ASoC: Automatically manage DAC deemphasis rate for WM8960

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

1 files changed, 64 insertions, 0 deletions

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index 6be3f4645b71..743d9a708a22 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -79,6 +79,8 @@ struct wm8960_priv {
         struct snd_soc_dapm_widget *lout1;
         struct snd_soc_dapm_widget *rout1;
         struct snd_soc_dapm_widget *out3;
+        bool deemph;
+        int playback_fs;
 };
 
 #define wm8960_reset(c) snd_soc_write(c, WM8960_RESET, 0)
@@ -100,6 +102,59 @@ static const struct soc_enum wm8960_enum[] = {
         SOC_ENUM_SINGLE(WM8960_ALC3, 8, 2, wm8960_alcmode),
 };
 
+static const int deemph_settings[] = { 0, 32000, 44100, 48000 };
+
+static int wm8960_set_deemph(struct snd_soc_codec *codec)
+{
+        struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
+        int val, i, best;
+
+        /* If we're using deemphasis select the nearest available sample
+         * rate.
+         */
+        if (wm8960->deemph) {
+                best = 1;
+                for (i = 2; i < ARRAY_SIZE(deemph_settings); i++) {
+                        if (abs(deemph_settings[i] - wm8960->playback_fs) <
+                            abs(deemph_settings[best] - wm8960->playback_fs))
+                                best = i;
+                }
+
+                val = best << 1;
+        } else {
+                val = 0;
+        }
+
+        dev_dbg(codec->dev, "Set deemphasis %d\n", val);
+
+        return snd_soc_update_bits(codec, WM8960_DACCTL1,
+                                   0x6, val);
+}
+
+static int wm8960_get_deemph(struct snd_kcontrol *kcontrol,
+                             struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+        struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
+
+        return wm8960->deemph;
+}
+
+static int wm8960_put_deemph(struct snd_kcontrol *kcontrol,
+                             struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+        struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
+        int deemph = ucontrol->value.enumerated.item[0];
+
+        if (deemph > 1)
+                return -EINVAL;
+
+        wm8960->deemph = deemph;
+
+        return wm8960_set_deemph(codec);
+}
+
 static const DECLARE_TLV_DB_SCALE(adc_tlv, -9700, 50, 0);
 static const DECLARE_TLV_DB_SCALE(dac_tlv, -12700, 50, 1);
 static const DECLARE_TLV_DB_SCALE(bypass_tlv, -2100, 300, 0);
@@ -133,6 +188,8 @@ SOC_ENUM("ADC Polarity", wm8960_enum[0]),
 SOC_SINGLE("ADC High Pass Filter Switch", WM8960_DACCTL1, 0, 1, 0),
 
 SOC_ENUM("DAC Polarity", wm8960_enum[2]),
+SOC_SINGLE_BOOL_EXT("DAC Deemphasis Switch", 0,
+                    wm8960_get_deemph, wm8960_put_deemph),
 
 SOC_ENUM("3D Filter Upper Cut-Off", wm8960_enum[2]),
 SOC_ENUM("3D Filter Lower Cut-Off", wm8960_enum[3]),
@@ -437,6 +494,7 @@ static int wm8960_hw_params(struct snd_pcm_substream *substream,
         struct snd_soc_pcm_runtime *rtd = substream->private_data;
         struct snd_soc_device *socdev = rtd->socdev;
         struct snd_soc_codec *codec = socdev->card->codec;
+        struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
         u16 iface = snd_soc_read(codec, WM8960_IFACE1) & 0xfff3;
 
         /* bit size */
@@ -451,6 +509,12 @@ static int wm8960_hw_params(struct snd_pcm_substream *substream,
                 break;
         }
 
+        /* Update filters for the new rate */
+        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                wm8960->playback_fs = params_rate(params);
+                wm8960_set_deemph(codec);
+        }
+
         /* set iface */
         snd_soc_write(codec, WM8960_IFACE1, iface);
         return 0;