Joystick:getGamepadMappingString
Gets the full gamepad mapping string of this Joystick, or nil if it's not recognized as a gamepad.

The mapping string contains binding information used to map the Joystick's buttons an axes to the standard gamepad layout, and can be used later with love.joystick.loadGamepadMappings.
mappingstring = Joystick:getGamepadMappingString()
mappingstring string A string containing the Joystick's gamepad mappings, or nil if the Joystick is not recognized as a gamepad.