Monitor Switch

#include <stdlib.h>
#include <stdio.h>

#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>

#include <linux/types.h>
#include <linux/i2c-dev.h>

struct i2c_msg {
    __u16 addr;
    __u16 flags;
    __u16 len;
    __u8 *buf;
};

int i, fd;

void send(const char* data, int len){
    struct i2c_rdwr_ioctl_data msg_rdwr;
    struct i2c_msg             i2cmsg;

    msg_rdwr.msgs = &i2cmsg;
    msg_rdwr.nmsgs = 1;

    i2cmsg.addr  = 0x37;
    i2cmsg.flags = 0;
    i2cmsg.len   = len;
    i2cmsg.buf   = (__u8*)data;

    if ((i = ioctl(fd, I2C_RDWR, &msg_rdwr)) < 0 )
    {
        perror("ioctl()");
        fprintf(stderr,"ioctl returned %d\n",i);
        exit(-1);
    }
}

void init(){
    fd = open("/dev/i2c-6",O_RDWR);
    if(fd < 0){
        printf("Failed to open bus 6\n");
        exit(-1);
    }
    send("\x00",1);
}

void print_usage(char* name){
    printf("USAGE: %s h1 - switches to HDMI1 input\n", name);
    printf("       %s h2 - switches to HDMI2 input\n", name);
}

int main(int argc, char** argv){

    if(argc < 2){
        print_usage(argv[0]);
        return -2;
    }else{
        char c = argv[1][0];
        if(c != 'h1' && c != 'h2'){
            print_usage(argv[0]);
            return -2;
        }else{
            init();
            if(c == 'h1'){
                printf("Switching to HDMI1\n");
                send("\x51\x84\x03\x60\x00\x11\xc9\x00", 7);
            }else if(c == 'h2'){
                printf("Switching to HDMI2\n");
                send("\x51\x84\x03\x60\x00\x10\xc8\x00", 7);
            }
            close(fd);
        }
    }
}