Ploopy Nano control by LED-Key BitMask shell script

about.md

A quick script to control lkbm firmware on the Ploopy Nano.

See this post for more features and more explanation.

lkbm.sh

#!/bin/sh
set -e

usage() {
	cat <<ENDUSAGE
$0: Send commands to Ploopy Trackball Nano that is running LKBM firmware via caps/scroll/num lock LED signals
Usage: $0 [scroll|dpi|reset|status|help]
See <https://github.com/qmk/qmk_firmware/tree/master/keyboards/ploopyco/trackball_nano/keymaps/lkbm>.
ENDUSAGE
}

# Find the /sys/class/leds/* path for caps/num/scroll-lock
inputdev=/dev/input/by-id/usb-PloopyCo_Trackball_Nano-event-kbd
evntname="$(basename "$(readlink -f $inputdev)")"
# e.g. "event22"
sysclassdev=/sys/class/input/$evntname/device
sysinputname="$(echo $sysclassdev/*::capslock | sed 's|.*/\(input[0-9]*\).*|\1|')"
# e.g. "input1251"
caps=/sys/class/leds/$sysinputname::capslock/brightness
scroll=/sys/class/leds/$sysinputname::scrolllock/brightness
num=/sys/class/leds/$sysinputname::numlock/brightness

# We have to wait a very small amount of time or the LED changes don't seem to register
# I use busybox sleep but should also work with GNU sleep (untested)
lkbmwait() {
	busybox sleep 0.0025s
}

# Toggle scroll behavior, between using the trackball as normal and using it as a 2D scroll ball
toggle_scroll() {
	echo 1 > "$num"
	lkbmwait
	echo 0 > "$num"
	lkbmwait
}

# Cycle between slow/med/fast DPI
cycle_dpi() {
	echo 1 > "$caps"
	lkbmwait
	echo 0 > "$caps"
	lkbmwait
}

# Enter reset mode to flash new firmware
enter_reset() {
	echo 1 > "$caps"
	lkbmwait
	echo 1 > "$num"
	lkbmwait
	echo 0 > "$num"
	lkbmwait
	echo 0 > "$caps"
	lkbmwait
}

# Read the current status of all the LEDs
read_status() {
	c="$(cat "$caps")"
	s="$(cat "$scroll")"
	n="$(cat "$num")"
	echo "Input device path:          $inputdev"
	echo "Event device name:          $evntname"
	echo "/sys/class even device:     $sysclassdev"
	echo "/sys/class input device:    $sysinputname"
	echo "Capslock:      $c"
	echo "Scroll lock:   $s"
	echo "Numlock:       $n"
}

case "$1" in
	scroll) toggle_scroll;;
	dpi) cycle_dpi;;
	reset) enter_reset;;
	status) read_status;;
	*) usage;;
esac