#!/bin/sh

PTT_BL_CF=/etc/brightness.conf

# in newer kernels device has been renamed:
if [ -f /sys/class/backlight/pcf50633-bl/brightness ]; then
	PTT_BL_IO=/sys/class/backlight/pcf50633-bl/brightness
	PTT_BL_MIN=7
	PTT_BL_MAX=60
	PTT_BL_STEP=14
else
	PTT_BL_IO=/sys/class/backlight/gta02-bl/brightness
	PTT_BL_MIN=28
	PTT_BL_MAX=230
	PTT_BL_STEP=52
fi

if [ $# -gt 0 ]; then
	echo $1 > $PTT_BL_IO
	echo $1 > $PTT_BL_CF
	exit 0
fi

PTT_BL=`cat $PTT_BL_IO`

if [ $PTT_BL -gt $PTT_BL_MAX ]; then
	PTT_BL=$PTT_BL_MIN
else
	PTT_BL=$((PTT_BL+PTT_BL_STEP))
fi
	
echo $PTT_BL > $PTT_BL_IO
# save to config file too
echo $PTT_BL > $PTT_BL_CF