sound/soc/codecs/cs4270.c - kernel/msm-4.9 - Gitiles

 /*
  * CS4270 ALSA SoC (ASoC) codec driver
  *
  * Author: Timur Tabi <timur@freescale.com>
  *
  * Copyright 2007 Freescale Semiconductor, Inc.  This file is licensed under
  * the terms of the GNU General Public License version 2.  This program
  * is licensed "as is" without any warranty of any kind, whether express
  * or implied.
  *
  * This is an ASoC device driver for the Cirrus Logic CS4270 codec.
  *
  * Current features/limitations:
  *
  * 1) Software mode is supported.  Stand-alone mode is not supported.
  * 2) Only I2C is supported, not SPI
  * 3) Only Master mode is supported, not Slave.
  * 4) The machine driver's 'startup' function must call
  *    cs4270_set_dai_sysclk() with the value of MCLK.
  * 5) Only I2S and left-justified modes are supported
  * 6) Power management is not supported
  * 7) The only supported control is volume and hardware mute (if enabled)
  */

 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <sound/core.h>
 #include <sound/soc.h>
 #include <sound/initval.h>
 #include <linux/i2c.h>

 #include "cs4270.h"

 /*
  * The codec isn't really big-endian or little-endian, since the I2S
  * interface requires data to be sent serially with the MSbit first.
  * However, to support BE and LE I2S devices, we specify both here.  That
  * way, ALSA will always match the bit patterns.
  */
 #define CS4270_FORMATS (SNDRV_PCM_FMTBIT_S8      | \
 			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_3LE | SNDRV_PCM_FMTBIT_S24_3BE | \
 			SNDRV_PCM_FMTBIT_S24_LE  | SNDRV_PCM_FMTBIT_S24_BE)

 /* CS4270 registers addresses */
 #define CS4270_CHIPID	0x01	/* Chip ID */
 #define CS4270_PWRCTL	0x02	/* Power Control */
 #define CS4270_MODE	0x03	/* Mode Control */
 #define CS4270_FORMAT	0x04	/* Serial Format, ADC/DAC Control */
 #define CS4270_TRANS	0x05	/* Transition Control */
 #define CS4270_MUTE	0x06	/* Mute Control */
 #define CS4270_VOLA	0x07	/* DAC Channel A Volume Control */
 #define CS4270_VOLB	0x08	/* DAC Channel B Volume Control */

 #define CS4270_FIRSTREG	0x01
 #define CS4270_LASTREG	0x08
 #define CS4270_NUMREGS	(CS4270_LASTREG - CS4270_FIRSTREG + 1)

 /* Bit masks for the CS4270 registers */
 #define CS4270_CHIPID_ID	0xF0
 #define CS4270_CHIPID_REV	0x0F
 #define CS4270_PWRCTL_FREEZE	0x80
 #define CS4270_PWRCTL_PDN_ADC	0x20
 #define CS4270_PWRCTL_PDN_DAC	0x02
 #define CS4270_PWRCTL_PDN	0x01
 #define CS4270_MODE_SPEED_MASK	0x30
 #define CS4270_MODE_1X		0x00
 #define CS4270_MODE_2X		0x10
 #define CS4270_MODE_4X		0x20
 #define CS4270_MODE_SLAVE	0x30
 #define CS4270_MODE_DIV_MASK	0x0E
 #define CS4270_MODE_DIV1	0x00
 #define CS4270_MODE_DIV15	0x02
 #define CS4270_MODE_DIV2	0x04
 #define CS4270_MODE_DIV3	0x06
 #define CS4270_MODE_DIV4	0x08
 #define CS4270_MODE_POPGUARD	0x01
 #define CS4270_FORMAT_FREEZE_A	0x80
 #define CS4270_FORMAT_FREEZE_B	0x40
 #define CS4270_FORMAT_LOOPBACK	0x20
 #define CS4270_FORMAT_DAC_MASK	0x18
 #define CS4270_FORMAT_DAC_LJ	0x00
 #define CS4270_FORMAT_DAC_I2S	0x08
 #define CS4270_FORMAT_DAC_RJ16	0x18
 #define CS4270_FORMAT_DAC_RJ24	0x10
 #define CS4270_FORMAT_ADC_MASK	0x01
 #define CS4270_FORMAT_ADC_LJ	0x00
 #define CS4270_FORMAT_ADC_I2S	0x01
 #define CS4270_TRANS_ONE_VOL	0x80
 #define CS4270_TRANS_SOFT	0x40
 #define CS4270_TRANS_ZERO	0x20
 #define CS4270_TRANS_INV_ADC_A	0x08
 #define CS4270_TRANS_INV_ADC_B	0x10
 #define CS4270_TRANS_INV_DAC_A	0x02
 #define CS4270_TRANS_INV_DAC_B	0x04
 #define CS4270_TRANS_DEEMPH	0x01
 #define CS4270_MUTE_AUTO	0x20
 #define CS4270_MUTE_ADC_A	0x08
 #define CS4270_MUTE_ADC_B	0x10
 #define CS4270_MUTE_POLARITY	0x04
 #define CS4270_MUTE_DAC_A	0x01
 #define CS4270_MUTE_DAC_B	0x02

 /* Private data for the CS4270 */
 struct cs4270_private {
 	struct snd_soc_codec codec;
 	u8 reg_cache[CS4270_NUMREGS];
 	unsigned int mclk; /* Input frequency of the MCLK pin */
 	unsigned int mode; /* The mode (I2S or left-justified) */
 };

