#include "project.h"

static int mutex = 0;

int
i2c_lock (void)
{
  if (__sync_add_and_fetch (&mutex, 1) != 1) {
    __sync_sub_and_fetch (&mutex, 1);
    return -1;
  }

  return 0;
}


void
i2c_unlock (void)
{
  __sync_sub_and_fetch (&mutex, 1);
}