GPIO.h

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/*
 * @file GPIO.h
 * @author Derek Molloy
 * @version 0.1
 *
 * Created on: 29 Apr 2014
 * Copyright (c) 2014 Derek Molloy (www.derekmolloy.ie)
 * Made available for the book "Exploring BeagleBone"
 * See: www.exploringbeaglebone.com
 * Licensed under the EUPL V.1.1
 *
 * This Software is provided to You under the terms of the European
 * Union Public License (the "EUPL") version 1.1 as published by the
 * European Union. Any use of this Software, other than as authorized
 * under this License is strictly prohibited (to the extent such use
 * is covered by a right of the copyright holder of this Software).
 *
 * This Software is provided under the License on an "AS IS" basis and
 * without warranties of any kind concerning the Software, including
 * without limitation merchantability, fitness for a particular purpose,
 * absence of defects or errors, accuracy, and non-infringement of
 * intellectual property rights other than copyright. This disclaimer
 * of warranty is an essential part of the License and a condition for
 * the grant of any rights to this Software.
 *
 * For more details, see http://www.derekmolloy.ie/
 */

#ifndef GPIO_H_
#define GPIO_H_
#include<string>
#include<fstream>
using std::string;
using std::ofstream;

#define GPIO_PATH "/sys/class/gpio/"

namespace exploringBB {

typedef int (*CallbackType)(int);

class GPIO {
public:
        enum DIRECTION{ INPUT, OUTPUT };
        enum VALUE{ LOW=0, HIGH=1 };
        enum EDGE{ NONE, RISING, FALLING, BOTH };

private:
        int number;                     
        int debounceTime;   
        string name;            
        string path;            
public:
        GPIO(int number);
        virtual int getNumber() { return number; } 
        // General Input and Output Settings
        virtual int setDirection(GPIO::DIRECTION);
        virtual GPIO::DIRECTION getDirection();
        virtual int setValue(GPIO::VALUE);
        virtual int toggleOutput();
        virtual GPIO::VALUE getValue();
        virtual int setActiveLow(bool isLow=true);  //low=1, high=0
        virtual int setActiveHigh(); //default
        //software debounce input (ms) - default 0
        virtual void setDebounceTime(int time) { this->debounceTime = time; }

        // Advanced OUTPUT: Faster write by keeping the stream alive (~20X)
        virtual int streamOpen();
        virtual int streamWrite(GPIO::VALUE);
        virtual int streamClose();

        virtual int toggleOutput(int time); //threaded invert output every X ms.
        virtual int toggleOutput(int numberOfTimes, int time);
        virtual void changeToggleTime(int time) { this->togglePeriod = time; }
        virtual void toggleCancel() { this->threadRunning = false; }

        // Advanced INPUT: Detect input edges; threaded and non-threaded
        virtual int setEdgeType(GPIO::EDGE);
        virtual GPIO::EDGE getEdgeType();
        virtual int waitForEdge(); // waits until button is pressed
        virtual int waitForEdge(CallbackType callback); // threaded with callback
        virtual void waitForEdgeCancel() { this->threadRunning = false; }

        virtual ~GPIO();  //destructor will unexport the pin

private:
        //int write(string path, string filename, string value);
        //int write(string path, string filename, int value);
        //string read(string path, string filename);
        int exportGPIO();
        int unexportGPIO();
        ofstream stream;
        pthread_t thread;
        CallbackType callbackFunction;
        bool threadRunning;
        int togglePeriod;  //default 100ms
        int toggleNumber;  //default -1 (infinite)
        friend void* threadedPoll(void *value);
        friend void* threadedToggle(void *value);
};

void* threadedPoll(void *value);
void* threadedToggle(void *value);

} /* namespace exploringBB */

#endif /* GPIO_H_ */