sound/soc/codecs/ad1938.c - kernel/msm-4.9 - Gitiles

 /*
  * File:         sound/soc/codecs/ad1938.c
  * Author:       Barry Song <Barry.Song@analog.com>
  *
  * Created:      June 04 2009
  * Description:  Driver for AD1938 sound chip
  *
  * Modified:
  *               Copyright 2009 Analog Devices Inc.
  *
  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see the file COPYING, or write
  * to the Free Software Foundation, Inc.,
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/initval.h>
 #include <sound/soc.h>
 #include <sound/tlv.h>
 #include <sound/soc-dapm.h>
 #include <linux/spi/spi.h>
 #include "ad1938.h"

 /* codec private data */
 struct ad1938_priv {
 	struct snd_soc_codec codec;
 	u8 reg_cache[AD1938_NUM_REGS];
 };

 static struct snd_soc_codec *ad1938_codec;
 struct snd_soc_codec_device soc_codec_dev_ad1938;
 static int ad1938_register(struct ad1938_priv *ad1938);
 static void ad1938_unregister(struct ad1938_priv *ad1938);

 /*
  * AD1938 volume/mute/de-emphasis etc. controls
  */
 static const char *ad1938_deemp[] = {"None", "48kHz", "44.1kHz", "32kHz"};

 static const struct soc_enum ad1938_deemp_enum =
 	SOC_ENUM_SINGLE(AD1938_DAC_CTRL2, 1, 4, ad1938_deemp);

 static const struct snd_kcontrol_new ad1938_snd_controls[] = {
 	/* DAC volume control */
 	SOC_DOUBLE_R("DAC1  Volume", AD1938_DAC_L1_VOL,
 			AD1938_DAC_R1_VOL, 0, 0xFF, 1),
 	SOC_DOUBLE_R("DAC2  Volume", AD1938_DAC_L2_VOL,
 			AD1938_DAC_R2_VOL, 0, 0xFF, 1),
 	SOC_DOUBLE_R("DAC3  Volume", AD1938_DAC_L3_VOL,
 			AD1938_DAC_R3_VOL, 0, 0xFF, 1),
 	SOC_DOUBLE_R("DAC4  Volume", AD1938_DAC_L4_VOL,
 			AD1938_DAC_R4_VOL, 0, 0xFF, 1),

 	/* ADC switch control */
 	SOC_DOUBLE("ADC1 Switch", AD1938_ADC_CTRL0, AD1938_ADCL1_MUTE,
 		AD1938_ADCR1_MUTE, 1, 1),
 	SOC_DOUBLE("ADC2 Switch", AD1938_ADC_CTRL0, AD1938_ADCL2_MUTE,
 		AD1938_ADCR2_MUTE, 1, 1),

 	/* DAC switch control */
 	SOC_DOUBLE("DAC1 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL1_MUTE,
 		AD1938_DACR1_MUTE, 1, 1),
 	SOC_DOUBLE("DAC2 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL2_MUTE,
 		AD1938_DACR2_MUTE, 1, 1),
 	SOC_DOUBLE("DAC3 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL3_MUTE,
 		AD1938_DACR3_MUTE, 1, 1),
 	SOC_DOUBLE("DAC4 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL4_MUTE,
 		AD1938_DACR4_MUTE, 1, 1),

 	/* ADC high-pass filter */
 	SOC_SINGLE("ADC High Pass Filter Switch", AD1938_ADC_CTRL0,
 			AD1938_ADC_HIGHPASS_FILTER, 1, 0),

