Document the MAE0621A PHY ID and its optional 125 MHz CLKOUT
setting. Boards which do not provide the property retain the hardware
strap or bootloader configuration.

Only the 125 MHz setting is exposed because it is the only setting
exercised on hardware.

Signed-off-by: Liu Changjie <liucj1228@outlook.com>
---
 .../bindings/net/maxio,mae0621a.yaml          | 38 +++++++++++++++++++
 .../devicetree/bindings/vendor-prefixes.yaml  |  2 +
 2 files changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/maxio,mae0621a.yaml

diff --git a/Documentation/devicetree/bindings/net/maxio,mae0621a.yaml b/Documentation/devicetree/bindings/net/maxio,mae0621a.yaml
new file mode 100644
index 000000000..f1ea54583
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/maxio,mae0621a.yaml
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/maxio,mae0621a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxio MAE0621A Ethernet PHY
+
+maintainers:
+  - Liu Changjie <liucj1228@outlook.com>
+
+allOf:
+  - $ref: ethernet-phy.yaml#
+
+properties:
+  compatible:
+    const: ethernet-phy-id7b74.4412
+
+  maxio,clk-out-frequency-hz:
+    description:
+      Selects a 125 MHz clock on the CLKOUT pin. If the property is absent,
+      the hardware strap or bootloader configuration is preserved.
+    const: 125000000
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    mdio {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ethernet-phy@1 {
+            compatible = "ethernet-phy-id7b74.4412";
+            reg = <1>;
+            maxio,clk-out-frequency-hz = <125000000>;
+        };
+    };
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 396044f36..eeaf0b7a1 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -1013,6 +1013,8 @@ patternProperties:
     description: MaxBotix Inc.
   "^maxim,.*":
     description: Maxim Integrated Products
+  "^maxio,.*":
+    description: Maxio Technology (Hangzhou) Co., Ltd.
   "^maxlinear,.*":
     description: MaxLinear Inc.
   "^maxtor,.*":
-- 
2.55.0