[Feature] Steam Deck (Steam Controller 2?) Support

[Jazztache]

With the recent murmurs of a second Steam controller happening, it's likely it will use similar technology to the Steam Deck for it's controller.

I recently came across a project called OpenSD that does this, however, it's currently broken, and doesn't have the autoswitch feature that JSM does (on the Deck itself as well if Wayland support is added). On top of this, it seems like the creator has abandoned the Internet all together. The config format is also INI based and not as intuitive as the JSM config.

https://codeberg.org/opensd/opensd

JSM would be a perfect for Steam Deck, as you can make the grip buttons function the same way as the side buttons. For compatibility with existing Joy-Con configs... LSL = L4 LSR = L5 RSR = R4 RSL = R5

Whilst Steam Input does exist, it is proprietary and fairly heavy. For people who only want a gyroscope-enabled input manager and a clean copy of Arch, or are just using Windows for anti-cheat games, JSM would be perfect.

Trackpad support is something I can live without, the lizard mode controls for that are fine, but if that is a second goal, that would be nice. Having a device that lets you use the same configs from the DS4/5 Trackpad and Switch Side buttons would be awesome.

A lot of other smaller projects like emulators and SDL-based games have full compatibility for the Steam Deck's controller. Seeing as a Steam Controller 2 is rumoured to be on the way, which will likely have the same top-notch gyro & controller that the Deck has, this is a great way to get preliminary support for that early.

Thanks for your consideration!