 	/* DAC de-emphasis */
 	SOC_ENUM("Playback Deemphasis", ad1938_deemp_enum),
 };

 static const struct snd_soc_dapm_widget ad1938_dapm_widgets[] = {
 	SND_SOC_DAPM_DAC("DAC", "Playback", AD1938_DAC_CTRL0, 0, 1),
 	SND_SOC_DAPM_ADC("ADC", "Capture", SND_SOC_NOPM, 0, 0),
 	SND_SOC_DAPM_SUPPLY("ADC_PWR", AD1938_ADC_CTRL0, 0, 1, NULL, 0),
 	SND_SOC_DAPM_OUTPUT("DAC1OUT"),
 	SND_SOC_DAPM_OUTPUT("DAC2OUT"),
 	SND_SOC_DAPM_OUTPUT("DAC3OUT"),
 	SND_SOC_DAPM_OUTPUT("DAC4OUT"),
 	SND_SOC_DAPM_INPUT("ADC1IN"),
 	SND_SOC_DAPM_INPUT("ADC2IN"),
 };

 static const struct snd_soc_dapm_route audio_paths[] = {
 	{ "DAC", NULL, "ADC_PWR" },
 	{ "ADC", NULL, "ADC_PWR" },
 	{ "DAC1OUT", "DAC1 Switch", "DAC" },
 	{ "DAC2OUT", "DAC2 Switch", "DAC" },
 	{ "DAC3OUT", "DAC3 Switch", "DAC" },
 	{ "DAC4OUT", "DAC4 Switch", "DAC" },
 	{ "ADC", "ADC1 Switch", "ADC1IN" },
 	{ "ADC", "ADC2 Switch", "ADC2IN" },
 };

 /*
  * DAI ops entries
  */

 static int ad1938_mute(struct snd_soc_dai *dai, int mute)
 {
 	struct snd_soc_codec *codec = dai->codec;
 	int reg;

 	reg = codec->read(codec, AD1938_DAC_CTRL2);
 	reg = (mute > 0) ? reg | AD1938_DAC_MASTER_MUTE : reg &
 		(~AD1938_DAC_MASTER_MUTE);
 	codec->write(codec, AD1938_DAC_CTRL2, reg);

 	return 0;
 }

 static inline int ad1938_pll_powerctrl(struct snd_soc_codec *codec, int cmd)
 {
 	int reg = codec->read(codec, AD1938_PLL_CLK_CTRL0);
 	reg = (cmd > 0) ? reg & (~AD1938_PLL_POWERDOWN) : reg |
 		AD1938_PLL_POWERDOWN;
 	codec->write(codec, AD1938_PLL_CLK_CTRL0, reg);

 	return 0;
 }

 static int ad1938_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx_mask,
 			       unsigned int mask, int slots, int width)
 {
 	struct snd_soc_codec *codec = dai->codec;
 	int dac_reg = codec->read(codec, AD1938_DAC_CTRL1);
 	int adc_reg = codec->read(codec, AD1938_ADC_CTRL2);

 	dac_reg &= ~AD1938_DAC_CHAN_MASK;
 	adc_reg &= ~AD1938_ADC_CHAN_MASK;

 	switch (slots) {
 	case 2:
 		dac_reg |= AD1938_DAC_2_CHANNELS << AD1938_DAC_CHAN_SHFT;
 		adc_reg |= AD1938_ADC_2_CHANNELS << AD1938_ADC_CHAN_SHFT;
 		break;
 	case 4:
 		dac_reg |= AD1938_DAC_4_CHANNELS << AD1938_DAC_CHAN_SHFT;
 		adc_reg |= AD1938_ADC_4_CHANNELS << AD1938_ADC_CHAN_SHFT;
 		break;
 	case 8:
 		dac_reg |= AD1938_DAC_8_CHANNELS << AD1938_DAC_CHAN_SHFT;
 		adc_reg |= AD1938_ADC_8_CHANNELS << AD1938_ADC_CHAN_SHFT;
 		break;
 	case 16:
 		dac_reg |= AD1938_DAC_16_CHANNELS << AD1938_DAC_CHAN_SHFT;
 		adc_reg |= AD1938_ADC_16_CHANNELS << AD1938_ADC_CHAN_SHFT;
 		break;
 	default:
 		return -EINVAL;
 	}

 	codec->write(codec, AD1938_DAC_CTRL1, dac_reg);
 	codec->write(codec, AD1938_ADC_CTRL2, adc_reg);

 	return 0;
 }

 static int ad1938_set_dai_fmt(struct snd_soc_dai *codec_dai,
 		unsigned int fmt)
 {
 	struct snd_soc_codec *codec = codec_dai->codec;
 	int adc_reg, dac_reg;

 	adc_reg = codec->read(codec, AD1938_ADC_CTRL2);
 	dac_reg = codec->read(codec, AD1938_DAC_CTRL1);

