franta-hg@0: #!/bin/bash
franta-hg@0: 
franta-hg@0: # GPIO.sh
franta-hg@0: # Copyright © 2016 František Kučera (frantovo.cz)
franta-hg@0: #
franta-hg@0: # This program is free software: you can redistribute it and/or modify
franta-hg@0: # it under the terms of the GNU General Public License as published by
franta-hg@0: # the Free Software Foundation, either version 3 of the License, or
franta-hg@0: # (at your option) any later version.
franta-hg@0: #
franta-hg@0: # This program is distributed in the hope that it will be useful,
franta-hg@0: # but WITHOUT ANY WARRANTY; without even the implied warranty of
franta-hg@0: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
franta-hg@0: # GNU General Public License for more details.
franta-hg@0: #
franta-hg@0: # You should have received a copy of the GNU General Public License
franta-hg@0: # along with this program. If not, see <http://www.gnu.org/licenses/>.
franta-hg@0: 
franta-hg@0: # GPIO.sh is a set of functions for controlling GPIO pins of Raspberry Pi or similar computer
franta-hg@0: 
franta-hg@0: _gpio_valid_port() {
franta-hg@0: 	case $1 in 0|1|4|7|8|9|10|11|14|15|17|18|21|22|23|24|25)
franta-hg@0: 		return 0;;
franta-hg@0: 	*)
franta-hg@0: 		return 1;;
franta-hg@0: 	esac
franta-hg@0: }
franta-hg@0: 
franta-hg@0: # export -f _gpio_valid_port
franta-hg@0: # seq 0 30 | xargs -n1 bash -c 'printf "%4s" "$0: "; _gpio_valid_port $0 ; if [ $? -eq 0 ]; then echo "valid port number"; else echo; fi'
franta-hg@0: 
franta-hg@0: 
franta-hg@0: _gpio_log_error() {
franta-hg@0: 	# TODO: $(date --rfc-3339=seconds) or ● ?
franta-hg@0: 	echo -e "\e[1;31m$1\e[0m"; > /dev/stderr;
franta-hg@0: }
franta-hg@0: 
franta-hg@0: _gpio_log_warning() {
franta-hg@0: 	echo -e "\e[2;33m$1 \e[0m"; > /dev/stderr;
franta-hg@0: }
franta-hg@0: 
franta-hg@0: 
franta-hg@0: # open (export) the port and set its direction
franta-hg@0: # parameters:
franta-hg@0: #	port number
franta-hg@0: #	direction: in/out
franta-hg@0: gpio_open() {
franta-hg@0: 	local port="$1";
franta-hg@0: 	local direction="$2";
franta-hg@0: 	if [ $# -ne 2 ] || [[ "$direction" != @("in"|"out") ]]; then _gpio_log_error "usage: ${FUNCNAME[0]} <port> <in|out>"; return 1; fi
franta-hg@0: 	if ! _gpio_valid_port "$port";                          then _gpio_log_error "invalid port number: $port";            return 1; fi;
franta-hg@0: 	
franta-hg@0: 	if [ -d  "/sys/class/gpio/gpio$port" ]; then 
franta-hg@0: 		_gpio_log_warning "port $port is already exported → will just set direction: $direction";
franta-hg@0: 	else
franta-hg@0: 		echo "$port" > "/sys/class/gpio/export" || return 1;
franta-hg@0: 	fi;
franta-hg@0: 	
franta-hg@0: 	echo "$direction" > "/sys/class/gpio/gpio$1/direction";
franta-hg@0: }
franta-hg@0: 
franta-hg@0: 
franta-hg@0: # close (unexport) the port and set its direction
franta-hg@0: # parameters:
franta-hg@0: #	port number
franta-hg@0: gpio_close() {
franta-hg@0: 	local port="$1";
franta-hg@0: 	if [ $# -ne 1 ];               then _gpio_log_error "usage: ${FUNCNAME[0]} <port>"; return 1; fi
franta-hg@0: 	if ! _gpio_valid_port "$port"; then _gpio_log_error "invalid port number: $port";   return 1; fi;
franta-hg@0: 	
franta-hg@0: 	if [ -d  "/sys/class/gpio/gpio$port" ]; then 
franta-hg@0: 		echo "$port" > "/sys/class/gpio/unexport";
franta-hg@0: 	else
franta-hg@0: 		_gpio_log_error "port $port is not open";
franta-hg@0: 		return 1;
franta-hg@0: 	fi;
franta-hg@0: }
franta-hg@0: 
franta-hg@0: # reads value of given port
franta-hg@0: # parameters:
franta-hg@0: #	port number
franta-hg@0: gpio_read() {
franta-hg@0: 	local port="$1";
franta-hg@0: 	if [ $# -ne 1 ];               then _gpio_log_error "usage: ${FUNCNAME[0]} <port>"; return 1; fi
franta-hg@0: 	if ! _gpio_valid_port "$port"; then _gpio_log_error "invalid port number: $port";   return 1; fi;
franta-hg@0: 	
franta-hg@0: 	if ! cat "/sys/class/gpio/gpio$port/value"; then
franta-hg@0: 		_gpio_log_error "unable to read value of port $port";
franta-hg@0: 		return 1;
franta-hg@0: 	fi
franta-hg@0: }
franta-hg@0: 
franta-hg@0: # writes the value to given port
franta-hg@0: # parameters:
franta-hg@0: #	port number
franta-hg@0: #	value: 0/1
franta-hg@0: gpio_write() {
franta-hg@0: 	local port="$1";
franta-hg@0: 	local value="$2";
franta-hg@0: 	if [ $# -ne 2 ] || [[ "$value" != @("0"|"1") ]]; then _gpio_log_error "usage: ${FUNCNAME[0]} <port> <0|1>"; return 1; fi
franta-hg@0: 	if ! _gpio_valid_port "$port";                          then _gpio_log_error "invalid port number: $port";  return 1; fi;
franta-hg@0: 	
franta-hg@0: 	if ! echo "$value" > "/sys/class/gpio/gpio$port/value"; then
franta-hg@0: 		_gpio_log_error "unable to write value $value to port $port";
franta-hg@0: 		return 1;
franta-hg@0: 	fi
franta-hg@0: }
franta-hg@0: