx_rpdrv->driver_data)
+		return -EINVAL;
+
+	drvdata = devm_kmemdup(dev, imx_rpdrv->driver_data, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	auxdata = devm_kzalloc(dev, sizeof(*auxdata) * 2, GFP_KERNEL);
+	if (!auxdata)
+		return -ENOMEM;
+
+	drvdata->rpdev = rpdev;
+	auxdata[0].compatible = devm_kstrdup(dev, imx_rpdrv->compat, GFP_KERNEL);
+	auxdata[0].platform_data = drvdata;
+	dev_set_drvdata(dev, drvdata);
+
+	of_platform_populate(drvdata->channel_node, NULL, auxdata, dev);
+
+	return 0;
+}
+
+static const char *imx_of_rpmsg_is_in_map(const char *name)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(channel_device_map); i++) {
+		if (strcmp(name, channel_device_map[i][0]) == 0)
+			return channel_device_map[i][1];
+	}
+
+	return NULL;
+}
+
+static int imx_of_rpmsg_register_rpdriver(struct device_node *channel,
+					  struct device *dev,
+					  const char *name,
+					  const char *compat)
+{
+	struct rpdev_platform_info *driver_data;
+	struct imx_rpmsg_driver *rp_driver;
+	struct rpmsg_device_id *rpdev_id;
+
+	/* rpmsg_device_id is a NULL terminated array */
+	rpdev_id = devm_kzalloc(dev, sizeof(*rpdev_id) * 2, GFP_KERNEL);
+	if (!rpdev_id)
+		return -ENOMEM;
+
+	strscpy(rpdev_id[0].name, name, RPMSG_NAME_SIZE);
+
+	rp_driver = devm_kzalloc(dev, sizeof(*rp_driver), GFP_KERNEL);
+	if (!rp_driver)
+		return -ENOMEM;
+
+	driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
+	if (!driver_data)
+		return -ENOMEM;
+
+	driver_data->rproc_name = dev->of_node->name;
+	driver_data->channel_node = channel;
+
+	rp_driver->rpdrv.drv.name = name;
+	rp_driver->rpdrv.id_table = rpdev_id;
+	rp_driver->rpdrv.probe = imx_rpmsg_endpoint_probe;
+	rp_driver->rpdrv.remove = imx_rpmsg_endpoint_remove;
+	rp_driver->rpdrv.callback = imx_rpmsg_endpoint_cb;
+	rp_driver->driver_data = driver_data;
+	rp_driver->compat = compat;
+
+	register_rpmsg_driver(&rp_driver->rpdrv);
+
+	return 0;
+}
+
+static int rproc_of_rpmsg_node_init(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const char *compat;
+	int ret;
+
+	struct device_node *np __free(device_node) = of_get_child_by_name(dev->of_node, "rpmsg");
+	if (!np)
+		return 0;
+
+	for_each_child_of_node_scoped(np, child) {
+		compat = imx_of_rpmsg_is_in_map(child->name);
+		if (!compat)
+			ret = of_platform_default_populate(child, NULL, dev);
+		else
+			ret = imx_of_rpmsg_register_rpdriver(child, dev, child->name, compat);
+
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int imx_rproc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1114,6 +1253,10 @@ static int imx_rproc_probe(struct platform_device *pdev)
 		goto err_put_pm;
 	}
 
+	ret = rproc_of_rpmsg_node_init(pdev);
+	if (ret < 0)
+		dev_info(dev, "populating 'rpmsg' node failed\n");
+
 	return 0;
 
