ramips: add support for ASUS RT-AX54

Specifications:
- Device: ASUS RT-AX54 (AX1800S/HP,AX54HP)
- SoC: MT7621AT
- Flash: 128MB
- RAM: 256MB
- Switch: 1 WAN, 4 LAN (10/100/1000 Mbps)
- WiFi: MT7905 2x2 2.4G + MT7975 2x2 5G
- LEDs: 1x POWER (blue, configurable)
        1x LAN (blue, configurable)
        1x WAN (blue, configurable)
	1x 2.4G (blue, not configurable)
	1x 5G (blue, not configurable)

Flash by U-Boot TFTP method:
- Configure your PC with IP 192.168.1.2
- Set up TFTP server and put the factory.bin image on your PC
- Connect serial port(rate:115200) and turn on AP, then interrupt "U-Boot Boot Menu" by hitting any key
   Select "2. Upgrade firmware"
   Press enter when show "Run firmware after upgrading? (Y/n):"
   Select 0 for TFTP method
   Input U-Boot's IP address: 192.168.1.1
   Input TFTP server's IP address: 192.168.1.2
   Input IP netmask: 255.255.255.0
   Input file name: openwrt-ramips-mt7621-asus_rt-ax1800hp-squashfs-factory.bin
- Restart AP aftre see the log "Firmware upgrade completed!"

Signed-off-by: Karl Chan <exkc@exkc.moe>

1 files changed, 186 insertions, 0 deletions

diff --git a/target/linux/ramips/dts/mt7621_asus_rt-ax54.dts b/target/linux/ramips/dts/mt7621_asus_rt-ax54.dts
new file mode 100644
index 0000000000..3191692e4e
--- /dev/null
+++ b/target/linux/ramips/dts/mt7621_asus_rt-ax54.dts
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include "mt7621.dtsi"
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/leds/common.h>
+
+/ {
+	compatible = "asus,rt-ax54", "mediatek,mt7621-soc";
+	model = "ASUS RT-AX54";
+
+	aliases {
+		led-boot = &led_power;
+		led-failsafe = &led_power;
+		led-running = &led_power;
+		led-upgrade = &led_power;
+		label-mac-device = &gmac0;
+	};
+
+	chosen {
+		bootargs = "console=ttyS0,115200";
+		bootargs-override = "console=ttyS0,115200";
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led_power: power {
+			label = "blue:power";
+			color = <LED_COLOR_ID_BLUE>;
+			function = LED_FUNCTION_POWER;
+			gpios = <&gpio 13 GPIO_ACTIVE_LOW>;
+		};
+
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		key-restart {
+			label = "reset";
+			gpios = <&gpio 16 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+
+		key-wps {
+			label = "wps";
+			gpios = <&gpio 15 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_WPS_BUTTON>;
+		};
+	};
+};
+
+&nand {
+	status = "okay";
+
+	mediatek,nmbm;
+	mediatek,bmt-max-ratio = <1>;
+	mediatek,bmt-max-reserved-blocks = <64>;
+	mediatek,bmt-remap-range = <0x000000 0x7e0000>;
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		partition@0 {
+			label = "u-boot";
+			reg = <0x0 0x80000>;
+			read-only;
+		};
+
+		/*
+		 * u-boot gets split here while keeping u-boot read-only,
+		 * which allows safe usage of fw_setenv
+		 */
+		partition@80000 {
+			label = "u-boot-env";
+			reg = <0x80000 0x60000>;
+		};
+
+		partition@e0000 {
+			label = "nvram";
+			reg = <0xe0000 0x100000>;
+			read-only;
+		};
+
+		factory: partition@1e0000 {
+			label = "factory";
+			reg = <0x1e0000 0x100000>;
+			read-only;
+
+			compatible = "nvmem-cells";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			macaddr_factory_4: macaddr@4 {
+				reg = <0x4 0x6>;
+			};
+		};
+
+		factory2: partition@2e0000 {
+			label = "factory2";
+			reg = <0x2e0000 0x100000>;
+			read-only;
+		};
+
+		partition@3e0000 {
+			label = "kernel";
+			reg = <0x3e0000 0x400000>;
+		};
+
+		partition@7e0000 {
+			label = "ubi";
+			reg = <0x7e0000 0x7020000>;
+		};
+
+		/* Last 8M are reserved for NMBM management (bad blocks) */
+	};
+};
+
+&pcie {
+	status = "okay";
+};
+
+&pcie1 {
+	wifi@0,0 {
+		compatible = "mediatek,mt76";
+		reg = <0x0000 0 0 0 0>;
+		mediatek,mtd-eeprom = <&factory 0x0000>;
+		mediatek,disable-radar-background;
+	};
+};
+
+&gmac0 {
+	nvmem-cells = <&macaddr_factory_4>;
+	nvmem-cell-names = "mac-address";
+};
+
+&gmac1 {
+	status = "okay";
+	label = "wan";
+	phy-handle = <&ethphy4>;
+
+	nvmem-cells = <&macaddr_factory_4>;
+	nvmem-cell-names = "mac-address";
+};
+
+&mdio {
+	ethphy4: ethernet-phy@4 {
+		reg = <4>;
+	};
+};
+
+&switch0 {
+	ports {
+		port@0 {
+			status = "okay";
+			label = "lan4";
+		};
+
+		port@1 {
+			status = "okay";
+			label = "lan3";
+		};
+
+		port@2 {
+			status = "okay";
+			label = "lan2";
+		};
+
+		port@3 {
+			status = "okay";
+			label = "lan1";
+		};
+	};
+};
+
+&state_default {
+	gpio {
+		groups = "i2c", "uart2", "uart3", "jtag", "wdt";
+		function = "gpio";
+	};
+};
+