diff --git a/driver/bc12/pi3usb9281.c b/driver/bc12/pi3usb9281.c
index b99be31d18..be1bfdee18 100644
--- a/driver/bc12/pi3usb9281.c
+++ b/driver/bc12/pi3usb9281.c
@@ -42,6 +42,7 @@ static int usb_switch_state[CONFIG_USB_PD_PORT_COUNT];
 static struct mutex usb_switch_lock[CONFIG_USB_PD_PORT_COUNT];
 
 static int pi3usb9281_reset(int port);
+static int pi3usb9281_get_interrupts(int port);
 
 static void select_chip(int port)
 {
@@ -139,7 +140,7 @@ static int pi3usb9281_set_interrupt_mask(int port, uint8_t mask)
 	return pi3usb9281_write(port, PI3USB9281_REG_INT_MASK, ~mask);
 }
 
-void pi3usb9281_init(int port)
+static void pi3usb9281_init(int port)
 {
 	uint8_t dev_id;
 
@@ -164,7 +165,7 @@ int pi3usb9281_enable_interrupts(int port)
 	return pi3usb9281_write_ctrl(port, ctrl & ~PI3USB9281_CTRL_INT_DIS);
 }
 
-int pi3usb9281_disable_interrupts(int port)
+static int pi3usb9281_disable_interrupts(int port)
 {
 	uint8_t ctrl = pi3usb9281_read(port, PI3USB9281_REG_CONTROL);
 	int rv;
@@ -177,17 +178,17 @@ int pi3usb9281_disable_interrupts(int port)
 	return rv;
 }
 
-int pi3usb9281_get_interrupts(int port)
+static int pi3usb9281_get_interrupts(int port)
 {
 	return pi3usb9281_read(port, PI3USB9281_REG_INT);
 }
 
-int pi3usb9281_get_device_type(int port)
+static int pi3usb9281_get_device_type(int port)
 {
 	return pi3usb9281_read(port, PI3USB9281_REG_DEV_TYPE) & 0x77;
 }
 
-int pi3usb9281_get_charger_status(int port)
+static int pi3usb9281_get_charger_status(int port)
 {
 	return pi3usb9281_read(port, PI3USB9281_REG_CHG_STATUS) & 0x1f;
 }
diff --git a/driver/pi3usb9281.h b/driver/pi3usb9281.h
index fc642435c6..fe19f0e977 100644
--- a/driver/pi3usb9281.h
+++ b/driver/pi3usb9281.h
@@ -71,23 +71,7 @@ struct pi3usb9281_config {
 /* Configuration struct defined at board level */
 extern struct pi3usb9281_config pi3usb9281_chips[];
 
-/* TODO: Make many of these functions static after Oak board changes. */
-/* Initialize chip and enable interrupts */
-void pi3usb9281_init(int port);
-
 /* Enable interrupts. */
 int pi3usb9281_enable_interrupts(int port);
 
-/* Disable all interrupts. */
-int pi3usb9281_disable_interrupts(int port);
-
-/* Get and clear current interrupt status. */
-int pi3usb9281_get_interrupts(int port);
-
-/* Get attached device type. */
-int pi3usb9281_get_device_type(int port);
-
-/* Get attached charger status. */
-int pi3usb9281_get_charger_status(int port);
-
 #endif /* __CROS_EC_PI3USB9281_H */