text: /*
   * cs42l51.c
   *
   * ASoC Driver for Cirrus Logic CS42L51 codecs
   *
   * Copyright (c) 2010 Arnaud Patard <apatard@mandriva.com>
   *
   * Based on cs4270.c - Copyright (c) Freescale Semiconductor
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * For now:
   *  - Only I2C is support. Not SPI
   *  - master mode *NOT* supported
   */
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <sound/core.h>
  #include <sound/soc.h>
  #include <sound/tlv.h>
  #include <sound/initval.h>
  #include <sound/pcm_params.h>
  #include <sound/pcm.h>
  #include <linux/regmap.h>
  
  #include "cs42l51.h"
  
  enum master_slave_mode {
  	MODE_SLAVE,
  	MODE_SLAVE_AUTO,
  	MODE_MASTER,
  };
  
  struct cs42l51_private {
  	unsigned int mclk;
  	unsigned int audio_mode;	/* The mode (I2S or left-justified) */
  	enum master_slave_mode func;
  };
  
  #define CS42L51_FORMATS ( \
  		SNDRV_PCM_FMTBIT_S16_LE  | SNDRV_PCM_FMTBIT_S16_BE  | \
  		SNDRV_PCM_FMTBIT_S18_3LE | SNDRV_PCM_FMTBIT_S18_3BE | \
  		SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S20_3BE | \
  		SNDRV_PCM_FMTBIT_S24_LE  | SNDRV_PCM_FMTBIT_S24_BE)
  
  static int cs42l51_get_chan_mix(struct snd_kcontrol *kcontrol,
  			struct snd_ctl_elem_value *ucontrol)
  {
  	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
  	unsigned long value = snd_soc_read(codec, CS42L51_PCM_MIXER)&3;
  
  	switch (value) {
  	default:
  	case 0:
  		ucontrol->value.enumerated.item[0] = 0;
  		break;
  	/* same value : (L+R)/2 and (R+L)/2 */
  	case 1:
  	case 2:
  		ucontrol->value.enumerated.item[0] = 1;
  		break;
  	case 3:
  		ucontrol->value.enumerated.item[0] = 2;
  		break;
  	}
  
  	return 0;
  }
  
  #define CHAN_MIX_NORMAL	0x00
  #define CHAN_MIX_BOTH	0x55
  #define CHAN_MIX_SWAP	0xFF
  
  static int cs42l51_set_chan_mix(struct snd_kcontrol *kcontrol,
  			struct snd_ctl_elem_value *ucontrol)
  {
  	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
  	unsigned char val;
  
  	switch (ucontrol->value.enumerated.item[0]) {
  	default:
  	case 0:
  		val = CHAN_MIX_NORMAL;
  		break;
  	case 1:
  		val = CHAN_MIX_BOTH;
  		break;
  	case 2:
  		val = CHAN_MIX_SWAP;
  		break;
  	}
  
  	snd_soc_write(codec, CS42L51_PCM_MIXER, val);
  
  	return 1;
  }
  
  static const DECLARE_TLV_DB_SCALE(adc_pcm_tlv, -5150, 50, 0);
  static const DECLARE_TLV_DB_SCALE(tone_tlv, -1050, 150, 0);
  
  static const DECLARE_TLV_DB_SCALE(aout_tlv, -10200, 50, 0);
  
  static const DECLARE_TLV_DB_SCALE(boost_tlv, 1600, 1600, 0);
  static const char *chan_mix[] = {
  	"L R",
  	"L+R",
  	"R L",
  };
  
  static SOC_ENUM_SINGLE_EXT_DECL(cs42l51_chan_mix, chan_mix);
  
