ASoC: Add WM8523 CODEC driver

The WM8523 is a high performance stereo DAC with integral charge
pump providing 2Vrms line driver outputs using a single 3.3V power
supply rail.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 755 insertions, 0 deletions

diff --git a/sound/soc/codecs/wm8523.c b/sound/soc/codecs/wm8523.c
new file mode 100644
index 000000000000..3b499ae7ce6c
--- /dev/null
+++ b/sound/soc/codecs/wm8523.c
@@ -0,0 +1,755 @@
+/*
+ * wm8523.c  --  WM8523 ALSA SoC Audio driver
+ *
+ * Copyright 2009 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ *
+ * 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/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-dapm.h>
+#include <sound/initval.h>
+#include <sound/tlv.h>
+
+#include "wm8523.h"
+
+static struct snd_soc_codec *wm8523_codec;
+struct snd_soc_codec_device soc_codec_dev_wm8523;
+
+#define WM8523_NUM_SUPPLIES 2
+static const char *wm8523_supply_names[WM8523_NUM_SUPPLIES] = {
+	"AVDD",
+	"LINEVDD",
+};
+
+#define WM8523_NUM_RATES 7
+
+/* codec private data */
+struct wm8523_priv {
+	struct snd_soc_codec codec;
+	u16 reg_cache[WM8523_REGISTER_COUNT];
+	struct regulator_bulk_data supplies[WM8523_NUM_SUPPLIES];
+	unsigned int sysclk;
+	unsigned int rate_constraint_list[WM8523_NUM_RATES];
+	struct snd_pcm_hw_constraint_list rate_constraint;
+};
+
+static const u16 wm8523_reg[WM8523_REGISTER_COUNT] = {
+	0x8523,     /* R0 - DEVICE_ID */
+	0x0001,     /* R1 - REVISION */
+	0x0000,     /* R2 - PSCTRL1 */
+	0x1812,     /* R3 - AIF_CTRL1 */
+	0x0000,     /* R4 - AIF_CTRL2 */
+	0x0001,     /* R5 - DAC_CTRL3 */
+	0x0190,     /* R6 - DAC_GAINL */
+	0x0190,     /* R7 - DAC_GAINR */
+	0x0000,     /* R8 - ZERO_DETECT */
+};
+
+static int wm8523_volatile(unsigned int reg)
+{
+	switch (reg) {
+	case WM8523_DEVICE_ID:
+	case WM8523_REVISION:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+static int wm8523_write(struct snd_soc_codec *codec, unsigned int reg,
+	unsigned int value)
+{
+	struct wm8523_priv *wm8523 = codec->private_data;
+	u8 data[3];
+
+	BUG_ON(reg > WM8523_MAX_REGISTER);
+
+	data[0] = reg;
+	data[1] = (value >> 8) & 0x00ff;
+	data[2] = value & 0x00ff;
+
+	if (!wm8523_volatile(reg))
+		wm8523->reg_cache[reg] = value;
+	if (codec->hw_write(codec->control_data, data, 3) == 3)
+		return 0;
+	else
+		return -EIO;
+}
+
+static int wm8523_reset(struct snd_soc_codec *codec)
+{
+	return wm8523_write(codec, WM8523_DEVICE_ID, 0);
+}
+
+static unsigned int wm8523_read_hw(struct snd_soc_codec *codec, u8 reg)
+{
+	struct i2c_msg xfer[2];
+	u16 data;
+	int ret;
+	struct i2c_client *i2c = codec->control_data;
