ASoC: Mediatek: MT8183: enable IIR filter

IIR fileter can remove DC offset. It must be enabled when
dmic or amic connected to pmic is used.
Signed-off-by: Shunli Wang <shunli.wang@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mediatek/mt8183/mt8183-dai-adda.c

@@ -176,9 +176,6 @@ static int mtk_adda_ul_event(struct snd_soc_dapm_widget *w,
 	case SND_SOC_DAPM_POST_PMD:
 		/* should delayed 1/fs(smallest is 8k) = 125us before afe off */
 		usleep_range(125, 135);
-
-		/* reset dmic */
-		afe_priv->mtkaif_dmic = 0;
 		break;
 	default:
 		break;
@@ -426,6 +423,17 @@ static int mtk_dai_adda_hw_params(struct snd_pcm_substream *substream,
 
 		ul_src_con0 |= (voice_mode << 17) & (0x7 << 17);
 
+		/* enable iir */
+		ul_src_con0 |= (1 << UL_IIR_ON_TMP_CTL_SFT) &
+			       UL_IIR_ON_TMP_CTL_MASK_SFT;
+
+		/* 35Hz @ 48k */
+		regmap_write(afe->regmap, AFE_ADDA_IIR_COEF_02_01, 0x00000000);
+		regmap_write(afe->regmap, AFE_ADDA_IIR_COEF_04_03, 0x00003FB8);
+		regmap_write(afe->regmap, AFE_ADDA_IIR_COEF_06_05, 0x3FB80000);
+		regmap_write(afe->regmap, AFE_ADDA_IIR_COEF_08_07, 0x3FB80000);
+		regmap_write(afe->regmap, AFE_ADDA_IIR_COEF_10_09, 0x0000C048);
+
 		regmap_write(afe->regmap, AFE_ADDA_UL_SRC_CON0, ul_src_con0);
 
 		/* mtkaif_rxif_data_mode = 0, amic */