The gl-e750 is a portable travel router that gives you safe access to
the internet while traveling.

Specifications:
- SoC: Qualcomm Atheros AR9531 (650MHz)
- RAM: 128 MB DDR2
- Flash: 16 MB SPI NOR (W25Q128FVSG) + 128 MB SPI NAND (GD5F1GQ4UFYIG)
- Ethernet: 10/100: 1xLAN
- Wireless: QCA9531 2.4GHz (bgn) + QCA9887 5GHz (ac)
- USB: 1x USB 2.0 port
- Switch: 1x switch
- Button: 1x reset button
- OLED Screen: 128*64 px

MAC addresses based on vendor firmware:
LAN *:a0 art 0x0
2.4GHz *:a1 art 0x1002
5GHz *:a2 art calculated from art 0x0 + 2

Flash firmware:
Since openwrt's kernel already exceeds 2MB, upgrading from the official
version of GL-inet (v3.100) using the sysupgrade command will break the
kernel image. Users who are using version 3.100 can only upgrade via
uboot. The official guidance for GL-inet is as follows:
https://docs.gl-inet.com/en/3/troubleshooting/debrick/

In the future, GL-inet will modify the firmware to support the sysupgrade
command, so users will be able to upgrade directly with the sysupgrade
command in future releases.

OLED screen control:
OLED controller is connected to QCA9531 through serial port, and can send
instructions to OLED controller directly through serial port.
Refer to the links below for a list of supported instructions:
https://github.com/gl-inet/GL-E750-MCU-instruction

Signed-off-by: Luochongjun <luochongjun@gl-inet.com>

    Specifications:
        - SOC: Qualcomm IPQ4019 ARM Quad-Core
        - RAM: 512 MiB
        - Flash: 16 MiB NOR - SPI0
        - EMMC: 8GB EMMC
        - ETH: Qualcomm QCA8075
        - WLAN1: Qualcomm Atheros QCA4019 2.4GHz 802.11b/g/n 2x2
        - WLAN2: Qualcomm Atheros QCA4019 5GHz 802.11n/ac W2 2x2
        - WLAN3: Qualcomm Atheros QCA9886 5GHz 802.11n/ac W2 2x2
        - INPUT: Reset, WPS
        - LED: Power, Internet
        - UART1: On board pin header near to LED (3.3V, TX, RX, GND), 3.3V without pin - 115200 8N1
        - UART2: On board with BLE module
        - SPI1: On board socket for Zigbee module

    Update firmware instructions
    ============================
    Pleae update firmware on uboot web(default 192.168.1.1).

Signed-off-by: Li Zhang <li.zhang@gl-inet.com>