arm64: dts: meson-g12a-x96-max: Add Gigabit Ethernet Support

Enable the network interface of the X96 Mac using an external
Realtek RTL8211F gigabit PHY, needing the same broken-eee properties
as the previous Amlogic SoC generations.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-g12a-x96-max.dts

@@ -15,6 +15,7 @@ / {
 
 	aliases {
 		serial0 = &uart_AO;
+		ethernet0 = &ethmac;
 	};
 	chosen {
 		stdout-path = "serial0:115200n8";
@@ -150,6 +151,27 @@ &ir {
 	pinctrl-names = "default";
 };
 
+&ext_mdio {
+	external_phy: ethernet-phy@0 {
+		/* Realtek RTL8211F (0x001cc916) */
+		reg = <0>;
+		max-speed = <1000>;
+		eee-broken-1000t;
+	};
+};
+
+&ethmac {
+	pinctrl-0 = <&eth_pins>, <&eth_rgmii_pins>;
+	pinctrl-names = "default";
+	status = "okay";
+	phy-mode = "rgmii";
+	phy-handle = <&external_phy>;
+	amlogic,tx-delay-ns = <2>;
+	snps,reset-gpio = <&gpio GPIOZ_14 0>;
+	snps,reset-delays-us = <0 10000 1000000>;
+	snps,reset-active-low;
+};
+
 &uart_A {
 	status = "okay";
 	pinctrl-0 = <&uart_a_pins>, <&uart_a_cts_rts_pins>;