ARM: dts: stm32: add initial support of stm32mp135f-dk board

Add support of stm32mp135f discovery board (part number: STM32MP135F-DK).
It embeds a STM32MP135F SOC with 512 MB of DDR3.
Several connections are available on this board:
    4*USB2.0, 1*USB2.0 typeC DRD, SDcard, 2*RJ45, HDMI, Combo Wifi/BT, ...

Only SD card, uart4 (console) and watchdog IPs are enabled in this commit.
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/Makefile

@@ -1113,6 +1113,7 @@ dtb-$(CONFIG_ARCH_STM32) += \
 	stm32h743i-eval.dtb \
 	stm32h743i-disco.dtb \
 	stm32h750i-art-pi.dtb \
+	stm32mp135f-dk.dtb \
 	stm32mp153c-dhcom-drc02.dtb \
 	stm32mp157a-avenger96.dtb \
 	stm32mp157a-dhcor-avenger96.dtb \

arch/arm/boot/dts/stm32mp13-pinctrl.dtsi

+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright (C) STMicroelectronics 2021 - All Rights Reserved
+ * Author: Alexandre Torgue <alexandre.torgue@foss.st.com>
+ */
+#include <dt-bindings/pinctrl/stm32-pinfunc.h>
+
+&pinctrl {
+	sdmmc1_b4_pins_a: sdmmc1-b4-0 {
+		pins1 {
+			pinmux = <STM32_PINMUX('C', 8, AF12)>, /* SDMMC1_D0 */
+				 <STM32_PINMUX('C', 9, AF12)>, /* SDMMC1_D1 */
+				 <STM32_PINMUX('C', 10, AF12)>, /* SDMMC1_D2 */
+				 <STM32_PINMUX('C', 11, AF12)>, /* SDMMC1_D3 */
+				 <STM32_PINMUX('D', 2, AF12)>; /* SDMMC1_CMD */
+			slew-rate = <1>;
+			drive-push-pull;
+			bias-disable;
+		};
+		pins2 {
+			pinmux = <STM32_PINMUX('C', 12, AF12)>; /* SDMMC1_CK */
+			slew-rate = <2>;
+			drive-push-pull;
+			bias-disable;
+		};
+	};
+
+	sdmmc1_b4_od_pins_a: sdmmc1-b4-od-0 {
+		pins1 {
+			pinmux = <STM32_PINMUX('C', 8, AF12)>, /* SDMMC1_D0 */
+				 <STM32_PINMUX('C', 9, AF12)>, /* SDMMC1_D1 */
+				 <STM32_PINMUX('C', 10, AF12)>, /* SDMMC1_D2 */
+				 <STM32_PINMUX('C', 11, AF12)>; /* SDMMC1_D3 */
+			slew-rate = <1>;
+			drive-push-pull;
+			bias-disable;
+		};
+		pins2 {
+			pinmux = <STM32_PINMUX('C', 12, AF12)>; /* SDMMC1_CK */
+			slew-rate = <2>;
+			drive-push-pull;
+			bias-disable;
+		};
+		pins3 {
+			pinmux = <STM32_PINMUX('D', 2, AF12)>; /* SDMMC1_CMD */
+			slew-rate = <1>;
+			drive-open-drain;
+			bias-disable;
+		};
+	};
+
+	uart4_pins_a: uart4-0 {
+		pins1 {
+			pinmux = <STM32_PINMUX('D', 6, AF8)>; /* UART4_TX */
+			bias-disable;
+			drive-push-pull;
+			slew-rate = <0>;
+		};
+		pins2 {
+			pinmux = <STM32_PINMUX('D', 8, AF8)>; /* UART4_RX */
+			bias-disable;
+		};
+	};
+};

arch/arm/boot/dts/stm32mp135f-dk.dts

+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright (C) STMicroelectronics 2021 - All Rights Reserved
+ * Author: Alexandre Torgue <alexandre.torgue@foss.st.com> for STMicroelectronics.
+ */
+
+/dts-v1/;
+
+#include "stm32mp135.dtsi"
+#include "stm32mp13xf.dtsi"
+#include "stm32mp13-pinctrl.dtsi"
+
+/ {
+	model = "STMicroelectronics STM32MP135F-DK Discovery Board";
+	compatible = "st,stm32mp135f-dk", "st,stm32mp135";
+
+	aliases {
+		serial0 = &uart4;
+	};
+
+	memory@c0000000 {
+		device_type = "memory";
+		reg = <0xc0000000 0x20000000>;
+	};
+
+	vdd_sd: vdd-sd {
+		compatible = "regulator-fixed";
+		regulator-name = "vdd_sd";
+		regulator-min-microvolt = <2900000>;
+		regulator-max-microvolt = <2900000>;
+		regulator-always-on;
+	};
+};
+
+&iwdg2 {
+	timeout-sec = <32>;
+	status = "okay";
+};
+
+&sdmmc1 {
+	pinctrl-names = "default", "opendrain";
+	pinctrl-0 = <&sdmmc1_b4_pins_a>;
+	pinctrl-1 = <&sdmmc1_b4_od_pins_a>;
+	broken-cd;
+	disable-wp;
+	st,neg-edge;
+	bus-width = <4>;
+	vmmc-supply = <&vdd_sd>;
+	status = "okay";
+};
+
+&uart4 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart4_pins_a>;
+	status = "okay";
+};