 	/* At present, the driver only support AUX ADC mode(SND_SOC_DAIFMT_I2S
 	 * with TDM) and ADC&DAC TDM mode(SND_SOC_DAIFMT_DSP_A)
 	 */
 	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
 	case SND_SOC_DAIFMT_I2S:
 		adc_reg &= ~AD1938_ADC_SERFMT_MASK;
 		adc_reg |= AD1938_ADC_SERFMT_TDM;
 		break;
 	case SND_SOC_DAIFMT_DSP_A:
 		adc_reg &= ~AD1938_ADC_SERFMT_MASK;
 		adc_reg |= AD1938_ADC_SERFMT_AUX;
 		break;
 	default:
 		return -EINVAL;
 	}

 	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
 	case SND_SOC_DAIFMT_NB_NF: /* normal bit clock + frame */
 		adc_reg &= ~AD1938_ADC_LEFT_HIGH;
 		adc_reg &= ~AD1938_ADC_BCLK_INV;
 		dac_reg &= ~AD1938_DAC_LEFT_HIGH;
 		dac_reg &= ~AD1938_DAC_BCLK_INV;
 		break;
 	case SND_SOC_DAIFMT_NB_IF: /* normal bclk + invert frm */
 		adc_reg |= AD1938_ADC_LEFT_HIGH;
 		adc_reg &= ~AD1938_ADC_BCLK_INV;
 		dac_reg |= AD1938_DAC_LEFT_HIGH;
 		dac_reg &= ~AD1938_DAC_BCLK_INV;
 		break;
 	case SND_SOC_DAIFMT_IB_NF: /* invert bclk + normal frm */
 		adc_reg &= ~AD1938_ADC_LEFT_HIGH;
 		adc_reg |= AD1938_ADC_BCLK_INV;
 		dac_reg &= ~AD1938_DAC_LEFT_HIGH;
 		dac_reg |= AD1938_DAC_BCLK_INV;
 		break;

 	case SND_SOC_DAIFMT_IB_IF: /* invert bclk + frm */
 		adc_reg |= AD1938_ADC_LEFT_HIGH;
 		adc_reg |= AD1938_ADC_BCLK_INV;
 		dac_reg |= AD1938_DAC_LEFT_HIGH;
 		dac_reg |= AD1938_DAC_BCLK_INV;
 		break;
 	default:
 		return -EINVAL;
 	}

 	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 	case SND_SOC_DAIFMT_CBM_CFM: /* codec clk & frm master */
 		adc_reg |= AD1938_ADC_LCR_MASTER;
 		adc_reg |= AD1938_ADC_BCLK_MASTER;
 		dac_reg |= AD1938_DAC_LCR_MASTER;
 		dac_reg |= AD1938_DAC_BCLK_MASTER;
 		break;
 	case SND_SOC_DAIFMT_CBS_CFM: /* codec clk slave & frm master */
 		adc_reg |= AD1938_ADC_LCR_MASTER;
 		adc_reg &= ~AD1938_ADC_BCLK_MASTER;
 		dac_reg |= AD1938_DAC_LCR_MASTER;
 		dac_reg &= ~AD1938_DAC_BCLK_MASTER;
 		break;
 	case SND_SOC_DAIFMT_CBM_CFS: /* codec clk master & frame slave */
 		adc_reg &= ~AD1938_ADC_LCR_MASTER;
 		adc_reg |= AD1938_ADC_BCLK_MASTER;
 		dac_reg &= ~AD1938_DAC_LCR_MASTER;
 		dac_reg |= AD1938_DAC_BCLK_MASTER;
 		break;
 	case SND_SOC_DAIFMT_CBS_CFS: /* codec clk & frm slave */
 		adc_reg &= ~AD1938_ADC_LCR_MASTER;
 		adc_reg &= ~AD1938_ADC_BCLK_MASTER;
 		dac_reg &= ~AD1938_DAC_LCR_MASTER;
 		dac_reg &= ~AD1938_DAC_BCLK_MASTER;
 		break;
 	default:
 		return -EINVAL;
 	}

