ramips: add support for Xiaomi Mi Router 4A (100M Edition)

- SoC:      MediaTek MT7628AN
- Flash:    16MB (Winbond W25Q128JV)
- RAM:      64MB
- Serial:   As marked on PCB, 3V3 logic, baudrate is 115200
- Ethernet: 3x 10/100 Mbps (switched, 2x LAN + WAN)
- WIFI0:    MT7628AN 2.4GHz 802.11b/g/n
- WIFI1:    MT7612EN 5GHz 802.11ac
- Antennas: 4x external (2 per radio), non-detachable
- LEDs:     Programmable power-LED (two-colored, yellow/blue)
            Non-programmable internet-LED (shows WAN-activity)
- Buttons:  Reset

INSTALLATION:

1. Connect to the serial port of the router and power it up.
   If you get a prompt asking for boot-mode, go to step 3.
2. Unplug the router after
       > Erasing SPI Flash...
       > raspi_erase: offs:20000 len:10000
   occurs on the serial port. Plug the router back in.
3. At the prompt select option 2 (Load system code then
   write to Flash via TFTP.)
4. Enter 192.168.1.1 as the device IP and 192.168.1.2 as the
   Server-IP.
5. Connect your computer to LAN1 and assign it as 192.168.1.2/24.
6. Rename the sysupgrade image to test.bin and serve it via TFTP.
7. Enter test.bin on the serial console and press enter.

Signed-off-by: Markus Scheck <markus@mscheck.de>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
[added mt76 compatible]

1 files changed, 147 insertions, 0 deletions

diff --git a/target/linux/ramips/dts/XIAOMI-MIR4A-100M.dts b/target/linux/ramips/dts/XIAOMI-MIR4A-100M.dts
new file mode 100644
index 0000000000..8a33745f7f
--- /dev/null
+++ b/target/linux/ramips/dts/XIAOMI-MIR4A-100M.dts
@@ -0,0 +1,147 @@
+//SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+/dts-v1/;
+
+#include "mt7628an.dtsi"
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+
+/ {
+	compatible = "xiaomi,mir4a-100m", "mediatek,mt7628an-soc";
+	model = "Xiaomi Mi Router 4A (100M Edition)";
+
+	chosen {
+		bootargs = "console=ttyS0,115200";
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x0 0x4000000>;
+	};
+
+	aliases {
+		led-boot = &power_yellow;
+		led-failsafe = &power_yellow;
+		led-running = &power_blue;
+		led-upgrade = &power_yellow;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		power_blue: power_blue {
+			label = "mir4a-100m:blue:power";
+			gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
+		};
+
+		power_yellow: power_yellow {
+			label = "mir4a-100m:yellow:power";
+			gpios = <&gpio1 12 GPIO_ACTIVE_LOW>;
+		};
+	};
+
+	keys {
+		compatible = "gpio-keys-polled";
+		poll-interval = <20>;
+
+		reset {
+			label = "reset";
+			gpios = <&gpio1 6 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+	};
+};
+
+&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 = "bootloader";
+				reg = <0x0 0x20000>;
+				read-only;
+			};
+
+			partition@20000 {
+				label = "config";
+				reg = <0x20000 0x10000>;
+				read-only;
+			};
+
+			factory: partition@30000 {
+				label = "factory";
+				reg = <0x30000 0x10000>;
+				read-only;
+			};
+
+			partition@40000 {
+				label = "crash";
+				reg = <0x40000 0x10000>;
+				read-only;
+			};
+
+			partition@50000 {
+				label = "cfg_bak";
+				reg = <0x50000 0x10000>;
+				read-only;
+			};
+
+			partition@60000 {
+				label = "overlay";
+				reg = <0x60000 0x100000>;
+				read-only;
+			};
+
+			partition@160000 {
+				label = "firmware";
+				reg = <0x160000 0xea0000>;
+				compatible = "denx,uimage";
+			};
+		};
+	};
+};
+
+&pcie {
+	status = "okay";
+};
+
+&pcie0 {
+	wifi@0,0 {
+		compatible = "mediatek,mt76";
+		reg = <0x0000 0 0 0 0>;
+		mediatek,mtd-eeprom = <&factory 0x8000>;
+		ieee80211-freq-limit = <5000000 6000000>;
+	};
+};
+
+&pinctrl {
+	state_default: pinctrl0 {
+		gpio {
+			ralink,group = "gpio", "wdt", "wled_an";
+			ralink,function = "gpio";
+		};
+	};
+};
+
+&ethernet {
+	mtd-mac-address = <&factory 0x4>;
+	mtd-mac-address-increment = <(-1)>;
+};
+
+&esw {
+	mediatek,portmap = <0x2f>;
+	mediatek,portdisable = <0x2a>;
+};
+
+&wmac {
+	status = "okay";
+};