TTY: provide drivers with tty_port_install

This will be used in tty_ops->install to set tty->port (and to call
tty_standard_install).
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_port.c

@@ -413,6 +413,14 @@ void tty_port_close(struct tty_port *port, struct tty_struct *tty,
 }
 EXPORT_SYMBOL(tty_port_close);
 
+int tty_port_install(struct tty_port *port, struct tty_driver *driver,
+		struct tty_struct *tty)
+{
+	tty->port = port;
+	return tty_standard_install(driver, tty);
+}
+EXPORT_SYMBOL_GPL(tty_port_install);
+
 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
 							struct file *filp)
 {

include/linux/tty.h

@@ -521,6 +521,8 @@ extern int tty_port_close_start(struct tty_port *port,
 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
 extern void tty_port_close(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp);
+extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
+				struct tty_struct *tty);
 extern int tty_port_open(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp);
 static inline int tty_port_users(struct tty_port *port)