dt-bindings: net: Add DT bindings for Toshiba Visconti TMPV7700 SoC

Add device tree bindings for ethernet controller of Toshiba Visconti
TMPV7700 SoC series.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/toshiba,visconti-dwmac.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/net/toshiba,visconti-dwmac.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Toshiba Visconti DWMAC Ethernet controller
+
+maintainers:
+  - Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
+
+select:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - toshiba,visconti-dwmac
+  required:
+    - compatible
+
+allOf:
+  - $ref: "snps,dwmac.yaml#"
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - toshiba,visconti-dwmac
+          - const: snps,dwmac-4.20a
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: main clock
+      - description: PHY reference clock
+
+  clock-names:
+    items:
+      - const: stmmaceth
+      - const: phy_ref_clk
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        piether: ethernet@28000000 {
+            compatible = "toshiba,visconti-dwmac", "snps,dwmac-4.20a";
+            reg = <0 0x28000000 0 0x10000>;
+            interrupts = <GIC_SPI 156 IRQ_TYPE_LEVEL_HIGH>;
+            interrupt-names = "macirq";
+            clocks = <&clk300mhz>, <&clk125mhz>;
+            clock-names = "stmmaceth", "phy_ref_clk";
+            snps,txpbl = <4>;
+            snps,rxpbl = <4>;
+            snps,tso;
+            phy-mode = "rgmii-id";
+            phy-handle = <&phy0>;
+
+            mdio0 {
+                #address-cells = <0x1>;
+                #size-cells = <0x0>;
+                compatible = "snps,dwmac-mdio";
+
+                phy0: ethernet-phy@1 {
+                    device_type = "ethernet-phy";
+                    reg = <0x1>;
+                };
+            };
+        };
+    };