+
+	/* Write register */
+	xfer[0].addr = i2c->addr;
+	xfer[0].flags = 0;
+	xfer[0].len = 1;
+	xfer[0].buf = &reg;
+
+	/* Read data */
+	xfer[1].addr = i2c->addr;
+	xfer[1].flags = I2C_M_RD;
+	xfer[1].len = 2;
+	xfer[1].buf = (u8 *)&data;
+
+	ret = i2c_transfer(i2c->adapter, xfer, 2);
+	if (ret != 2) {
+		dev_err(codec->dev, "Failed to read 0x%x: %d\n", reg, ret);
+		return 0;
+	}
+
+	return (data >> 8) | ((data & 0xff) << 8);
+}
+
+
+static unsigned int wm8523_read(struct snd_soc_codec *codec,
+				unsigned int reg)
+{
+	u16 *reg_cache = codec->reg_cache;
+
+	BUG_ON(reg > WM8523_MAX_REGISTER);
+
+	if (wm8523_volatile(reg))
+		return wm8523_read_hw(codec, reg);
+	else
+		return reg_cache[reg];
+}
+
+static const DECLARE_TLV_DB_SCALE(dac_tlv, -10000, 25, 0);
+
+static const char *wm8523_zd_count_text[] = {
+	"1024",
+	"2048",
+};
+
+static const struct soc_enum wm8523_zc_count =
+	SOC_ENUM_SINGLE(WM8523_ZERO_DETECT, 0, 2, wm8523_zd_count_text);
+
+static const struct snd_kcontrol_new wm8523_snd_controls[] = {
+SOC_DOUBLE_R_TLV("Playback Volume", WM8523_DAC_GAINL, WM8523_DAC_GAINR,
+		 0, 448, 0, dac_tlv),
+SOC_SINGLE("ZC Switch", WM8523_DAC_CTRL3, 4, 1, 0),
+SOC_SINGLE("Playback Deemphasis Switch", WM8523_AIF_CTRL1, 8, 1, 0),
+SOC_DOUBLE("Playback Switch", WM8523_DAC_CTRL3, 2, 3, 1, 1),
+SOC_SINGLE("Volume Ramp Up Switch", WM8523_DAC_CTRL3, 1, 1, 0),
+SOC_SINGLE("Volume Ramp Down Switch", WM8523_DAC_CTRL3, 0, 1, 0),
+SOC_ENUM("Zero Detect Count", wm8523_zc_count),
+};
+
+static const struct snd_soc_dapm_widget wm8523_dapm_widgets[] = {
+SND_SOC_DAPM_DAC("DAC", "Playback", SND_SOC_NOPM, 0, 0),
+SND_SOC_DAPM_OUTPUT("LINEVOUTL"),
+SND_SOC_DAPM_OUTPUT("LINEVOUTR"),
+};
+
+static const struct snd_soc_dapm_route intercon[] = {
+	{ "LINEVOUTL", NULL, "DAC" },
+	{ "LINEVOUTR", NULL, "DAC" },
+};
+
+static int wm8523_add_widgets(struct snd_soc_codec *codec)
+{
+	snd_soc_dapm_new_controls(codec, wm8523_dapm_widgets,
+				  ARRAY_SIZE(wm8523_dapm_widgets));
+
+	snd_soc_dapm_add_routes(codec, intercon, ARRAY_SIZE(intercon));
+
+	snd_soc_dapm_new_widgets(codec);
+	return 0;
+}
+
+static struct {
+	int value;
+	int ratio;
+} lrclk_ratios[WM8523_NUM_RATES] = {
+	{ 1, 128 },
+	{ 2, 192 },
+	{ 3, 256 },
+	{ 4, 384 },
+	{ 5, 512 },
+	{ 6, 768 },
+	{ 7, 1152 },
+};
+
+static int wm8523_startup(struct snd_pcm_substream *substream,
+			  struct snd_soc_dai *dai)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	struct wm8523_priv *wm8523 = codec->private_data;
+
+	/* The set of sample rates that can be supported depends on the
+	 * MCLK supplied to the CODEC - enforce this.