 /*
  * Clock Ratio Selection for Master Mode with I2C enabled
  *
  * The data for this chart is taken from Table 5 of the CS4270 reference
  * manual.
  *
  * This table is used to determine how to program the Mode Control register.
  * It is also used by cs4270_set_dai_sysclk() to tell ALSA which sampling
  * rates the CS4270 currently supports.
  *
  * Each element in this array corresponds to the ratios in mclk_ratios[].
  * These two arrays need to be in sync.
  *
  * 'speed_mode' is the corresponding bit pattern to be written to the
  * MODE bits of the Mode Control Register
  *
  * 'mclk' is the corresponding bit pattern to be wirten to the MCLK bits of
  * the Mode Control Register.
  *
  * In situations where a single ratio is represented by multiple speed
  * modes, we favor the slowest speed.  E.g, for a ratio of 128, we pick
  * double-speed instead of quad-speed.  However, the CS4270 errata states
  * that Divide-By-1.5 can cause failures, so we avoid that mode where
  * possible.
  *
  * ERRATA: There is an errata for the CS4270 where divide-by-1.5 does not
  * work if VD = 3.3V.  If this effects you, select the
  * CONFIG_SND_SOC_CS4270_VD33_ERRATA Kconfig option, and the driver will
  * never select any sample rates that require divide-by-1.5.
  */
 static struct {
 	unsigned int ratio;
 	u8 speed_mode;
 	u8 mclk;
 } cs4270_mode_ratios[] = {
 	{64, CS4270_MODE_4X, CS4270_MODE_DIV1},
 #ifndef CONFIG_SND_SOC_CS4270_VD33_ERRATA
 	{96, CS4270_MODE_4X, CS4270_MODE_DIV15},
 #endif
 	{128, CS4270_MODE_2X, CS4270_MODE_DIV1},
 	{192, CS4270_MODE_4X, CS4270_MODE_DIV3},
 	{256, CS4270_MODE_1X, CS4270_MODE_DIV1},
 	{384, CS4270_MODE_2X, CS4270_MODE_DIV3},
 	{512, CS4270_MODE_1X, CS4270_MODE_DIV2},
 	{768, CS4270_MODE_1X, CS4270_MODE_DIV3},
 	{1024, CS4270_MODE_1X, CS4270_MODE_DIV4}
 };

 /* The number of MCLK/LRCK ratios supported by the CS4270 */
 #define NUM_MCLK_RATIOS		ARRAY_SIZE(cs4270_mode_ratios)

 /*
  * Determine the CS4270 samples rates.
  *
  * 'freq' is the input frequency to MCLK.  The other parameters are ignored.
  *
  * The value of MCLK is used to determine which sample rates are supported
  * by the CS4270.  The ratio of MCLK / Fs must be equal to one of nine
  * support values: 64, 96, 128, 192, 256, 384, 512, 768, and 1024.
  *
  * This function calculates the nine ratios and determines which ones match
  * a standard sample rate.  If there's a match, then it is added to the list
  * of support sample rates.
  *
  * This function must be called by the machine driver's 'startup' function,
  * otherwise the list of supported sample rates will not be available in
  * time for ALSA.
  *
  * Note that in stand-alone mode, the sample rate is determined by input
  * pins M0, M1, MDIV1, and MDIV2.  Also in stand-alone mode, divide-by-3
  * is not a programmable option.  However, divide-by-3 is not an available
  * option in stand-alone mode.  This cases two problems: a ratio of 768 is
  * not available (it requires divide-by-3) and B) ratios 192 and 384 can
  * only be selected with divide-by-1.5, but there is an errate that make
  * this selection difficult.
  *
  * In addition, there is no mechanism for communicating with the machine
  * driver what the input settings can be.  This would need to be implemented
  * for stand-alone mode to work.
  */
 static int cs4270_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 cs4270_private *cs4270 = codec->private_data;
 	unsigned int rates = 0;
 	unsigned int rate_min = -1;
 	unsigned int rate_max = 0;
 	unsigned int i;

 	cs4270->mclk = freq;

 	for (i = 0; i < NUM_MCLK_RATIOS; i++) {
 		unsigned int rate = freq / cs4270_mode_ratios[i].ratio;
 		rates |= snd_pcm_rate_to_rate_bit(rate);
 		if (rate < rate_min)
 			rate_min = rate;
 		if (rate > rate_max)
 			rate_max = rate;
 	}
 	/* FIXME: soc should support a rate list */
 	rates &= ~SNDRV_PCM_RATE_KNOT;

 	if (!rates) {
 		printk(KERN_ERR "cs4270: could not find a valid sample rate\n");
 		return -EINVAL;
 	}

 	codec_dai->playback.rates = rates;
 	codec_dai->playback.rate_min = rate_min;
 	codec_dai->playback.rate_max = rate_max;

 	codec_dai->capture.rates = rates;
 	codec_dai->capture.rate_min = rate_min;
 	codec_dai->capture.rate_max = rate_max;

 	return 0;
 }

 /*
  * Configure the codec for the selected audio format
  *
  * This function takes a bitmask of SND_SOC_DAIFMT_x bits and programs the
  * codec accordingly.
  *
  * Currently, this function only supports SND_SOC_DAIFMT_I2S and
  * SND_SOC_DAIFMT_LEFT_J.  The CS4270 codec also supports right-justified
  * data for playback only, but ASoC currently does not support different
  * formats for playback vs. record.
  */
 static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
 			      unsigned int format)
 {
 	struct snd_soc_codec *codec = codec_dai->codec;
 	struct cs4270_private *cs4270 = codec->private_data;
 	int ret = 0;

 	switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
 	case SND_SOC_DAIFMT_I2S:
 	case SND_SOC_DAIFMT_LEFT_J:
 		cs4270->mode = format & SND_SOC_DAIFMT_FORMAT_MASK;
 		break;
 	default:
 		printk(KERN_ERR "cs4270: invalid DAI format\n");
 		ret = -EINVAL;
 	}

 	return ret;
 }

 /*
  * Pre-fill the CS4270 register cache.
  *
  * We use the auto-increment feature of the CS4270 to read all registers in
  * one shot.
  */
 static int cs4270_fill_cache(struct snd_soc_codec *codec)
 {
 	u8 *cache = codec->reg_cache;
 	struct i2c_client *i2c_client = codec->control_data;
 	s32 length;

 	length = i2c_smbus_read_i2c_block_data(i2c_client,
 		CS4270_FIRSTREG | 0x80, CS4270_NUMREGS, cache);

 	if (length != CS4270_NUMREGS) {
 		printk(KERN_ERR "cs4270: I2C read failure, addr=0x%x\n",
 		       i2c_client->addr);
 		return -EIO;
 	}

 	return 0;
 }

 /*
  * Read from the CS4270 register cache.
  *
  * This CS4270 registers are cached to avoid excessive I2C I/O operations.
  * After the initial read to pre-fill the cache, the CS4270 never updates
  * the register values, so we won't have a cache coherncy problem.
  */
 static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
 	unsigned int reg)
 {
 	u8 *cache = codec->reg_cache;

 	if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
 		return -EIO;

 	return cache[reg - CS4270_FIRSTREG];
 }

 /*
  * Write to a CS4270 register via the I2C bus.
  *
  * This function writes the given value to the given CS4270 register, and
  * also updates the register cache.
  *
  * Note that we don't use the hw_write function pointer of snd_soc_codec.
  * That's because it's too clunky: the hw_write_t prototype does not match
  * i2c_smbus_write_byte_data(), and it's just another layer of overhead.
  */
 static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
 			    unsigned int value)
 {
 	u8 *cache = codec->reg_cache;

 	if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
 		return -EIO;

