ARM: dts: sun9i: cubieboard4: Enable GMAC

The Cubieboard4 has a Realtek RTL8211E ethernet PHY which uses RGMII to
talk to the MAC. The PHY is powered by 2 regulators: cldo1 for the PHY's
core logic and gpio1-ldo for I/O. The latter also powers the SoC side
pins. As there is no binding to model a second regulator supply for the
PHY, it is omitted. It is however properly modeled for the PIO.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm/boot/dts/sun9i-a80-cubieboard4.dts

@@ -133,6 +133,19 @@ &de {
 	status = "okay";
 };
 
+&gmac {
+	pinctrl-names = "default";
+	pinctrl-0 = <&gmac_rgmii_pins>;
+	phy = <&phy1>;
+	phy-mode = "rgmii";
+	phy-supply = <&reg_cldo1>;
+	status = "okay";
+
+	phy1: ethernet-phy@1 {
+		reg = <1>;
+	};
+};
+
 &i2c3 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&i2c3_pins>;
@@ -402,6 +415,14 @@ reg_cldo1: cldo1 {
 				 */
 				regulator-min-microvolt = <3300000>;
 				regulator-max-microvolt = <3300000>;
+				/*
+				 * The PHY requires 20ms after all voltages
+				 * are applied until core logic is ready and
+				 * 30ms after the reset pin is de-asserted.
+				 * Set a 100ms delay to account for PMIC
+				 * ramp time and board traces.
+				 */
+				regulator-enable-ramp-delay = <100000>;
 				regulator-name = "vcc-gmac-phy";
 			};