 err_put_pm:
diff --git a/include/linux/rpmsg/rpdev_info.h b/include/linux/rpmsg/rpdev_info.h
new file mode 100644
index 000000000000..13e020cd028b
--- /dev/null
+++ b/include/linux/rpmsg/rpdev_info.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright 2025 NXP */
+
+/*
+ * @file linux/rpdev_info.h
+ *
+ * @brief Global header file for RPDEV Info
+ *
+ * @ingroup RPMSG
+ */
+#ifndef __LINUX_RPDEV_INFO_H__
+#define __LINUX_RPDEV_INFO_H__
+
+#define MAX_DEV_PER_CHANNEL    10
+
+/**
+ * rpdev_platform_info - store the platform information of rpdev
+ * @rproc_name: the name of the remote proc.
+ * @rpdev: rpmsg channel device
+ * @device_node: pointer to the device node of the rpdev.
+ * @rx_callback: rx callback handler of the rpdev.
+ * @channel_devices: an array of the devices related to the rpdev.
+ */
+struct rpdev_platform_info {
+	const char *rproc_name;
+	struct rpmsg_device *rpdev;
+	struct device_node *channel_node;
+	int (*rx_callback)(struct rpmsg_device *rpdev, void *data,
+			   int len, void *priv, u32 src);
+	void *channel_devices[MAX_DEV_PER_CHANNEL];
+};
+
+#endif /* __LINUX_RPDEV_INFO_H__ */
-- 
2.43.0

[PATCH v6 3/5] docs: driver-api: gpio: generic gpio driver over rpmsg bus

[Shenwei Wang]

Describes the gpio rpmsg transport protocol over the rpmsg bus between
the cores.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 Documentation/driver-api/gpio/gpio-rpmsg.rst | 232 +++++++++++++++++++
 Documentation/driver-api/gpio/index.rst      |   1 +
 2 files changed, 233 insertions(+)
 create mode 100644 Documentation/driver-api/gpio/gpio-rpmsg.rst