 	/* Only perform an I2C operation if the new value is different */
 	if (cache[reg - CS4270_FIRSTREG] != value) {
 		struct i2c_client *client = codec->control_data;
 		if (i2c_smbus_write_byte_data(client, reg, value)) {
 			printk(KERN_ERR "cs4270: I2C write failed\n");
 			return -EIO;
 		}

 		/* We've written to the hardware, so update the cache */
 		cache[reg - CS4270_FIRSTREG] = value;
 	}

 	return 0;
 }

 /*
  * Program the CS4270 with the given hardware parameters.
  *
  * The .ops functions are used to provide board-specific data, like
  * input frequencies, to this driver.  This function takes that information,
  * combines it with the hardware parameters provided, and programs the
  * hardware accordingly.
  */
 static int cs4270_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->codec;
 	struct cs4270_private *cs4270 = codec->private_data;
 	int ret;
 	unsigned int i;
 	unsigned int rate;
 	unsigned int ratio;
 	int reg;

 	/* Figure out which MCLK/LRCK ratio to use */

 	rate = params_rate(params);	/* Sampling rate, in Hz */
 	ratio = cs4270->mclk / rate;	/* MCLK/LRCK ratio */

 	for (i = 0; i < NUM_MCLK_RATIOS; i++) {
 		if (cs4270_mode_ratios[i].ratio == ratio)
 			break;
 	}

 	if (i == NUM_MCLK_RATIOS) {
 		/* We did not find a matching ratio */
 		printk(KERN_ERR "cs4270: could not find matching ratio\n");
 		return -EINVAL;
 	}

 	/* Freeze and power-down the codec */

 	ret = snd_soc_write(codec, CS4270_PWRCTL, CS4270_PWRCTL_FREEZE |
 			    CS4270_PWRCTL_PDN_ADC | CS4270_PWRCTL_PDN_DAC |
 			    CS4270_PWRCTL_PDN);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: I2C write failed\n");
 		return ret;
 	}

 	/* Program the mode control register */

 	reg = snd_soc_read(codec, CS4270_MODE);
 	reg &= ~(CS4270_MODE_SPEED_MASK | CS4270_MODE_DIV_MASK);
 	reg |= cs4270_mode_ratios[i].speed_mode | cs4270_mode_ratios[i].mclk;

 	ret = snd_soc_write(codec, CS4270_MODE, reg);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: I2C write failed\n");
 		return ret;
 	}

 	/* Program the format register */

 	reg = snd_soc_read(codec, CS4270_FORMAT);
 	reg &= ~(CS4270_FORMAT_DAC_MASK | CS4270_FORMAT_ADC_MASK);

 	switch (cs4270->mode) {
 	case SND_SOC_DAIFMT_I2S:
 		reg |= CS4270_FORMAT_DAC_I2S | CS4270_FORMAT_ADC_I2S;
 		break;
 	case SND_SOC_DAIFMT_LEFT_J:
 		reg |= CS4270_FORMAT_DAC_LJ | CS4270_FORMAT_ADC_LJ;
 		break;
 	default:
 		printk(KERN_ERR "cs4270: unknown format\n");
 		return -EINVAL;
 	}

 	ret = snd_soc_write(codec, CS4270_FORMAT, reg);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: I2C write failed\n");
 		return ret;
 	}

 	/* Disable auto-mute.  This feature appears to be buggy, because in
 	   some situations, auto-mute will not deactivate when it should. */

 	reg = snd_soc_read(codec, CS4270_MUTE);
 	reg &= ~CS4270_MUTE_AUTO;
 	ret = snd_soc_write(codec, CS4270_MUTE, reg);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: I2C write failed\n");
 		return ret;
 	}

 	/* Disable automatic volume control.  It's enabled by default, and
 	 * it causes volume change commands to be delayed, sometimes until
 	 * after playback has started.
 	 */

 	reg = cs4270_read_reg_cache(codec, CS4270_TRANS);
 	reg &= ~(CS4270_TRANS_SOFT | CS4270_TRANS_ZERO);
 	ret = cs4270_i2c_write(codec, CS4270_TRANS, reg);
 	if (ret < 0) {
 		printk(KERN_ERR "I2C write failed\n");
 		return ret;
 	}

 	/* Thaw and power-up the codec */

 	ret = snd_soc_write(codec, CS4270_PWRCTL, 0);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: I2C write failed\n");
 		return ret;
 	}

 	return ret;
 }

 #ifdef CONFIG_SND_SOC_CS4270_HWMUTE
 /*
  * Set the CS4270 external mute
  *
  * This function toggles the mute bits in the MUTE register.  The CS4270's
  * mute capability is intended for external muting circuitry, so if the
  * board does not have the MUTEA or MUTEB pins connected to such circuitry,
  * then this function will do nothing.
  */
 static int cs4270_mute(struct snd_soc_dai *dai, int mute)
 {
 	struct snd_soc_codec *codec = dai->codec;
 	int reg6;

 	reg6 = snd_soc_read(codec, CS4270_MUTE);

 	if (mute)
 		reg6 |= CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B |
 			CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B;
 	else
 		reg6 &= ~(CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B |
 			  CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B);

 	return snd_soc_write(codec, CS4270_MUTE, reg6);
 }
 #else
 #define cs4270_mute NULL
 #endif

 /* A list of non-DAPM controls that the CS4270 supports */
 static const struct snd_kcontrol_new cs4270_snd_controls[] = {
 	SOC_DOUBLE_R("Master Playback Volume",
 		CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 1)
 };

 /*
  * Global variable to store socdev for i2c probe function.
  *
  * If struct i2c_driver had a private_data field, we wouldn't need to use
  * cs4270_socdec.  This is the only way to pass the socdev structure to
  * cs4270_i2c_probe().
  *
  * The real solution to cs4270_socdev is to create a mechanism
  * that maps I2C addresses to snd_soc_device structures.  Perhaps the
  * creation of the snd_soc_device object should be moved out of
  * cs4270_probe() and into cs4270_i2c_probe(), but that would make this
  * driver dependent on I2C.  The CS4270 supports "stand-alone" mode, whereby
  * the chip is *not* connected to the I2C bus, but is instead configured via
  * input pins.
  */
 static struct snd_soc_device *cs4270_socdev;

 struct snd_soc_dai cs4270_dai = {
 	.name = "cs4270",
 	.playback = {
 		.stream_name = "Playback",
 		.channels_min = 1,
 		.channels_max = 2,
 		.rates = 0,
 		.formats = CS4270_FORMATS,
 	},
 	.capture = {
 		.stream_name = "Capture",
 		.channels_min = 1,
 		.channels_max = 2,
 		.rates = 0,
 		.formats = CS4270_FORMATS,
 	},
 	.ops = {
 		.hw_params = cs4270_hw_params,
 		.set_sysclk = cs4270_set_dai_sysclk,
 		.set_fmt = cs4270_set_dai_fmt,
 		.digital_mute = cs4270_mute,
 	},
 };
 EXPORT_SYMBOL_GPL(cs4270_dai);

