[alsa-devel] [PATCHv4 2/9] WM8971 modifies the control of deemphasis

[Xavier Hsu]

This patch improves WM8971.
We modifies the control of deemphasis

Signed-off-by: Xavier Hsu <xavier.hsu at linaro.org>
Signed-off-by: Andy Green <andy.green at linaro.org>
---
Any comments about improving the patch are welcome.
Thanks.

 sound/soc/codecs/wm8971.c |   77 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 2 deletions(-)
 mode change 100644 => 100755 sound/soc/codecs/wm8971.c

diff --git a/sound/soc/codecs/wm8971.c b/sound/soc/codecs/wm8971.c
old mode 100644
new mode 100755
index c0f7e9b..1b4f457
--- a/sound/soc/codecs/wm8971.c
+++ b/sound/soc/codecs/wm8971.c
@@ -7,6 +7,10 @@
  *
  * Based on wm8753.c by Liam Girdwood
  *
+ * WM8971 Improve Copyright (C) 2014 Linaro, Ltd
+ * Author: Xavier Hsu <xavier.hsu at linaro.org>
+ *         Andy Green <andy.green at linaro.org>
+ *
  *  This program is free software; you can redistribute  it and/or modify it
  *  under  the terms of  the GNU General  Public License as published by the
  *  Free Software Foundation;  either version 2 of the  License, or (at your
@@ -36,6 +40,11 @@ static struct workqueue_struct *wm8971_workq;
 /* codec private data */
 struct wm8971_priv {
 	unsigned int sysclk;
+
+	/* De-emphasis */
+	struct mutex deemph_mutex;
+	int playback_fs;
+	bool deemph;
 };
 
 /*
@@ -100,7 +109,6 @@ static const char const *wm8971_alc_func[] = {"Off", "Right",
 					      "Left", "Stereo"};
 static const char const *wm8971_ng_type[] = {"Constant PGA Gain",
 					     "Mute ADC Output"};
-static const char const *wm8971_deemp[] = {"None", "32kHz", "44.1kHz", "48kHz"};
 static const char const *wm8971_mono_mux[] = {"Stereo", "Mono (Left)",
 					      "Mono (Right)", "Digital Mono"};
 static const char const *wm8971_dac_phase[] = {"Non Inverted", "Inverted"};
@@ -114,6 +122,66 @@ static const char const *wm8971_rpga_sel[] = {"Line", "Mic", "NC",
 					      "Differential"};
 static const char const *wm8971_adcpol[] = {"Normal", "L Invert",
 					    "R Invert", "L + R Invert"};
+static const char const *wm8971_deemp[] = {"None", "32kHz",
+					   "44.1kHz", "48kHz"};
+
+static int wm8971_set_deemph(struct snd_soc_codec *codec)
+{
+	struct wm8971_priv *wm8971 = snd_soc_codec_get_drvdata(codec);
+	int val = 0, i, best = 0;
+
+	/* If we're using deemphasis select the nearest available sample
+	 * rate.
+	*/
+	if (wm8971->deemph) {
+		best = 1;
+		for (i = 2; i < ARRAY_SIZE(wm8971_deemp); i++) {
+			if (abs(wm8971_deemp[i] - wm8971->playback_fs) <
+			    abs(wm8971_deemp[best] - wm8971->playback_fs))
+				best = i;
+		}
+		val = best << 1;
+	}
+
+	dev_dbg(codec->dev, "Set deemphasis %d (%dHz)\n",
+		best, wm8971_deemp[best]);
+
+	return snd_soc_update_bits(codec, WM8971_ADCDAC, 0x6, val);
+}
+
+static int wm8971_get_deemph(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
+	struct wm8971_priv *wm8971 = snd_soc_codec_get_drvdata(codec);
+
+	ucontrol->value.enumerated.item[0] = wm8971->deemph;
+
+	return 0;
+}
+
+static int wm8971_put_deemph(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
+	struct wm8971_priv *wm8971 = snd_soc_codec_get_drvdata(codec);
+	int deemph = ucontrol->value.enumerated.item[0];
+	int ret = 0;
+
+	if (deemph > 1)
+		return -EINVAL;
+
+	mutex_lock(&wm8971->deemph_mutex);
+	if (wm8971->deemph != deemph) {
+		wm8971->deemph = deemph;
+		wm8971_set_deemph(codec);
+
+		ret = 1;
+	}
+	mutex_unlock(&wm8971->deemph_mutex);
+
+	return ret;
+}
 
 static const struct soc_enum wm8971_enum[] = {
 	SOC_ENUM_SINGLE(WM8971_BASS, 7, 2, wm8971_bass),	/* 0 */
@@ -184,7 +252,8 @@ static const struct snd_kcontrol_new wm8971_snd_controls[] = {
 	SOC_SINGLE("Capture 6dB Attenuate", WM8971_ADCDAC, 8, 1, 0),
 	SOC_SINGLE("Playback 6dB Attenuate", WM8971_ADCDAC, 7, 1, 0),
 
-	SOC_ENUM("Playback De-emphasis", wm8971_enum[5]),
+	SOC_SINGLE_BOOL_EXT("Playback De-emphasis Switch", 0,
+			    wm8971_get_deemph, wm8971_put_deemph),
 	SOC_ENUM("Playback Function", wm8971_enum[6]),
 	SOC_ENUM("Playback Phase", wm8971_enum[7]),
 
@@ -534,6 +603,8 @@ static int wm8971_pcm_hw_params(struct snd_pcm_substream *substream,
 		break;
 	}
 
+	wm8971_set_deemph(codec);
+
 	/* set iface & srate */
 	snd_soc_write(codec, WM8971_IFACE, iface);
 	if (coeff >= 0)
@@ -727,6 +798,8 @@ static int wm8971_i2c_probe(struct i2c_client *i2c,
 	if (wm8971 == NULL)
 		return -ENOMEM;
 
+	mutex_init(&wm8971->deemph_mutex);
+
 	regmap = devm_regmap_init_i2c(i2c, &wm8971_regmap);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
-- 
1.7.9.5