Unfortunately there is nothing generic about HID controllers on the Mac, the code was tested with three different controllers so should be able to enumerate any device that reports itself as kHIDUsage_GD_Joystick, kHIDUsage_GD_GamePad, or kHIDUsage_GD_MultiAxisController classes.
Exactly what joystick are you testing with?
Exactly what joystick are you testing with?