 /*
  * Initialize the I2C interface of the CS4270
  *
  * This function is called for whenever the I2C subsystem finds a device
  * at a particular address.
  *
  * Note: snd_soc_new_pcms() must be called before this function can be called,
  * because of snd_ctl_add().
  */
 static int cs4270_i2c_probe(struct i2c_client *i2c_client,
 	const struct i2c_device_id *id)
 {
 	struct snd_soc_device *socdev = cs4270_socdev;
 	struct snd_soc_codec *codec;
 	struct cs4270_private *cs4270;
 	int i;
 	int ret = 0;

 	/* Verify that we have a CS4270 */

 	ret = i2c_smbus_read_byte_data(i2c_client, CS4270_CHIPID);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: failed to read I2C\n");
 		return ret;
 	}
 	/* The top four bits of the chip ID should be 1100. */
 	if ((ret & 0xF0) != 0xC0) {
 		printk(KERN_ERR "cs4270: device at addr %X is not a CS4270\n",
 		       i2c_client->addr);
 		return -ENODEV;
 	}

 	printk(KERN_INFO "cs4270: found device at I2C address %X\n",
 		i2c_client->addr);
 	printk(KERN_INFO "cs4270: hardware revision %X\n", ret & 0xF);

 	/* Allocate enough space for the snd_soc_codec structure
 	   and our private data together. */
 	cs4270 = kzalloc(sizeof(struct cs4270_private), GFP_KERNEL);
 	if (!cs4270) {
 		printk(KERN_ERR "cs4270: Could not allocate codec structure\n");
 		return -ENOMEM;
 	}
 	codec = &cs4270->codec;
 	socdev->codec = codec;

 	mutex_init(&codec->mutex);
 	INIT_LIST_HEAD(&codec->dapm_widgets);
 	INIT_LIST_HEAD(&codec->dapm_paths);

 	codec->name = "CS4270";
 	codec->owner = THIS_MODULE;
 	codec->dai = &cs4270_dai;
 	codec->num_dai = 1;
 	codec->private_data = cs4270;
 	codec->control_data = i2c_client;
 	codec->read = cs4270_read_reg_cache;
 	codec->write = cs4270_i2c_write;
 	codec->reg_cache = cs4270->reg_cache;
 	codec->reg_cache_size = CS4270_NUMREGS;

 	/* The I2C interface is set up, so pre-fill our register cache */

 	ret = cs4270_fill_cache(codec);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: failed to fill register cache\n");
 		goto error_free_codec;
 	}

 	/* Register PCMs */

 	ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: failed to create PCMs\n");
 		goto error_free_codec;
 	}

 	/* Add the non-DAPM controls */

 	for (i = 0; i < ARRAY_SIZE(cs4270_snd_controls); i++) {
 		struct snd_kcontrol *kctrl;

 		kctrl = snd_soc_cnew(&cs4270_snd_controls[i], codec, NULL);
 		if (!kctrl) {
 			printk(KERN_ERR "cs4270: error creating control '%s'\n",
 			       cs4270_snd_controls[i].name);
 			ret = -ENOMEM;
 			goto error_free_pcms;
 		}

 		ret = snd_ctl_add(codec->card, kctrl);
 		if (ret < 0) {
 			printk(KERN_ERR "cs4270: error adding control '%s'\n",
 			       cs4270_snd_controls[i].name);
 			goto error_free_pcms;
 		}
 	}

 	/* Initialize the SOC device */

 	ret = snd_soc_init_card(socdev);
 	if (ret < 0) {
 		printk(KERN_ERR "cs4270: failed to register card\n");
 		goto error_free_pcms;;
 	}

 	i2c_set_clientdata(i2c_client, socdev);

 	return 0;

 error_free_pcms:
 	snd_soc_free_pcms(socdev);

 error_free_codec:
 	kfree(cs4270);

 	return ret;
 }

 static int cs4270_i2c_remove(struct i2c_client *i2c_client)
 {
 	struct snd_soc_device *socdev = i2c_get_clientdata(i2c_client);
 	struct snd_soc_codec *codec = socdev->codec;
 	struct cs4270_private *cs4270 = codec->private_data;

 	snd_soc_free_pcms(socdev);
 	kfree(cs4270);

 	return 0;
 }

 static struct i2c_device_id cs4270_id[] = {
 	{"cs4270", 0},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, cs4270_id);

 static struct i2c_driver cs4270_i2c_driver = {
 	.driver = {
 		.name = "cs4270",
 		.owner = THIS_MODULE,
 	},
 	.id_table = cs4270_id,
 	.probe = cs4270_i2c_probe,
 	.remove = cs4270_i2c_remove,
 };

 /*
  * ASoC probe function
  *
  * This function is called when the machine driver calls
  * platform_device_add().
  */
 static int cs4270_probe(struct platform_device *pdev)
 {
 	cs4270_socdev = platform_get_drvdata(pdev);;

 	return i2c_add_driver(&cs4270_i2c_driver);
 }

 static int cs4270_remove(struct platform_device *pdev)
 {
 	i2c_del_driver(&cs4270_i2c_driver);

 	return 0;
 }

 /*
  * ASoC codec device structure
  *
  * Assign this variable to the codec_dev field of the machine driver's
  * snd_soc_device structure.
  */
 struct snd_soc_codec_device soc_codec_device_cs4270 = {
 	.probe = 	cs4270_probe,
 	.remove = 	cs4270_remove
 };
 EXPORT_SYMBOL_GPL(soc_codec_device_cs4270);

 static int __init cs4270_init(void)
 {
 	printk(KERN_INFO "Cirrus Logic CS4270 ALSA SoC Codec Driver\n");

 	return snd_soc_register_dai(&cs4270_dai);
 }
 module_init(cs4270_init);

 static void __exit cs4270_exit(void)
 {
 	snd_soc_unregister_dai(&cs4270_dai);
 }
 module_exit(cs4270_exit);

