ASoC: tas2552: Add control for selecting DIN source

'DIN source' enum can be used to select the DIN Source (muted, left, right
or average of left and right channels).
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/codecs/tas2552.c

@@ -553,9 +553,20 @@ static struct snd_soc_dai_driver tas2552_dai[] = {
  */
 static DECLARE_TLV_DB_SCALE(dac_tlv, -7, 100, 0);
 
+static const char * const tas2552_din_source_select[] = {
+	"Muted",
+	"Left",
+	"Right",
+	"Left + Right average",
+};
+static SOC_ENUM_SINGLE_DECL(tas2552_din_source_enum,
+			    TAS2552_CFG_3, 3,
+			    tas2552_din_source_select);
+
 static const struct snd_kcontrol_new tas2552_snd_controls[] = {
 	SOC_SINGLE_TLV("Speaker Driver Playback Volume",
 			 TAS2552_PGA_GAIN, 0, 0x1f, 0, dac_tlv),
+	SOC_ENUM("DIN source", tas2552_din_source_enum),
 };
 
 static int tas2552_codec_probe(struct snd_soc_codec *codec)