dt-bindings: net: Add support for Sophgo CV1800 dwmac

The GMAC IP on CV1800 series SoC is a standard Synopsys
DesignWare MAC (version 3.70a).

Add necessary compatible string for this device.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20250703021220.124195-1-inochiama@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/net/sophgo,cv1800b-dwmac.yaml

@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/sophgo,cv1800b-dwmac.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo CV1800B DWMAC glue layer
+
+maintainers:
+  - Inochi Amaoto <inochiama@gmail.com>
+
+select:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - sophgo,cv1800b-dwmac
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: sophgo,cv1800b-dwmac
+      - const: snps,dwmac-3.70a
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: GMAC main clock
+      - description: PTP clock
+
+  clock-names:
+    items:
+      - const: stmmaceth
+      - const: ptp_ref
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-names:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: stmmaceth
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+  - interrupt-names
+  - resets
+  - reset-names
+
+allOf:
+  - $ref: snps,dwmac.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    ethernet@4070000 {
+      compatible = "sophgo,cv1800b-dwmac", "snps,dwmac-3.70a";
+      reg = <0x04070000 0x10000>;
+      clocks = <&clk 35>, <&clk 36>;
+      clock-names = "stmmaceth", "ptp_ref";
+      interrupts = <31 IRQ_TYPE_LEVEL_HIGH>;
+      interrupt-names = "macirq";
+      phy-handle = <&internal_ephy>;
+      phy-mode = "internal";
+      resets = <&rst 12>;
+      reset-names = "stmmaceth";
+      rx-fifo-depth = <8192>;
+      tx-fifo-depth = <8192>;
+      snps,multicast-filter-bins = <0>;
+      snps,perfect-filter-entries = <1>;
+      snps,aal;
+      snps,txpbl = <8>;
+      snps,rxpbl = <8>;
+      snps,mtl-rx-config = <&gmac0_mtl_rx_setup>;
+      snps,mtl-tx-config = <&gmac0_mtl_tx_setup>;
+      snps,axi-config = <&gmac0_stmmac_axi_setup>;
+
+      mdio {
+        compatible = "snps,dwmac-mdio";
+        #address-cells = <1>;
+        #size-cells = <0>;
+      };
+
+      gmac0_mtl_rx_setup: rx-queues-config {
+        snps,rx-queues-to-use = <1>;
+        queue0 {};
+      };
+
+      gmac0_mtl_tx_setup: tx-queues-config {
+        snps,tx-queues-to-use = <1>;
+        queue0 {};
+      };
+
+      gmac0_stmmac_axi_setup: stmmac-axi-config {
+        snps,blen = <16 8 4 0 0 0 0>;
+        snps,rd_osr_lmt = <2>;
+        snps,wr_osr_lmt = <1>;
+      };
+    };