[PATCH net-next 1/2] dt-bindings: net: document Microchip PIC64-HPSC/HX MDIO controller

[Charles Perry]

This MDIO hardware is based on a Microsemi design supported in Linux by
mdio-mscc-miim.c. However, The register interface is completely different
with pic64hpsc, hence the need for separate documentation.

The hardware supports C22 and C45.

The documentation recommends an input clock of 156.25MHz and a prescaler
of 39, which yields an MDIO clock of 1.95MHz.

The hardware supports an interrupt pin to signal transaction completion
which is not strictly needed as the software can also poll a "TRIGGER"
bit for this.

Signed-off-by: Charles Perry <charles.perry@xxxxxxxxxxxxx>
---
 .../net/microchip,pic64hpsc-mdio.yaml         | 61 +++++++++++++++++++
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 create mode 100644 Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml

diff --git a/Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml b/Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml
new file mode 100644
index 000000000000..21c76199c11b
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/microchip,pic64hpsc-mdio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip PIC64-HPSC/HX MDIO controller
+
+maintainers:
+  - Charles Perry <charles.perry@xxxxxxxxxxxxx>
+
+description: |
+  Microchip PIC64-HPSC/HX SoCs have two MDIO bus controller. This MDIO bus
+  controller supports C22 and C45 register access. It is named "MDIO Initiator"
+  in the documentation.
+
+allOf:
+  - $ref: mdio.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - const: microchip,pic64hpsc-mdio
+      - items:
+          - const: microchip,pic64hx-mdio
+          - const: microchip,pic64hpsc-mdio
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-frequency: true
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    bus {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        mdio@4000C21E000 {
+            compatible = "microchip,pic64hpsc-mdio";
+            reg = <0x400 0x0C21E000 0x0 0x1000>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            phy0: ethernet-phy@0 {
+                reg = <0>;
+            };
+        };
+    };
-- 
2.47.3