diff --git a/Documentation/driver-api/gpio/gpio-rpmsg.rst b/Documentation/driver-api/gpio/gpio-rpmsg.rst
new file mode 100644
index 000000000000..c78d10a9a85c
--- /dev/null
+++ b/Documentation/driver-api/gpio/gpio-rpmsg.rst
@@ -0,0 +1,232 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+GPIO RPMSG Protocol
+===================
+
+The GPIO RPMSG transport protocol is used for communication and interaction
+with GPIO controllers located on remote cores on the RPMSG bus.
+
+Message Format
+--------------
+
+The RPMSG message consists of a 14-byte packet with the following layout:
+
+.. code-block:: none
+
+   +-----+-------+--------+-----+-----+------------+-----+-----+-----+----+
+   |0x00 |0x01   |0x02    |0x03 |0x04 |0x05..0x09  |0x0A |0x0B |0x0C |0x0D|
+   | ID  |vendor |version |type |cmd  |reserved[5] |line |port |  data    |
+   +-----+-------+--------+-----+-----+------------+-----+-----+-----+----+
+
+- **ID (Message Identification Code)**: Always be 0x5. Indicates the GPIO message.
+
+- **Vendor**: Vendor ID number.
+  - 0: Reserved
+  - 1: NXP
+
+- **Version**: Vendor-specific version number (such as software release).
+
+- **Type (Message Type)**: The message type can be one of:
+
+  - 0: GPIO_RPMSG_SETUP
+  - 1: GPIO_RPMSG_REPLY
+  - 2: GPIO_RPMSG_NOTIFY
+
+- **Cmd**: Command code, used for GPIO_RPMSG_SETUP messages.
+
+- **reserved[5]**: Reserved bytes. Should always be 0.
+
+- **line**: The GPIO line index.
+
+- **port**: The GPIO controller index.
+
+- **data**: See details in the command description below.
+
+GPIO Commands
+-------------
+
+Commands are specified in the **Cmd** field for **GPIO_RPMSG_SETUP** (Type=0) messages.
+
+The SETUP message is always sent from Linux to the remote firmware. Each
+SETUP corresponds to a single REPLY message. The GPIO driver should
+serialize messages and determine whether a REPLY message is required. If a
+REPLY message is expected but not received within the specified timeout
+period (currently 1 second in the Linux driver), the driver should return
+-ETIMEOUT.
+
+GPIO_RPMSG_INPUT_INIT (Cmd=0)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+**Request:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 0   | 0   |  0        |line |port | val | wk |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+- **val**: Interrupt trigger type.
+
+  - 0: Interrupt disabled
+  - 1: Rising edge trigger
+  - 2: Falling edge trigger
+  - 3: Both edge trigger
+  - 4: Low level trigger
+  - 5: High level trigger
+
+- **wk**: Wakeup enable.
+
+  The remote system should always aim to stay in a power-efficient state by
+  shutting down or clock-gating the GPIO blocks that aren't in use. Since
+  the remoteproc driver is responsibe for managing the power states of the
+  remote firmware, the GPIO driver does not require to konow the firmware's
+  running states.
+
+  When the wakeup bit is set, the remote firmware should configure the line
+  as a wakeup source. The firmware should send the notification message to
+  Linux after it is woken from the GPIO line.
+
+  - 0: Disable wakeup from GPIO
+  - 1: Enable wakeup from GPIO
+
+**Reply:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 1   | 1   |  0        |line |port | err | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+- **err**: Error code from the remote core.
+
+  - 0: Success
+  - 1: General error (early remote software only returns this unclassified error)
+  - 2: Not supported (A command is not supported by the remote firmware)
+  - 3: Resource not available (The resource is not allocated to the Linux)
+  - 4: Resource busy (The resource is already used)
+  - 5: Parameter error
+
+GPIO_RPMSG_OUTPUT_INIT (Cmd=1)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+**Request:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 0   | 1   |  0        |line |port | val | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+- **val**: Output level.
+
+  - 0: Low
+  - 1: High
+
+**Reply:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 1   | 1   |  0        |line |port | err | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+- **err**: See above for definitions.
+
+GPIO_RPMSG_INPUT_GET (Cmd=2)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+**Request:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 0   | 2   |  0        |line |port | 0   | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+**Reply:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+-----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D |
+   | 5   | 1   | 0   | 1   | 2   |  0        |line |port | err |level|
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+-----+
+
+- **err**: See above for definitions.
+
+- **level**: Input level.
+
+  - 0: Low
+  - 1: High
+
+GPIO_RPMSG_GET_DIRECTION (Cmd=3)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+**Request:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 0   | 3   |  0        |line |port | 0   | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+**Reply:**
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+-----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D |
+   | 5   | 1   | 0   | 1   | 3   |  0        |line |port | err | dir |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+-----+
+
+- **err**: See above for definitions.
+
+- **dir**: Direction.
+
+  - 0: Output
+  - 1: Input
+
+Notification Message
+--------------------
+
+Notifications are sent with **Type=2 (GPIO_RPMSG_NOTIFY)**:
+
+When a GPIO line asserts an interrupt on the remote processor, the firmware
+should immediately mask the corresponding interrupt source and send a
+notification message to the Linux. Upon completion of the interrupt
+handling on the Linux side, the driver should issue a
+**GPIO_RPMSG_INPUT_INIT** command to the firmware to unmask the interrupt.
+
+A Notification message can arrive between a SETUP and its REPLY message,
+and the driver is expected to handle this scenario.
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 2   | 0   |  0        |line |port | 0   | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+- **line**: The GPIO line index.
+- **port**: The GPIO controller index.
+
+The reply message for the notification is optional. The remote firmware can
+implement it to simulate the interrupt acknowledgment behavior.
+
+The notification reply is sent with the byte index 0x4=1.
+
+.. code-block:: none
+
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+   |0x00 |0x01 |0x02 |0x03 |0x04 |0x05..0x09 |0x0A |0x0B |0x0C |0x0D|
+   | 5   | 1   | 0   | 2   | 1   |  0        |line |port | 0   | 0  |
+   +-----+-----+-----+-----+-----+-----------+-----+-----+-----+----+
+
+- **line**: The GPIO line index.
+- **port**: The GPIO controller index.
diff --git a/Documentation/driver-api/gpio/index.rst b/Documentation/driver-api/gpio/index.rst
index bee58f709b9a..e5eb1f82f01f 100644
--- a/Documentation/driver-api/gpio/index.rst
+++ b/Documentation/driver-api/gpio/index.rst
@@ -16,6 +16,7 @@ Contents:
    drivers-on-gpio
    bt8xxgpio
    pca953x
+   gpio-rpmsg
 
 Core
 ====
-- 
2.43.0

[PATCH v6 4/5] gpio: rpmsg: add generic rpmsg GPIO driver

[Shenwei Wang]

On an AMP platform, the system may include two processors:
	- An MCU running an RTOS
	- An MPU running Linux

