gpiocomm

#!/bin/bash
#Copyright 2016 Kenta Ishii All Rights Reserved.
#This software is under GNU GPL (General Public License) Version 3
#This Shell Script is for Raspbian Jessie on Raspberry Pi 2 Model B and licensed under GNU License.
#Written by Kenta Ishii, Tokyo.
#Make sure to change permissions of this file. e.g. chmod 0744 gpiocomm.
#If you meet any freezen shell, interrupt through ctrl+c or so...
#CAUTION! This software and Kenta Ishii are exempt from all warranty and all compensation caused by all damage as a result of using this software.
#CAUTION! Don't use gpio pins which your Raspberry Pi DOES NOT serve as out-world I/O.
#CAUTION! Available pins of my Raspberry Pi 2 Model B are No.2 to No.27. Otherwise, you'll meet fatal mess...

DEST="/sys/class/gpio"
readonly DEST
MINPIN=2
readonly MINPIN
MAXPIN=27
readonly MAXPIN

#Initially, to use pins, make a pin enable. First is pin's number, second is in or out.
__gpio_set () {
    local pin=$1
    local stat=$2
    local file_dir=${DEST}/gpio${pin}
    local pin_value=2

    echo $pin > ${DEST}/export

    #NEED SPACES AS FOLLOWS AS A SYNTAX
    while [ ! -e $file_dir ]
    do
        echo -e "%Cheking...\n"
    done

    #NEED SLLEP IN ANY WAY
    sleep 0.5

    if [ -e $file_dir ]; then
        #Wild card is to default
        case "$stat" in
            "in")
                echo $stat > ${file_dir}/direction
                pin_value=$(cat ${file_dir}/value)
            ;;
            "out")
                echo $stat > ${file_dir}/direction
                pin_value=$(cat ${file_dir}/value)
            ;;
            * ) echo -e "%Wrong Status..."
                return -1 
            ;;
        esac
    else
       return -1 
    fi

    return $pin_value
}

gpio_set () {
    echo -e "%Pin's number?"
    read pin_number
    if [ ! $pin_number -lt $MINPIN ] && [ ! $pin_number -gt $MAXPIN ]; then
        echo -e "%in or out?"
        read pin_status
        if [ "$pin_status" = "in" ] || [ "$pin_status" = "out" ]; then
            __gpio_set $pin_number $pin_status
            local ret=$?
            echo -e "%Pin${pin_number}'s Status: $pin_status"
            echo -e "%Pin${pin_number}'s Value: $ret"
            return 0
        else
            echo -e "%Wrong Status..."
            return 1
        fi
    else
        echo -e "%Wrong Number..."
        return 1
    fi
}

#To End, unset a pin. First is pin's number
__gpio_unset () {
    local pin=$1
    echo $pin > ${DEST}/unexport      
}

gpio_unset () {
    echo -e "%Pin's number?"
    read pin_number
    if [ ! $pin_number -lt $MINPIN ] && [ ! $pin_number -gt $MAXPIN ]; then
        __gpio_unset $pin_number
        ret=$?
        if [ $ret == 0 ]; then
            echo -e "%Unset gpio${pin_number} successfully"
            return 0
        else
            echo -e "%Error in Unsettting gpio${pin_number}..."
            return 1
        fi
    else
        echo -e "%Wrong Number..."
        return 1
    fi
}

#Send high or low only at output pins.
__gpio_signal () {
    local pin=$1
    local file_dir=${DEST}/gpio${pin}
    local value=$2
    echo $value > ${file_dir}/value
}

gpio_signal () {
    echo -e "%Pin's number?"
    read pin_number

    if [ ! $pin_number -lt $MINPIN ] && [ ! $pin_number -gt $MAXPIN ]; then
        echo -e "%High (1) or Low (0) ?"
        read pin_value
        if [ $pin_value -eq 0 ] || [ $pin_value -eq 1 ]; then
            __gpio_signal $pin_number $pin_value
            ret=$?
            if [ $ret == 0 ]; then
                echo -e "%Signaled gpio${pin_number} successfully"
                return 0
            else
                echo -e "%Error in signaling gpio${pin_number}..."
                return 1
            fi
        else
            echo -e "%Press 1 or 0..."
            return 1
        fi
    else
        echo -e "%Wrong Number..."
        return 1
    fi
}

#Check value of a pin.
__gpio_value () {
    local pin=$1
    local file_dir=${DEST}/gpio${pin}
    cat ${file_dir}/value
}

gpio_value () {
    echo -e "%Pin's number?"
    read pin_number
    __gpio_value $pin_number
}

#Show the list of enable pins.
gpio_list () {
    local i=$MINPIN
    while [ $i -le $MAXPIN ]
    do
        local word="gpio${i}"

        #You should use find rather than grep which is for a raw serching
        local result=$(find ${DEST} -name "${word}")
        if [ $result ]; then
            local file_dir=${DEST}/gpio${i}
            local stat=$(cat ${file_dir}/direction)
            local value=$(cat ${file_dir}/value)
            echo -e "No.${i} I/O ${stat} Value ${value}"
            #Make Sure to Back quotation mark
            i=`expr $i + 1`
        else
            i=`expr $i + 1`
        fi
    done
}

#Interactive loop
main () {
    while :
    do
        echo -e "\n%setup/unset/list/value/signal/exit"
        read comm
        if [ "$comm" = "exit" ]; then
            break
        fi

        case "$comm" in
            "setup")
                gpio_set
            ;;
            "unset")
                gpio_unset
            ;;
            "list")
                gpio_list
            ;;
            "value")
                gpio_value
            ;;
            "signal")
                gpio_signal
            ;;
            * )
                echo -e "%Type Anything Good"
            ;;
        esac
    done
}

if [ ! "$1" = "--functions" ]; then
    echo -e "\n\t[GPIO Interactive Commands Ver1.001]\n\tCopyright 2016 Kenta Ishii All Rights Reserved."
    main
fi