ramips: mt76x8: add support for Yuncore M300

Hardware:
 - SoC: MediaTek MT7628DAN (MIPS 580MHz)
 - Flash: 8 MiB Spansion S25FL064K
 - RAM: 64 MiB (built-into SoC)
 - WLAN: 2.4 GHz (MT7628)
 - Ethernet: 1x 10/100 Mbps WAN, 1x 10/100 LAN (MT7628)
 - Buttons: 1 Reset button
 - LEDs: 1x Red, 1x Green
 - Serial console: unpopulated header, 57600 8n1 (RX only)
 - Power: 12 VDC, 1 A

There are unpopulated areas on the board for 5 GHz WiFi via PCIe as well
as (most likely) Quectel EG25-G 4G module. As both are not populated on
my board support for both is missing for now.

Installation:
The installation can be done via the recovery HTTP server which is built
into the bootloader. Hold down the reset button while connecting the
device to power and keep holding a bit more than 3 seconds. Connect to
http://192.168.188.253/ and upload sysupgrade.bin file.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

target/linux/ramips/dts/mt7628an_yuncore_m300.dts

@@ -0,0 +1,147 @@
+#include "mt7628an.dtsi"
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/leds/common.h>
+
+/ {
+	compatible = "yuncore,m300", "mediatek,mt7628an-soc";
+
+	chosen {
+		bootargs = "console=ttyS0,57600";
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		reset {
+			label = "reset";
+			gpios = <&gpio 38 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+	};
+
+	aliases {
+		label-mac = &ethernet;
+		led-boot = &led_indicator;
+		led-failsafe = &led_indicator;
+		led-running = &led_indicator;
+		led-upgrade = &led_indicator;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led_indicator: indicator {
+			function = LED_FUNCTION_INDICATOR;
+			color = <LED_COLOR_ID_RED>;
+			gpios = <&gpio 11 GPIO_ACTIVE_LOW>;
+		};
+
+		lan {
+			function = LED_FUNCTION_LAN;
+			color = <LED_COLOR_ID_GREEN>;
+			gpios = <&gpio 40 GPIO_ACTIVE_LOW>;
+		};
+
+		wan {
+			function = LED_FUNCTION_WAN;
+			color = <LED_COLOR_ID_GREEN>;
+			gpios = <&gpio 39 GPIO_ACTIVE_LOW>;
+		};
+	};
+
+	watchdog {
+		compatible = "linux,wdt-gpio";
+		gpios = <&gpio 37 GPIO_ACTIVE_HIGH>;
+		hw_algo = "toggle";
+		hw_margin_ms = <20000>;
+		always-running;
+	};
+};
+
+&spi0 {
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <10000000>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "u-boot";
+				reg = <0x0 0x30000>;
+				read-only;
+			};
+
+			partition@30000 {
+				label = "u-boot-env";
+				reg = <0x30000 0x10000>;
+				read-only;
+			};
+
+			partition@40000 {
+				label = "factory";
+				reg = <0x40000 0x10000>;
+				read-only;
+
+				nvmem-layout {
+					compatible = "fixed-layout";
+					#address-cells = <1>;
+					#size-cells = <1>;
+
+					eeprom_factory_0: eeprom@0 {
+						reg = <0x0 0x400>;
+					};
+
+					macaddr_factory_4: macaddr@4 {
+						reg = <0x4 0x6>;
+					};
+				};
+			};
+
+			partition@50000 {
+				compatible = "denx,uimage";
+				label = "firmware";
+				reg = <0x50000 0x7b0000>;
+			};
+		};
+	};
+};
+
+&ethernet {
+	nvmem-cells = <&macaddr_factory_4>;
+	nvmem-cell-names = "mac-address";
+};
+
+&esw {
+	mediatek,portmap = <0x3e>;
+};
+
+&wmac {
+	status = "okay";
+
+	nvmem-cells = <&eeprom_factory_0>;
+	nvmem-cell-names = "eeprom";
+};
+
+&state_default {
+	gpio {
+		groups = "pwm1", "pwm0", "uart2", "uart1", "i2c", "refclk",
+			 "perst", "wdt", "sdmode", "i2s", "spi cs1", "spis",
+			 "gpio", "p0led_an", "p1led_an", "p2led_an", "p3led_an",
+			 "p4led_an", "wled_kn", "p0led_kn", "p1led_kn",
+			 "p2led_kn", "p3led_kn", "p4led_kn";
+		function = "gpio";
+	};
+
+	wlan {
+		groups = "wled_an";
+		function = "wled_an";
+	};
+};

target/linux/ramips/image/mt76x8.mk

@@ -1136,6 +1136,13 @@ define Device/xiaomi_mi-ra75
 endef
 TARGET_DEVICES += xiaomi_mi-ra75
 
+define Device/yuncore_m300
+  IMAGE_SIZE := 7872k
+  DEVICE_VENDOR := Yuncore
+  DEVICE_MODEL := M300
+endef
+TARGET_DEVICES += yuncore_m300
+
 define Device/zbtlink_zbt-we1226
   IMAGE_SIZE := 7872k
   DEVICE_VENDOR := Zbtlink

target/linux/ramips/mt76x8/base-files/etc/board.d/01_leds

@@ -18,7 +18,8 @@ asus,rt-n11p-b1|\
 asus,rt-n12-vp-b1|\
 netgear,r6020|\
 netgear,r6080|\
-netgear,r6120)
+netgear,r6120|\
+yuncore,m300)
 	ucidef_set_led_switch "lan" "lan" "green:lan" "switch0" "0xf"
 	ucidef_set_led_switch "wan" "wan" "green:wan" "switch0" "0x10"
 	;;

target/linux/ramips/mt76x8/base-files/etc/board.d/02_network

@@ -81,7 +81,8 @@ ramips_setup_interfaces()
 	buffalo,wcr-1166ds|\
 	elecom,wrc-1167fs|\
 	wavlink,wl-wn577a2|\
-	wavlink,wl-wn578a2)
+	wavlink,wl-wn578a2|\
+	yuncore,m300)
 		ucidef_add_switch "switch0" \
 			"3:lan" "4:wan" "6@eth0"
 		;;

target/linux/ramips/mt76x8/config-6.6

@@ -84,6 +84,8 @@ CONFIG_GPIO_CDEV=y
 CONFIG_GPIO_GENERIC=y
 CONFIG_GPIO_MT7621=y
 # CONFIG_GPIO_RALINK is not set
+CONFIG_GPIO_WATCHDOG=y
+# CONFIG_GPIO_WATCHDOG_ARCH_INITCALL is not set
 CONFIG_HARDWARE_WATCHPOINTS=y
 CONFIG_HAS_DMA=y
 CONFIG_HAS_IOMEM=y