diff --git a/sound/soc/uniphier/aio-core.c b/sound/soc/uniphier/aio-core.c
index 8b09bbb0f8d0..9bcba06ba52e 100644
--- a/sound/soc/uniphier/aio-core.c
+++ b/sound/soc/uniphier/aio-core.c
@@ -327,7 +327,7 @@ static int aio_port_set_ch(struct uniphier_aio_sub *sub)
  *
  * Return: Zero if successful, otherwise a negative value on error.
  */
-int aio_port_set_rate(struct uniphier_aio_sub *sub, int rate)
+static int aio_port_set_rate(struct uniphier_aio_sub *sub, int rate)
 {
 	struct regmap *r = sub->aio->chip->regmap;
 	struct device *dev = &sub->aio->chip->pdev->dev;
@@ -446,7 +446,7 @@ int aio_port_set_rate(struct uniphier_aio_sub *sub, int rate)
  *
  * Return: Zero if successful, otherwise a negative value on error.
  */
-int aio_port_set_fmt(struct uniphier_aio_sub *sub)
+static int aio_port_set_fmt(struct uniphier_aio_sub *sub)
 {
 	struct regmap *r = sub->aio->chip->regmap;
 	struct device *dev = &sub->aio->chip->pdev->dev;
@@ -511,7 +511,7 @@ int aio_port_set_fmt(struct uniphier_aio_sub *sub)
  *
  * Return: Zero if successful, otherwise a negative value on error.
  */
-int aio_port_set_clk(struct uniphier_aio_sub *sub)
+static int aio_port_set_clk(struct uniphier_aio_sub *sub)
 {
 	struct uniphier_aio_chip *chip = sub->aio->chip;
 	struct device *dev = &sub->aio->chip->pdev->dev;
diff --git a/sound/soc/uniphier/aio.h b/sound/soc/uniphier/aio.h
index 23a5c3c68658..ca6ccbae0ee8 100644
--- a/sound/soc/uniphier/aio.h
+++ b/sound/soc/uniphier/aio.h
@@ -325,9 +325,6 @@ int aio_chip_set_pll(struct uniphier_aio_chip *chip, int pll_id,
 void aio_chip_init(struct uniphier_aio_chip *chip);
 int aio_init(struct uniphier_aio_sub *sub);
 void aio_port_reset(struct uniphier_aio_sub *sub);
-int aio_port_set_rate(struct uniphier_aio_sub *sub, int rate);
-int aio_port_set_fmt(struct uniphier_aio_sub *sub);
-int aio_port_set_clk(struct uniphier_aio_sub *sub);
 int aio_port_set_param(struct uniphier_aio_sub *sub, int pass_through,
 		       const struct snd_pcm_hw_params *params);
 void aio_port_set_enable(struct uniphier_aio_sub *sub, int enable);