 	codec->write(codec, AD1938_ADC_CTRL2, adc_reg);
 	codec->write(codec, AD1938_DAC_CTRL1, dac_reg);

 	return 0;
 }

 static int ad1938_hw_params(struct snd_pcm_substream *substream,
 		struct snd_pcm_hw_params *params,
 		struct snd_soc_dai *dai)
 {
 	int word_len = 0, reg = 0;

 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct snd_soc_device *socdev = rtd->socdev;
 	struct snd_soc_codec *codec = socdev->card->codec;

 	/* bit size */
 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
 		word_len = 3;
 		break;
 	case SNDRV_PCM_FORMAT_S20_3LE:
 		word_len = 1;
 		break;
 	case SNDRV_PCM_FORMAT_S24_LE:
 	case SNDRV_PCM_FORMAT_S32_LE:
 		word_len = 0;
 		break;
 	}

 	reg = codec->read(codec, AD1938_DAC_CTRL2);
 	reg = (reg & (~AD1938_DAC_WORD_LEN_MASK)) | word_len;
 	codec->write(codec, AD1938_DAC_CTRL2, reg);

 	reg = codec->read(codec, AD1938_ADC_CTRL1);
 	reg = (reg & (~AD1938_ADC_WORD_LEN_MASK)) | word_len;
 	codec->write(codec, AD1938_ADC_CTRL1, reg);

 	return 0;
 }

 static int ad1938_set_bias_level(struct snd_soc_codec *codec,
 		enum snd_soc_bias_level level)
 {
 	switch (level) {
 	case SND_SOC_BIAS_ON:
 		ad1938_pll_powerctrl(codec, 1);
 		break;
 	case SND_SOC_BIAS_PREPARE:
 		break;
 	case SND_SOC_BIAS_STANDBY:
 	case SND_SOC_BIAS_OFF:
 		ad1938_pll_powerctrl(codec, 0);
 		break;
 	}
 	codec->bias_level = level;
 	return 0;
 }

 /*
  * interface to read/write ad1938 register
  */

 #define AD1938_SPI_ADDR    0x4
 #define AD1938_SPI_READ    0x1
 #define AD1938_SPI_BUFLEN  3

 /*
  * write to the ad1938 register space
  */

 static int ad1938_write_reg(struct snd_soc_codec *codec, unsigned int reg,
 		unsigned int value)
 {
 	u8 *reg_cache = codec->reg_cache;
 	int ret = 0;

 	if (value != reg_cache[reg]) {
 		uint8_t buf[AD1938_SPI_BUFLEN];
 		struct spi_transfer t = {
 			.tx_buf = buf,
 			.len = AD1938_SPI_BUFLEN,
 		};
 		struct spi_message m;

 		buf[0] = AD1938_SPI_ADDR << 1;
 		buf[1] = reg;
 		buf[2] = value;
 		spi_message_init(&m);
 		spi_message_add_tail(&t, &m);
 		ret = spi_sync(codec->control_data, &m);
 		if (ret == 0)
 			reg_cache[reg] = value;
 	}

 	return ret;
 }

 /*
  * read from the ad1938 register space cache
  */

 static unsigned int ad1938_read_reg_cache(struct snd_soc_codec *codec,
 					  unsigned int reg)
 {
 	u8 *reg_cache = codec->reg_cache;

