ARM: dts: stm32: Add Engicam MicroGEA STM32MP1 SoM

MicroGEA STM32MP1 is a STM32MP157A based Micro SoM.

General features:
- STM32MP157AAC
- Up to 1GB DDR3L-800
- 512MB Nand flash
- I2S

MicroGEA STM32MP1 needs to mount on top of Engicam MicroDev carrier
boards for creating complete platform solutions.

Add support for it.
Signed-off-by: Matteo Lisi <matteo.lisi@engicam.com>
Signed-off-by: Francesco Utel <francesco.utel@engicam.com>
Signed-off-by: Mirko Ardinghi <mirko.ardinghi@engicam.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/stm32mp157a-microgea-stm32mp1.dtsi

+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright (c) STMicroelectronics 2019 - All Rights Reserved
+ * Copyright (c) 2020 Engicam srl
+ * Copyright (c) 2020 Amarula Solutons(India)
+ */
+
+/ {
+	compatible = "engicam,microgea-stm32mp1", "st,stm32mp157";
+
+	memory@c0000000 {
+		device_type = "memory";
+		reg = <0xc0000000 0x10000000>;
+	};
+
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		mcuram2: mcuram2@10000000 {
+			compatible = "shared-dma-pool";
+			reg = <0x10000000 0x40000>;
+			no-map;
+		};
+
+		vdev0vring0: vdev0vring0@10040000 {
+			compatible = "shared-dma-pool";
+			reg = <0x10040000 0x1000>;
+			no-map;
+		};
+
+		vdev0vring1: vdev0vring1@10041000 {
+			compatible = "shared-dma-pool";
+			reg = <0x10041000 0x1000>;
+			no-map;
+		};
+
+		vdev0buffer: vdev0buffer@10042000 {
+			compatible = "shared-dma-pool";
+			reg = <0x10042000 0x4000>;
+			no-map;
+		};
+
+		mcuram: mcuram@30000000 {
+			compatible = "shared-dma-pool";
+			reg = <0x30000000 0x40000>;
+			no-map;
+		};
+
+		retram: retram@38000000 {
+			compatible = "shared-dma-pool";
+			reg = <0x38000000 0x10000>;
+			no-map;
+		};
+	};
+
+	vin: regulator-vin {
+		compatible = "regulator-fixed";
+		regulator-name = "vin";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		regulator-always-on;
+	};
+
+	vddcore: regulator-vddcore {
+		compatible = "regulator-fixed";
+		regulator-name = "vddcore";
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1200000>;
+		regulator-always-on;
+		vin-supply = <&vin>;
+	};
+
+	vdd: regulator-vdd {
+		compatible = "regulator-fixed";
+		regulator-name = "vdd";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-always-on;
+		vin-supply = <&vin>;
+	};
+
+	vddq_ddr: regulator-vddq-ddr {
+		compatible = "regulator-fixed";
+		regulator-name = "vddq_ddr";
+		regulator-min-microvolt = <1350000>;
+		regulator-max-microvolt = <1350000>;
+		regulator-always-on;
+		vin-supply = <&vin>;
+	};
+};
+
+&dts {
+	status = "okay";
+};
+
+&fmc {
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&fmc_pins_a>;
+	pinctrl-1 = <&fmc_sleep_pins_a>;
+	status = "okay";
+
+	nand-controller@4,0 {
+		status = "okay";
+
+		nand@0 {
+			reg = <0>;
+			nand-on-flash-bbt;
+			#address-cells = <1>;
+			#size-cells = <1>;
+		};
+	};
+};
+
+&ipcc {
+	status = "okay";
+};
+
+&iwdg2{
+	timeout-sec = <32>;
+	status = "okay";
+};
+
+&m4_rproc{
+	memory-region = <&retram>, <&mcuram>, <&mcuram2>, <&vdev0vring0>,
+			<&vdev0vring1>, <&vdev0buffer>;
+	mboxes = <&ipcc 0>, <&ipcc 1>, <&ipcc 2>;
+	mbox-names = "vq0", "vq1", "shutdown";
+	interrupt-parent = <&exti>;
+	interrupts = <68 1>;
+	status = "okay";
+};
+
+&rng1 {
+	status = "okay";
+};
+
+&rtc{
+	status = "okay";
+};
+
+&vrefbuf {
+	regulator-min-microvolt = <2500000>;
+	regulator-max-microvolt = <2500000>;
+	vdda-supply = <&vdd>;
+	status = "okay";
+};