cs42l51.c

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/*
 * cs42l51.c
 *
 * ASoC Driver for Cirrus Logic CS42L51 codecs
 *
 * Copyright (c) 2010 Arnaud Patard <[email protected]>
 *
 * 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/i2c.h>

#include "cs42l51.h"

enum master_slave_mode {
    MODE_SLAVE,
    MODE_SLAVE_AUTO,
    MODE_MASTER,
};

struct cs42l51_private {
    enum snd_soc_control_type control_type;
    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_fill_cache(struct snd_soc_codec *codec)
{
    u8 *cache = codec->reg_cache + 1;
    struct i2c_client *i2c_client = to_i2c_client(codec->dev);
    s32 length;

    length = i2c_smbus_read_i2c_block_data(i2c_client,
            CS42L51_FIRSTREG | 0x80, CS42L51_NUMREGS, cache);
    if (length != CS42L51_NUMREGS) {
        dev_err(&i2c_client->dev,
                "I2C read failure, addr=0x%x (ret=%d vs %d)\n",
                i2c_client->addr, length, CS42L51_NUMREGS);
        return -EIO;
    }

    return 0;
}

static int cs42l51_get_chan_mix(struct snd_kcontrol *kcontrol,
            struct snd_ctl_elem_value *ucontrol)
{
    struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
    unsigned long value = snd_soc_read(codec, CS42L51_PCM_MIXER)&3;

    switch (value) {
    default:
    case 0:
        ucontrol->value.integer.value[0] = 0;
        break;
    /* same value : (L+R)/2 and (R+L)/2 */
    case 1:
    case 2:
        ucontrol->value.integer.value[0] = 1;
        break;
    case 3:
        ucontrol->value.integer.value[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_kcontrol_chip(kcontrol);
    unsigned char val;

    switch (ucontrol->value.integer.value[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);
/* This is a lie. after -102 db, it stays at -102 */
/* maybe a range would be better */
static const DECLARE_TLV_DB_SCALE(aout_tlv, -11550, 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 const struct soc_enum cs42l51_chan_mix =
    SOC_ENUM_SINGLE_EXT(ARRAY_SIZE(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,
            6, 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,
            6, 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)
{
    switch (event) {
    case SND_SOC_DAPM_PRE_PMD:
        snd_soc_update_bits(w->codec, CS42L51_POWER_CTL1,
                    CS42L51_POWER_CTL1_PDN,
                    CS42L51_POWER_CTL1_PDN);
        break;
    default:
    case SND_SOC_DAPM_POST_PMD:
        snd_soc_update_bits(w->codec, CS42L51_POWER_CTL1,
                    CS42L51_POWER_CTL1_PDN, 0);
        break;
    }

    return 0;
}

static const char *cs42l51_dac_names[] = {"Direct PCM",
    "DSP PCM", "ADC"};
static const struct soc_enum cs42l51_dac_mux_enum =
    SOC_ENUM_SINGLE(CS42L51_DAC_CTL, 6, 3, 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 const struct soc_enum cs42l51_adcl_mux_enum =
    SOC_ENUM_SINGLE(CS42L51_ADC_INPUT, 4, 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 const struct soc_enum cs42l51_adcr_mux_enum =
    SOC_ENUM_SINGLE(CS42L51_ADC_INPUT, 6, 4, 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_format(params)) {
        case SNDRV_PCM_FORMAT_S16_LE:
        case SNDRV_PCM_FORMAT_S16_BE:
            fmt = CS42L51_DAC_DIF_RJ16;
            break;
        case SNDRV_PCM_FORMAT_S18_3LE:
        case SNDRV_PCM_FORMAT_S18_3BE:
            fmt = CS42L51_DAC_DIF_RJ18;
            break;
        case SNDRV_PCM_FORMAT_S20_3LE:
        case SNDRV_PCM_FORMAT_S20_3BE:
            fmt = CS42L51_DAC_DIF_RJ20;
            break;
        case SNDRV_PCM_FORMAT_S24_LE:
        case SNDRV_PCM_FORMAT_S24_BE:
            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_probe(struct snd_soc_codec *codec)
{
    struct cs42l51_private *cs42l51 = snd_soc_codec_get_drvdata(codec);
    int ret, reg;

    ret = cs42l51_fill_cache(codec);
    if (ret < 0) {
        dev_err(codec->dev, "failed to fill register cache\n");
        return ret;
    }

    ret = snd_soc_codec_set_cache_io(codec, 8, 8, cs42l51->control_type);
    if (ret < 0) {
        dev_err(codec->dev, "Failed to set cache I/O: %d\n", ret);
        return ret;
    }

    /*
     * 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_probe,
    .reg_cache_size = CS42L51_NUMREGS + 1,
    .reg_word_size = sizeof(u8),

    .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),
};

static int cs42l51_i2c_probe(struct i2c_client *i2c_client,
    const struct i2c_device_id *id)
{
    struct cs42l51_private *cs42l51;
    int ret;

    /* Verify that we have a CS42L51 */
    ret = i2c_smbus_read_byte_data(i2c_client, CS42L51_CHIP_REV_ID);
    if (ret < 0) {
        dev_err(&i2c_client->dev, "failed to read I2C\n");
        goto error;
    }

    if ((ret != CS42L51_MK_CHIP_REV(CS42L51_CHIP_ID, CS42L51_CHIP_REV_A)) &&
        (ret != CS42L51_MK_CHIP_REV(CS42L51_CHIP_ID, CS42L51_CHIP_REV_B))) {
        dev_err(&i2c_client->dev, "Invalid chip id\n");
        ret = -ENODEV;
        goto error;
    }

    dev_info(&i2c_client->dev, "found device cs42l51 rev %d\n",
                ret & 7);

    cs42l51 = devm_kzalloc(&i2c_client->dev, sizeof(struct cs42l51_private),
                   GFP_KERNEL);
    if (!cs42l51) {
        dev_err(&i2c_client->dev, "could not allocate codec\n");
        return -ENOMEM;
    }

    i2c_set_clientdata(i2c_client, cs42l51);
    cs42l51->control_type = SND_SOC_I2C;

    ret =  snd_soc_register_codec(&i2c_client->dev,
            &soc_codec_device_cs42l51, &cs42l51_dai, 1);
error:
    return ret;
}

static int cs42l51_i2c_remove(struct i2c_client *client)
{
    snd_soc_unregister_codec(&client->dev);
    return 0;
}

static const struct i2c_device_id cs42l51_id[] = {
    {"cs42l51", 0},
    {}
};
MODULE_DEVICE_TABLE(i2c, cs42l51_id);

static struct i2c_driver cs42l51_i2c_driver = {
    .driver = {
        .name = "cs42l51-codec",
        .owner = THIS_MODULE,
    },
    .id_table = cs42l51_id,
    .probe = cs42l51_i2c_probe,
    .remove = cs42l51_i2c_remove,
};

module_i2c_driver(cs42l51_i2c_driver);

MODULE_AUTHOR("Arnaud Patard <[email protected]>");
MODULE_DESCRIPTION("Cirrus Logic CS42L51 ALSA SoC Codec Driver");
MODULE_LICENSE("GPL");