 	if (reg >= codec->reg_cache_size)
 		return -EINVAL;

 	return reg_cache[reg];
 }

 /*
  * read from the ad1938 register space
  */

 static unsigned int ad1938_read_reg(struct snd_soc_codec *codec,
 						unsigned int reg)
 {
 	char w_buf[AD1938_SPI_BUFLEN];
 	char r_buf[AD1938_SPI_BUFLEN];
 	int ret;

 	struct spi_transfer t = {
 		.tx_buf = w_buf,
 		.rx_buf = r_buf,
 		.len = AD1938_SPI_BUFLEN,
 	};
 	struct spi_message m;

 	w_buf[0] = (AD1938_SPI_ADDR << 1) | AD1938_SPI_READ;
 	w_buf[1] = reg;
 	w_buf[2] = 0;

 	spi_message_init(&m);
 	spi_message_add_tail(&t, &m);
 	ret = spi_sync(codec->control_data, &m);
 	if (ret == 0)
 		return	r_buf[2];
 	else
 		return -EIO;
 }

 static int ad1938_fill_cache(struct snd_soc_codec *codec)
 {
 	int i;
 	u8 *reg_cache = codec->reg_cache;
 	struct spi_device *spi = codec->control_data;

 	for (i = 0; i < codec->reg_cache_size; i++) {
 		int ret = ad1938_read_reg(codec, i);
 		if (ret == -EIO) {
 			dev_err(&spi->dev, "AD1938 SPI read failure\n");
 			return ret;
 		}
 		reg_cache[i] = ret;
 	}

 	return 0;
 }

 static int __devinit ad1938_spi_probe(struct spi_device *spi)
 {
 	struct snd_soc_codec *codec;
 	struct ad1938_priv *ad1938;

 	ad1938 = kzalloc(sizeof(struct ad1938_priv), GFP_KERNEL);
 	if (ad1938 == NULL)
 		return -ENOMEM;

 	codec = &ad1938->codec;
 	codec->control_data = spi;
 	codec->dev = &spi->dev;

 	dev_set_drvdata(&spi->dev, ad1938);

 	return ad1938_register(ad1938);
 }

 static int __devexit ad1938_spi_remove(struct spi_device *spi)
 {
 	struct ad1938_priv *ad1938 = dev_get_drvdata(&spi->dev);

 	ad1938_unregister(ad1938);
 	return 0;
 }

 static struct spi_driver ad1938_spi_driver = {
 	.driver = {
 		.name	= "ad1938",
 		.owner	= THIS_MODULE,
 	},
 	.probe		= ad1938_spi_probe,
 	.remove		= __devexit_p(ad1938_spi_remove),
 };

 static struct snd_soc_dai_ops ad1938_dai_ops = {
 	.hw_params = ad1938_hw_params,
 	.digital_mute = ad1938_mute,
 	.set_tdm_slot = ad1938_set_tdm_slot,
 	.set_fmt = ad1938_set_dai_fmt,
 };

 /* codec DAI instance */
 struct snd_soc_dai ad1938_dai = {
 	.name = "AD1938",
 	.playback = {
 		.stream_name = "Playback",
 		.channels_min = 2,
 		.channels_max = 8,
 		.rates = SNDRV_PCM_RATE_48000,
 		.formats = SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S16_LE |
 			SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S24_LE,
 	},
 	.capture = {
 		.stream_name = "Capture",
 		.channels_min = 2,
 		.channels_max = 4,
 		.rates = SNDRV_PCM_RATE_48000,
 		.formats = SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S16_LE |
 			SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S24_LE,
 	},
 	.ops = &ad1938_dai_ops,
 };
 EXPORT_SYMBOL_GPL(ad1938_dai);

 static int ad1938_register(struct ad1938_priv *ad1938)
 {
 	int ret;
 	struct snd_soc_codec *codec = &ad1938->codec;

 	if (ad1938_codec) {
 		dev_err(codec->dev, "Another ad1938 is registered\n");
 		return -EINVAL;
 	}

