A few more informations on reports and commands.

[cvuchener]

I have written a Linux kernel driver from the few things I found, it may contains some features you don't know (or that I did not found in your code, I am not really comfortable with python, I may have missed things).

https://github.com/cvuchener/steamcontroller-linux-kernel

It supports wired and wireless devices with connection management (not pairing) and exposes them as generic gamepads (with a sysfs attribute to enable the default mouse). You may want to have a look at valve_sc_raw_event (that parses input interrupts) and any call to valve_sc_send_request.

For input events, I don't think there is anything new for you, but I also parse connection events.

The settings command (0x87) is more detailed than in your readme with separate settings for mouse (0x08) and orientation sensors (0x30). It is not present in this driver, but I also found that 0x18 change the mouse/trackball inertia.

I also use the commands for retrieving the serial (0xae), or getting the connection state (0xb4), or disabling key events (0x81).

I hope this will help. Don't hesitate to ask questions or correct any mistake I may have made.