Enable the Ethernet subsystem on OpenWrt One board with dual-MAC
configuration:
- GMAC0: Connected to external Airoha EN8811H 2.5GbE PHY via SGMII
  (2500base-x mode) for WAN connectivity with LED indicators
- GMAC1: Connected to internal MT7981 1GbE PHY (GMII mode) for LAN

Ethernet aliases are defined to provide consistent network interface
naming (ethernet0 = LAN, ethernet1 = WAN).

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
---
V1 -> V2:
  - Switch gmac0 phy irq to Level
  - Update mac nvmem label name
---
 .../boot/dts/mediatek/mt7981b-openwrt-one.dts      | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts b/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts
index 183e48d985ed7..90edb9f493c6d 100644
--- a/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts
+++ b/arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts
@@ -3,6 +3,8 @@
 /dts-v1/;
 
 #include "mt7981b.dtsi"
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/leds/common.h>
 #include "dt-bindings/pinctrl/mt65xx.h"
 
 / {
@@ -10,6 +12,8 @@ / {
 	model = "OpenWrt One";
 
 	aliases {
+		ethernet0 = &gmac1;
+		ethernet1 = &gmac0;
 		serial0 = &uart0;
 	};
 
@@ -41,6 +45,58 @@ reg_5v: regulator-5v {
 	};
 };
 
+&eth {
+	status = "okay";
+
+	/* WAN interface */
+	gmac0: mac@0 {
+		compatible = "mediatek,eth-mac";
+		reg = <0>;
+		nvmem-cells = <&wan_factory_mac 0>;
+		nvmem-cell-names = "mac-address";
+		phy-mode = "2500base-x";
+		phy-handle = <&phy15>;
+	};
+
+	/* LAN interface */
+	gmac1: mac@1 {
+		compatible = "mediatek,eth-mac";
+		reg = <1>;
+		phy-mode = "gmii";
+		phy-handle = <&int_gbe_phy>;
+	};
+};
+
+&mdio_bus {
+	phy15: ethernet-phy@f {
+		compatible = "ethernet-phy-id03a2.a411";
+		reg = <0xf>;
+		interrupt-parent = <&pio>;
+		interrupts = <38 IRQ_TYPE_LEVEL_LOW>;
+		reset-gpios = <&pio 39 GPIO_ACTIVE_LOW>;
+		reset-assert-us = <10000>;
+		reset-deassert-us = <20000>;
+		airoha,pnswap-rx;
+
+		leds {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			led@0 {
+				reg = <0>;
+				function = LED_FUNCTION_WAN;
+				color = <LED_COLOR_ID_AMBER>;
+			};
+
+			led@1 {
+				reg = <1>;
+				function = LED_FUNCTION_WAN;
+				color = <LED_COLOR_ID_GREEN>;
+			};
+		};
+	};
+};
+
 &pcie {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pcie_pins>;
@@ -132,6 +188,10 @@ partition@180000 {
 	};
 };
 
+&sgmiisys0 {
+	mediatek,pnswap;
+};
+
 &uart0 {
 	status = "okay";
 };

-- 
2.51.0