GPIOClass.cpp

// Source: https://github.com/halherta/RaspberryPi-GPIOClass-v2

#include "GPIOClass.h"

using namespace std;

GPIOClass::GPIOClass():valuefd(-1),directionfd(-1),exportfd(-1),unexportfd(-1),gpionum("4")
{
        //GPIO4 is default
    this->export_gpio();
}

GPIOClass::GPIOClass(string gnum):valuefd(-1),directionfd(-1),exportfd(-1),unexportfd(-1),gpionum(gnum)
{
    //Instatiate GPIOClass object for GPIO pin number "gnum"
    this->export_gpio();
}

GPIOClass::~GPIOClass()
{
    this->unexport_gpio();
}


int GPIOClass::export_gpio()
{
    int statusVal = -1;
    string exportStr = "/sys/class/gpio/export";
    this->exportfd = statusVal = open(exportStr.c_str(),  O_WRONLY|O_SYNC);
    if (statusVal < 0){
        perror("could not open SYSFS GPIO export device");
        exit(1);
    }

    stringstream ss;
    ss << this->gpionum;
    string numStr = ss.str();
    statusVal = write(this->exportfd, numStr.c_str(), numStr.length());
    if (statusVal < 0){
        perror("could not write to SYSFS GPIO export device");
        exit(1);
    }

    statusVal = close(this->exportfd);
    if (statusVal < 0){
        perror("could not close SYSFS GPIO export device");
        exit(1);
    }

    return statusVal;
}

int GPIOClass::unexport_gpio()
{
    int statusVal = -1;
    string unexportStr = "/sys/class/gpio/unexport";
    this->unexportfd = statusVal = open(unexportStr.c_str(),  O_WRONLY|O_SYNC);
    if (statusVal < 0){
        perror("could not open SYSFS GPIO unexport device");
        exit(1);
    }

    stringstream ss;
    ss << this->gpionum;
    string numStr = ss.str();
    statusVal = write(this->unexportfd, numStr.c_str(), numStr.length());
    if (statusVal < 0){
        perror("could not write to SYSFS GPIO unexport device");
        exit(1);
    }

    statusVal = close(this->unexportfd);
    if (statusVal < 0){
        perror("could not close SYSFS GPIO unexport device");
        exit(1);
    }

    return statusVal;
}

int GPIOClass::setdir_gpio(string dir)
{
    int statusVal = -1;
    string setdirStr ="/sys/class/gpio/gpio" + this->gpionum + "/direction";


    this->directionfd = statusVal = open(setdirStr.c_str(), O_WRONLY|O_SYNC); // open direction file for gpio
        if (statusVal < 0){
            perror("could not open SYSFS GPIO direction device");
        exit(1);
        }

    if (dir.compare("in") != 0 && dir.compare("out") != 0 ) {
        fprintf(stderr, "Invalid direction value. Should be \"in\" or \"out\". \n");
        exit(1);
    }

    statusVal = write(this->directionfd, dir.c_str(), dir.length());
    if (statusVal < 0){
        perror("could not write to SYSFS GPIO direction device");
        exit(1);
    }

    statusVal = close(this->directionfd);
    if (statusVal < 0){
        perror("could not close SYSFS GPIO direction device");
        exit(1);
    }

        return statusVal;
}


int GPIOClass::setval_gpio(string val)
{

    int statusVal = -1;
    string setValStr = "/sys/class/gpio/gpio" + this->gpionum + "/value";

    this->valuefd = statusVal = open(setValStr.c_str(), O_WRONLY|O_SYNC);
    if (statusVal < 0){
            perror("could not open SYSFS GPIO value device");
        exit(1);
    }

    if (val.compare("1") != 0 && val.compare("0") != 0 ) {
        fprintf(stderr, "Invalid  value. Should be \"1\" or \"0\". \n");
        exit(1);
    }

    statusVal = write(this->valuefd, val.c_str(), val.length());
    if (statusVal < 0){
        perror("could not write to SYSFS GPIO value device");
        exit(1);
    }

    statusVal = close(this->valuefd);
    if (statusVal < 0){
        perror("could not close SYSFS GPIO value device");
        exit(1);
    }

        return statusVal;
}


int GPIOClass::getval_gpio(string& val){

    string getValStr = "/sys/class/gpio/gpio" + this->gpionum + "/value";
    char buff[10];
    int statusVal = -1;
    this->valuefd = statusVal = open(getValStr.c_str(), O_RDONLY|O_SYNC);
    if (statusVal < 0){
            perror("could not open SYSFS GPIO value device");
        exit(1);
    }

    statusVal = read(this->valuefd, &buff, 1);
    if (statusVal < 0){
        perror("could not read SYSFS GPIO value device");
        exit(1);
    }

    buff[1]='\0';

    val = string(buff);

    if (val.compare("1") != 0 && val.compare("0") != 0 ) {
        fprintf(stderr, "Invalid  value read. Should be \"1\" or \"0\". \n");
        exit(1);
    }

    statusVal = close(this->valuefd);
    if (statusVal < 0){
        perror("could not close SYSFS GPIO value device");
        exit(1);
    }

    return statusVal;
}


string GPIOClass::get_gpionum(){

return this->gpionum;

}