  static const struct snd_kcontrol_new cs42l51_snd_controls[] = {
  	SOC_DOUBLE_R_SX_TLV("PCM Playback Volume",
  			CS42L51_PCMA_VOL, CS42L51_PCMB_VOL,
  			0, 0x19, 0x7F, adc_pcm_tlv),
  	SOC_DOUBLE_R("PCM Playback Switch",
  			CS42L51_PCMA_VOL, CS42L51_PCMB_VOL, 7, 1, 1),
  	SOC_DOUBLE_R_SX_TLV("Analog Playback Volume",
  			CS42L51_AOUTA_VOL, CS42L51_AOUTB_VOL,
  			0, 0x34, 0xE4, aout_tlv),
  	SOC_DOUBLE_R_SX_TLV("ADC Mixer Volume",
  			CS42L51_ADCA_VOL, CS42L51_ADCB_VOL,
  			0, 0x19, 0x7F, adc_pcm_tlv),
  	SOC_DOUBLE_R("ADC Mixer Switch",
  			CS42L51_ADCA_VOL, CS42L51_ADCB_VOL, 7, 1, 1),
  	SOC_SINGLE("Playback Deemphasis Switch", CS42L51_DAC_CTL, 3, 1, 0),
  	SOC_SINGLE("Auto-Mute Switch", CS42L51_DAC_CTL, 2, 1, 0),
  	SOC_SINGLE("Soft Ramp Switch", CS42L51_DAC_CTL, 1, 1, 0),
  	SOC_SINGLE("Zero Cross Switch", CS42L51_DAC_CTL, 0, 0, 0),
  	SOC_DOUBLE_TLV("Mic Boost Volume",
  			CS42L51_MIC_CTL, 0, 1, 1, 0, boost_tlv),
  	SOC_SINGLE_TLV("Bass Volume", CS42L51_TONE_CTL, 0, 0xf, 1, tone_tlv),
  	SOC_SINGLE_TLV("Treble Volume", CS42L51_TONE_CTL, 4, 0xf, 1, tone_tlv),
  	SOC_ENUM_EXT("PCM channel mixer",
  			cs42l51_chan_mix,
  			cs42l51_get_chan_mix, cs42l51_set_chan_mix),
  };
  
  /*
   * to power down, one must:
   * 1.) Enable the PDN bit
   * 2.) enable power-down for the select channels
   * 3.) disable the PDN bit.
   */
  static int cs42l51_pdn_event(struct snd_soc_dapm_widget *w,
  		struct snd_kcontrol *kcontrol, int event)
  {
  	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);
  
  	switch (event) {
  	case SND_SOC_DAPM_PRE_PMD:
  		snd_soc_update_bits(codec, CS42L51_POWER_CTL1,
  				    CS42L51_POWER_CTL1_PDN,
  				    CS42L51_POWER_CTL1_PDN);
  		break;
  	default:
  	case SND_SOC_DAPM_POST_PMD:
  		snd_soc_update_bits(codec, CS42L51_POWER_CTL1,
  				    CS42L51_POWER_CTL1_PDN, 0);
  		break;
  	}
  
  	return 0;
  }
  
  static const char *cs42l51_dac_names[] = {"Direct PCM",
  	"DSP PCM", "ADC"};
  static SOC_ENUM_SINGLE_DECL(cs42l51_dac_mux_enum,
  			    CS42L51_DAC_CTL, 6, cs42l51_dac_names);
  static const struct snd_kcontrol_new cs42l51_dac_mux_controls =
  	SOC_DAPM_ENUM("Route", cs42l51_dac_mux_enum);
  
  static const char *cs42l51_adcl_names[] = {"AIN1 Left", "AIN2 Left",
  	"MIC Left", "MIC+preamp Left"};
  static SOC_ENUM_SINGLE_DECL(cs42l51_adcl_mux_enum,
  			    CS42L51_ADC_INPUT, 4, cs42l51_adcl_names);
  static const struct snd_kcontrol_new cs42l51_adcl_mux_controls =
  	SOC_DAPM_ENUM("Route", cs42l51_adcl_mux_enum);
  
  static const char *cs42l51_adcr_names[] = {"AIN1 Right", "AIN2 Right",
  	"MIC Right", "MIC+preamp Right"};
  static SOC_ENUM_SINGLE_DECL(cs42l51_adcr_mux_enum,
  			    CS42L51_ADC_INPUT, 6, cs42l51_adcr_names);
  static const struct snd_kcontrol_new cs42l51_adcr_mux_controls =
  	SOC_DAPM_ENUM("Route", cs42l51_adcr_mux_enum);
  
