dt-bindings: net: Add support for Spacemit K3 dwmac

The GMAC IP on Spacemit K3 is almost a standard Synopsys DesignWare
MAC (version 5.40a) with some extra clock.

Add necessary compatible string for this device.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260316010041.164360-2-inochiama@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/net/snps,dwmac.yaml

@@ -109,6 +109,7 @@ properties:
         - snps,dwmac-5.10a
         - snps,dwmac-5.20
         - snps,dwmac-5.30a
+        - snps,dwmac-5.40a
         - snps,dwxgmac
         - snps,dwxgmac-2.10
         - sophgo,sg2042-dwmac
@@ -656,6 +657,7 @@ allOf:
                 - snps,dwmac-5.10a
                 - snps,dwmac-5.20
                 - snps,dwmac-5.30a
+                - snps,dwmac-5.40a
                 - snps,dwxgmac
                 - snps,dwxgmac-2.10
                 - st,spear600-gmac

Documentation/devicetree/bindings/net/spacemit,k3-dwmac.yaml

@@ -0,0 +1,102 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/spacemit,k3-dwmac.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spacemit K3 DWMAC glue layer
+
+maintainers:
+  - Inochi Amaoto <inochiama@gmail.com>
+
+select:
+  properties:
+    compatible:
+      contains:
+        const: spacemit,k3-dwmac
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: spacemit,k3-dwmac
+      - const: snps,dwmac-5.40a
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: GMAC application clock
+      - description: PTP clock
+      - description: TX clock
+
+  clock-names:
+    items:
+      - const: stmmaceth
+      - const: ptp_ref
+      - const: tx
+
+  interrupts:
+    minItems: 1
+    items:
+      - description: MAC interrupt
+      - description: MAC wake interrupt
+
+  interrupt-names:
+    minItems: 1
+    items:
+      - const: macirq
+      - const: eth_wake_irq
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: stmmaceth
+
+  spacemit,apmu:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: phandle to the syscon node which control the glue register
+          - description: offset of the control register
+          - description: offset of the dline register
+    description:
+      A phandle to syscon with offset to control registers for this MAC
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+  - interrupt-names
+  - resets
+  - reset-names
+  - spacemit,apmu
+
+allOf:
+  - $ref: snps,dwmac.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    ethernet@cac80000 {
+      compatible = "spacemit,k3-dwmac", "snps,dwmac-5.40a";
+      reg = <0xcac80000 0x2000>;
+      clocks = <&syscon_apmu 66>, <&syscon_apmu 68>,
+               <&syscon_apmu 69>;
+      clock-names = "stmmaceth", "ptp_ref", "tx";
+      interrupts = <131 IRQ_TYPE_LEVEL_HIGH>, <276 IRQ_TYPE_LEVEL_HIGH>;
+      interrupt-names = "macirq", "eth_wake_irq";
+      phy-mode = "rgmii-id";
+      phy-handle = <&phy0>;
+      resets = <&syscon_apmu 67>;
+      reset-names = "stmmaceth";
+      spacemit,apmu = <&syscon_apmu 0x384 0x38c>;
+    };