static int belkin_sa_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg);
static void belkin_sa_break_ctl (struct usb_serial_port *port, int break_state );
static int belkin_sa_tiocmget (struct usb_serial_port *port, struct file *file);
static int belkin_sa_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg);
static void belkin_sa_break_ctl (struct usb_serial_port *port, int break_state );
static int belkin_sa_tiocmget (struct usb_serial_port *port, struct file *file);