  static const struct snd_soc_dapm_widget cs42l51_dapm_widgets[] = {
  	SND_SOC_DAPM_MICBIAS("Mic Bias", CS42L51_MIC_POWER_CTL, 1, 1),
  	SND_SOC_DAPM_PGA_E("Left PGA", CS42L51_POWER_CTL1, 3, 1, NULL, 0,
  		cs42l51_pdn_event, SND_SOC_DAPM_PRE_POST_PMD),
  	SND_SOC_DAPM_PGA_E("Right PGA", CS42L51_POWER_CTL1, 4, 1, NULL, 0,
  		cs42l51_pdn_event, SND_SOC_DAPM_PRE_POST_PMD),
  	SND_SOC_DAPM_ADC_E("Left ADC", "Left HiFi Capture",
  		CS42L51_POWER_CTL1, 1, 1,
  		cs42l51_pdn_event, SND_SOC_DAPM_PRE_POST_PMD),
  	SND_SOC_DAPM_ADC_E("Right ADC", "Right HiFi Capture",
  		CS42L51_POWER_CTL1, 2, 1,
  		cs42l51_pdn_event, SND_SOC_DAPM_PRE_POST_PMD),
  	SND_SOC_DAPM_DAC_E("Left DAC", "Left HiFi Playback",
  		CS42L51_POWER_CTL1, 5, 1,
  		cs42l51_pdn_event, SND_SOC_DAPM_PRE_POST_PMD),
  	SND_SOC_DAPM_DAC_E("Right DAC", "Right HiFi Playback",
  		CS42L51_POWER_CTL1, 6, 1,
  		cs42l51_pdn_event, SND_SOC_DAPM_PRE_POST_PMD),
  
  	/* analog/mic */
  	SND_SOC_DAPM_INPUT("AIN1L"),
  	SND_SOC_DAPM_INPUT("AIN1R"),
  	SND_SOC_DAPM_INPUT("AIN2L"),
  	SND_SOC_DAPM_INPUT("AIN2R"),
  	SND_SOC_DAPM_INPUT("MICL"),
  	SND_SOC_DAPM_INPUT("MICR"),
  
  	SND_SOC_DAPM_MIXER("Mic Preamp Left",
  		CS42L51_MIC_POWER_CTL, 2, 1, NULL, 0),
  	SND_SOC_DAPM_MIXER("Mic Preamp Right",
  		CS42L51_MIC_POWER_CTL, 3, 1, NULL, 0),
  
  	/* HP */
  	SND_SOC_DAPM_OUTPUT("HPL"),
  	SND_SOC_DAPM_OUTPUT("HPR"),
  
  	/* mux */
  	SND_SOC_DAPM_MUX("DAC Mux", SND_SOC_NOPM, 0, 0,
  		&cs42l51_dac_mux_controls),
  	SND_SOC_DAPM_MUX("PGA-ADC Mux Left", SND_SOC_NOPM, 0, 0,
  		&cs42l51_adcl_mux_controls),
  	SND_SOC_DAPM_MUX("PGA-ADC Mux Right", SND_SOC_NOPM, 0, 0,
  		&cs42l51_adcr_mux_controls),
  };
  
  static const struct snd_soc_dapm_route cs42l51_routes[] = {
  	{"HPL", NULL, "Left DAC"},
  	{"HPR", NULL, "Right DAC"},
  
  	{"Left ADC", NULL, "Left PGA"},
  	{"Right ADC", NULL, "Right PGA"},
  
  	{"Mic Preamp Left",  NULL,  "MICL"},
  	{"Mic Preamp Right", NULL,  "MICR"},
  
  	{"PGA-ADC Mux Left",  "AIN1 Left",        "AIN1L" },
  	{"PGA-ADC Mux Left",  "AIN2 Left",        "AIN2L" },
  	{"PGA-ADC Mux Left",  "MIC Left",         "MICL"  },
  	{"PGA-ADC Mux Left",  "MIC+preamp Left",  "Mic Preamp Left" },
  	{"PGA-ADC Mux Right", "AIN1 Right",       "AIN1R" },
  	{"PGA-ADC Mux Right", "AIN2 Right",       "AIN2R" },
  	{"PGA-ADC Mux Right", "MIC Right",        "MICR" },
  	{"PGA-ADC Mux Right", "MIC+preamp Right", "Mic Preamp Right" },
  
  	{"Left PGA", NULL, "PGA-ADC Mux Left"},
  	{"Right PGA", NULL, "PGA-ADC Mux Right"},
  };
  
  static int cs42l51_set_dai_fmt(struct snd_soc_dai *codec_dai,
  		unsigned int format)
  {
  	struct snd_soc_codec *codec = codec_dai->codec;
  	struct cs42l51_private *cs42l51 = snd_soc_codec_get_drvdata(codec);
  
  	switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
  	case SND_SOC_DAIFMT_I2S:
  	case SND_SOC_DAIFMT_LEFT_J:
  	case SND_SOC_DAIFMT_RIGHT_J:
  		cs42l51->audio_mode = format & SND_SOC_DAIFMT_FORMAT_MASK;
  		break;
  	default:
  		dev_err(codec->dev, "invalid DAI format\n");
  		return -EINVAL;
  	}
  
