[PATCH 3/5] dt-bindings: Add Bao I/O dispatcher driver binding

[joaopeixoto at osyx.tech]

From: João Peixoto <joaopeixoto at osyx.tech>

This patch adds a Device Tree binding for the Bao I/O Dispatcher kernel
module, which can be loaded into backend VMs. The I/O Dispatcher
provides the bridge between the Bao hypervisor Remote I/O system and the
frontend device model in userspace, offering a unified API to support
various VirtIO backends.

The dispatcher handles hypercalls to the Bao hypervisor, IRQ/eventfd
forwarding, and provides a character device interface for frontend
devices, enabling efficient communication between the hypervisor and
userspace device models.

The binding documents the following properties:
  - compatible: "bao,io-dispatcher"
  - reg: Memory regions for the dispatcher (multiple VirtIO devices)
  - interrupts: Interrupts used by the devices
  - interrupt-parent: Parent interrupt controller

This enables kernel drivers to correctly instantiate and configure Bao
I/O Dispatcher modules based on the DT description.

Signed-off-by: João Peixoto <joaopeixoto at osyx.tech>
---
 .../bindings/bao/io-dispatcher.yaml           | 67 +++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/bao/io-dispatcher.yaml

diff --git a/Documentation/devicetree/bindings/bao/io-dispatcher.yaml b/Documentation/devicetree/bindings/bao/io-dispatcher.yaml
new file mode 100644
index 000000000000..7795f55d3ff9
--- /dev/null
+++ b/Documentation/devicetree/bindings/bao/io-dispatcher.yaml
@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/bao/io-dispatcher.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Bao I/O Dispatcher Device
+
+maintainers:
+  - João Peixoto <joaopeixoto at osyx.tech>
+  - José Martins <jose at osyx.tech>
+  - David Cerdeira <davidmcerdeira at osyx.tech>
+
+description: |
+  I/O Dispatcher device for Bao hypervisor guests. Handles multiple VirtIO
+  backend devices and their interrupts.
+
+properties:
+  compatible:
+    const: "bao,io-dispatcher"
+    description: Device compatible string.
+
+  reg:
+    description: |
+      Memory regions for each VirtIO backend device.
+    maxItems: 20
+    type: array
+    items:
+      type: integer
+
+  interrupts:
+    description: |
+      Interrupt numbers for each VirtIO backend device.
+    type: array
+    items:
+      type: integer
+    minItems: 3
+    maxItems: 3
+
+  interrupt-parent:
+    description: Parent interrupt controller node
+    type: string
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-parent
+
+additionalProperties: false
+
+examples:
+  - |
+    bao_io_dispatcher: bao-io-dispatcher {
+        compatible = "bao,io-dispatcher";
+        reg = <0x0 0x50000000 0x0 0x01000000
+               0x0 0x51000000 0x0 0x01000000
+               0x0 0x52000000 0x0 0x01000000
+               0x0 0x53000000 0x0 0x01000000
+               0x0 0x54000000 0x0 0x01000000>;
+        interrupts = <0x0 0x08 0x1
+                      0x0 0x09 0x1
+                      0x0 0x0a 0x1
+                      0x0 0x0b 0x1
+                      0x0 0x0c 0x1>;
+        interrupt-parent = <&gic>;
+    };
-- 
2.43.0