#include "spi.h"

SPI::SPI(int device)
{
    spi_device = device;
}

SPI::~SPI()
{
    //
}

//spi_device	0=CS0, 1=CS1
int SPI::SpiOpenPort()
{
	int status_value = -1;


    //----- SET SPI MODE -----
    //SPI_MODE_0 (0,0) 	CPOL = 0, CPHA = 0, Clock idle low, data is clocked in on rising edge, output data (change) on falling edge
    //SPI_MODE_1 (0,1) 	CPOL = 0, CPHA = 1, Clock idle low, data is clocked in on falling edge, output data (change) on rising edge
    //SPI_MODE_2 (1,0) 	CPOL = 1, CPHA = 0, Clock idle high, data is clocked in on falling edge, output data (change) on rising edge
    //SPI_MODE_3 (1,1) 	CPOL = 1, CPHA = 1, Clock idle high, data is clocked in on rising, edge output data (change) on falling edge
    spi_mode = SPI_MODE_3;
    
    //----- SET BITS PER WORD -----
    spi_bitsPerWord = 8;
    
    //----- SET SPI BUS SPEED -----
    spi_speed = 1000000;		//1000000 = 1MHz (1uS per bit) 


    if (spi_device)
    	this->spi_cs_fd = open(std::string("/dev/spidev0.1").c_str(), O_RDWR);
    else
    	this->spi_cs_fd = open(std::string("/dev/spidev0.0").c_str(), O_RDWR);

    if (this->spi_cs_fd < 0)
    {
        perror("Error - Could not open SPI device");
        exit(1);
    }

    status_value = ioctl(this->spi_cs_fd, SPI_IOC_WR_MODE, &spi_mode);
    if(status_value < 0)
    {
        perror("Could not set SPIMode (WR)...ioctl fail");
        exit(1);
    }

    status_value = ioctl(this->spi_cs_fd, SPI_IOC_RD_MODE, &spi_mode);
    if(status_value < 0)
    {
      perror("Could not set SPIMode (RD)...ioctl fail");
      exit(1);
    }

    status_value = ioctl(this->spi_cs_fd, SPI_IOC_WR_BITS_PER_WORD, &spi_bitsPerWord);
    if(status_value < 0)
    {
      perror("Could not set SPI bitsPerWord (WR)...ioctl fail");
      exit(1);
    }

    status_value = ioctl(this->spi_cs_fd, SPI_IOC_RD_BITS_PER_WORD, &spi_bitsPerWord);
    if(status_value < 0)
    {
      perror("Could not set SPI bitsPerWord(RD)...ioctl fail");
      exit(1);
    }

    status_value = ioctl(this->spi_cs_fd, SPI_IOC_WR_MAX_SPEED_HZ, &spi_speed);
    if(status_value < 0)
    {
      perror("Could not set SPI speed (WR)...ioctl fail");
      exit(1);
    }

    status_value = ioctl(this->spi_cs_fd, SPI_IOC_RD_MAX_SPEED_HZ, &spi_speed);
    if(status_value < 0)
    {
      perror("Could not set SPI speed (RD)...ioctl fail");
      exit(1);
    }
    return(status_value);
}


int SPI::SpiClosePort()
{
	int status_value = -1;


    status_value = close(this->spi_cs_fd);
    if(status_value < 0)
    {
    	perror("Error - Could not close SPI device");
    	exit(1);
    }
    return(status_value);
}



int SPI::SpiWriteAndRead(unsigned char *data, int length)
{
	struct spi_ioc_transfer spi[length];
	int i = 0;
	int retVal = -1;

	//one spi transfer for each byte

	for (i = 0 ; i < length ; i++)
	{
		memset(&spi[i], 0, sizeof (spi[i]));
		spi[i].tx_buf        = (unsigned long)(data + i); // transmit from "data"
		spi[i].rx_buf        = (unsigned long)(data + i) ; // receive into "data"
		spi[i].len           = sizeof(*(data + i)) ;
		spi[i].delay_usecs   = 0 ;
		spi[i].speed_hz      = spi_speed ;
		spi[i].bits_per_word = spi_bitsPerWord ;
		spi[i].cs_change = 0;
	}

	retVal = ioctl(this->spi_cs_fd, SPI_IOC_MESSAGE(length), &spi) ;

	if(retVal < 0)
	{
		perror("Error - Problem transmitting spi data..ioctl");
		exit(1);
	}

	return retVal;
}