diff --git a/sound/soc/codecs/rt5640.c b/sound/soc/codecs/rt5640.c
index 84ee7ef8eb17..19634d0992bc 100644
--- a/sound/soc/codecs/rt5640.c
+++ b/sound/soc/codecs/rt5640.c
@@ -480,7 +480,7 @@ static int set_dmic_clk(struct snd_soc_dapm_widget *w,
 	return idx;
 }
 
-static int check_sysclk1_source(struct snd_soc_dapm_widget *source,
+static int is_sys_clk_from_pll(struct snd_soc_dapm_widget *source,
 			 struct snd_soc_dapm_widget *sink)
 {
 	unsigned int val;
@@ -1273,22 +1273,22 @@ static const struct snd_soc_dapm_route rt5640_dapm_routes[] = {
 	{"Stereo ADC MIXL", "ADC1 Switch", "Stereo ADC L1 Mux"},
 	{"Stereo ADC MIXL", "ADC2 Switch", "Stereo ADC L2 Mux"},
 	{"Stereo ADC MIXL", NULL, "Stereo Filter"},
-	{"Stereo Filter", NULL, "PLL1", check_sysclk1_source},
+	{"Stereo Filter", NULL, "PLL1", is_sys_clk_from_pll},
 
 	{"Stereo ADC MIXR", "ADC1 Switch", "Stereo ADC R1 Mux"},
 	{"Stereo ADC MIXR", "ADC2 Switch", "Stereo ADC R2 Mux"},
 	{"Stereo ADC MIXR", NULL, "Stereo Filter"},
-	{"Stereo Filter", NULL, "PLL1", check_sysclk1_source},
+	{"Stereo Filter", NULL, "PLL1", is_sys_clk_from_pll},
 
 	{"Mono ADC MIXL", "ADC1 Switch", "Mono ADC L1 Mux"},
 	{"Mono ADC MIXL", "ADC2 Switch", "Mono ADC L2 Mux"},
 	{"Mono ADC MIXL", NULL, "Mono Left Filter"},
-	{"Mono Left Filter", NULL, "PLL1", check_sysclk1_source},
+	{"Mono Left Filter", NULL, "PLL1", is_sys_clk_from_pll},
 
 	{"Mono ADC MIXR", "ADC1 Switch", "Mono ADC R1 Mux"},
 	{"Mono ADC MIXR", "ADC2 Switch", "Mono ADC R2 Mux"},
 	{"Mono ADC MIXR", NULL, "Mono Right Filter"},
-	{"Mono Right Filter", NULL, "PLL1", check_sysclk1_source},
+	{"Mono Right Filter", NULL, "PLL1", is_sys_clk_from_pll},
 
 	{"IF2 ADC L", NULL, "Mono ADC MIXL"},
 	{"IF2 ADC R", NULL, "Mono ADC MIXR"},
@@ -1377,13 +1377,13 @@ static const struct snd_soc_dapm_route rt5640_dapm_routes[] = {
 	{"DIG MIXR", "DAC R2 Switch", "DAC R2 Mux"},
 
 	{"DAC L1", NULL, "Stereo DAC MIXL"},
-	{"DAC L1", NULL, "PLL1", check_sysclk1_source},
+	{"DAC L1", NULL, "PLL1", is_sys_clk_from_pll},
 	{"DAC R1", NULL, "Stereo DAC MIXR"},
-	{"DAC R1", NULL, "PLL1", check_sysclk1_source},
+	{"DAC R1", NULL, "PLL1", is_sys_clk_from_pll},
 	{"DAC L2", NULL, "Mono DAC MIXL"},
-	{"DAC L2", NULL, "PLL1", check_sysclk1_source},
+	{"DAC L2", NULL, "PLL1", is_sys_clk_from_pll},
 	{"DAC R2", NULL, "Mono DAC MIXR"},
-	{"DAC R2", NULL, "PLL1", check_sysclk1_source},
+	{"DAC R2", NULL, "PLL1", is_sys_clk_from_pll},
 
 	{"SPK MIXL", "REC MIXL Switch", "RECMIXL"},
 	{"SPK MIXL", "INL Switch", "INL VOL"},