Add support for Tinkerboard 2

[p1r473]

Hi Linus, been a while. Hope all is well.
I have recently purchased a Tinkerboard 2 and am adding support for it.
I'd like you to check over the changes and make sure its implemented how youd like. If not, I am happy to make any changes.

[linusg]

Looks great! Let's rename TINKER_BOARD2 to TINKER_BOARD_2 and tinker-board2 to tinker-board-2, and give the README sections that mention Tinker Board an update, e.g. by adding a sentence below the Tinker Board code example: "For Tinker Board 2, use BoardType.TINKER_BOARD_2."

[p1r473]

Thanks Linus, I have made the changes. Let me know what you think.

[linusg]

🚀

[p1r473]

Thanks Linus!

[linusg]

I'll release this in a new version later today, will let you know. :)

[p1r473]

By the way,
Is there any modifications we can make to initiate the board type as either a Pi, Tinker 1 or 2, and not have to initiate it in both CLI and also init files?
So we can initialize the board type in just 1 location?

[linusg]

Done! https://pypi.org/project/rpi-backlight/2.3.0

Is there any modifications we can make to initiate the board type as either a Pi, Tinker 1 or 2, and not have to initiate it in both CLI and also init files?

I suppose if there's a reliable way to detect the board type, we could have automatic detection if no board type is explicitly provided - perhaps by checking the existence of each path in _BACKLIGHT_SYSFS_PATHS?

[p1r473]

Done! https://pypi.org/project/rpi-backlight/2.3.0

Is there any modifications we can make to initiate the board type as either a Pi, Tinker 1 or 2, and not have to initiate it in both CLI and also init files?

I suppose if there's a reliable way to detect the board type, we could have automatic detection if no board type is explicitly provided - perhaps by checking the existence of each path in _BACKLIGHT_SYSFS_PATHS?

I was thinking of using /proc/device-tree/model

root@Harbormaster:~# cat /proc/device-tree/model
ASUS Tinker Board 2 (Linux Opensource)

What is the output on the Pi?