In case anyone was wondering, the new Steam Controller does work on Haiku, atleast in a Fallback mode. The D-Pad works as left right up down on a keyboard, the touchpad works as a mouse, and the triggers as mouse buttons, and the left touchpad as a scrollwheel.
I’ve not seen any functionality for the other buttons.
In the input preferences it appears as 8 devices, which is a bit annoying. I hope that we can group these in the future based on some relationship, though ideally the steam controller puck would just be displayed as a single device
though I don’t ever think I’ll see that happen though. I would like to see something like