+ * struct tty_struct * (*lookup)(struct tty_driver *self, int idx)
+ *
+ * Return the tty device corresponding to idx, NULL if there is not
+ * one currently in use and an ERR_PTR value on error. Called under
+ * tty_mutex (for now!)
+ *
+ * Optional method. Default behaviour is to use the ttys array
+ *
+ * int (*install)(struct tty_driver *self, struct tty_struct *tty)
+ *
+ * Install a new tty into the tty driver internal tables. Used in
+ * conjunction with lookup and remove methods.
+ *
+ * Optional method. Default behaviour is to use the ttys array
+ *
+ * void (*remove)(struct tty_driver *self, struct tty_struct *tty)
+ *
+ * Remove a closed tty from the tty driver internal tables. Used in
+ * conjunction with lookup and remove methods.
+ *
+ * Optional method. Default behaviour is to use the ttys array
+ *