 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
 MODULE_DESCRIPTION("Cirrus Logic CS4270 ALSA SoC Codec Driver");
 MODULE_LICENSE("GPL");
	/*
	* CS4270 ALSA SoC (ASoC) codec driver
	*
	* Author: Timur Tabi <timur@freescale.com>
	*
	* Copyright 2007 Freescale Semiconductor, Inc. This file is licensed under
	* the terms of the GNU General Public License version 2. This program
	* is licensed "as is" without any warranty of any kind, whether express
	* or implied.
	*
	* This is an ASoC device driver for the Cirrus Logic CS4270 codec.
	*
	* Current features/limitations:
	*
	* 1) Software mode is supported. Stand-alone mode is not supported.
	* 2) Only I2C is supported, not SPI
	* 3) Only Master mode is supported, not Slave.
	* 4) The machine driver's 'startup' function must call
	* cs4270_set_dai_sysclk() with the value of MCLK.
	* 5) Only I2S and left-justified modes are supported
	* 6) Power management is not supported
	* 7) The only supported control is volume and hardware mute (if enabled)
	*/

	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <sound/core.h>
	#include <sound/soc.h>
	#include <sound/initval.h>
	#include <linux/i2c.h>

	#include "cs4270.h"

	/*
	* The codec isn't really big-endian or little-endian, since the I2S
	* interface requires data to be sent serially with the MSbit first.
	* However, to support BE and LE I2S devices, we specify both here. That
	* way, ALSA will always match the bit patterns.
	*/
	#define CS4270_FORMATS (SNDRV_PCM_FMTBIT_S8 \| \
	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_3LE \| SNDRV_PCM_FMTBIT_S24_3BE \| \
	SNDRV_PCM_FMTBIT_S24_LE \| SNDRV_PCM_FMTBIT_S24_BE)

	/* CS4270 registers addresses */
	#define CS4270_CHIPID 0x01 /* Chip ID */
	#define CS4270_PWRCTL 0x02 /* Power Control */
	#define CS4270_MODE 0x03 /* Mode Control */
	#define CS4270_FORMAT 0x04 /* Serial Format, ADC/DAC Control */
	#define CS4270_TRANS 0x05 /* Transition Control */
	#define CS4270_MUTE 0x06 /* Mute Control */
	#define CS4270_VOLA 0x07 /* DAC Channel A Volume Control */
	#define CS4270_VOLB 0x08 /* DAC Channel B Volume Control */

	#define CS4270_FIRSTREG 0x01
	#define CS4270_LASTREG 0x08
	#define CS4270_NUMREGS (CS4270_LASTREG - CS4270_FIRSTREG + 1)

	/* Bit masks for the CS4270 registers */
	#define CS4270_CHIPID_ID 0xF0
	#define CS4270_CHIPID_REV 0x0F
	#define CS4270_PWRCTL_FREEZE 0x80
	#define CS4270_PWRCTL_PDN_ADC 0x20
	#define CS4270_PWRCTL_PDN_DAC 0x02
	#define CS4270_PWRCTL_PDN 0x01
	#define CS4270_MODE_SPEED_MASK 0x30
	#define CS4270_MODE_1X 0x00
	#define CS4270_MODE_2X 0x10
	#define CS4270_MODE_4X 0x20
	#define CS4270_MODE_SLAVE 0x30
	#define CS4270_MODE_DIV_MASK 0x0E
	#define CS4270_MODE_DIV1 0x00
	#define CS4270_MODE_DIV15 0x02
	#define CS4270_MODE_DIV2 0x04
	#define CS4270_MODE_DIV3 0x06
	#define CS4270_MODE_DIV4 0x08
	#define CS4270_MODE_POPGUARD 0x01
	#define CS4270_FORMAT_FREEZE_A 0x80
	#define CS4270_FORMAT_FREEZE_B 0x40
	#define CS4270_FORMAT_LOOPBACK 0x20
	#define CS4270_FORMAT_DAC_MASK 0x18
	#define CS4270_FORMAT_DAC_LJ 0x00
	#define CS4270_FORMAT_DAC_I2S 0x08
	#define CS4270_FORMAT_DAC_RJ16 0x18
	#define CS4270_FORMAT_DAC_RJ24 0x10
	#define CS4270_FORMAT_ADC_MASK 0x01
	#define CS4270_FORMAT_ADC_LJ 0x00
	#define CS4270_FORMAT_ADC_I2S 0x01
	#define CS4270_TRANS_ONE_VOL 0x80
	#define CS4270_TRANS_SOFT 0x40
	#define CS4270_TRANS_ZERO 0x20
	#define CS4270_TRANS_INV_ADC_A 0x08
	#define CS4270_TRANS_INV_ADC_B 0x10
	#define CS4270_TRANS_INV_DAC_A 0x02
	#define CS4270_TRANS_INV_DAC_B 0x04
	#define CS4270_TRANS_DEEMPH 0x01
	#define CS4270_MUTE_AUTO 0x20
	#define CS4270_MUTE_ADC_A 0x08
	#define CS4270_MUTE_ADC_B 0x10
	#define CS4270_MUTE_POLARITY 0x04
	#define CS4270_MUTE_DAC_A 0x01
	#define CS4270_MUTE_DAC_B 0x02

	/* Private data for the CS4270 */
	struct cs4270_private {
	struct snd_soc_codec codec;
	u8 reg_cache[CS4270_NUMREGS];
	unsigned int mclk; /* Input frequency of the MCLK pin */
	unsigned int mode; /* The mode (I2S or left-justified) */
	};