+	 */
+	if (!wm8523->sysclk) {
+		dev_err(codec->dev,
+			"No MCLK configured, call set_sysclk() on init\n");
+		return -EINVAL;
+	}
+
+	return 0;
+	snd_pcm_hw_constraint_list(substream->runtime, 0,
+				   SNDRV_PCM_HW_PARAM_RATE,
+				   &wm8523->rate_constraint);
+
+	return 0;
+}
+
+static int wm8523_hw_params(struct snd_pcm_substream *substream,
+			    struct snd_pcm_hw_params *params,
+			    struct snd_soc_dai *dai)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_device *socdev = rtd->socdev;
+	struct snd_soc_codec *codec = socdev->card->codec;
+	struct wm8523_priv *wm8523 = codec->private_data;
+	int i;
+	u16 aifctrl1 = wm8523_read(codec, WM8523_AIF_CTRL1);
+	u16 aifctrl2 = wm8523_read(codec, WM8523_AIF_CTRL2);
+
+	/* Find a supported LRCLK ratio */
+	for (i = 0; i < ARRAY_SIZE(lrclk_ratios); i++) {
+		if (wm8523->sysclk / params_rate(params) ==
+		    lrclk_ratios[i].ratio)
+			break;
+	}
+
+	/* Should never happen, should be handled by constraints */
+	if (i == ARRAY_SIZE(lrclk_ratios)) {
+		dev_err(codec->dev, "MCLK/fs ratio %d unsupported\n",
+			wm8523->sysclk / params_rate(params));
+		return -EINVAL;
+	}
+
+	aifctrl2 &= ~WM8523_SR_MASK;
+	aifctrl2 |= lrclk_ratios[i].value;
+
+	aifctrl1 &= ~WM8523_WL_MASK;
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		break;
+	case SNDRV_PCM_FORMAT_S20_3LE:
+		aifctrl1 |= 0x8;
+		break;
+	case SNDRV_PCM_FORMAT_S24_LE:
+		aifctrl1 |= 0x10;
+		break;
+	case SNDRV_PCM_FORMAT_S32_LE:
+		aifctrl1 |= 0x18;
+		break;
+	}
+
+	wm8523_write(codec, WM8523_AIF_CTRL1, aifctrl1);
+	wm8523_write(codec, WM8523_AIF_CTRL2, aifctrl2);
+
+	return 0;
+}
+
+static int wm8523_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 wm8523_priv *wm8523 = codec->private_data;
+	unsigned int val;
+	int i;
+
+	wm8523->sysclk = freq;
+
+	wm8523->rate_constraint.count = 0;
+	for (i = 0; i < ARRAY_SIZE(lrclk_ratios); i++) {
+		val = freq / lrclk_ratios[i].ratio;
+		/* Check that it's a standard rate since core can't
+		 * cope with others and having the odd rates confuses
+		 * constraint matching.
+		 */
+		switch (val) {
+		case 8000:
+		case 11025:
+		case 16000:
+		case 22050:
+		case 32000:
+		case 44100:
+		case 48000:
+		case 64000:
+		case 88200:
+		case 96000:
+		case 176400:
+		case 192000:
+			dev_dbg(codec->dev, "Supported sample rate: %dHz\n",
+				val);
+			wm8523->rate_constraint_list[i] = val;
+			wm8523->rate_constraint.count++;
+			break;
+		default:
+			dev_dbg(codec->dev, "Skipping sample rate: %dHz\n",
+				val);
+		}
+	}
+
+	/* Need at least one supported rate... */
+	if (wm8523->rate_constraint.count == 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+
+static int wm8523_set_dai_fmt(struct snd_soc_dai *codec_dai,
+		unsigned int fmt)
+{
+	struct snd_soc_codec *codec = codec_dai->codec;
+	u16 aifctrl1 = wm8523_read(codec, WM8523_AIF_CTRL1);
+
+	aifctrl1 &= ~(WM8523_BCLK_INV_MASK | WM8523_LRCLK_INV_MASK |
+		      WM8523_FMT_MASK | WM8523_AIF_MSTR_MASK);
+
+	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	case SND_SOC_DAIFMT_CBM_CFM:
+		aifctrl1 |= WM8523_AIF_MSTR;
+		break;
+	case SND_SOC_DAIFMT_CBS_CFS:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		aifctrl1 |= 0x0002;
+		break;
+	case SND_SOC_DAIFMT_RIGHT_J:
+		break;
+	case SND_SOC_DAIFMT_LEFT_J:
+		aifctrl1 |= 0x0001;
