fdts: stm32mp1: add support for the Seeed Odyssey SoM and board

Seeed Studio’s SoM‐STM32MP157C is a System‐on‐Module that integrates the
STM32MP157C MPU (the 650 MHz dual‐core variant with a GPU and a
cryptographic processor) the STPMIC1A PMIC, 512 MB of DDR3 RAM and a
4 GB eMMC. There are two LEDs as well, one hardwired to the PMIC’s VDD
output, and the other available at the MPU’s port PG3. The SoM can be
plugged into a carrier board using its three 70‑pin connectors.

Seeed Odyssey‐STM32MP157C is the reference carrier board for the SoM in
a Raspberry Pi‐like form factor. It features a WiFi/Bluetooth chip, a
microSD card port and various I/O interfaces.

The device tree is based on the DKx boards. TF‑A was successfully tested
on the board with Buildroot 2021.02 and U-Boot 2021.04.

Signed-off-by: Grzegorz Szymaszek <gszymaszek@short.pl>
Change-Id: I2c9aecc925561e8d338dddbb192d3bb23a533914
diff --git a/fdts/stm32mp157c-odyssey.dts b/fdts/stm32mp157c-odyssey.dts
new file mode 100644
index 0000000..03800f9
--- /dev/null
+++ b/fdts/stm32mp157c-odyssey.dts
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2019, STMicroelectronics. All Rights Reserved.
+ * Copyright (C) 2021, Grzegorz Szymaszek.
+ *
+ * SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-3-Clause)
+ */
+
+/dts-v1/;
+
+#include "stm32mp157c-odyssey-som.dtsi"
+
+/ {
+	model = "Seeed Studio Odyssey-STM32MP157C Board";
+	compatible = "seeed,stm32mp157c-odyssey",
+		     "seeed,stm32mp157c-odyssey-som", "st,stm32mp157";
+
+	aliases {
+		serial0 = &uart4;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+};
+
+&sdmmc1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&sdmmc1_b4_pins_a>;
+	disable-wp;
+	st,neg-edge;
+	bus-width = <4>;
+	vmmc-supply = <&v3v3>;
+	status = "okay";
+};
+
+&uart4 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart4_pins_a>;
+	status = "okay";
+};