	/*
	* Clock Ratio Selection for Master Mode with I2C enabled
	*
	* The data for this chart is taken from Table 5 of the CS4270 reference
	* manual.
	*
	* This table is used to determine how to program the Mode Control register.
	* It is also used by cs4270_set_dai_sysclk() to tell ALSA which sampling
	* rates the CS4270 currently supports.
	*
	* Each element in this array corresponds to the ratios in mclk_ratios[].
	* These two arrays need to be in sync.
	*
	* 'speed_mode' is the corresponding bit pattern to be written to the
	* MODE bits of the Mode Control Register
	*
	* 'mclk' is the corresponding bit pattern to be wirten to the MCLK bits of
	* the Mode Control Register.
	*
	* In situations where a single ratio is represented by multiple speed
	* modes, we favor the slowest speed. E.g, for a ratio of 128, we pick
	* double-speed instead of quad-speed. However, the CS4270 errata states
	* that Divide-By-1.5 can cause failures, so we avoid that mode where
	* possible.
	*
	* ERRATA: There is an errata for the CS4270 where divide-by-1.5 does not
	* work if VD = 3.3V. If this effects you, select the
	* CONFIG_SND_SOC_CS4270_VD33_ERRATA Kconfig option, and the driver will
	* never select any sample rates that require divide-by-1.5.
	*/
	static struct {
	unsigned int ratio;
	u8 speed_mode;
	u8 mclk;
	} cs4270_mode_ratios[] = {
	{64, CS4270_MODE_4X, CS4270_MODE_DIV1},
	#ifndef CONFIG_SND_SOC_CS4270_VD33_ERRATA
	{96, CS4270_MODE_4X, CS4270_MODE_DIV15},
	#endif
	{128, CS4270_MODE_2X, CS4270_MODE_DIV1},
	{192, CS4270_MODE_4X, CS4270_MODE_DIV3},
	{256, CS4270_MODE_1X, CS4270_MODE_DIV1},
	{384, CS4270_MODE_2X, CS4270_MODE_DIV3},
	{512, CS4270_MODE_1X, CS4270_MODE_DIV2},
	{768, CS4270_MODE_1X, CS4270_MODE_DIV3},
	{1024, CS4270_MODE_1X, CS4270_MODE_DIV4}
	};

	/* The number of MCLK/LRCK ratios supported by the CS4270 */
	#define NUM_MCLK_RATIOS ARRAY_SIZE(cs4270_mode_ratios)

	/*
	* Determine the CS4270 samples rates.
	*
	* 'freq' is the input frequency to MCLK. The other parameters are ignored.
	*
	* The value of MCLK is used to determine which sample rates are supported
	* by the CS4270. The ratio of MCLK / Fs must be equal to one of nine
	* support values: 64, 96, 128, 192, 256, 384, 512, 768, and 1024.
	*
	* This function calculates the nine ratios and determines which ones match
	* a standard sample rate. If there's a match, then it is added to the list
	* of support sample rates.
	*
	* This function must be called by the machine driver's 'startup' function,
	* otherwise the list of supported sample rates will not be available in
	* time for ALSA.
	*
	* Note that in stand-alone mode, the sample rate is determined by input
	* pins M0, M1, MDIV1, and MDIV2. Also in stand-alone mode, divide-by-3
	* is not a programmable option. However, divide-by-3 is not an available
	* option in stand-alone mode. This cases two problems: a ratio of 768 is
	* not available (it requires divide-by-3) and B) ratios 192 and 384 can
	* only be selected with divide-by-1.5, but there is an errate that make
	* this selection difficult.
	*
	* In addition, there is no mechanism for communicating with the machine
	* driver what the input settings can be. This would need to be implemented
	* for stand-alone mode to work.
	*/
	static int cs4270_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 cs4270_private *cs4270 = codec->private_data;
	unsigned int rates = 0;
	unsigned int rate_min = -1;
	unsigned int rate_max = 0;
	unsigned int i;

	cs4270->mclk = freq;

	for (i = 0; i < NUM_MCLK_RATIOS; i++) {
	unsigned int rate = freq / cs4270_mode_ratios[i].ratio;
	rates \|= snd_pcm_rate_to_rate_bit(rate);
	if (rate < rate_min)
	rate_min = rate;
	if (rate > rate_max)
	rate_max = rate;
	}
	/* FIXME: soc should support a rate list */
	rates &= ~SNDRV_PCM_RATE_KNOT;

	if (!rates) {
	printk(KERN_ERR "cs4270: could not find a valid sample rate\n");
	return -EINVAL;
	}

	codec_dai->playback.rates = rates;
	codec_dai->playback.rate_min = rate_min;
	codec_dai->playback.rate_max = rate_max;

	codec_dai->capture.rates = rates;
	codec_dai->capture.rate_min = rate_min;
	codec_dai->capture.rate_max = rate_max;

	return 0;
	}

	/*
	* Configure the codec for the selected audio format
	*
	* This function takes a bitmask of SND_SOC_DAIFMT_x bits and programs the
	* codec accordingly.
	*
	* Currently, this function only supports SND_SOC_DAIFMT_I2S and
	* SND_SOC_DAIFMT_LEFT_J. The CS4270 codec also supports right-justified
	* data for playback only, but ASoC currently does not support different
	* formats for playback vs. record.
	*/
	static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
	unsigned int format)
	{
	struct snd_soc_codec *codec = codec_dai->codec;
	struct cs4270_private *cs4270 = codec->private_data;
	int ret = 0;

	switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
	case SND_SOC_DAIFMT_LEFT_J:
	cs4270->mode = format & SND_SOC_DAIFMT_FORMAT_MASK;
	break;
	default:
	printk(KERN_ERR "cs4270: invalid DAI format\n");
	ret = -EINVAL;
	}

	return ret;
	}

	/*
	* Pre-fill the CS4270 register cache.
	*
	* We use the auto-increment feature of the CS4270 to read all registers in
	* one shot.
	*/
	static int cs4270_fill_cache(struct snd_soc_codec *codec)
	{
	u8 *cache = codec->reg_cache;
	struct i2c_client *i2c_client = codec->control_data;
	s32 length;

	length = i2c_smbus_read_i2c_block_data(i2c_client,
	CS4270_FIRSTREG \| 0x80, CS4270_NUMREGS, cache);

	if (length != CS4270_NUMREGS) {
	printk(KERN_ERR "cs4270: I2C read failure, addr=0x%x\n",
	i2c_client->addr);
	return -EIO;
	}

	return 0;
	}

	/*
	* Read from the CS4270 register cache.
	*
	* This CS4270 registers are cached to avoid excessive I2C I/O operations.
	* After the initial read to pre-fill the cache, the CS4270 never updates
	* the register values, so we won't have a cache coherncy problem.
	*/
	static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
	unsigned int reg)
	{
	u8 *cache = codec->reg_cache;

	if ((reg < CS4270_FIRSTREG) \|\| (reg > CS4270_LASTREG))
	return -EIO;

	return cache[reg - CS4270_FIRSTREG];
	}

	/*
	* Write to a CS4270 register via the I2C bus.
	*
	* This function writes the given value to the given CS4270 register, and
	* also updates the register cache.
	*
	* Note that we don't use the hw_write function pointer of snd_soc_codec.
	* That's because it's too clunky: the hw_write_t prototype does not match
	* i2c_smbus_write_byte_data(), and it's just another layer of overhead.
	*/
	static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
	unsigned int value)
	{
	u8 *cache = codec->reg_cache;

	if ((reg < CS4270_FIRSTREG) \|\| (reg > CS4270_LASTREG))
	return -EIO;

