wm8731.c

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/*
 * wm8731.c  --  WM8731 ALSA SoC Audio driver
 *
 * Copyright 2005 Openedhand Ltd.
 * Copyright 2006-12 Wolfson Microelectronics, plc
 *
 * Author: Richard Purdie <[email protected]>
 *
 * Based on wm8753.c by Liam Girdwood
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/pm.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/of_device.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/initval.h>
#include <sound/tlv.h>

#include "wm8731.h"

#define WM8731_NUM_SUPPLIES 4
static const char *wm8731_supply_names[WM8731_NUM_SUPPLIES] = {
    "AVDD",
    "HPVDD",
    "DCVDD",
    "DBVDD",
};

/* codec private data */
struct wm8731_priv {
    struct regmap *regmap;
    struct regulator_bulk_data supplies[WM8731_NUM_SUPPLIES];
    unsigned int sysclk;
    int sysclk_type;
    int playback_fs;
    bool deemph;
};


/*
 * wm8731 register cache
 */
static const struct reg_default wm8731_reg_defaults[] = {
    { 0, 0x0097 },
    { 1, 0x0097 },
    { 2, 0x0079 },
    { 3, 0x0079 },
    { 4, 0x000a },
    { 5, 0x0008 },
    { 6, 0x009f },
    { 7, 0x000a },
    { 8, 0x0000 },
    { 9, 0x0000 },
};

static bool wm8731_volatile(struct device *dev, unsigned int reg)
{
    return reg == WM8731_RESET;
}

static bool wm8731_writeable(struct device *dev, unsigned int reg)
{
    return reg <= WM8731_RESET;
}

#define wm8731_reset(c) snd_soc_write(c, WM8731_RESET, 0)

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

static const struct soc_enum wm8731_insel_enum =
    SOC_ENUM_SINGLE(WM8731_APANA, 2, 2, wm8731_input_select);

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);
static const DECLARE_TLV_DB_SCALE(out_tlv, -12100, 100, 1);
static const DECLARE_TLV_DB_SCALE(mic_tlv, 0, 2000, 0);

static const struct snd_kcontrol_new wm8731_snd_controls[] = {

SOC_DOUBLE_R_TLV("Master Playback Volume", WM8731_LOUT1V, WM8731_ROUT1V,
         0, 127, 0, out_tlv),
SOC_DOUBLE_R("Master Playback ZC Switch", WM8731_LOUT1V, WM8731_ROUT1V,
    7, 1, 0),

SOC_DOUBLE_R_TLV("Capture Volume", WM8731_LINVOL, WM8731_RINVOL, 0, 31, 0,
         in_tlv),
SOC_DOUBLE_R("Line Capture Switch", WM8731_LINVOL, WM8731_RINVOL, 7, 1, 1),

SOC_SINGLE_TLV("Mic Boost Volume", WM8731_APANA, 0, 1, 0, mic_tlv),
SOC_SINGLE("Mic Capture Switch", WM8731_APANA, 1, 1, 1),

SOC_SINGLE_TLV("Sidetone Playback Volume", WM8731_APANA, 6, 3, 1,
           sidetone_tlv),

SOC_SINGLE("ADC High Pass Filter Switch", WM8731_APDIGI, 0, 1, 1),
SOC_SINGLE("Store DC Offset Switch", WM8731_APDIGI, 4, 1, 0),

SOC_SINGLE_BOOL_EXT("Playback Deemphasis Switch", 0,
            wm8731_get_deemph, wm8731_put_deemph),
};

/* Output Mixer */
static const struct snd_kcontrol_new wm8731_output_mixer_controls[] = {
SOC_DAPM_SINGLE("Line Bypass Switch", WM8731_APANA, 3, 1, 0),
SOC_DAPM_SINGLE("Mic Sidetone Switch", WM8731_APANA, 5, 1, 0),
SOC_DAPM_SINGLE("HiFi Playback Switch", WM8731_APANA, 4, 1, 0),
};

