ramips: add support for Qding QC202

ramips: add support for Qding QC202

This is a smart door lock device equipped with OpenWrt 14.07 OEM
modified version Qdwrt

The OEM has closed down, This commit is intended to maximize the
remaining value of these devices. It can flash OpenWrt to become
an AP

Specification:
- SoC: MediaTek MT7628NN
- Flash: 8 MB
- RAM: 64 MB
- Power: DC 5V - 25V
- Ethernet: 1 x RJ45 (10/100 Mbps)
- Wireless radio: 802.11n 2.4g-only
- On-Board LED:
  Status 1: GPIO/43 active-low
  Status 2: GPIO/44 active-low
  Power: AlwaysOn
- Button:
  WPS / RESET: GPIO/14  active-low
- Bluetooth: CC2541 via UART1 (ttyS1) and GPIO/26-29
- RFID: MF RC522 on I2C@28
- RTC: DS1339 on I2C@68
- Shell (via CON1 cable)
  - LED (Swipe card area):
     -  Green  GPIO/3  active-high
     -  Red    GPIO/11 active-high
  - Matrix keypad: (active-low)
                 GPIO/20 GPIO/21 GPIO/19 (Rows)
        GPIO/24        1       2       3
        GPIO/25        4       5       6
        GPIO/22        7       8       9
        GPIO/23     BACK       0   ENTER
        (Cols)
- UART: 1 x UART on PCB - 57600 8N1
- GPIO Relay: GPIO/42 active-high
- GPIO Buzzer: GPIO/15 active-high

Warning:
The original firmware does not use the device tree.
This device tree is written based on the content of /sys/devices/platform
and has been tested

Note:
- On the device, matrix keypad rows actually are columns, and the columns actually are rows
- The key code of the CLEAR key of the matrix keypad is BACK in the original firmware.

Issue:
- No drivers in mainline kernel for RFID and Bluetooth.

Flash Instruction:
Using SSH/Telnet:
1. Connect the board to the computer via RJ45 Ethernet
2. Login 10.10.10.1 with root password "szqdingnet123" (SSH Port 22, Telnet Port 9900)
3. Download openwrt firmware on the computer.
4. Setup a http server on computer. And use wget download openwrt firmware from computer
5. Use command "mtd -r write openwrt-ramips-mt76x8-qding_qc202-squashfs-sysupgrade.bin firmware"
   to flash

Using U-Boot WebUI:
1. Configure PC with a static IP address 10.10.10.2/24.
2. Open http://10.10.10.1
3. Use "mkqdimg -B qc202 -f openwrt-ramips-mt76x8-qding_qc202-squashfs-sysupgrade.bin" to
   make image.
4. Upload factory.bin via U-Boot WebUI.

Original Firmware Dump / More details:
https://blog.gov.cooking/archives/research-qianding-smart-locker-and-flash.html

Original U-Boot firmware image tools:
https://gitlab.com/CoiaPrant/mkqdimg

Signed-off-by: Coia Prant <coiaprant@gmail.com>
Tested-by: Coia Prant <coiaprant@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/17471
(cherry picked from commit b2f814fed469f435fbb6b5ec9f79e1012caabc3f)
Link: https://github.com/openwrt/openwrt/pull/20159
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>