R-01 library for small OS

[ylyamin]

Hi all,

I created bare-metal library for R-01 (for Allwinner D1H RISC-V SOC).
Tested in ClockworkPi DevTerm R-01
Everything actually is based on @robots allwinner_t113 and @ua1arn hftrx projects, these guys are genius.

Is minimal low-level library could be used to run own OS, or Doom or whatever.

Now is have:

• Bootloader, could run from SD card.
• USB keyboard working well
• TWI (I2C) supported AXP228 Power management chip for Display backlight and USB power.
• UART, GPIO

To run need configure UART adapter to 115200 baud rate.
Insert flashed SD card to device should see output like this:

[INF]:  \ | /
[INF]:  - Allwinner D1 HAL [ver: 0.0.1-5-gd69c9f1]
[INF]:  / | \
[INF]:  SoC: D1H
[INF]:  Platform: ClockworkPi Devterm R-01
[DBG]:irq_init
[DBG]:twi_init

With Display I have a big problem is work with external board with LCD RGB(ST7701S SPI) but with ClockworkPi LCD MIPI not work.
My dream to have just one C file to init LCD and framebuffer, but LCD driver stack is very complicated.

I found drivers in Linux and RT-Thread OS but is very big and I could not extract from it what should be set.
Tried configure registers the same as in Linux but is still not work.

Perhaps someone would enjoy diving deep into the LCD world to solve this riddle. Ready for issue reports and pull requests!

Also I accumulated many knowledge and write articles when run RT-Thread OS in DevTerm/uConsole R-01, in this OS LCD and USB work well.

[zoenggit]

@ylyamin 在 R-01 library for small OS 中说：

requests

Since LCD RGB is working, DE probably working fine. So what is left could be LCD MIPI part.

Allwinner tends to use the same code everywhere, so there could be a problem to find alternatives. Mainline Linux kernel maybe the only place to look at. Also logic analyzer maybe needed for this kind of task.

Another reference could be xboot project: https://github.com/xboot/xboot , but seems main activities goes into LCD RGB.