/* Input mux */
static const struct snd_kcontrol_new wm8731_input_mux_controls =
SOC_DAPM_ENUM("Input Select", wm8731_insel_enum);

static const struct snd_soc_dapm_widget wm8731_dapm_widgets[] = {
SND_SOC_DAPM_SUPPLY("ACTIVE",WM8731_ACTIVE, 0, 0, NULL, 0),
SND_SOC_DAPM_SUPPLY("OSC", WM8731_PWR, 5, 1, NULL, 0),
SND_SOC_DAPM_MIXER("Output Mixer", WM8731_PWR, 4, 1,
    &wm8731_output_mixer_controls[0],
    ARRAY_SIZE(wm8731_output_mixer_controls)),
SND_SOC_DAPM_DAC("DAC", "HiFi Playback", WM8731_PWR, 3, 1),
SND_SOC_DAPM_OUTPUT("LOUT"),
SND_SOC_DAPM_OUTPUT("LHPOUT"),
SND_SOC_DAPM_OUTPUT("ROUT"),
SND_SOC_DAPM_OUTPUT("RHPOUT"),
SND_SOC_DAPM_ADC("ADC", "HiFi Capture", WM8731_PWR, 2, 1),
SND_SOC_DAPM_MUX("Input Mux", SND_SOC_NOPM, 0, 0, &wm8731_input_mux_controls),
SND_SOC_DAPM_PGA("Line Input", WM8731_PWR, 0, 1, NULL, 0),
SND_SOC_DAPM_MICBIAS("Mic Bias", WM8731_PWR, 1, 1),
SND_SOC_DAPM_INPUT("MICIN"),
SND_SOC_DAPM_INPUT("RLINEIN"),
SND_SOC_DAPM_INPUT("LLINEIN"),
};

static int wm8731_check_osc(struct snd_soc_dapm_widget *source,
                struct snd_soc_dapm_widget *sink)
{
    struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(source->codec);

    return wm8731->sysclk_type == WM8731_SYSCLK_XTAL;
}

static const struct snd_soc_dapm_route wm8731_intercon[] = {
    {"DAC", NULL, "OSC", wm8731_check_osc},
    {"ADC", NULL, "OSC", wm8731_check_osc},
    {"DAC", NULL, "ACTIVE"},
    {"ADC", NULL, "ACTIVE"},

    /* output mixer */
    {"Output Mixer", "Line Bypass Switch", "Line Input"},
    {"Output Mixer", "HiFi Playback Switch", "DAC"},
    {"Output Mixer", "Mic Sidetone Switch", "Mic Bias"},

    /* outputs */
    {"RHPOUT", NULL, "Output Mixer"},
    {"ROUT", NULL, "Output Mixer"},
    {"LHPOUT", NULL, "Output Mixer"},
    {"LOUT", NULL, "Output Mixer"},

    /* input mux */
    {"Input Mux", "Line In", "Line Input"},
    {"Input Mux", "Mic", "Mic Bias"},
    {"ADC", NULL, "Input Mux"},

    /* inputs */
    {"Line Input", NULL, "LLINEIN"},
    {"Line Input", NULL, "RLINEIN"},
    {"Mic Bias", NULL, "MICIN"},
};

struct _coeff_div {
    u32 mclk;
    u32 rate;
    u16 fs;
    u8 sr:4;
    u8 bosr:1;
    u8 usb:1;
};

/* codec mclk clock divider coefficients */
static const struct _coeff_div coeff_div[] = {
    /* 48k */
    {12288000, 48000, 256, 0x0, 0x0, 0x0},
    {18432000, 48000, 384, 0x0, 0x1, 0x0},
    {12000000, 48000, 250, 0x0, 0x0, 0x1},

    /* 32k */
    {12288000, 32000, 384, 0x6, 0x0, 0x0},
    {18432000, 32000, 576, 0x6, 0x1, 0x0},
    {12000000, 32000, 375, 0x6, 0x0, 0x1},