	/* Only perform an I2C operation if the new value is different */
	if (cache[reg - CS4270_FIRSTREG] != value) {
	struct i2c_client *client = codec->control_data;
	if (i2c_smbus_write_byte_data(client, reg, value)) {
	printk(KERN_ERR "cs4270: I2C write failed\n");
	return -EIO;
	}

	/* We've written to the hardware, so update the cache */
	cache[reg - CS4270_FIRSTREG] = value;
	}

	return 0;
	}

	/*
	* Program the CS4270 with the given hardware parameters.
	*
	* The .ops functions are used to provide board-specific data, like
	* input frequencies, to this driver. This function takes that information,
	* combines it with the hardware parameters provided, and programs the
	* hardware accordingly.
	*/
	static int cs4270_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->codec;
	struct cs4270_private *cs4270 = codec->private_data;
	int ret;
	unsigned int i;
	unsigned int rate;
	unsigned int ratio;
	int reg;

	/* Figure out which MCLK/LRCK ratio to use */

	rate = params_rate(params); /* Sampling rate, in Hz */
	ratio = cs4270->mclk / rate; /* MCLK/LRCK ratio */

	for (i = 0; i < NUM_MCLK_RATIOS; i++) {
	if (cs4270_mode_ratios[i].ratio == ratio)
	break;
	}

	if (i == NUM_MCLK_RATIOS) {
	/* We did not find a matching ratio */
	printk(KERN_ERR "cs4270: could not find matching ratio\n");
	return -EINVAL;
	}

	/* Freeze and power-down the codec */

	ret = snd_soc_write(codec, CS4270_PWRCTL, CS4270_PWRCTL_FREEZE \|
	CS4270_PWRCTL_PDN_ADC \| CS4270_PWRCTL_PDN_DAC \|
	CS4270_PWRCTL_PDN);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: I2C write failed\n");
	return ret;
	}

	/* Program the mode control register */

	reg = snd_soc_read(codec, CS4270_MODE);
	reg &= ~(CS4270_MODE_SPEED_MASK \| CS4270_MODE_DIV_MASK);
	reg \|= cs4270_mode_ratios[i].speed_mode \| cs4270_mode_ratios[i].mclk;

	ret = snd_soc_write(codec, CS4270_MODE, reg);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: I2C write failed\n");
	return ret;
	}

	/* Program the format register */

	reg = snd_soc_read(codec, CS4270_FORMAT);
	reg &= ~(CS4270_FORMAT_DAC_MASK \| CS4270_FORMAT_ADC_MASK);

	switch (cs4270->mode) {
	case SND_SOC_DAIFMT_I2S:
	reg \|= CS4270_FORMAT_DAC_I2S \| CS4270_FORMAT_ADC_I2S;
	break;
	case SND_SOC_DAIFMT_LEFT_J:
	reg \|= CS4270_FORMAT_DAC_LJ \| CS4270_FORMAT_ADC_LJ;
	break;
	default:
	printk(KERN_ERR "cs4270: unknown format\n");
	return -EINVAL;
	}

	ret = snd_soc_write(codec, CS4270_FORMAT, reg);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: I2C write failed\n");
	return ret;
	}

	/* Disable auto-mute. This feature appears to be buggy, because in
	some situations, auto-mute will not deactivate when it should. */

	reg = snd_soc_read(codec, CS4270_MUTE);
	reg &= ~CS4270_MUTE_AUTO;
	ret = snd_soc_write(codec, CS4270_MUTE, reg);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: I2C write failed\n");
	return ret;
	}

	/* Disable automatic volume control. It's enabled by default, and
	* it causes volume change commands to be delayed, sometimes until
	* after playback has started.
	*/

	reg = cs4270_read_reg_cache(codec, CS4270_TRANS);
	reg &= ~(CS4270_TRANS_SOFT \| CS4270_TRANS_ZERO);
	ret = cs4270_i2c_write(codec, CS4270_TRANS, reg);
	if (ret < 0) {
	printk(KERN_ERR "I2C write failed\n");
	return ret;
	}

	/* Thaw and power-up the codec */

	ret = snd_soc_write(codec, CS4270_PWRCTL, 0);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: I2C write failed\n");
	return ret;
	}

	return ret;
	}

	#ifdef CONFIG_SND_SOC_CS4270_HWMUTE
	/*
	* Set the CS4270 external mute
	*
	* This function toggles the mute bits in the MUTE register. The CS4270's
	* mute capability is intended for external muting circuitry, so if the
	* board does not have the MUTEA or MUTEB pins connected to such circuitry,
	* then this function will do nothing.
	*/
	static int cs4270_mute(struct snd_soc_dai *dai, int mute)
	{
	struct snd_soc_codec *codec = dai->codec;
	int reg6;

	reg6 = snd_soc_read(codec, CS4270_MUTE);

	if (mute)
	reg6 \|= CS4270_MUTE_ADC_A \| CS4270_MUTE_ADC_B \|
	CS4270_MUTE_DAC_A \| CS4270_MUTE_DAC_B;
	else
	reg6 &= ~(CS4270_MUTE_ADC_A \| CS4270_MUTE_ADC_B \|
	CS4270_MUTE_DAC_A \| CS4270_MUTE_DAC_B);

	return snd_soc_write(codec, CS4270_MUTE, reg6);
	}
	#else
	#define cs4270_mute NULL
	#endif

	/* A list of non-DAPM controls that the CS4270 supports */
	static const struct snd_kcontrol_new cs4270_snd_controls[] = {
	SOC_DOUBLE_R("Master Playback Volume",
	CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 1)
	};

