ASoC: tlv320adcx140: Add the config to configure Tx ASI output

Add code to allow the ASI Tx output to be placed into High-z mode
during unused ASI cycles.  This allows for other devices that may be on
the bus to drive the ASI out. By default the 320adcx140 sends 0's for
unused cycles.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20200915190606.1744-4-dmurphy@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/tlv320adcx140.c

@@ -876,6 +876,7 @@ static int adcx140_codec_probe(struct snd_soc_component *component)
 	u32 gpi_input_val = 0;
 	int i;
 	int ret;
+	bool tx_high_z;
 
 	ret = device_property_read_u32(adcx140->dev, "ti,mic-bias-source",
 				      &bias_source);
@@ -967,6 +968,16 @@ static int adcx140_codec_probe(struct snd_soc_component *component)
 	if (ret)
 		dev_err(adcx140->dev, "setting MIC bias failed %d\n", ret);
 
+	tx_high_z = device_property_read_bool(adcx140->dev, "ti,asi-tx-drive");
+	if (tx_high_z) {
+		ret = regmap_update_bits(adcx140->regmap, ADCX140_ASI_CFG0,
+				 ADCX140_TX_FILL, ADCX140_TX_FILL);
+		if (ret) {
+			dev_err(adcx140->dev, "Setting Tx drive failed %d\n", ret);
+			goto out;
+		}
+	}
+
 	adcx140_pwr_ctrl(adcx140, true);
 out:
 	return ret;

sound/soc/codecs/tlv320adcx140.h

@@ -146,5 +146,6 @@
 #define ADCX140_GPO_CFG_MAX		4
 #define ADCX140_GPO_DRV_MAX		5
 
+#define ADCX140_TX_FILL    BIT(0)
 
 #endif /* _TLV320ADCX140_ */