  	switch (format & SND_SOC_DAIFMT_MASTER_MASK) {
  	case SND_SOC_DAIFMT_CBM_CFM:
  		cs42l51->func = MODE_MASTER;
  		break;
  	case SND_SOC_DAIFMT_CBS_CFS:
  		cs42l51->func = MODE_SLAVE_AUTO;
  		break;
  	default:
  		dev_err(codec->dev, "Unknown master/slave configuration\n");
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  struct cs42l51_ratios {
  	unsigned int ratio;
  	unsigned char speed_mode;
  	unsigned char mclk;
  };
  
  static struct cs42l51_ratios slave_ratios[] = {
  	{  512, CS42L51_QSM_MODE, 0 }, {  768, CS42L51_QSM_MODE, 0 },
  	{ 1024, CS42L51_QSM_MODE, 0 }, { 1536, CS42L51_QSM_MODE, 0 },
  	{ 2048, CS42L51_QSM_MODE, 0 }, { 3072, CS42L51_QSM_MODE, 0 },
  	{  256, CS42L51_HSM_MODE, 0 }, {  384, CS42L51_HSM_MODE, 0 },
  	{  512, CS42L51_HSM_MODE, 0 }, {  768, CS42L51_HSM_MODE, 0 },
  	{ 1024, CS42L51_HSM_MODE, 0 }, { 1536, CS42L51_HSM_MODE, 0 },
  	{  128, CS42L51_SSM_MODE, 0 }, {  192, CS42L51_SSM_MODE, 0 },
  	{  256, CS42L51_SSM_MODE, 0 }, {  384, CS42L51_SSM_MODE, 0 },
  	{  512, CS42L51_SSM_MODE, 0 }, {  768, CS42L51_SSM_MODE, 0 },
  	{  128, CS42L51_DSM_MODE, 0 }, {  192, CS42L51_DSM_MODE, 0 },
  	{  256, CS42L51_DSM_MODE, 0 }, {  384, CS42L51_DSM_MODE, 0 },
  };
  
  static struct cs42l51_ratios slave_auto_ratios[] = {
  	{ 1024, CS42L51_QSM_MODE, 0 }, { 1536, CS42L51_QSM_MODE, 0 },
  	{ 2048, CS42L51_QSM_MODE, 1 }, { 3072, CS42L51_QSM_MODE, 1 },
  	{  512, CS42L51_HSM_MODE, 0 }, {  768, CS42L51_HSM_MODE, 0 },
  	{ 1024, CS42L51_HSM_MODE, 1 }, { 1536, CS42L51_HSM_MODE, 1 },
  	{  256, CS42L51_SSM_MODE, 0 }, {  384, CS42L51_SSM_MODE, 0 },
  	{  512, CS42L51_SSM_MODE, 1 }, {  768, CS42L51_SSM_MODE, 1 },
  	{  128, CS42L51_DSM_MODE, 0 }, {  192, CS42L51_DSM_MODE, 0 },
  	{  256, CS42L51_DSM_MODE, 1 }, {  384, CS42L51_DSM_MODE, 1 },
  };
  
  static int cs42l51_set_dai_sysclk(struct snd_soc_dai *codec_dai,
  		int clk_id, unsigned int freq, int dir)
  {
  	struct snd_soc_codec *codec = codec_dai->codec;
  	struct cs42l51_private *cs42l51 = snd_soc_codec_get_drvdata(codec);
  
  	cs42l51->mclk = freq;
  	return 0;
  }
  
  static int cs42l51_hw_params(struct snd_pcm_substream *substream,
  		struct snd_pcm_hw_params *params,
  		struct snd_soc_dai *dai)
  {
  	struct snd_soc_codec *codec = dai->codec;
  	struct cs42l51_private *cs42l51 = snd_soc_codec_get_drvdata(codec);
  	int ret;
  	unsigned int i;
  	unsigned int rate;
  	unsigned int ratio;
  	struct cs42l51_ratios *ratios = NULL;
  	int nr_ratios = 0;
  	int intf_ctl, power_ctl, fmt;
  
  	switch (cs42l51->func) {
  	case MODE_MASTER:
  		return -EINVAL;
  	case MODE_SLAVE:
  		ratios = slave_ratios;
  		nr_ratios = ARRAY_SIZE(slave_ratios);
  		break;
  	case MODE_SLAVE_AUTO:
  		ratios = slave_auto_ratios;
  		nr_ratios = ARRAY_SIZE(slave_auto_ratios);
  		break;
  	}
  
