arm64: dts: n5x: Add support for Intel's eASIC N5X platform

The Intel eASIC N5X platform shares the same register map as the Agilex
platform, thus, we can re-use the socfpga_agilex.dtsi as the base
DTSI.
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

arch/arm64/Kconfig.platforms

@@ -13,6 +13,11 @@ config ARCH_AGILEX
 	help
 	  This enables support for Intel's Agilex SoCFPGA Family.
 
+config ARCH_N5X
+	bool "Intel's eASIC N5X SoCFPGA Family"
+	help
+	  This enables support for Intel's eASIC N5X SoCFPGA Family.
+
 config ARCH_SUNXI
 	bool "Allwinner sunxi 64-bit SoC Family"
 	select ARCH_HAS_RESET_CONTROLLER

arch/arm64/boot/dts/intel/Makefile

@@ -2,3 +2,4 @@
 dtb-$(CONFIG_ARCH_AGILEX) += socfpga_agilex_socdk.dtb \
 			     socfpga_agilex_socdk_nand.dtb
 dtb-$(CONFIG_ARCH_KEEMBAY) += keembay-evm.dtb
+dtb-$(CONFIG_ARCH_N5X) += socfpga_n5x_socdk.dtb

arch/arm64/boot/dts/intel/socfpga_n5x_socdk.dts

+// SPDX-License-Identifier:     GPL-2.0
+/*
+ * Copyright (C) 2021, Intel Corporation
+ */
+#include "socfpga_agilex.dtsi"
+
+/ {
+	model = "eASIC N5X SoCDK";
+
+	aliases {
+		serial0 = &uart0;
+		ethernet0 = &gmac0;
+		ethernet1 = &gmac1;
+		ethernet2 = &gmac2;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
+	memory {
+		device_type = "memory";
+		/* We expect the bootloader to fill in the reg */
+		reg = <0 0 0 0>;
+	};
+
+	soc {
+		clocks {
+			osc1 {
+				clock-frequency = <25000000>;
+			};
+		};
+	};
+};
+
+&clkmgr {
+	compatible = "intel,easic-n5x-clkmgr";
+};
+
+&mmc {
+	status = "okay";
+	cap-sd-highspeed;
+	broken-cd;
+	bus-width = <4>;
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&watchdog0 {
+	status = "okay";
+};