ASoC: Add function "rl6231_get_pre_div" to correct the dmic clock calculation

Signed-off-by: Bard Liao <bardliao@realtek.com>
Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/rt5651.c b/sound/soc/codecs/rt5651.c
index a3506e1..8df690a 100644
--- a/sound/soc/codecs/rt5651.c
+++ b/sound/soc/codecs/rt5651.c
@@ -378,10 +378,11 @@
 {
 	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);
 	struct rt5651_priv *rt5651 = snd_soc_codec_get_drvdata(codec);
-	int idx = -EINVAL;
+	int idx, rate;
 
-	idx = rl6231_calc_dmic_clk(rt5651->sysclk);
-
+	rate = rt5651->sysclk / rl6231_get_pre_div(rt5651->regmap,
+		RT5651_ADDA_CLK1, RT5651_I2S_PD1_SFT);
+	idx = rl6231_calc_dmic_clk(rate);
 	if (idx < 0)
 		dev_err(codec->dev, "Failed to set DMIC clock\n");
 	else