ASoC: twl6040 - Add method to query optimum PDM_DL1 gain

The DL1 PDM interface adds a little gain depending on the output device.
Add a method to retrieve the gain value for machine driver usage.
Signed-off-by: Liam Girdwood <lrg@ti.com>

sound/soc/codecs/twl6040.c

@@ -33,6 +33,7 @@
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/soc.h>
+#include <sound/soc-dapm.h>
 #include <sound/initval.h>
 #include <sound/tlv.h>
 
@@ -1012,6 +1013,28 @@ static int twl6040_pll_put_enum(struct snd_kcontrol *kcontrol,
 	return 0;
 }
 
+int twl6040_get_dl1_gain(struct snd_soc_codec *codec)
+{
+	struct snd_soc_dapm_context *dapm = &codec->dapm;
+
+	if (snd_soc_dapm_get_pin_status(dapm, "EP"))
+		return -1; /* -1dB */
+
+	if (snd_soc_dapm_get_pin_status(dapm, "HSOR") ||
+		snd_soc_dapm_get_pin_status(dapm, "HSOL")) {
+
+		u8 val = snd_soc_read(codec, TWL6040_REG_HSLCTL);
+		if (val & TWL6040_HSDACMODE)
+			/* HSDACL in LP mode */
+			return -8; /* -8dB */
+		else
+			/* HSDACL in HP mode */
+			return -1; /* -1dB */
+	}
+	return 0; /* 0dB */
+}
+EXPORT_SYMBOL_GPL(twl6040_get_dl1_gain);
+
 int twl6040_get_clk_id(struct snd_soc_codec *codec)
 {
 	struct twl6040_data *priv = snd_soc_codec_get_drvdata(codec);

sound/soc/codecs/twl6040.h

@@ -34,6 +34,7 @@ enum twl6040_trim {
 #define TWL6040_HSF_TRIM_LEFT(x)	(x & 0x0f)
 #define TWL6040_HSF_TRIM_RIGHT(x)	((x >> 4) & 0x0f)
 
+int twl6040_get_dl1_gain(struct snd_soc_codec *codec);
 void twl6040_hs_jack_detect(struct snd_soc_codec *codec,
 			    struct snd_soc_jack *jack, int report);
 int twl6040_get_clk_id(struct snd_soc_codec *codec);