diff --git a/drivers/serial/serial_uniphier.c b/drivers/serial/serial_uniphier.c
index faa69f0..3f3d415 100644
--- a/drivers/serial/serial_uniphier.c
+++ b/drivers/serial/serial_uniphier.c
@@ -55,7 +55,7 @@
 #define uniphier_serial_port(dev)	\
 	((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
 
-int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
+static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
 	struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
@@ -103,7 +103,7 @@
 		return !(readb(&port->lsr) & UART_LSR_THRE);
 }
 
-int uniphier_serial_probe(struct udevice *dev)
+static int uniphier_serial_probe(struct udevice *dev)
 {
 	struct uniphier_serial_private_data *priv = dev_get_priv(dev);
 	struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
@@ -116,7 +116,7 @@
 	return 0;
 }
 
-int uniphier_serial_remove(struct udevice *dev)
+static int uniphier_serial_remove(struct udevice *dev)
 {
 	unmap_sysmem(uniphier_serial_port(dev));