ARM: dts: Add Raspberry Pi Compute Module 4

The Raspberry Pi Compute Module 4 (CM4) are SoMs which contain the
following:
* BCM2711 quad core processor
* up to 8 GB RAM
* up to 32 GB eMMC
* a GPIO expander
* Gigabit PHY BCM54210PE
* Wifi/BT module with internal and external antenna

The eMMC and the Wifi/BT module are optional.

Signed-off-by: Stefan Wahren <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Nicolas Saenz Julienne <[e-mail]>

arch/arm/boot/dts/bcm2711-rpi-cm4.dtsi

···
+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+#include "bcm2711.dtsi"
+#include "bcm2711-rpi.dtsi"
+#include "bcm283x-rpi-wifi-bt.dtsi"
+
+/ {
+	compatible = "raspberrypi,4-compute-module", "brcm,bcm2711";
+
+	chosen {
+		/* 8250 auxiliary UART instead of pl011 */
+		stdout-path = "serial1:115200n8";
+	};
+
+	sd_io_1v8_reg: sd_io_1v8_reg {
+		compatible = "regulator-gpio";
+		regulator-name = "vdd-sd-io";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-boot-on;
+		regulator-always-on;
+		regulator-settling-time-us = <5000>;
+		gpios = <&expgpio 4 GPIO_ACTIVE_HIGH>;
+		states = <1800000 0x1>,
+			 <3300000 0x0>;
+		status = "okay";
+	};
+
+	sd_vcc_reg: sd_vcc_reg {
+		compatible = "regulator-fixed";
+		regulator-name = "vcc-sd";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-boot-on;
+		enable-active-high;
+		gpio = <&expgpio 6 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&bt {
+	shutdown-gpios = <&expgpio 0 GPIO_ACTIVE_HIGH>;
+};
+
+/* EMMC2 is used to drive the eMMC */
+&emmc2 {
+	bus-width = <8>;
+	vqmmc-supply = <&sd_io_1v8_reg>;
+	vmmc-supply = <&sd_vcc_reg>;
+	broken-cd;
+	/* Even the IP block is limited to 100 MHz
+	 * this provides a throughput gain
+	 */
+	mmc-hs200-1_8v;
+	status = "okay";
+};
+
+&expgpio {
+	gpio-line-names = "BT_ON",
+			  "WL_ON",
+			  "PWR_LED_OFF",
+			  "ANT1",
+			  "VDD_SD_IO_SEL",
+			  "CAM_GPIO",
+			  "SD_PWR_ON",
+			  "ANT2";
+
+	ant1: ant1-hog {
+		gpio-hog;
+		gpios = <3 GPIO_ACTIVE_HIGH>;
+		/* internal antenna enabled */
+		output-high;
+		line-name = "ant1";
+	};
+
+	ant2: ant2-hog {
+		gpio-hog;
+		gpios = <7 GPIO_ACTIVE_HIGH>;
+		/* external antenna disabled */
+		output-low;
+		line-name = "ant2";
+	};
+};
+
+&genet {
+	phy-handle = <&phy1>;
+	phy-mode = "rgmii-rxid";
+	status = "okay";
+};
+
+&genet_mdio {
+	phy1: ethernet-phy@0 {
+		/* No PHY interrupt */
+		reg = <0x0>;
+	};
+};
+
+/* uart0 communicates with the BT module */
+&uart0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart0_ctsrts_gpio30 &uart0_gpio32>;
+	uart-has-rtscts;
+};
+
+/* uart1 is mapped to the pin header */
+&uart1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart1_gpio14>;
+	status = "okay";
+};
+
+&wifi_pwrseq {
+	reset-gpios = <&expgpio 1 GPIO_ACTIVE_LOW>;
+};