diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index bab1b143b8a6..b6638f9f40d2 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -137,6 +137,7 @@ static int ttyport_open(struct serdev_controller *ctrl)
 err_unlock:
 	tty_unlock(tty);
 	tty_release_struct(tty, serport->tty_idx);
+	serport->tty = NULL;
 
 	return ret;
 }
@@ -154,6 +155,7 @@ static void ttyport_close(struct serdev_controller *ctrl)
 	tty_unlock(tty);
 
 	tty_release_struct(tty, serport->tty_idx);
+	serport->tty = NULL;
 }
 
 static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)