These processors communicate via the RPMSG protocol.
The driver implements the standard GPIO interface, allowing
the Linux side to control GPIO controllers which reside in
the remote processor via RPMSG protocol.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 drivers/gpio/Kconfig      |  16 ++
 drivers/gpio/Makefile     |   1 +
 drivers/gpio/gpio-rpmsg.c | 490 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 507 insertions(+)
 create mode 100644 drivers/gpio/gpio-rpmsg.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index bd185482a7fd..7a72b5dbd4a9 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1883,6 +1883,22 @@ config GPIO_SODAVILLE
 
 endmenu
 
+menu "RPMSG GPIO drivers"
+	depends on RPMSG
+
+config GPIO_RPMSG
+	tristate "Generic RPMSG GPIO support"
+	select GPIOLIB_IRQCHIP
+	default REMOTEPROC
+	help
+	  Say yes here to support the generic GPIO functions over the RPMSG
+	  bus. Currently supported devices: i.MX7ULP, i.MX8ULP, i.MX8x,and
+	  i.MX9x.
+
+	  If unsure, say N.
+
+endmenu
+
 menu "SPI GPIO expanders"
 	depends on SPI_MASTER
 
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 2421a8fd3733..b1373ec274c8 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -156,6 +156,7 @@ obj-$(CONFIG_GPIO_RDC321X)		+= gpio-rdc321x.o
 obj-$(CONFIG_GPIO_REALTEK_OTTO)		+= gpio-realtek-otto.o
 obj-$(CONFIG_GPIO_REG)			+= gpio-reg.o
 obj-$(CONFIG_GPIO_ROCKCHIP)	+= gpio-rockchip.o
+obj-$(CONFIG_GPIO_RPMSG)		+= gpio-rpmsg.o
 obj-$(CONFIG_GPIO_RTD)			+= gpio-rtd.o
 obj-$(CONFIG_ARCH_SA1100)		+= gpio-sa1100.o
 obj-$(CONFIG_GPIO_SAMA5D2_PIOBU)	+= gpio-sama5d2-piobu.o
diff --git a/drivers/gpio/gpio-rpmsg.c b/drivers/gpio/gpio-rpmsg.c
new file mode 100644
index 000000000000..cf10e2958374
--- /dev/null
+++ b/drivers/gpio/gpio-rpmsg.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 NXP
+ *
+ * The driver exports a standard gpiochip interface to control
+ * the GPIO controllers via RPMSG on a remote processor.
+ */
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/init.h>
+#include <linux/irqdomain.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rpmsg.h>
+#include <linux/rpmsg/rpdev_info.h>
+
+#define RPMSG_GPIO_ID		5
+#define RPMSG_VENDOR		1
+#define RPMSG_VERSION		0
+
+#define GPIOS_PER_PORT		32
+#define RPMSG_TIMEOUT		1000
+
+enum gpio_input_trigger_type {
+	GPIO_RPMSG_TRI_IGNORE,
+	GPIO_RPMSG_TRI_RISING,
+	GPIO_RPMSG_TRI_FALLING,
+	GPIO_RPMSG_TRI_BOTH_EDGE,
+	GPIO_RPMSG_TRI_LOW_LEVEL,
+	GPIO_RPMSG_TRI_HIGH_LEVEL,
+};
+
+enum gpio_rpmsg_header_type {
+	GPIO_RPMSG_SETUP,
+	GPIO_RPMSG_REPLY,
+	GPIO_RPMSG_NOTIFY,
+};
+
+enum gpio_rpmsg_header_cmd {
+	GPIO_RPMSG_INPUT_INIT,
+	GPIO_RPMSG_OUTPUT_INIT,
+	GPIO_RPMSG_INPUT_GET,
+	GPIO_RPMSG_DIRECTION_GET,
+};
+
+struct gpio_rpmsg_head {
+	u8 id;		/* Message ID Code */
+	u8 vendor;	/* Vendor ID number */
+	u8 version;	/* Vendor-specific version number */
+	u8 type;	/* Message type */
+	u8 cmd;		/* Command code */
+	u8 reserved[5];
+} __packed;
+
+struct gpio_rpmsg_packet {
+	struct gpio_rpmsg_head header;
+	u8 pin_idx;
+	u8 port_idx;
+	union {
+		u8 event;
+		u8 retcode;
+		u8 value;
+	} out;
+	union {
+		u8 wakeup;
+		u8 value;
+	} in;
+} __packed __aligned(8);
+
+struct gpio_rpmsg_pin {
+	u8 irq_shutdown;
+	u8 irq_unmask;
+	u8 irq_mask;
+	u32 irq_wake_enable;
+	u32 irq_type;
+	struct gpio_rpmsg_packet msg;
+};
+
+struct gpio_rpmsg_info {
+	struct rpmsg_device *rpdev;
+	struct gpio_rpmsg_packet *notify_msg;
+	struct gpio_rpmsg_packet *reply_msg;
+	struct completion cmd_complete;
+	struct mutex lock;
+	void **port_store;
+};
+
+struct rpmsg_gpio_port {
