120 struct tty_driver {  struct
134 	struct tty_driver *other; /* only used for the PTY driver */  argument
139 	struct tty_struct **table;
140 	struct termios **termios;
141 	struct termios **termios_locked;
142 	void *driver_state;	/* only used for the PTY driver */
148 	int  (*open)(struct tty_struct * tty, struct file * filp);
149 	void (*close)(struct tty_struct * tty, struct file * filp);
150 	int  (*write)(struct tty_struct * tty, int from_user,
152 	void (*put_char)(struct tty_struct *tty, unsigned char ch);
153 	void (*flush_chars)(struct tty_struct *tty);
177 	struct tty_driver *next;  argument
178 	struct tty_driver *prev;  argument