+		break;
+	case SND_SOC_DAIFMT_DSP_A:
+		aifctrl1 |= 0x0003;
+		break;
+	case SND_SOC_DAIFMT_DSP_B:
+		aifctrl1 |= 0x0023;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+		break;
+	case SND_SOC_DAIFMT_IB_IF:
+		aifctrl1 |= WM8523_BCLK_INV | WM8523_LRCLK_INV;
+		break;
+	case SND_SOC_DAIFMT_IB_NF:
+		aifctrl1 |= WM8523_BCLK_INV;
+		break;
+	case SND_SOC_DAIFMT_NB_IF:
+		aifctrl1 |= WM8523_LRCLK_INV;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	wm8523_write(codec, WM8523_AIF_CTRL1, aifctrl1);
+
+	return 0;
+}
+
+static int wm8523_set_bias_level(struct snd_soc_codec *codec,
+				 enum snd_soc_bias_level level)
+{
+	struct wm8523_priv *wm8523 = codec->private_data;
+	int ret, i;
+
+	switch (level) {
+	case SND_SOC_BIAS_ON:
+		break;
+
+	case SND_SOC_BIAS_PREPARE:
+		/* Full power on */
+		snd_soc_update_bits(codec, WM8523_PSCTRL1,
+				    WM8523_SYS_ENA_MASK, 3);
+		break;
+
+	case SND_SOC_BIAS_STANDBY:
+		if (codec->bias_level == SND_SOC_BIAS_OFF) {
+			ret = regulator_bulk_enable(ARRAY_SIZE(wm8523->supplies),
+						    wm8523->supplies);
+			if (ret != 0) {
+				dev_err(codec->dev,
+					"Failed to enable supplies: %d\n",
+					ret);
+				return ret;
+			}
+
+			/* Initial power up */
+			snd_soc_update_bits(codec, WM8523_PSCTRL1,
+					    WM8523_SYS_ENA_MASK, 1);
+
+			/* Sync back default/cached values */
+			for (i = WM8523_AIF_CTRL1;
+			     i < WM8523_MAX_REGISTER; i++)
+				wm8523_write(codec, i, wm8523->reg_cache[i]);
+
+
+			msleep(100);
+		}
+
+		/* Power up to mute */
+		snd_soc_update_bits(codec, WM8523_PSCTRL1,
+				    WM8523_SYS_ENA_MASK, 2);
+
+		break;
+
+	case SND_SOC_BIAS_OFF:
+		/* The chip runs through the power down sequence for us. */
+		snd_soc_update_bits(codec, WM8523_PSCTRL1,
+				    WM8523_SYS_ENA_MASK, 0);
+		msleep(100);
+
+		regulator_bulk_disable(ARRAY_SIZE(wm8523->supplies),
+				       wm8523->supplies);
+		break;
+	}
+	codec->bias_level = level;
+	return 0;
+}
+
+#define WM8523_RATES SNDRV_PCM_RATE_8000_192000
+
+#define WM8523_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE |\
+			SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE)
+
+static struct snd_soc_dai_ops wm8523_dai_ops = {
+	.startup	= wm8523_startup,
+	.hw_params	= wm8523_hw_params,
+	.set_sysclk	= wm8523_set_dai_sysclk,
+	.set_fmt	= wm8523_set_dai_fmt,
+};
+
+struct snd_soc_dai wm8523_dai = {
+	.name = "WM8523",
+	.playback = {
+		.stream_name = "Playback",
+		.channels_min = 2,  /* Mono modes not yet supported */
+		.channels_max = 2,
+		.rates = WM8523_RATES,
+		.formats = WM8523_FORMATS,
+	},
+	.ops = &wm8523_dai_ops,
+};
+EXPORT_SYMBOL_GPL(wm8523_dai);
+
+#ifdef CONFIG_PM
+static int wm8523_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+	struct snd_soc_codec *codec = socdev->card->codec;
+
+	wm8523_set_bias_level(codec, SND_SOC_BIAS_OFF);
+	return 0;
+}
+
+static int wm8523_resume(struct platform_device *pdev)
+{
+	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+	struct snd_soc_codec *codec = socdev->card->codec;
+
+	wm8523_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
+
+	return 0;
+}
+#else
+#define wm8523_suspend NULL
+#define wm8523_resume NULL
+#endif
+
+static int wm8523_probe(struct platform_device *pdev)
+{
+	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+	struct snd_soc_codec *codec;