+	struct gpio_chip gc;
+	struct gpio_rpmsg_pin gpio_pins[GPIOS_PER_PORT];
+	struct gpio_rpmsg_info info;
+	int idx;
+};
+
+static int gpio_send_message(struct rpmsg_gpio_port *port,
+			     struct gpio_rpmsg_packet *msg,
+			     bool sync)
+{
+	struct gpio_rpmsg_info *info = &port->info;
+	int err;
+
+	if (!info->rpdev) {
+		pr_err("rpmsg channel doesn't exist, is remote core ready?\n");
+		return -EINVAL;
+	}
+
+	reinit_completion(&info->cmd_complete);
+	err = rpmsg_send(info->rpdev->ept, (void *)msg,
+			 sizeof(struct gpio_rpmsg_packet));
+	if (err) {
+		dev_err(&info->rpdev->dev, "rpmsg_send failed: %d\n", err);
+		return err;
+	}
+
+	if (sync) {
+		err = wait_for_completion_timeout(&info->cmd_complete,
+						  msecs_to_jiffies(RPMSG_TIMEOUT));
+		if (!err) {
+			dev_err(&info->rpdev->dev, "rpmsg_send timeout!\n");
+			return -ETIMEDOUT;
+		}
+
+		if (info->reply_msg->out.retcode != 0) {
+			dev_err(&info->rpdev->dev, "remote core replies an error: %d!\n",
+				info->reply_msg->out.retcode);
+			return -EINVAL;
+		}
+
+		/* copy the reply message */
+		memcpy(&port->gpio_pins[info->reply_msg->pin_idx].msg,
+		       info->reply_msg, sizeof(*info->reply_msg));
+	}
+
+	return 0;
+}
+
+static struct gpio_rpmsg_packet *gpio_setup_msg_header(struct rpmsg_gpio_port *port,
+						       unsigned int offset,
+						       u8 cmd)
+{
+	struct gpio_rpmsg_packet *msg = &port->gpio_pins[offset].msg;
+
+	memset(msg, 0, sizeof(struct gpio_rpmsg_packet));
+	msg->header.id = RPMSG_GPIO_ID;
+	msg->header.vendor = RPMSG_VENDOR;
+	msg->header.version = RPMSG_VERSION;
+	msg->header.type = GPIO_RPMSG_SETUP;
+	msg->header.cmd = cmd;
+	msg->pin_idx = offset;
+	msg->port_idx = port->idx;
+
+	return msg;
+};
+
+static int rpmsg_gpio_get(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct rpmsg_gpio_port *port = gpiochip_get_data(gc);
+	struct gpio_rpmsg_packet *msg = NULL;
+	int ret;
+
+	guard(mutex)(&port->info.lock);
+
+	msg = gpio_setup_msg_header(port, gpio, GPIO_RPMSG_INPUT_GET);
+
+	ret = gpio_send_message(port, msg, true);
+	if (!ret)
+		ret = !!port->gpio_pins[gpio].msg.in.value;
+
+	return ret;
+}
+
+static int rpmsg_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct rpmsg_gpio_port *port = gpiochip_get_data(gc);
+	struct gpio_rpmsg_packet *msg = NULL;
+	int ret;
+
+	guard(mutex)(&port->info.lock);
+
+	msg = gpio_setup_msg_header(port, gpio, GPIO_RPMSG_DIRECTION_GET);
+
+	ret = gpio_send_message(port, msg, true);
+	if (!ret)
+		ret = !!port->gpio_pins[gpio].msg.in.value;
+
+	return ret;
+}
+
+static int rpmsg_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct rpmsg_gpio_port *port = gpiochip_get_data(gc);
+	struct gpio_rpmsg_packet *msg = NULL;
+
+	guard(mutex)(&port->info.lock);
+
+	msg = gpio_setup_msg_header(port, gpio, GPIO_RPMSG_INPUT_INIT);
+
+	return gpio_send_message(port, msg, true);
+}
+
+static int rpmsg_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct rpmsg_gpio_port *port = gpiochip_get_data(gc);
+	struct gpio_rpmsg_packet *msg = NULL;
+
+	guard(mutex)(&port->info.lock);
+
+	msg = gpio_setup_msg_header(port, gpio, GPIO_RPMSG_OUTPUT_INIT);
+	msg->out.value = val;
+
+	return gpio_send_message(port, msg, true);
+}
+
+static int rpmsg_gpio_direction_output(struct gpio_chip *gc,
+				       unsigned int gpio,
+				       int val)
+{
+
+	return rpmsg_gpio_set(gc, gpio, val);
+}
+
+static int gpio_rpmsg_irq_set_type(struct irq_data *d, u32 type)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+	u32 gpio_idx = d->hwirq;
+	int edge = 0;
+	int ret = 0;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+		edge = GPIO_RPMSG_TRI_RISING;
