ASoC: Automatically manage WM8903 deemphasis rate

Provide the user with a boolean control then automatically select
the deemphasis filter most closely matching the sample rate.

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

1 files changed, 74 insertions, 8 deletions

diff --git a/sound/soc/codecs/wm8903.c b/sound/soc/codecs/wm8903.c
index f9ae403715c6..d015745a886b 100644
--- a/sound/soc/codecs/wm8903.c
+++ b/sound/soc/codecs/wm8903.c
@@ -218,6 +218,9 @@ struct wm8903_priv {
         int sysclk;
         int irq;
 
+        int fs;
+        int deemph;
+
         /* Reference count */
         int class_w_users;
 
@@ -457,6 +460,72 @@ static int wm8903_class_w_put(struct snd_kcontrol *kcontrol,
         .private_value =  SOC_SINGLE_VALUE(reg, shift, max, invert) }
 
 
+static int wm8903_deemph[] = { 0, 32000, 44100, 48000 };
+
+static int wm8903_set_deemph(struct snd_soc_codec *codec)
+{
+        struct wm8903_priv *wm8903 = snd_soc_codec_get_drvdata(codec);
+        int val, i, best;
+
+        /* If we're using deemphasis select the nearest available sample
+         * rate.
+         */
+        if (wm8903->deemph) {
+                best = 1;
+                for (i = 2; i < ARRAY_SIZE(wm8903_deemph); i++) {
+                        if (abs(wm8903_deemph[i] - wm8903->fs) <
+                            abs(wm8903_deemph[best] - wm8903->fs))
+                                best = i;
+                }
+
+                val = best << WM8903_DEEMPH_SHIFT;
+        } else {
+                best = 0;
+                val = 0;
+        }
+
+        dev_dbg(codec->dev, "Set deemphasis %d (%dHz)\n",
+                best, wm8903_deemph[best]);
+
+        return snd_soc_update_bits(codec, WM8903_DAC_DIGITAL_1,
+                                   WM8903_DEEMPH_MASK, val);
+}
+
+static int wm8903_get_deemph(struct snd_kcontrol *kcontrol,
+                             struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+        struct wm8903_priv *wm8903 = snd_soc_codec_get_drvdata(codec);
+
+        ucontrol->value.enumerated.item[0] = wm8903->deemph;
+
+        return 0;
+}
+
+static int wm8903_put_deemph(struct snd_kcontrol *kcontrol,
+                             struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+        struct wm8903_priv *wm8903 = snd_soc_codec_get_drvdata(codec);
+        int deemph = ucontrol->value.enumerated.item[0];
+        int ret = 0;
+
+        if (deemph > 1)
+                return -EINVAL;
+
+        mutex_lock(&codec->mutex);
+        if (wm8903->deemph != deemph) {
+                wm8903->deemph = deemph;
+
+                wm8903_set_deemph(codec);
+
+                ret = 1;
+        }
+        mutex_unlock(&codec->mutex);
+
+        return ret;
+}
+
 /* ALSA can only do steps of .01dB */
 static const DECLARE_TLV_DB_SCALE(digital_tlv, -7200, 75, 1);
 
@@ -548,13 +617,6 @@ static const char *mute_mode_text[] = {
 static const struct soc_enum mute_mode =
         SOC_ENUM_SINGLE(WM8903_DAC_DIGITAL_1, 9, 2, mute_mode_text);
 
-static const char *dac_deemphasis_text[] = {
-        "Disabled", "32kHz", "44.1kHz", "48kHz"
-};
-
-static const struct soc_enum dac_deemphasis =
-        SOC_ENUM_SINGLE(WM8903_DAC_DIGITAL_1, 1, 4, dac_deemphasis_text);
-
 static const char *companding_text[] = {
         "ulaw", "alaw"
 };
@@ -662,9 +724,10 @@ SOC_DOUBLE_R_TLV("Digital Playback Volume", WM8903_DAC_DIGITAL_VOLUME_LEFT,
 SOC_ENUM("DAC Soft Mute Rate", soft_mute),
 SOC_ENUM("DAC Mute Mode", mute_mode),
 SOC_SINGLE("DAC Mono Switch", WM8903_DAC_DIGITAL_1, 12, 1, 0),
-SOC_ENUM("DAC De-emphasis", dac_deemphasis),
 SOC_ENUM("DAC Companding Mode", dac_companding),
 SOC_SINGLE("DAC Companding Switch", WM8903_AUDIO_INTERFACE_0, 1, 1, 0),
+SOC_SINGLE_BOOL_EXT("Playback Deemphasis Switch", 0,
+                    wm8903_get_deemph, wm8903_put_deemph),
 
 /* Headphones */
 SOC_DOUBLE_R("Headphone Switch",
@@ -1374,6 +1437,9 @@ static int wm8903_hw_params(struct snd_pcm_substream *substream,
         aif2 |= bclk_divs[bclk_div].div;
         aif3 |= bclk / fs;
 
+        wm8903->fs = params_rate(params);
+        wm8903_set_deemph(codec);
+
         snd_soc_write(codec, WM8903_CLOCK_RATES_0, clock0);
         snd_soc_write(codec, WM8903_CLOCK_RATES_1, clock1);
         snd_soc_write(codec, WM8903_AUDIO_INTERFACE_1, aif1);