arm64: dts: imx8mp-debix: add USB host support

This adds support for the 4 USB3 host ports on the board, which are
connected to the i.MX8MP SoC via a Realtek RTS5411 hub.

As the schematic for the board is not available, I could not validate
that this really reflects the reality, but I modeled things after the
hacked in usage of the GPIOs in the downstream kernel.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp-debix-model-a.dts

@@ -43,6 +43,17 @@ reg_usdhc2_vmmc: regulator-usdhc2 {
 		gpio = <&gpio2 19 GPIO_ACTIVE_HIGH>;
 		enable-active-high;
 	};
+
+	reg_usb_hub: regulator-usb-hub {
+		compatible = "regulator-fixed";
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_reg_usb_hub>;
+		regulator-name = "USB_HUB";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		gpio = <&gpio4 26 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+	};
 };
 
 &A53_0 {
@@ -254,6 +265,41 @@ &uart4 {
 	status = "okay";
 };
 
+&usb3_phy1 {
+	status = "okay";
+};
+
+&usb3_1 {
+	status = "okay";
+};
+
+&usb_dwc3_1 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_usb1>;
+	dr_mode = "host";
+	status = "okay";
+
+	/* 2.x hub on port 1 */
+	usb_hub_2_x: hub@1 {
+		compatible = "usbbda,5411";
+		reg = <1>;
+		reset-gpios = <&gpio4 25 GPIO_ACTIVE_LOW>;
+		vdd-supply = <&reg_usb_hub>;
+		peer-hub = <&usb_hub_3_x>;
+	};
+
+	/* 3.x hub on port 2 */
+	usb_hub_3_x: hub@2 {
+		compatible = "usbbda,411";
+		reg = <2>;
+		reset-gpios = <&gpio4 25 GPIO_ACTIVE_LOW>;
+		vdd-supply = <&reg_usb_hub>;
+		peer-hub = <&usb_hub_2_x>;
+	};
+};
+
 /* SD Card */
 &usdhc2 {
 	pinctrl-names = "default", "state_100mhz", "state_200mhz";
@@ -384,6 +430,12 @@ MX8MP_IOMUXC_SD2_RESET_B__GPIO2_IO19				0x41
 		>;
 	};
 
+	pinctrl_reg_usb_hub: regusbhubgrp {
+		fsl,pins = <
+			MX8MP_IOMUXC_SAI2_TXD0__GPIO4_IO26				0x19
+		>;
+	};
+
 	pinctrl_rtc_int: rtcintgrp {
 		fsl,pins = <
 			MX8MP_IOMUXC_SD1_STROBE__GPIO2_IO11				0x140
@@ -411,6 +463,13 @@ MX8MP_IOMUXC_UART4_TXD__UART4_DCE_TX				0x49
 		>;
 	};
 
+	pinctrl_usb1: usb1grp {
+		fsl,pins = <
+			MX8MP_IOMUXC_GPIO1_IO14__USB2_OTG_PWR				0x10
+			MX8MP_IOMUXC_SAI2_TXC__GPIO4_IO25				0x19
+		>;
+	};
+
 	pinctrl_usdhc2: usdhc2grp {
 		fsl,pins = <
 			MX8MP_IOMUXC_SD2_CLK__USDHC2_CLK				0x190