    /* 8k */
    {12288000, 8000, 1536, 0x3, 0x0, 0x0},
    {18432000, 8000, 2304, 0x3, 0x1, 0x0},
    {11289600, 8000, 1408, 0xb, 0x0, 0x0},
    {16934400, 8000, 2112, 0xb, 0x1, 0x0},
    {12000000, 8000, 1500, 0x3, 0x0, 0x1},

    /* 96k */
    {12288000, 96000, 128, 0x7, 0x0, 0x0},
    {18432000, 96000, 192, 0x7, 0x1, 0x0},
    {12000000, 96000, 125, 0x7, 0x0, 0x1},

    /* 44.1k */
    {11289600, 44100, 256, 0x8, 0x0, 0x0},
    {16934400, 44100, 384, 0x8, 0x1, 0x0},
    {12000000, 44100, 272, 0x8, 0x1, 0x1},

    /* 88.2k */
    {11289600, 88200, 128, 0xf, 0x0, 0x0},
    {16934400, 88200, 192, 0xf, 0x1, 0x0},
    {12000000, 88200, 136, 0xf, 0x1, 0x1},
};

static inline int get_coeff(int mclk, int rate)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(coeff_div); i++) {
        if (coeff_div[i].rate == rate && coeff_div[i].mclk == mclk)
            return i;
    }
    return 0;
}

static int wm8731_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 wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);
    u16 iface = snd_soc_read(codec, WM8731_IFACE) & 0xfff3;
    int i = get_coeff(wm8731->sysclk, params_rate(params));
    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 */
    switch (params_format(params)) {
    case SNDRV_PCM_FORMAT_S16_LE:
        break;
    case SNDRV_PCM_FORMAT_S20_3LE:
        iface |= 0x0004;
        break;
    case SNDRV_PCM_FORMAT_S24_LE:
        iface |= 0x0008;
        break;
    }

    wm8731_set_deemph(codec);

    snd_soc_write(codec, WM8731_IFACE, iface);
    return 0;
}

static int wm8731_mute(struct snd_soc_dai *dai, int mute)
{
    struct snd_soc_codec *codec = dai->codec;
    u16 mute_reg = snd_soc_read(codec, WM8731_APDIGI) & 0xfff7;

    if (mute)
        snd_soc_write(codec, WM8731_APDIGI, mute_reg | 0x8);
    else
        snd_soc_write(codec, WM8731_APDIGI, mute_reg);
    return 0;
}

static int wm8731_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 wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);

    switch (clk_id) {
    case WM8731_SYSCLK_XTAL:
    case WM8731_SYSCLK_MCLK:
        wm8731->sysclk_type = clk_id;
        break;
    default:
        return -EINVAL;
    }

    switch (freq) {
    case 11289600:
    case 12000000:
    case 12288000:
    case 16934400:
    case 18432000:
        wm8731->sysclk = freq;
        break;
    default:
        return -EINVAL;
    }

    snd_soc_dapm_sync(&codec->dapm);

    return 0;
}


static int wm8731_set_dai_fmt(struct snd_soc_dai *codec_dai,
        unsigned int fmt)
{
    struct snd_soc_codec *codec = codec_dai->codec;
    u16 iface = 0;

    /* set master/slave audio interface */
    switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
    case SND_SOC_DAIFMT_CBM_CFM:
        iface |= 0x0040;
        break;
    case SND_SOC_DAIFMT_CBS_CFS:
        break;
    default:
        return -EINVAL;
    }

    /* interface format */
    switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
    case SND_SOC_DAIFMT_I2S:
        iface |= 0x0002;
        break;
    case SND_SOC_DAIFMT_RIGHT_J:
        break;
    case SND_SOC_DAIFMT_LEFT_J:
        iface |= 0x0001;
        break;
    case SND_SOC_DAIFMT_DSP_A:
        iface |= 0x0003;
        break;
    case SND_SOC_DAIFMT_DSP_B:
        iface |= 0x0013;
        break;
    default:
        return -EINVAL;
    }

