ASoC: wcd9310/9304: Pull down Mic Bias output by default.

If Mic Bias is high Z by default and when the LDOH is enabled,
the Mic Bias output can pull-up to a non-zero voltage if there
is no loading or if the load leakage is very small.  Pulling
down the Mic Bias output so it is not in high Z to eliminate
the floating voltage.

Change-Id: I38e76a8c03107879727564f177b2713c9dfa4631
CRs-Fixed: 368898
Signed-off-by: Kuirong Wang <kuirongw@codeaurora.org>
diff --git a/sound/soc/codecs/wcd9310.c b/sound/soc/codecs/wcd9310.c
index 68892c1..15a5567 100644
--- a/sound/soc/codecs/wcd9310.c
+++ b/sound/soc/codecs/wcd9310.c
@@ -7590,6 +7590,11 @@
 	{TABLA_A_RX_LINE_3_GAIN, 0x10, 0x10},
 	{TABLA_A_RX_LINE_4_GAIN, 0x10, 0x10},
 
+	/* Set the MICBIAS default output as pull down*/
+	{TABLA_A_MICB_1_CTL, 0x01, 0x01},
+	{TABLA_A_MICB_2_CTL, 0x01, 0x01},
+	{TABLA_A_MICB_3_CTL, 0x01, 0x01},
+
 	/* Initialize mic biases to differential mode */
 	{TABLA_A_MICB_1_INT_RBIAS, 0x24, 0x24},
 	{TABLA_A_MICB_2_INT_RBIAS, 0x24, 0x24},
@@ -7645,11 +7650,16 @@
 };
 
 static const struct tabla_reg_mask_val tabla_1_x_codec_reg_init_val[] = {
+	/* Set the MICBIAS default output as pull down*/
+	{TABLA_1_A_MICB_4_CTL, 0x01, 0x01},
 	/* Initialize mic biases to differential mode */
 	{TABLA_1_A_MICB_4_INT_RBIAS, 0x24, 0x24},
 };
 
 static const struct tabla_reg_mask_val tabla_2_higher_codec_reg_init_val[] = {
+
+	/* Set the MICBIAS default output as pull down*/
+	{TABLA_2_A_MICB_4_CTL, 0x01, 0x01},
 	/* Initialize mic biases to differential mode */
 	{TABLA_2_A_MICB_4_INT_RBIAS, 0x24, 0x24},
 };