diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 2a76b330e108..fc94988f0283 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -249,7 +249,7 @@ static void unset_locked_termios(struct tty_struct *tty, struct ktermios *old)
  *	in some cases where only minimal reconfiguration is supported
  */
 
-void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
+void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old)
 {
 	/* The bits a dumb device handles in software. Smart devices need
 	   to always provide a set_termios method */
diff --git a/include/linux/tty.h b/include/linux/tty.h
index cf5ab26de73d..ae41893f8653 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -458,7 +458,7 @@ static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
 unsigned char tty_get_char_size(unsigned int cflag);
 unsigned char tty_get_frame_size(unsigned int cflag);
 
-void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
+void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old);
 int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
 int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);