+		irq_set_handler_locked(d, handle_simple_irq);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		edge = GPIO_RPMSG_TRI_FALLING;
+		irq_set_handler_locked(d, handle_simple_irq);
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		edge = GPIO_RPMSG_TRI_BOTH_EDGE;
+		irq_set_handler_locked(d, handle_simple_irq);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		edge = GPIO_RPMSG_TRI_LOW_LEVEL;
+		irq_set_handler_locked(d, handle_level_irq);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		edge = GPIO_RPMSG_TRI_HIGH_LEVEL;
+		irq_set_handler_locked(d, handle_level_irq);
+		break;
+	default:
+		ret = -EINVAL;
+		irq_set_handler_locked(d, handle_bad_irq);
+		break;
+	}
+
+	port->gpio_pins[gpio_idx].irq_type = edge;
+
+	return ret;
+}
+
+static int gpio_rpmsg_irq_set_wake(struct irq_data *d, u32 enable)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+	u32 gpio_idx = d->hwirq;
+
+	port->gpio_pins[gpio_idx].irq_wake_enable = enable;
+
+	return 0;
+}
+
+/*
+ * This function will be called at:
+ *  - one interrupt setup.
+ *  - the end of one interrupt happened
+ * The gpio over rpmsg driver will not write the real register, so save
+ * all infos before this function and then send all infos to M core in this
+ * step.
+ */
+static void gpio_rpmsg_unmask_irq(struct irq_data *d)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+	u32 gpio_idx = d->hwirq;
+
+	port->gpio_pins[gpio_idx].irq_unmask = 1;
+}
+
+static void gpio_rpmsg_mask_irq(struct irq_data *d)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+	u32 gpio_idx = d->hwirq;
+	/*
+	 * No need to implement the callback at A core side.
+	 * M core will mask interrupt after a interrupt occurred, and then
+	 * sends a notify to A core.
+	 * After A core dealt with the notify, A core will send a rpmsg to
+	 * M core to unmask this interrupt again.
+	 */
+	port->gpio_pins[gpio_idx].irq_mask = 1;
+}
+
+static void gpio_rpmsg_irq_shutdown(struct irq_data *d)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+	u32 gpio_idx = d->hwirq;
+
+	port->gpio_pins[gpio_idx].irq_shutdown = 1;
+}
+
+static void gpio_rpmsg_irq_bus_lock(struct irq_data *d)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+
+	mutex_lock(&port->info.lock);
+}
+
+static void gpio_rpmsg_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct rpmsg_gpio_port *port = irq_data_get_irq_chip_data(d);
+	struct gpio_rpmsg_packet *msg = NULL;
+	u32 gpio_idx = d->hwirq;
+
+	if (!port)
+		return;
+
+	/*
+	 * For mask irq, do nothing here.
+	 * M core will mask interrupt after a interrupt occurred, and then
+	 * sends a notify to A core.
+	 * After A core dealt with the notify, A core will send a rpmsg to
+	 * M core to unmask this interrupt again.
+	 */
+
+	if (port->gpio_pins[gpio_idx].irq_mask && !port->gpio_pins[gpio_idx].irq_unmask) {
+		port->gpio_pins[gpio_idx].irq_mask = 0;
+		mutex_unlock(&port->info.lock);
+		return;
+	}
+
+	msg = gpio_setup_msg_header(port, gpio_idx, GPIO_RPMSG_INPUT_INIT);
+
+	if (port->gpio_pins[gpio_idx].irq_shutdown) {
+		msg->out.event = GPIO_RPMSG_TRI_IGNORE;
+		msg->in.wakeup = 0;
+		port->gpio_pins[gpio_idx].irq_shutdown = 0;
+	} else {
+		 /* if not set irq type, then use low level as trigger type */
+		msg->out.event = port->gpio_pins[gpio_idx].irq_type;
+		if (!msg->out.event)
+			msg->out.event = GPIO_RPMSG_TRI_LOW_LEVEL;
+		if (port->gpio_pins[gpio_idx].irq_unmask) {
+			msg->in.wakeup = 0;
+			port->gpio_pins[gpio_idx].irq_unmask = 0;
+		} else /* irq set wake */
+			msg->in.wakeup = port->gpio_pins[gpio_idx].irq_wake_enable;
+	}
