I was just attempting to use the /dev/buz device on a TomTom One V3 for debugging purposes but the test code below failed on the attempt to open the device driver despite trying a few combinations of open flags. The device seemed to be installed OK but I noticed in the Barcelona kernel source it is written for exclusive access so presumably the main ttn application opens it. I need the navigator application open while debugging my app so tomorrow will take a look at getting something out of a serial port.
int fd = open("/dev/buz", O_RDONLY | O_NONBLOCK | O_NOCTTY);
cout << "fd: " << fd << endl;
int result = ioctl(_IO('U', 3), 0);
cout << "result: " << result << endl;
sleep(10);
close(fd);
exit(0);