diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index c6f372d..90cc680 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -2326,7 +2326,7 @@
 	.get_icount = mxser_get_icount,
 };
 
-struct tty_port_operations mxser_port_ops = {
+static struct tty_port_operations mxser_port_ops = {
 	.carrier_raised = mxser_carrier_raised,
 	.dtr_rts = mxser_dtr_rts,
 	.activate = mxser_activate,