Rather than have a bunch of separate rule files for each USB HID device I’ll be using with LinuxCNC on the M2, here they are in one lump:
cat /etc/udev/rules.d/hal-input.rules # Rules to configure input device permissions for hal_input ATTRS{product}=="Nostromo SpeedPad2",GROUP="plugdev",MODE="0660" ATTRS{product}=="Arduino Leonardo",GROUP="plugdev",MODE="0660" ATTRS{product}=="Logitech Dual Action",GROUP="plugdev",MODE="0660"
The strings are case-sensitive and must match exactly. That post (among others) describes the whole dance required to get all the information.
Remember to add yourself to the plugdev
group, too.