/*
2014/8/8 Rev1.0
Copyright (C) Sadaji Sunaga
This module is free.
*/

#include "my_i2c_sensors.h"
#include "i2c-dev.h"

static int writeSensor(int fd, int sensorAddr, u_char regNo, u_char data);

int openI2C(char* deviceName){
  int fd = open(deviceName, O_RDWR);
  if (fd < 0) {
    return -1;
  }
  return fd;
}




int SetSmbus (int fd, char rw, int command, int size, union i2c_smbus_data *data)
{
  struct i2c_smbus_ioctl_data args ;


  args.read_write = rw ;
  args.command    = command ;
  args.size       = size ;
  args.data       = data ;
  return ioctl(fd, I2C_SMBUS, &args) ;
}




static u_char readSensor(int fd, int sensorAddr, u_char regNo)
{

	union i2c_smbus_data data;
  	if (ioctl(fd, I2C_SLAVE, sensorAddr) < 0) 
  	{
    	return -1;
  	}

 	if (SetSmbus (fd, I2C_SMBUS_READ, regNo, I2C_SMBUS_BYTE_DATA, &data) < 0)
 	 {
		  return 0;
  	}
  	return ( u_char)(data.byte & 0xFF);
 
}

static int writeSensor(int fd, int sensorAddr, u_char regNo, u_char data)
{
  u_char buf[2];

  	if (ioctl(fd, I2C_SLAVE, sensorAddr) < 0) 
  	{
    	return -1;
  	}

  buf[0] = regNo;
  buf[1] = data;
  
  if((write(fd,buf,2))!=2)
  {
    return -1;
  }
  return 1;
}


float getTempareture(int fd)
{
	float temp = 0.0f;

	int h,l;
	
	l = readSensor(fd,  LPS331AP_ADDR, 0x2b);
 	h = readSensor(fd,  LPS331AP_ADDR, 0x2c);
	short t = (short)((h << 8) + l);
	temp = (float)t / 480.0f + 42.5f;
	return temp;
}

float getPressure(int fd)
{
	int h,m,l;	

	l = readSensor(fd,  LPS331AP_ADDR, 0x28);
 	m = readSensor(fd,  LPS331AP_ADDR, 0x29);
 	h = readSensor(fd,  LPS331AP_ADDR, 0x2a);

	int data =  (h << 16) + (m << 8) + l;
	float press = (float)data / 4096.0f;

	return press;
}

int activateLPS331AP(int fd)
{
	return writeSensor(fd, LPS331AP_ADDR, 0x20, 0x90);
}