mediatek: add support for AsiaRF AP7622-WH1

mediatek: add support for AsiaRF AP7622-WH1

- SoC           : MediaTek MT7622A, dual-core 1.35 Ghz ARM Cortex-A53 CPU
- RAM           : DDR3 512 MiB (Nanya NT5CC256M16ER-EKI)
- Flash         : SPI-NAND 128 MiB (Winbond W25N01GVZEIG)
- Ethernet      : 5 port Switch
    - LAN :
        4x 10/100/1000 Mbps RJ-45 Port
    - WAN :
        1x 10/100/1000 Mbps RJ-45 Port
- LED           : 10x LEDs
    1x Power (Blue, GPIO)
    1x WiFi (Green, GPIO)
    2x MiniPCIe (Orange)
    1x M.2 B Key (Red)
    5x Ethernet activity (White)
- UART          : 1x4 pin header on PCB [J19]
    - arrangement : 3.3V, TX, RX, GND
    - settings    : 115200, 8n1
- Button        : 2x (Reset, WPS)
- GPS           : 1x (Quectel L76-L)
- WiFi          : 2x
    WiFi 4 (MediaTek MT7622A)
    WiFI HaLow (AsiaRF MM610X-001)
- BT            : BT 4.2/BLE 5.0 (MediaTek MT7622A)
- Socket        :
    2x MiniPCIe (PCIe Gen2 + USB 2.0) with extra SPI interface (NI)
    1x M.2 B key (USB 3.0)
    1x SIM Card
    1x USB-A (USB 2.0)
- Power         : 12V DC, 1A

MAC addresses :
    WLAN:       00:0A:52:xx:xx:xx   (Factory, 0x6)
    LAN:        00:0A:52:xx:xx:xx   (Factory, 0x7fff4)
    WAN:        00:0A:52:xx:xx:xx   (Factory, 0x7fffa)

Note: To use SPI interface on mPCIe slot, weld 4x 0402 0R resistors on [R832-835] or [R960-963]
mPCIe mapping:
    45# - SPI_CLK
    47# - SPI_MISO
    49# - SPI_MOSI
    51# - SPI_CSN

Flash instruction through LuCI:

This device is flashed OpenWRT base firmware with this target.
The LuCI webpage is integrated in default for upgrading.

Flash instruction through u-boot:

1. Prepare the TFTP server on PC.
2. Connect uart to PC, select "2. System Load Linux Kernel then write to Flash via TFTP." in u-boot menu.
3. input flashed bin file path, server IP, client IP
4. Wait about 20 seconds to complete flashing

Signed-off-by: Elwin Huang <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/19962
Signed-off-by: Hauke Mehrtens <[email protected]>