diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
index 3379990ef637..8b1f3e12eac0 100644
--- a/drivers/clk/rockchip/clk.c
+++ b/drivers/clk/rockchip/clk.c
@@ -165,11 +165,9 @@ static int rockchip_clk_frac_notifier_cb(struct notifier_block *nb,
  * fractional divider must set that denominator is 20 times larger than
  * numerator to generate precise clock frequency.
  */
-void rockchip_fractional_approximation(struct clk_hw *hw,
-				       unsigned long rate,
-				       unsigned long *parent_rate,
-				       unsigned long *m,
-				       unsigned long *n)
+static void rockchip_fractional_approximation(struct clk_hw *hw,
+		unsigned long rate, unsigned long *parent_rate,
+		unsigned long *m, unsigned long *n)
 {
 	struct clk_fractional_divider *fd = to_clk_fd(hw);
 	unsigned long p_rate, p_parent_rate;