+	int ret = 0;
+
+	if (wm8523_codec == NULL) {
+		dev_err(&pdev->dev, "Codec device not registered\n");
+		return -ENODEV;
+	}
+
+	socdev->card->codec = wm8523_codec;
+	codec = wm8523_codec;
+
+	/* register pcms */
+	ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to create pcms: %d\n", ret);
+		goto pcm_err;
+	}
+
+	snd_soc_add_controls(codec, wm8523_snd_controls,
+			     ARRAY_SIZE(wm8523_snd_controls));
+	wm8523_add_widgets(codec);
+	ret = snd_soc_init_card(socdev);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to register card: %d\n", ret);
+		goto card_err;
+	}
+
+	return ret;
+
+card_err:
+	snd_soc_free_pcms(socdev);
+	snd_soc_dapm_free(socdev);
+pcm_err:
+	return ret;
+}
+
+static int wm8523_remove(struct platform_device *pdev)
+{
+	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+
+	snd_soc_free_pcms(socdev);
+	snd_soc_dapm_free(socdev);
+
+	return 0;
+}
+
+struct snd_soc_codec_device soc_codec_dev_wm8523 = {
+	.probe = 	wm8523_probe,
+	.remove = 	wm8523_remove,
+	.suspend = 	wm8523_suspend,
+	.resume =	wm8523_resume,
+};
+EXPORT_SYMBOL_GPL(soc_codec_dev_wm8523);
+
+static int wm8523_register(struct wm8523_priv *wm8523)
+{
+	int ret;
+	struct snd_soc_codec *codec = &wm8523->codec;
+	int i;
+
+	if (wm8523_codec) {
+		dev_err(codec->dev, "Another WM8523 is registered\n");
+		return -EINVAL;
+	}
+
+	mutex_init(&codec->mutex);
+	INIT_LIST_HEAD(&codec->dapm_widgets);
+	INIT_LIST_HEAD(&codec->dapm_paths);
+
+	codec->private_data = wm8523;
+	codec->name = "WM8523";
+	codec->owner = THIS_MODULE;
+	codec->read = wm8523_read;
+	codec->write = wm8523_write;
+	codec->bias_level = SND_SOC_BIAS_OFF;
+	codec->set_bias_level = wm8523_set_bias_level;
+	codec->dai = &wm8523_dai;
+	codec->num_dai = 1;
+	codec->reg_cache_size = WM8523_REGISTER_COUNT;
+	codec->reg_cache = &wm8523->reg_cache;
+
+	wm8523->rate_constraint.list = &wm8523->rate_constraint_list[0];
+	wm8523->rate_constraint.count =
+		ARRAY_SIZE(wm8523->rate_constraint_list);
+
+	memcpy(codec->reg_cache, wm8523_reg, sizeof(wm8523_reg));
+
+	for (i = 0; i < ARRAY_SIZE(wm8523->supplies); i++)
+		wm8523->supplies[i].supply = wm8523_supply_names[i];
+
+	ret = regulator_bulk_get(codec->dev, ARRAY_SIZE(wm8523->supplies),
+				 wm8523->supplies);
+	if (ret != 0) {
+		dev_err(codec->dev, "Failed to request supplies: %d\n", ret);
+		goto err;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(wm8523->supplies),
+				    wm8523->supplies);
+	if (ret != 0) {
+		dev_err(codec->dev, "Failed to enable supplies: %d\n", ret);
+		goto err_get;
+	}
+
+	ret = wm8523_read(codec, WM8523_DEVICE_ID);
+	if (ret < 0) {
+		dev_err(codec->dev, "Failed to read ID register\n");
+		goto err_enable;
+	}
+	if (ret != wm8523_reg[WM8523_DEVICE_ID]) {
+		dev_err(codec->dev, "Device is not a WM8523, ID is %x\n", ret);
+		ret = -EINVAL;
+		goto err_enable;
+	}
+
+	ret = wm8523_read(codec, WM8523_REVISION);
+	if (ret < 0) {
+		dev_err(codec->dev, "Failed to read revision register\n");
+		goto err_enable;
+	}
+	dev_info(codec->dev, "revision %c\n",
+		 (ret & WM8523_CHIP_REV_MASK) + 'A');
+
+	ret = wm8523_reset(codec);
+	if (ret < 0) {
+		dev_err(codec->dev, "Failed to issue reset\n");
+		goto err_enable;
+	}
+
+	wm8523_dai.dev = codec->dev;
+
+	/* Change some default settings - latch VU and enable ZC */
