Document support for Airoha AN8855 5-port Gigabit Switch.

It does expose the 5 Internal PHYs on the MDIO bus and each port
can access the Switch register space by configurting the PHY page.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 .../net/dsa/airoha,an8855-switch.yaml         | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/dsa/airoha,an8855-switch.yaml

diff --git a/Documentation/devicetree/bindings/net/dsa/airoha,an8855-switch.yaml b/Documentation/devicetree/bindings/net/dsa/airoha,an8855-switch.yaml
new file mode 100644
index 000000000000..fbb9219fadae
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/dsa/airoha,an8855-switch.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/dsa/airoha,an8855-switch.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Airoha AN8855 Gigabit Switch
+
+maintainers:
+  - Christian Marangi <ansuelsmth@gmail.com>
+
+description: >
+  Airoha AN8855 is a 5-port Gigabit Switch.
+
+  It does expose the 5 Internal PHYs on the MDIO bus and each port
+  can access the Switch register space by configurting the PHY page.
+
+$ref: dsa.yaml#/$defs/ethernet-ports
+
+properties:
+  compatible:
+    const: airoha,an8855-switch
+
+required:
+  - compatible
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    ethernet-switch {
+        compatible = "airoha,an8855-switch";
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+                label = "lan1";
+                phy-mode = "internal";
+                phy-handle = <&internal_phy1>;
+            };
+
+            port@1 {
+                reg = <1>;
+                label = "lan2";
+                phy-mode = "internal";
+                phy-handle = <&internal_phy2>;
+            };
+
+            port@2 {
+                reg = <2>;
+                label = "lan3";
+                phy-mode = "internal";
+                phy-handle = <&internal_phy3>;
+            };
+
+            port@3 {
+                reg = <3>;
+                label = "lan4";
+                phy-mode = "internal";
+                phy-handle = <&internal_phy4>;
+            };
+
+            port@4 {
+                reg = <4>;
+                label = "wan";
+                phy-mode = "internal";
+                phy-handle = <&internal_phy5>;
+            };
+
+            port@5 {
+                reg = <5>;
+                label = "cpu";
+                ethernet = <&gmac0>;
+                phy-mode = "2500base-x";
+
+                fixed-link {
+                    speed = <2500>;
+                    full-duplex;
+                    pause;
+                };
+            };
+        };
+    };
-- 
2.48.1