Adding the PS3 sixaxis controller (for linux) using SDL2 gamepad tool was a sinch. Unfortunately the switch pro controller is not recognized by the tool.
Here is the PS3 controller if you want to add it:
050000004c0500006802000000800000,Sony PLAYSTATION(R)3 Controller,platform:Linux,a:b0,b:b1,x:b3,y:b2,back:b8,guide:b10,start:b9,leftstick:b11,rightstick:b12,leftshoulder:b4,rightshoulder:b5,dpup:b13,dpdown:b14,dpleft:b15,dpright:b16,leftx:a0,lefty:a1,rightx:a3,righty:a4,lefttrigger:a2,righttrigger:a5,