 	mutex_init(&codec->mutex);
 	INIT_LIST_HEAD(&codec->dapm_widgets);
 	INIT_LIST_HEAD(&codec->dapm_paths);
 	codec->private_data = ad1938;
 	codec->reg_cache = ad1938->reg_cache;
 	codec->reg_cache_size = AD1938_NUM_REGS;
 	codec->name = "AD1938";
 	codec->owner = THIS_MODULE;
 	codec->dai = &ad1938_dai;
 	codec->num_dai = 1;
 	codec->write = ad1938_write_reg;
 	codec->read = ad1938_read_reg_cache;
 	codec->set_bias_level = ad1938_set_bias_level;
 	INIT_LIST_HEAD(&codec->dapm_widgets);
 	INIT_LIST_HEAD(&codec->dapm_paths);

 	ad1938_dai.dev = codec->dev;
 	ad1938_codec = codec;

 	/* default setting for ad1938 */

 	/* unmute dac channels */
 	codec->write(codec, AD1938_DAC_CHNL_MUTE, 0x0);
 	/* de-emphasis: 48kHz, powedown dac */
 	codec->write(codec, AD1938_DAC_CTRL2, 0x1A);
 	/* powerdown dac, dac in tdm mode */
 	codec->write(codec, AD1938_DAC_CTRL0, 0x41);
 	/* high-pass filter enable */
 	codec->write(codec, AD1938_ADC_CTRL0, 0x3);
 	/* sata delay=1, adc aux mode */
 	codec->write(codec, AD1938_ADC_CTRL1, 0x43);
 	/* pll input: mclki/xi */
 	codec->write(codec, AD1938_PLL_CLK_CTRL0, 0x9D);
 	codec->write(codec, AD1938_PLL_CLK_CTRL1, 0x04);

 	ad1938_fill_cache(codec);

 	ret = snd_soc_register_codec(codec);
 	if (ret != 0) {
 		dev_err(codec->dev, "Failed to register codec: %d\n", ret);
 		kfree(ad1938);
 		return ret;
 	}

 	ret = snd_soc_register_dai(&ad1938_dai);
 	if (ret != 0) {
 		dev_err(codec->dev, "Failed to register DAI: %d\n", ret);
 		snd_soc_unregister_codec(codec);
 		kfree(ad1938);
 		return ret;
 	}

 	return 0;
 }

 static void ad1938_unregister(struct ad1938_priv *ad1938)
 {
 	ad1938_set_bias_level(&ad1938->codec, SND_SOC_BIAS_OFF);
 	snd_soc_unregister_dai(&ad1938_dai);
 	snd_soc_unregister_codec(&ad1938->codec);
 	kfree(ad1938);
 	ad1938_codec = NULL;
 }

 static int ad1938_probe(struct platform_device *pdev)
 {
 	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 	struct snd_soc_codec *codec;
 	int ret = 0;

 	if (ad1938_codec == NULL) {
 		dev_err(&pdev->dev, "Codec device not registered\n");
 		return -ENODEV;
 	}

 	socdev->card->codec = ad1938_codec;
 	codec = ad1938_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, ad1938_snd_controls,
 			     ARRAY_SIZE(ad1938_snd_controls));
 	snd_soc_dapm_new_controls(codec, ad1938_dapm_widgets,
 				  ARRAY_SIZE(ad1938_dapm_widgets));
 	snd_soc_dapm_add_routes(codec, audio_paths, ARRAY_SIZE(audio_paths));
 	snd_soc_dapm_new_widgets(codec);

 	ad1938_set_bias_level(codec, SND_SOC_BIAS_STANDBY);

 	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;
 }

 /* power down chip */
 static int ad1938_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;
 }