+
+	gpio_send_message(port, msg, false);
+	mutex_unlock(&port->info.lock);
+}
+
+static const struct irq_chip gpio_rpmsg_irq_chip = {
+	.irq_mask = gpio_rpmsg_mask_irq,
+	.irq_unmask = gpio_rpmsg_unmask_irq,
+	.irq_set_wake = gpio_rpmsg_irq_set_wake,
+	.irq_set_type = gpio_rpmsg_irq_set_type,
+	.irq_shutdown = gpio_rpmsg_irq_shutdown,
+	.irq_bus_lock = gpio_rpmsg_irq_bus_lock,
+	.irq_bus_sync_unlock = gpio_rpmsg_irq_bus_sync_unlock,
+	.flags = IRQCHIP_IMMUTABLE,
+};
+
+static int rpmsg_gpio_callback(struct rpmsg_device *rpdev,
+			       void *data, int len, void *priv, u32 src)
+{
+	struct gpio_rpmsg_packet *msg = (struct gpio_rpmsg_packet *)data;
+	struct rpmsg_gpio_port *port = NULL;
+	struct rpdev_platform_info *drvdata;
+
+	drvdata = dev_get_drvdata(&rpdev->dev);
+	if (msg)
+		port = drvdata->channel_devices[msg->port_idx];
+
+	if (!port)
+		return -ENODEV;
+
+	if (msg->header.type == GPIO_RPMSG_REPLY) {
+		port->info.reply_msg = msg;
+		complete(&port->info.cmd_complete);
+	} else if (msg->header.type == GPIO_RPMSG_NOTIFY) {
+		port->info.notify_msg = msg;
+		generic_handle_domain_irq_safe(port->gc.irq.domain, msg->pin_idx);
+	} else
+		dev_err(&rpdev->dev, "wrong command type!\n");
+
+	return 0;
+}
+
+static void rpmsg_gpio_remove_action(void *data)
+{
+	struct rpmsg_gpio_port *port = data;
+
+	port->info.port_store[port->idx] = NULL;
+}
+
+static int rpmsg_gpio_probe(struct platform_device *pdev)
+{
+	struct rpdev_platform_info *pltdata = pdev->dev.platform_data;
+	struct rpmsg_gpio_port *port;
+	struct gpio_irq_chip *girq;
+	struct gpio_chip *gc;
+	int ret;
+
+	if (!pltdata)
+		return -EPROBE_DEFER;
+
+	port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	ret = device_property_read_u32(&pdev->dev, "reg", &port->idx);
+	if (ret)
+		return ret;
+
+	if (port->idx > MAX_DEV_PER_CHANNEL)
+		return -EINVAL;
+
+	ret = devm_mutex_init(&pdev->dev, &port->info.lock);
+	if (ret)
+		return ret;
+
+	init_completion(&port->info.cmd_complete);
+	port->info.rpdev = pltdata->rpdev;
+	port->info.port_store = pltdata->channel_devices;
+	port->info.port_store[port->idx] = port;
+	if (!pltdata->rx_callback)
+		pltdata->rx_callback = rpmsg_gpio_callback;
+
+	gc = &port->gc;
+	gc->owner = THIS_MODULE;
+	gc->parent = &pdev->dev;
+	gc->label = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s-gpio%d",
+				   pltdata->rproc_name, port->idx);
+	gc->ngpio = GPIOS_PER_PORT;
+	gc->base = -1;
+
+	gc->direction_input = rpmsg_gpio_direction_input;
+	gc->direction_output = rpmsg_gpio_direction_output;
+	gc->get_direction = rpmsg_gpio_get_direction;
+	gc->get = rpmsg_gpio_get;
+	gc->set = rpmsg_gpio_set;
+
+	platform_set_drvdata(pdev, port);
+	girq = &gc->irq;
+	gpio_irq_chip_set_chip(girq, &gpio_rpmsg_irq_chip);
+	girq->parent_handler = NULL;
+	girq->num_parents = 0;
+	girq->parents = NULL;
+	girq->chip->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s-gpio%d",
+					  pltdata->rproc_name, port->idx);
+
+	ret = devm_add_action_or_reset(&pdev->dev, rpmsg_gpio_remove_action, port);
+	if (ret)
+		return ret;
+
+	return devm_gpiochip_add_data(&pdev->dev, gc, port);
+}
+
+static const struct of_device_id rpmsg_gpio_dt_ids[] = {
+	{ .compatible = "rpmsg-gpio" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver rpmsg_gpio_driver = {
+	.driver	= {
+		.name = "gpio-rpmsg",
+		.of_match_table = rpmsg_gpio_dt_ids,
+	},
+	.probe = rpmsg_gpio_probe,
+};
+
+module_platform_driver(rpmsg_gpio_driver);
+
+MODULE_AUTHOR("Shenwei Wang <shenwei.wang@nxp.com>");
+MODULE_DESCRIPTION("generic rpmsg gpio driver");
+MODULE_LICENSE("GPL");
-- 
2.43.0

