backlight-pi

#!/bin/bash
#
# Created by: Westley K
# email: westley@sylabs.io
# Date: Aug 6, 2018
# version-1.0.5
# https://github.com/WestleyK/backlight
#
# Verry simple, yet packed with feature!
# Designed and tested for raspberry pi with official 7 inch touchdcreen.
#
#
# MIT License
#
# Copyright (c) 2018 WestleyK
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#


# incase somthing gose wrong
set -e

VERSION_SCRIPT="version-1.0.5"
DATE_SCRIPT="Date: Aug 6, 2018"

INCREMENT_UP=20
INCREMENT_DOWN=20
BACKLIGHT_BRIGHTNESS="/sys/class/backlight/rpi_backlight/brightness"
BACKLIGHT_POWER="/sys/class/backlight/rpi_backlight/bl_power"

CURRENT=$( cat $BACKLIGHT_BRIGHTNESS )

help_menu() {
	echo "Usage: backlight-pi [OPTION]
	h | help (print help menu)
	15-255 (adjust from 15-255)
	u | up (adjust up by 20)
	d | down (adjust down by 20)
	s | sleep (enter sleep mode)
	v | version (print version)
Source code: https://github.com/WestleyK/backlight"
	exit 0
}

is_writable() {
	if [[ ! -w $BACKLIGHT_BRIGHTNESS ]]; then
		echo -e -n "\033[0;31mERROR: \033[0m"
		echo "file not writable: "$BACKLIGHT_BRIGHTNESS
		echo "Try: sudo backlight-pi"
		exit 1
	fi
}

sleep_mode() {
	is_writable
	echo "Press <ENTER> to exit this mode:"
	sleep 1s
	echo 1 > $BACKLIGHT_POWER
	read INPUT_SLEEP
	echo 0 > $BACKLIGHT_POWER
	exit 0
}

if [[ -n $1 ]]; then
	if [[ $1 = "h" || $1 = "help" ]]; then
		help_menu
		exit 0
	elif [[ $1 = "u" || $1 = "up" ]]; then
		NEW=$((CURRENT + $INCREMENT_UP))
	elif [[ $1 = "d" || $1 = "down" ]]; then
		NEW=$((CURRENT - $INCREMENT_DOWN))
	elif [[ $1 = "s" || $1 = "sleep" ]]; then
		sleep_mode
	elif [[ $1 -ge 15 && $1 -le 255 ]]; then
		NEW=$1
	elif [[ $1 = "v" || $1 = "version" ]]; then
		echo $VERSION_SCRIPT
		echo $DATE_SCRIPT
		exit 0
	else
		echo "Option not found: "$1
		exit 1
	fi
fi

if [[ -z $1 ]]; then
	echo "Current brightness: "$CURRENT
	exit 0
fi

if [[ $NEW -ge 255 ]]; then
	NEW=255
	echo "Max brightness!"
elif [[ $NEW -lt 15 ]]; then
	NEW=15
	echo "Min brightness"
fi
is_writable
echo $NEW > $BACKLIGHT_BRIGHTNESS
echo "Current brightness: "$NEW

exit 0


#
# End script
#