/******************************************************************************
 *  Copyright (c) 2016, Xilinx, Inc.
 *  All rights reserved.
 * 
 *  Redistribution and use in source and binary forms, with or without 
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1.  Redistributions of source code must retain the above copyright notice, 
 *     this list of conditions and the following disclaimer.
 *
 *  2.  Redistributions in binary form must reproduce the above copyright 
 *      notice, this list of conditions and the following disclaimer in the 
 *      documentation and/or other materials provided with the distribution.
 *
 *  3.  Neither the name of the copyright holder nor the names of its 
 *      contributors may be used to endorse or promote products derived from 
 *      this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 *  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 *  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 *  OR BUSINESS INTERRUPTION). HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 *  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
 *  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
 *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *****************************************************************************/
/******************************************************************************
 *
 *
 * @file i2cps.c
 *
 * Functions to interact with linux I2C. No safe checks here, so users must
 * know what they are doing.
 *
 * <pre>
 * MODIFICATION HISTORY:
 *
 * Ver   Who  Date     Changes
 * ----- --- ------- -----------------------------------------------
 * 1.00a gn  02/03/16 release
 * 1.00b yrq 08/31/16 add license header
 *
 * </pre>
 *
 *****************************************************************************/

#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "i2cps.h"

int setI2C(unsigned int index, long slave_addr){
    int i2c_fd;
    char buf[50];
    sprintf(buf, "/dev/i2c-%d", index);          
    if((i2c_fd = open(buf, O_RDWR)) < 0)
        return -1;
    if (ioctl(i2c_fd, I2C_SLAVE, slave_addr) < 0)
        return -1;
    return i2c_fd;
}

int unsetI2C(int i2c_fd){
    close(i2c_fd);
    return 0;    
}

int writeI2C_asFile(int i2c_fd, unsigned char writebuffer[], 
                    unsigned char bytes){
    unsigned char bytesWritten = write(i2c_fd, writebuffer, bytes);
    if(bytes != bytesWritten)
        return -1;
    return 0;
}

int readI2C_asFile(int i2c_fd, unsigned char readbuffer[], 
                   unsigned char bytes){
    unsigned char bytesRead = read(i2c_fd, readbuffer, bytes);
    if(bytes != bytesRead)
        return -1;
    return 0;
}