[PATCH v6 5/5] arm64: dts: imx8ulp: Add rpmsg node under imx_rproc

[Shenwei Wang]

Add the RPMSG bus node along with its GPIO subnodes to the device
tree.

Enable remote device communication and GPIO control via RPMSG on
the i.MX platform.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 arch/arm64/boot/dts/freescale/imx8ulp.dtsi | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8ulp.dtsi b/arch/arm64/boot/dts/freescale/imx8ulp.dtsi
index 13b01f3aa2a4..93846435c6c1 100644
--- a/arch/arm64/boot/dts/freescale/imx8ulp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8ulp.dtsi
@@ -191,6 +191,33 @@ scmi_sensor: protocol@15 {
 	cm33: remoteproc-cm33 {
 		compatible = "fsl,imx8ulp-cm33";
 		status = "disabled";
+
+		rpmsg {
+			rpmsg-io-channel {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				rpmsg_gpioa: gpio@0 {
+					compatible = "rpmsg-gpio";
+					reg = <0>;
+					gpio-controller;
+					#gpio-cells = <2>;
+					#interrupt-cells = <2>;
+					interrupt-controller;
+					interrupt-parent = <&rpmsg_gpioa>;
+				};
+
+				rpmsg_gpiob: gpio@1 {
+					compatible = "rpmsg-gpio";
+					reg = <1>;
+					gpio-controller;
+					#gpio-cells = <2>;
+					#interrupt-cells = <2>;
+					interrupt-controller;
+					interrupt-parent = <&rpmsg_gpiob>;
+				};
+			};
+		};
 	};
 
 	soc: soc@0 {
-- 
2.43.0