// Compile with:
// gcc -g -Wall -Wextra -Wno-missing-field-initializers -I. -Ilinux -I/usr/lib/gcc/arm-linux-gnueabihf/4.6/include -static i2cget.c i2cbusses.c util.c -o i2cget

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <i2c-dev.h>
#include <i2cbusses.h>
#include <util.h>

int main()
{
    int res, file;
    char filename[20] = "/dev/i2c-0";
    int axis = 0, byte = 0, count = 0;
    
    file = open_i2c_dev(0, filename, 0);
    set_slave_addr(file, 0x0e, 0);
    
    // set registers
    //                   DR(3)             OS(2)         FR(1)
    unsigned char reg0 = (0b000 << 5) + (0b00 << 3) +   (0 << 2)
    //                   TRIG(1)    ACT(1)
                        + (0 << 1) + (1 << 0);
    //                   ARST(1)   Res(1)  RAW(1)      RST(1)   Res(4)
    unsigned char reg1 = (0b1 << 7) +     (0b0 << 5) + (0b0 << 4);
    i2c_smbus_write_byte_data(file, 0x10, reg0);
    i2c_smbus_write_byte_data(file, 0x11, reg1);
    
    // set x, y, z offset
    i2c_smbus_write_byte_data(file, 0x09, 0);
    i2c_smbus_write_byte_data(file, 0x0A, 0);
    i2c_smbus_write_byte_data(file, 0x0B, 0);
    i2c_smbus_write_byte_data(file, 0x0C, 0);
    i2c_smbus_write_byte_data(file, 0x0D, 0b11110110);
    i2c_smbus_write_byte_data(file, 0x0E, 0b11111111);
    
    float fullScale = 925.0;
    
    while ( 1 ) {
        count++;
        res = i2c_smbus_read_byte_data(file, 0x00);
        if ( res != 0xff )
            continue;
        for ( axis = 0; axis < 3; axis++ ) {
            int value = 0;
            for ( byte = 0; byte <= 1; byte++ ) {
                value += i2c_smbus_read_byte_data(file, axis*2 + 1 + byte) << (1-byte)*8;
            }
            if ( value >= (1 << 15) ) {
                value -= 1 << 16;
            }
            printf("%i ", (int) ( value / fullScale * 360 ));
        }
        printf("\n");
        fflush(stdout);
    }
    exit(0);
}