    /* clock inversion */
    switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
    case SND_SOC_DAIFMT_NB_NF:
        break;
    case SND_SOC_DAIFMT_IB_IF:
        iface |= 0x0090;
        break;
    case SND_SOC_DAIFMT_IB_NF:
        iface |= 0x0080;
        break;
    case SND_SOC_DAIFMT_NB_IF:
        iface |= 0x0010;
        break;
    default:
        return -EINVAL;
    }

    /* set iface */
    snd_soc_write(codec, WM8731_IFACE, iface);
    return 0;
}

static int wm8731_set_bias_level(struct snd_soc_codec *codec,
                 enum snd_soc_bias_level level)
{
    struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);
    int ret;
    u16 reg;

    switch (level) {
    case SND_SOC_BIAS_ON:
        break;
    case SND_SOC_BIAS_PREPARE:
        break;
    case SND_SOC_BIAS_STANDBY:
        if (codec->dapm.bias_level == SND_SOC_BIAS_OFF) {
            ret = regulator_bulk_enable(ARRAY_SIZE(wm8731->supplies),
                            wm8731->supplies);
            if (ret != 0)
                return ret;

            regcache_sync(wm8731->regmap);
        }

        /* Clear PWROFF, gate CLKOUT, everything else as-is */
        reg = snd_soc_read(codec, WM8731_PWR) & 0xff7f;
        snd_soc_write(codec, WM8731_PWR, reg | 0x0040);
        break;
    case SND_SOC_BIAS_OFF:
        snd_soc_write(codec, WM8731_PWR, 0xffff);
        regulator_bulk_disable(ARRAY_SIZE(wm8731->supplies),
                       wm8731->supplies);
        regcache_mark_dirty(wm8731->regmap);
        break;
    }
    codec->dapm.bias_level = level;
    return 0;
}

#define WM8731_RATES SNDRV_PCM_RATE_8000_96000

#define WM8731_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE |\
    SNDRV_PCM_FMTBIT_S24_LE)

static const struct snd_soc_dai_ops wm8731_dai_ops = {
    .hw_params  = wm8731_hw_params,
    .digital_mute   = wm8731_mute,
    .set_sysclk = wm8731_set_dai_sysclk,
    .set_fmt    = wm8731_set_dai_fmt,
};

static struct snd_soc_dai_driver wm8731_dai = {
    .name = "wm8731-hifi",
    .playback = {
        .stream_name = "Playback",
        .channels_min = 1,
        .channels_max = 2,
        .rates = WM8731_RATES,
        .formats = WM8731_FORMATS,},
    .capture = {
        .stream_name = "Capture",
        .channels_min = 1,
        .channels_max = 2,
        .rates = WM8731_RATES,
        .formats = WM8731_FORMATS,},
    .ops = &wm8731_dai_ops,
    .symmetric_rates = 1,
};

#ifdef CONFIG_PM
static int wm8731_suspend(struct snd_soc_codec *codec)
{
    wm8731_set_bias_level(codec, SND_SOC_BIAS_OFF);

    return 0;
}

static int wm8731_resume(struct snd_soc_codec *codec)
{
    wm8731_set_bias_level(codec, SND_SOC_BIAS_STANDBY);

    return 0;
}
#else
#define wm8731_suspend NULL
#define wm8731_resume NULL
#endif

static int wm8731_probe(struct snd_soc_codec *codec)
{
    struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);
    int ret = 0, i;

    codec->control_data = wm8731->regmap;
    ret = snd_soc_codec_set_cache_io(codec, 7, 9, SND_SOC_REGMAP);
    if (ret < 0) {
        dev_err(codec->dev, "Failed to set cache I/O: %d\n", ret);
        return ret;
    }