	/*
	* Global variable to store socdev for i2c probe function.
	*
	* If struct i2c_driver had a private_data field, we wouldn't need to use
	* cs4270_socdec. This is the only way to pass the socdev structure to
	* cs4270_i2c_probe().
	*
	* The real solution to cs4270_socdev is to create a mechanism
	* that maps I2C addresses to snd_soc_device structures. Perhaps the
	* creation of the snd_soc_device object should be moved out of
	* cs4270_probe() and into cs4270_i2c_probe(), but that would make this
	* driver dependent on I2C. The CS4270 supports "stand-alone" mode, whereby
	* the chip is not connected to the I2C bus, but is instead configured via
	* input pins.
	*/
	static struct snd_soc_device *cs4270_socdev;

	struct snd_soc_dai cs4270_dai = {
	.name = "cs4270",
	.playback = {
	.stream_name = "Playback",
	.channels_min = 1,
	.channels_max = 2,
	.rates = 0,
	.formats = CS4270_FORMATS,
	},
	.capture = {
	.stream_name = "Capture",
	.channels_min = 1,
	.channels_max = 2,
	.rates = 0,
	.formats = CS4270_FORMATS,
	},
	.ops = {
	.hw_params = cs4270_hw_params,
	.set_sysclk = cs4270_set_dai_sysclk,
	.set_fmt = cs4270_set_dai_fmt,
	.digital_mute = cs4270_mute,
	},
	};
	EXPORT_SYMBOL_GPL(cs4270_dai);

	/*
	* Initialize the I2C interface of the CS4270
	*
	* This function is called for whenever the I2C subsystem finds a device
	* at a particular address.
	*
	* Note: snd_soc_new_pcms() must be called before this function can be called,
	* because of snd_ctl_add().
	*/
	static int cs4270_i2c_probe(struct i2c_client *i2c_client,
	const struct i2c_device_id *id)
	{
	struct snd_soc_device *socdev = cs4270_socdev;
	struct snd_soc_codec *codec;
	struct cs4270_private *cs4270;
	int i;
	int ret = 0;

	/* Verify that we have a CS4270 */

	ret = i2c_smbus_read_byte_data(i2c_client, CS4270_CHIPID);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: failed to read I2C\n");
	return ret;
	}
	/* The top four bits of the chip ID should be 1100. */
	if ((ret & 0xF0) != 0xC0) {
	printk(KERN_ERR "cs4270: device at addr %X is not a CS4270\n",
	i2c_client->addr);
	return -ENODEV;
	}

	printk(KERN_INFO "cs4270: found device at I2C address %X\n",
	i2c_client->addr);
	printk(KERN_INFO "cs4270: hardware revision %X\n", ret & 0xF);

	/* Allocate enough space for the snd_soc_codec structure
	and our private data together. */
	cs4270 = kzalloc(sizeof(struct cs4270_private), GFP_KERNEL);
	if (!cs4270) {
	printk(KERN_ERR "cs4270: Could not allocate codec structure\n");
	return -ENOMEM;
	}
	codec = &cs4270->codec;
	socdev->codec = codec;

	mutex_init(&codec->mutex);
	INIT_LIST_HEAD(&codec->dapm_widgets);
	INIT_LIST_HEAD(&codec->dapm_paths);

	codec->name = "CS4270";
	codec->owner = THIS_MODULE;
	codec->dai = &cs4270_dai;
	codec->num_dai = 1;
	codec->private_data = cs4270;
	codec->control_data = i2c_client;
	codec->read = cs4270_read_reg_cache;
	codec->write = cs4270_i2c_write;
	codec->reg_cache = cs4270->reg_cache;
	codec->reg_cache_size = CS4270_NUMREGS;

	/* The I2C interface is set up, so pre-fill our register cache */

	ret = cs4270_fill_cache(codec);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: failed to fill register cache\n");
	goto error_free_codec;
	}

	/* Register PCMs */

	ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: failed to create PCMs\n");
	goto error_free_codec;
	}

	/* Add the non-DAPM controls */

	for (i = 0; i < ARRAY_SIZE(cs4270_snd_controls); i++) {
	struct snd_kcontrol *kctrl;

	kctrl = snd_soc_cnew(&cs4270_snd_controls[i], codec, NULL);
	if (!kctrl) {
	printk(KERN_ERR "cs4270: error creating control '%s'\n",
	cs4270_snd_controls[i].name);
	ret = -ENOMEM;
	goto error_free_pcms;
	}

	ret = snd_ctl_add(codec->card, kctrl);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: error adding control '%s'\n",
	cs4270_snd_controls[i].name);
	goto error_free_pcms;
	}
	}

	/* Initialize the SOC device */

	ret = snd_soc_init_card(socdev);
	if (ret < 0) {
	printk(KERN_ERR "cs4270: failed to register card\n");
	goto error_free_pcms;;
	}

	i2c_set_clientdata(i2c_client, socdev);

	return 0;

	error_free_pcms:
	snd_soc_free_pcms(socdev);

	error_free_codec:
	kfree(cs4270);

	return ret;
	}

	static int cs4270_i2c_remove(struct i2c_client *i2c_client)
	{
	struct snd_soc_device *socdev = i2c_get_clientdata(i2c_client);
	struct snd_soc_codec *codec = socdev->codec;
	struct cs4270_private *cs4270 = codec->private_data;

	snd_soc_free_pcms(socdev);
	kfree(cs4270);

	return 0;
	}

	static struct i2c_device_id cs4270_id[] = {
	{"cs4270", 0},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, cs4270_id);

	static struct i2c_driver cs4270_i2c_driver = {
	.driver = {
	.name = "cs4270",
	.owner = THIS_MODULE,
	},
	.id_table = cs4270_id,
	.probe = cs4270_i2c_probe,
	.remove = cs4270_i2c_remove,
	};

	/*
	* ASoC probe function
	*
	* This function is called when the machine driver calls
	* platform_device_add().
	*/
	static int cs4270_probe(struct platform_device *pdev)
	{
	cs4270_socdev = platform_get_drvdata(pdev);;

	return i2c_add_driver(&cs4270_i2c_driver);
	}

	static int cs4270_remove(struct platform_device *pdev)
	{
	i2c_del_driver(&cs4270_i2c_driver);

	return 0;
	}

	/*
	* ASoC codec device structure
	*
	* Assign this variable to the codec_dev field of the machine driver's
	* snd_soc_device structure.
	*/
	struct snd_soc_codec_device soc_codec_device_cs4270 = {
	.probe = cs4270_probe,
	.remove = cs4270_remove
	};
	EXPORT_SYMBOL_GPL(soc_codec_device_cs4270);

	static int __init cs4270_init(void)
	{
	printk(KERN_INFO "Cirrus Logic CS4270 ALSA SoC Codec Driver\n");

	return snd_soc_register_dai(&cs4270_dai);
	}
	module_init(cs4270_init);

	static void __exit cs4270_exit(void)
	{
	snd_soc_unregister_dai(&cs4270_dai);
	}
	module_exit(cs4270_exit);

	MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
	MODULE_DESCRIPTION("Cirrus Logic CS4270 ALSA SoC Codec Driver");
	MODULE_LICENSE("GPL");