+	wm8523->reg_cache[WM8523_DAC_GAINR] |= WM8523_DACR_VU;
+	wm8523->reg_cache[WM8523_DAC_CTRL3] |= WM8523_ZC;
+
+	wm8523_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
+
+	/* Bias level configuration will have done an extra enable */
+	regulator_bulk_disable(ARRAY_SIZE(wm8523->supplies), wm8523->supplies);
+
+	wm8523_codec = codec;
+
+	ret = snd_soc_register_codec(codec);
+	if (ret != 0) {
+		dev_err(codec->dev, "Failed to register codec: %d\n", ret);
+		return ret;
+	}
+
+	ret = snd_soc_register_dai(&wm8523_dai);
+	if (ret != 0) {
+		dev_err(codec->dev, "Failed to register DAI: %d\n", ret);
+		snd_soc_unregister_codec(codec);
+		return ret;
+	}
+
+	return 0;
+
+err_enable:
+	regulator_bulk_disable(ARRAY_SIZE(wm8523->supplies), wm8523->supplies);
+err_get:
+	regulator_bulk_free(ARRAY_SIZE(wm8523->supplies), wm8523->supplies);
+err:
+	kfree(wm8523);
+	return ret;
+}
+
+static void wm8523_unregister(struct wm8523_priv *wm8523)
+{
+	wm8523_set_bias_level(&wm8523->codec, SND_SOC_BIAS_OFF);
+	regulator_bulk_free(ARRAY_SIZE(wm8523->supplies), wm8523->supplies);
+	snd_soc_unregister_dai(&wm8523_dai);
+	snd_soc_unregister_codec(&wm8523->codec);
+	kfree(wm8523);
+	wm8523_codec = NULL;
+}
+
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+static __devinit int wm8523_i2c_probe(struct i2c_client *i2c,
+				      const struct i2c_device_id *id)
+{
+	struct wm8523_priv *wm8523;
+	struct snd_soc_codec *codec;
+
+	wm8523 = kzalloc(sizeof(struct wm8523_priv), GFP_KERNEL);
+	if (wm8523 == NULL)
+		return -ENOMEM;
+
+	codec = &wm8523->codec;
+	codec->hw_write = (hw_write_t)i2c_master_send;
+
+	i2c_set_clientdata(i2c, wm8523);
+	codec->control_data = i2c;
+
+	codec->dev = &i2c->dev;
+
+	return wm8523_register(wm8523);
+}
+
+static __devexit int wm8523_i2c_remove(struct i2c_client *client)
+{
+	struct wm8523_priv *wm8523 = i2c_get_clientdata(client);
+	wm8523_unregister(wm8523);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int wm8523_i2c_suspend(struct i2c_client *i2c, pm_message_t msg)
+{
+	return snd_soc_suspend_device(&i2c->dev);
+}
+
+static int wm8523_i2c_resume(struct i2c_client *i2c)
+{
+	return snd_soc_resume_device(&i2c->dev);
+}
+#else
+#define wm8523_i2c_suspend NULL
+#define wm8523_i2c_resume NULL
+#endif
+
+static const struct i2c_device_id wm8523_i2c_id[] = {
+	{ "wm8523", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, wm8523_i2c_id);
+
+static struct i2c_driver wm8523_i2c_driver = {
+	.driver = {
+		.name = "WM8523",
+		.owner = THIS_MODULE,
+	},
+	.probe =    wm8523_i2c_probe,
+	.remove =   __devexit_p(wm8523_i2c_remove),
+	.suspend =  wm8523_i2c_suspend,
+	.resume =   wm8523_i2c_resume,
+	.id_table = wm8523_i2c_id,
+};
+#endif
+
+static int __init wm8523_modinit(void)
+{
+	int ret;
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+	ret = i2c_add_driver(&wm8523_i2c_driver);
+	if (ret != 0) {
+		printk(KERN_ERR "Failed to register WM8523 I2C driver: %d\n",
+		       ret);
+	}
+#endif
+	return 0;
+}
+module_init(wm8523_modinit);
+
+static void __exit wm8523_exit(void)
+{
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+	i2c_del_driver(&wm8523_i2c_driver);
+#endif
+}
+module_exit(wm8523_exit);
+
+MODULE_DESCRIPTION("ASoC WM8523 driver");
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
+MODULE_LICENSE("GPL");