diff --git a/drivers/power/supply/cpcap-charger.c b/drivers/power/supply/cpcap-charger.c
index 40d96b8c00a8..c0d452e3dc8b 100644
--- a/drivers/power/supply/cpcap-charger.c
+++ b/drivers/power/supply/cpcap-charger.c
@@ -560,7 +560,7 @@ static void cpcap_charger_update_state(struct cpcap_charger_ddata *ddata,
 	dev_dbg(ddata->dev, "state: %s\n", status);
 }
 
-int cpcap_charger_voltage_to_regval(int voltage)
+static int cpcap_charger_voltage_to_regval(int voltage)
 {
 	int offset;