gpio-virtio represents a virtio GPIO controller and this patch adds
binding for the same. The gpio-virtio subnode can be part of a
virtio,mmio node and is based on its binding.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Depends on:

https://lore.kernel.org/lkml/7c716c2eb7ace5b5a560d8502af93101dbb53d24.1626170146.git.viresh.kumar@linaro.org/ (local)
---
 .../devicetree/bindings/gpio/gpio-virtio.yaml | 67 +++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-virtio.yaml

diff --git a/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
new file mode 100644
index 000000000000..c813cdfd60fd
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml

@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/gpio-virtio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtio memory mapped GPIO controller
+
+maintainers:
+  - Viresh Kumar <viresh.kumar@linaro.org>
+
+description:
+  Virtio GPIO controller, see /schemas/virtio/mmio.yaml for more details.
+
+allOf:
+  - $ref: /schemas/gpio/gpio.yaml#
+
+properties:
+  $nodename:
+    pattern: '^gpio-virtio@[0-9]+$'
+
+  reg:
+    description:
+      The cell is the device ID of the GPIO device (VIRTIO_ID_GPIO) as per
+      dt-bindings/virtio/virtio_ids.h.
+    const: 41
+    $ref: /schemas/virtio/mmio.yaml#/properties/reg
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+required:
+  - reg
+  - gpio-controller
+  - "#gpio-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/virtio/virtio_ids.h>
+
+    virtio@3000 {
+        compatible = "virtio,mmio";
+        reg = <0x3000 0x100>;
+        interrupts = <41>;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        gpio-virtio@0 {
+            reg = <VIRTIO_ID_GPIO>;
+            gpio-controller;
+            #gpio-cells = <2>;
+            interrupt-controller;
+            #interrupt-cells = <2>;