arm64: dts: rockchip: Enable USB 2.0 ports on Radxa E20C

The Radxa E20C has one USB2.0 Type-A HOST port and one USB2.0 Type-C port.

The Type-C port is conneced to a FE1.1s_QFN USB hub on the board, with its
ports being connected to the XHCI usb controller and an usb-uart bridge.

This also means, the XHCI controller can only be used in device-mode.

Add support for using the USB 2.0 ports on Radxa E20C.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
[set xhci to peripheral and add comment about the outward-facing hub]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20260529190355.4148175-3-heiko@sntech.de

Author: Kwiboo

arch/arm64/boot/dts/rockchip/rk3528-radxa-e20c.dts

@@ -134,6 +134,18 @@
 		regulator-max-microvolt = <5000000>;
 	};
 
+	vcc5v0_usb20: regulator-5v0-vcc-usb20 {
+		compatible = "regulator-fixed";
+		enable-active-high;
+		gpios = <&gpio0 RK_PA1 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&usb_host_en>;
+		regulator-name = "vcc5v0_usb20";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		vin-supply = <&vcc5v0_sys>;
+	};
+
 	vccio_sd: regulator-vccio-sd {
 		compatible = "regulator-gpio";
 		gpios = <&gpio4 RK_PB6 GPIO_ACTIVE_HIGH>;
@@ -273,6 +285,12 @@
 			rockchip,pins = <4 RK_PB6 RK_FUNC_GPIO &pcfg_pull_none>;
 		};
 	};
+
+	usb {
+		usb_host_en: usb-host-en {
+			rockchip,pins = <0 RK_PA1 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+	};
 };
 
 &pwm1 {
@@ -320,3 +338,45 @@
 	pinctrl-0 = <&uart0m0_xfer>;
 	status = "okay";
 };
+
+&usb_host0_ehci {
+	status = "okay";
+};
+
+&usb_host0_ohci {
+	status = "okay";
+};
+
+/*
+ * The usb controller can only work in peripheral mode, as it is
+ * connected to one of the ports of an outward-facing usb hub.
+ *
+ * type_c-port (hub-input)
+ *          |
+ *       usb-hub
+ *     |         |
+ * uart-usb   usb-host0
+ *     |
+ *   uart0
+ */
+&usb_host0_xhci {
+	dr_mode = "peripheral";
+	extcon = <&usb2phy>;
+	maximum-speed = "high-speed";
+	phys = <&usb2phy_otg>;
+	phy-names = "usb2-phy";
+	status = "okay";
+};
+
+&usb2phy {
+	status = "okay";
+};
+
+&usb2phy_host {
+	phy-supply = <&vcc5v0_usb20>;
+	status = "okay";
+};
+
+&usb2phy_otg {
+	status = "okay";
+};