Commit dd31b310 authored by Mark Brown's avatar Mark Brown
Browse files

ASoC: Automatically manage WM8731 deemphasis 



The deemphasis filter should be selected based on sample rate for
optimal performance.

Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: default avatarLiam Girdwood <lrg@slimlogic.co.uk>
parent 59f72970

sound/soc/codecs/wm8731.c

+71 −5
Original line number Diff line number Diff line
@@ -46,6 +46,8 @@ struct wm8731_priv { 
	u16 reg_cache[WM8731_CACHEREGNUM];

	unsigned int sysclk;

	int sysclk_type;

	int playback_fs;

	bool deemph;

};
@@ -65,14 +67,73 @@ static const u16 wm8731_reg[WM8731_CACHEREGNUM] = { 


static const char *wm8731_input_select[] = {"Line In", "Mic"};



static const char *wm8731_deemph[] = {"None", "32Khz", "44.1Khz", "48Khz"};



static const struct soc_enum wm8731_insel_enum =

	SOC_ENUM_SINGLE(WM8731_APANA, 2, 2, wm8731_input_select);



static const struct soc_enum wm8731_deemph_enum =

	SOC_ENUM_SINGLE(WM8731_APDIGI, 1, 4, wm8731_deemph);

static int wm8731_deemph[] = { 0, 32000, 44100, 48000 };



static int wm8731_set_deemph(struct snd_soc_codec *codec)

{

	struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);

	int val, i, best;



	/* If we're using deemphasis select the nearest available sample

	 * rate.

	 */

	if (wm8731->deemph) {

		best = 1;

		for (i = 2; i < ARRAY_SIZE(wm8731_deemph); i++) {

			if (abs(wm8731_deemph[i] - wm8731->playback_fs) <

			    abs(wm8731_deemph[best] - wm8731->playback_fs))

				best = i;

		}



		val = best << 1;

	} else {

		best = 0;

		val = 0;

	}



	dev_dbg(codec->dev, "Set deemphasis %d (%dHz)\n",

		best, wm8731_deemph[best]);



	return snd_soc_update_bits(codec, WM8731_APDIGI, 0x6, val);

}



static int wm8731_get_deemph(struct snd_kcontrol *kcontrol,

			     struct snd_ctl_elem_value *ucontrol)

{

	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);

	struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);



	ucontrol->value.enumerated.item[0] = wm8731->deemph;



	return 0;

}



static int wm8731_put_deemph(struct snd_kcontrol *kcontrol,

			     struct snd_ctl_elem_value *ucontrol)

{

	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);

	struct wm8731_priv *wm8731 = 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 (wm8731->deemph != deemph) {

		wm8731->deemph = deemph;



		wm8731_set_deemph(codec);



		ret = 1;

	}

	mutex_unlock(&codec->mutex);



	return ret;

}



static const DECLARE_TLV_DB_SCALE(in_tlv, -3450, 150, 0);

static const DECLARE_TLV_DB_SCALE(sidetone_tlv, -1500, 300, 0);
@@ -99,7 +160,8 @@ SOC_SINGLE_TLV("Sidetone Playback Volume", WM8731_APANA, 6, 3, 1, 
SOC_SINGLE("ADC High Pass Filter Switch", WM8731_APDIGI, 0, 1, 1),

SOC_SINGLE("Store DC Offset Switch", WM8731_APDIGI, 4, 1, 0),



SOC_ENUM("Playback De-emphasis", wm8731_deemph_enum),

SOC_SINGLE_BOOL_EXT("Playback Deemphasis Switch", 0,

		    wm8731_get_deemph, wm8731_put_deemph),

};



/* Output Mixer */
@@ -243,6 +305,8 @@ static int wm8731_hw_params(struct snd_pcm_substream *substream, 
	u16 srate = (coeff_div[i].sr << 2) |

		(coeff_div[i].bosr << 1) | coeff_div[i].usb;



	wm8731->playback_fs = params_rate(params);



	snd_soc_write(codec, WM8731_SRATE, srate);



	/* bit size */
@@ -257,6 +321,8 @@ static int wm8731_hw_params(struct snd_pcm_substream *substream, 
		break;

	}



	wm8731_set_deemph(codec);



	snd_soc_write(codec, WM8731_IFACE, iface);

	return 0;

}