    for (i = 0; i < ARRAY_SIZE(wm8731->supplies); i++)
        wm8731->supplies[i].supply = wm8731_supply_names[i];

    ret = regulator_bulk_get(codec->dev, ARRAY_SIZE(wm8731->supplies),
                 wm8731->supplies);
    if (ret != 0) {
        dev_err(codec->dev, "Failed to request supplies: %d\n", ret);
        return ret;
    }

    ret = regulator_bulk_enable(ARRAY_SIZE(wm8731->supplies),
                    wm8731->supplies);
    if (ret != 0) {
        dev_err(codec->dev, "Failed to enable supplies: %d\n", ret);
        goto err_regulator_get;
    }

    ret = wm8731_reset(codec);
    if (ret < 0) {
        dev_err(codec->dev, "Failed to issue reset: %d\n", ret);
        goto err_regulator_enable;
    }

    wm8731_set_bias_level(codec, SND_SOC_BIAS_STANDBY);

    /* Latch the update bits */
    snd_soc_update_bits(codec, WM8731_LOUT1V, 0x100, 0);
    snd_soc_update_bits(codec, WM8731_ROUT1V, 0x100, 0);
    snd_soc_update_bits(codec, WM8731_LINVOL, 0x100, 0);
    snd_soc_update_bits(codec, WM8731_RINVOL, 0x100, 0);

    /* Disable bypass path by default */
    snd_soc_update_bits(codec, WM8731_APANA, 0x8, 0);

    /* Regulators will have been enabled by bias management */
    regulator_bulk_disable(ARRAY_SIZE(wm8731->supplies), wm8731->supplies);

    return 0;

err_regulator_enable:
    regulator_bulk_disable(ARRAY_SIZE(wm8731->supplies), wm8731->supplies);
err_regulator_get:
    regulator_bulk_free(ARRAY_SIZE(wm8731->supplies), wm8731->supplies);

    return ret;
}

/* power down chip */
static int wm8731_remove(struct snd_soc_codec *codec)
{
    struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);

    wm8731_set_bias_level(codec, SND_SOC_BIAS_OFF);

    regulator_bulk_disable(ARRAY_SIZE(wm8731->supplies), wm8731->supplies);
    regulator_bulk_free(ARRAY_SIZE(wm8731->supplies), wm8731->supplies);

    return 0;
}

static struct snd_soc_codec_driver soc_codec_dev_wm8731 = {
    .probe =    wm8731_probe,
    .remove =   wm8731_remove,
    .suspend =  wm8731_suspend,
    .resume =   wm8731_resume,
    .set_bias_level = wm8731_set_bias_level,
    .dapm_widgets = wm8731_dapm_widgets,
    .num_dapm_widgets = ARRAY_SIZE(wm8731_dapm_widgets),
    .dapm_routes = wm8731_intercon,
    .num_dapm_routes = ARRAY_SIZE(wm8731_intercon),
    .controls = wm8731_snd_controls,
    .num_controls = ARRAY_SIZE(wm8731_snd_controls),
};

static const struct of_device_id wm8731_of_match[] = {
    { .compatible = "wlf,wm8731", },
    { }
};

MODULE_DEVICE_TABLE(of, wm8731_of_match);

static const struct regmap_config wm8731_regmap = {
    .reg_bits = 7,
    .val_bits = 9,

    .max_register = WM8731_RESET,
    .volatile_reg = wm8731_volatile,
    .writeable_reg = wm8731_writeable,

    .cache_type = REGCACHE_RBTREE,
    .reg_defaults = wm8731_reg_defaults,
    .num_reg_defaults = ARRAY_SIZE(wm8731_reg_defaults),
};