  	/* Figure out which MCLK/LRCK ratio to use */
  	rate = params_rate(params);     /* Sampling rate, in Hz */
  	ratio = cs42l51->mclk / rate;    /* MCLK/LRCK ratio */
  	for (i = 0; i < nr_ratios; i++) {
  		if (ratios[i].ratio == ratio)
  			break;
  	}
  
  	if (i == nr_ratios) {
  		/* We did not find a matching ratio */
  		dev_err(codec->dev, "could not find matching ratio\n");
  		return -EINVAL;
  	}
  
  	intf_ctl = snd_soc_read(codec, CS42L51_INTF_CTL);
  	power_ctl = snd_soc_read(codec, CS42L51_MIC_POWER_CTL);
  
  	intf_ctl &= ~(CS42L51_INTF_CTL_MASTER | CS42L51_INTF_CTL_ADC_I2S
  			| CS42L51_INTF_CTL_DAC_FORMAT(7));
  	power_ctl &= ~(CS42L51_MIC_POWER_CTL_SPEED(3)
  			| CS42L51_MIC_POWER_CTL_MCLK_DIV2);
  
  	switch (cs42l51->func) {
  	case MODE_MASTER:
  		intf_ctl |= CS42L51_INTF_CTL_MASTER;
  		power_ctl |= CS42L51_MIC_POWER_CTL_SPEED(ratios[i].speed_mode);
  		break;
  	case MODE_SLAVE:
  		power_ctl |= CS42L51_MIC_POWER_CTL_SPEED(ratios[i].speed_mode);
  		break;
  	case MODE_SLAVE_AUTO:
  		power_ctl |= CS42L51_MIC_POWER_CTL_AUTO;
  		break;
  	}
  
  	switch (cs42l51->audio_mode) {
  	case SND_SOC_DAIFMT_I2S:
  		intf_ctl |= CS42L51_INTF_CTL_ADC_I2S;
  		intf_ctl |= CS42L51_INTF_CTL_DAC_FORMAT(CS42L51_DAC_DIF_I2S);
  		break;
  	case SND_SOC_DAIFMT_LEFT_J:
  		intf_ctl |= CS42L51_INTF_CTL_DAC_FORMAT(CS42L51_DAC_DIF_LJ24);
  		break;
  	case SND_SOC_DAIFMT_RIGHT_J:
  		switch (params_width(params)) {
  		case 16:
  			fmt = CS42L51_DAC_DIF_RJ16;
  			break;
  		case 18:
  			fmt = CS42L51_DAC_DIF_RJ18;
  			break;
  		case 20:
  			fmt = CS42L51_DAC_DIF_RJ20;
  			break;
  		case 24:
  			fmt = CS42L51_DAC_DIF_RJ24;
  			break;
  		default:
  			dev_err(codec->dev, "unknown format\n");
  			return -EINVAL;
  		}
  		intf_ctl |= CS42L51_INTF_CTL_DAC_FORMAT(fmt);
  		break;
  	default:
  		dev_err(codec->dev, "unknown format\n");
  		return -EINVAL;
  	}
  
  	if (ratios[i].mclk)
  		power_ctl |= CS42L51_MIC_POWER_CTL_MCLK_DIV2;
  
  	ret = snd_soc_write(codec, CS42L51_INTF_CTL, intf_ctl);
  	if (ret < 0)
  		return ret;
  
  	ret = snd_soc_write(codec, CS42L51_MIC_POWER_CTL, power_ctl);
  	if (ret < 0)
  		return ret;
  
  	return 0;
  }
  
  static int cs42l51_dai_mute(struct snd_soc_dai *dai, int mute)
  {
  	struct snd_soc_codec *codec = dai->codec;
  	int reg;
  	int mask = CS42L51_DAC_OUT_CTL_DACA_MUTE|CS42L51_DAC_OUT_CTL_DACB_MUTE;
  
  	reg = snd_soc_read(codec, CS42L51_DAC_OUT_CTL);
  
  	if (mute)
  		reg |= mask;
  	else
  		reg &= ~mask;
  
  	return snd_soc_write(codec, CS42L51_DAC_OUT_CTL, reg);
  }
  
  static const struct snd_soc_dai_ops cs42l51_dai_ops = {
  	.hw_params      = cs42l51_hw_params,
  	.set_sysclk     = cs42l51_set_dai_sysclk,
  	.set_fmt        = cs42l51_set_dai_fmt,
  	.digital_mute   = cs42l51_dai_mute,
  };
  
  static struct snd_soc_dai_driver cs42l51_dai = {
  	.name = "cs42l51-hifi",
  	.playback = {
  		.stream_name = "Playback",
  		.channels_min = 1,
  		.channels_max = 2,
  		.rates = SNDRV_PCM_RATE_8000_96000,
  		.formats = CS42L51_FORMATS,
  	},
  	.capture = {
  		.stream_name = "Capture",
  		.channels_min = 1,
  		.channels_max = 2,
  		.rates = SNDRV_PCM_RATE_8000_96000,
  		.formats = CS42L51_FORMATS,
  	},
  	.ops = &cs42l51_dai_ops,
  };
  
  static int cs42l51_codec_probe(struct snd_soc_codec *codec)
  {
  	int ret, reg;
  
  	/*
  	 * DAC configuration
  	 * - Use signal processor
  	 * - auto mute
  	 * - vol changes immediate
  	 * - no de-emphasize
  	 */
  	reg = CS42L51_DAC_CTL_DATA_SEL(1)
  		| CS42L51_DAC_CTL_AMUTE | CS42L51_DAC_CTL_DACSZ(0);
  	ret = snd_soc_write(codec, CS42L51_DAC_CTL, reg);
  	if (ret < 0)
  		return ret;
  
  	return 0;
  }
  
  static struct snd_soc_codec_driver soc_codec_device_cs42l51 = {
  	.probe = cs42l51_codec_probe,
  
  	.controls = cs42l51_snd_controls,
  	.num_controls = ARRAY_SIZE(cs42l51_snd_controls),
  	.dapm_widgets = cs42l51_dapm_widgets,
  	.num_dapm_widgets = ARRAY_SIZE(cs42l51_dapm_widgets),
  	.dapm_routes = cs42l51_routes,
  	.num_dapm_routes = ARRAY_SIZE(cs42l51_routes),
  };
  
  const struct regmap_config cs42l51_regmap = {
  	.max_register = CS42L51_CHARGE_FREQ,
  	.cache_type = REGCACHE_RBTREE,
  };
  EXPORT_SYMBOL_GPL(cs42l51_regmap);
  
  int cs42l51_probe(struct device *dev, struct regmap *regmap)
  {
  	struct cs42l51_private *cs42l51;
  	unsigned int val;
  	int ret;
  
  	if (IS_ERR(regmap))
  		return PTR_ERR(regmap);
  
  	cs42l51 = devm_kzalloc(dev, sizeof(struct cs42l51_private),
  			       GFP_KERNEL);
  	if (!cs42l51)
  		return -ENOMEM;
  
  	dev_set_drvdata(dev, cs42l51);
  
  	/* Verify that we have a CS42L51 */
  	ret = regmap_read(regmap, CS42L51_CHIP_REV_ID, &val);
  	if (ret < 0) {
  		dev_err(dev, "failed to read I2C\n");
  		goto error;
  	}
  
  	if ((val != CS42L51_MK_CHIP_REV(CS42L51_CHIP_ID, CS42L51_CHIP_REV_A)) &&
  	    (val != CS42L51_MK_CHIP_REV(CS42L51_CHIP_ID, CS42L51_CHIP_REV_B))) {
  		dev_err(dev, "Invalid chip id: %x\n", val);
  		ret = -ENODEV;
  		goto error;
  	}
  	dev_info(dev, "Cirrus Logic CS42L51, Revision: %02X\n",
  		 val & CS42L51_CHIP_REV_MASK);
  
  	ret =  snd_soc_register_codec(dev,
  			&soc_codec_device_cs42l51, &cs42l51_dai, 1);
  error:
  	return ret;
  }
  EXPORT_SYMBOL_GPL(cs42l51_probe);
  
  const struct of_device_id cs42l51_of_match[] = {
  	{ .compatible = "cirrus,cs42l51", },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, cs42l51_of_match);
  EXPORT_SYMBOL_GPL(cs42l51_of_match);
  
  MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>");
  MODULE_DESCRIPTION("Cirrus Logic CS42L51 ALSA SoC Codec Driver");
  MODULE_LICENSE("GPL");
  