#if defined(CONFIG_SPI_MASTER)
static int __devinit wm8731_spi_probe(struct spi_device *spi)
{
    struct wm8731_priv *wm8731;
    int ret;

    wm8731 = devm_kzalloc(&spi->dev, sizeof(struct wm8731_priv),
                  GFP_KERNEL);
    if (wm8731 == NULL)
        return -ENOMEM;

    wm8731->regmap = devm_regmap_init_spi(spi, &wm8731_regmap);
    if (IS_ERR(wm8731->regmap)) {
        ret = PTR_ERR(wm8731->regmap);
        dev_err(&spi->dev, "Failed to allocate register map: %d\n",
            ret);
        return ret;
    }

    spi_set_drvdata(spi, wm8731);

    ret = snd_soc_register_codec(&spi->dev,
            &soc_codec_dev_wm8731, &wm8731_dai, 1);
    if (ret != 0) {
        dev_err(&spi->dev, "Failed to register CODEC: %d\n", ret);
        return ret;
    }

    return 0;
}

static int __devexit wm8731_spi_remove(struct spi_device *spi)
{
    snd_soc_unregister_codec(&spi->dev);
    return 0;
}

static struct spi_driver wm8731_spi_driver = {
    .driver = {
        .name   = "wm8731",
        .owner  = THIS_MODULE,
        .of_match_table = wm8731_of_match,
    },
    .probe      = wm8731_spi_probe,
    .remove     = __devexit_p(wm8731_spi_remove),
};
#endif /* CONFIG_SPI_MASTER */

#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
static __devinit int wm8731_i2c_probe(struct i2c_client *i2c,
                      const struct i2c_device_id *id)
{
    struct wm8731_priv *wm8731;
    int ret;

    wm8731 = devm_kzalloc(&i2c->dev, sizeof(struct wm8731_priv),
                  GFP_KERNEL);
    if (wm8731 == NULL)
        return -ENOMEM;

    wm8731->regmap = devm_regmap_init_i2c(i2c, &wm8731_regmap);
    if (IS_ERR(wm8731->regmap)) {
        ret = PTR_ERR(wm8731->regmap);
        dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
            ret);
        return ret;
    }

    i2c_set_clientdata(i2c, wm8731);

    ret = snd_soc_register_codec(&i2c->dev,
            &soc_codec_dev_wm8731, &wm8731_dai, 1);
    if (ret != 0) {
        dev_err(&i2c->dev, "Failed to register CODEC: %d\n", ret);
        return ret;
    }

    return 0;
}

static __devexit int wm8731_i2c_remove(struct i2c_client *client)
{
    snd_soc_unregister_codec(&client->dev);
    return 0;
}

static const struct i2c_device_id wm8731_i2c_id[] = {
    { "wm8731", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, wm8731_i2c_id);

static struct i2c_driver wm8731_i2c_driver = {
    .driver = {
        .name = "wm8731",
        .owner = THIS_MODULE,
        .of_match_table = wm8731_of_match,
    },
    .probe =    wm8731_i2c_probe,
    .remove =   __devexit_p(wm8731_i2c_remove),
    .id_table = wm8731_i2c_id,
};
#endif

static int __init wm8731_modinit(void)
{
    int ret = 0;
#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
    ret = i2c_add_driver(&wm8731_i2c_driver);
    if (ret != 0) {
        printk(KERN_ERR "Failed to register WM8731 I2C driver: %d\n",
               ret);
    }
#endif
#if defined(CONFIG_SPI_MASTER)
    ret = spi_register_driver(&wm8731_spi_driver);
    if (ret != 0) {
        printk(KERN_ERR "Failed to register WM8731 SPI driver: %d\n",
               ret);
    }
#endif
    return ret;
}
module_init(wm8731_modinit);

static void __exit wm8731_exit(void)
{
#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
    i2c_del_driver(&wm8731_i2c_driver);
#endif
#if defined(CONFIG_SPI_MASTER)
    spi_unregister_driver(&wm8731_spi_driver);
#endif
}
module_exit(wm8731_exit);

MODULE_DESCRIPTION("ASoC WM8731 driver");
MODULE_AUTHOR("Richard Purdie");
MODULE_LICENSE("GPL");