 #ifdef CONFIG_PM
 static int ad1938_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;

 	ad1938_set_bias_level(codec, SND_SOC_BIAS_OFF);
 	return 0;
 }

 static int ad1938_resume(struct platform_device *pdev)
 {
 	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 	struct snd_soc_codec *codec = socdev->card->codec;

 	if (codec->suspend_bias_level == SND_SOC_BIAS_ON)
 		ad1938_set_bias_level(codec, SND_SOC_BIAS_ON);

 	return 0;
 }
 #else
 #define ad1938_suspend NULL
 #define ad1938_resume NULL
 #endif

 struct snd_soc_codec_device soc_codec_dev_ad1938 = {
 	.probe = 	ad1938_probe,
 	.remove = 	ad1938_remove,
 	.suspend =      ad1938_suspend,
 	.resume =       ad1938_resume,
 };
 EXPORT_SYMBOL_GPL(soc_codec_dev_ad1938);

 static int __init ad1938_init(void)
 {
 	int ret;

 	ret = spi_register_driver(&ad1938_spi_driver);
 	if (ret != 0) {
 		printk(KERN_ERR "Failed to register ad1938 SPI driver: %d\n",
 				ret);
 	}

 	return ret;
 }
 module_init(ad1938_init);

 static void __exit ad1938_exit(void)
 {
 	spi_unregister_driver(&ad1938_spi_driver);
 }
 module_exit(ad1938_exit);

 MODULE_DESCRIPTION("ASoC ad1938 driver");
 MODULE_AUTHOR("Barry Song ");
 MODULE_LICENSE("GPL");
	/*
	* File: sound/soc/codecs/ad1938.c
	* Author: Barry Song <Barry.Song@analog.com>
	*
	* Created: June 04 2009
	* Description: Driver for AD1938 sound chip
	*
	* Modified:
	* Copyright 2009 Analog Devices Inc.
	*
	* Bugs: Enter bugs at http://blackfin.uclinux.org/
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see the file COPYING, or write
	* to the Free Software Foundation, Inc.,
	* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/device.h>
	#include <sound/core.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>
	#include <sound/initval.h>
	#include <sound/soc.h>
	#include <sound/tlv.h>
	#include <sound/soc-dapm.h>
	#include <linux/spi/spi.h>
	#include "ad1938.h"

	/* codec private data */
	struct ad1938_priv {
	struct snd_soc_codec codec;
	u8 reg_cache[AD1938_NUM_REGS];
	};

	static struct snd_soc_codec *ad1938_codec;
	struct snd_soc_codec_device soc_codec_dev_ad1938;
	static int ad1938_register(struct ad1938_priv *ad1938);
	static void ad1938_unregister(struct ad1938_priv *ad1938);

	/*
	* AD1938 volume/mute/de-emphasis etc. controls
	*/
	static const char *ad1938_deemp[] = {"None", "48kHz", "44.1kHz", "32kHz"};

	static const struct soc_enum ad1938_deemp_enum =
	SOC_ENUM_SINGLE(AD1938_DAC_CTRL2, 1, 4, ad1938_deemp);

	static const struct snd_kcontrol_new ad1938_snd_controls[] = {
	/* DAC volume control */
	SOC_DOUBLE_R("DAC1 Volume", AD1938_DAC_L1_VOL,
	AD1938_DAC_R1_VOL, 0, 0xFF, 1),
	SOC_DOUBLE_R("DAC2 Volume", AD1938_DAC_L2_VOL,
	AD1938_DAC_R2_VOL, 0, 0xFF, 1),
	SOC_DOUBLE_R("DAC3 Volume", AD1938_DAC_L3_VOL,
	AD1938_DAC_R3_VOL, 0, 0xFF, 1),
	SOC_DOUBLE_R("DAC4 Volume", AD1938_DAC_L4_VOL,
	AD1938_DAC_R4_VOL, 0, 0xFF, 1),

	/* ADC switch control */
	SOC_DOUBLE("ADC1 Switch", AD1938_ADC_CTRL0, AD1938_ADCL1_MUTE,
	AD1938_ADCR1_MUTE, 1, 1),
	SOC_DOUBLE("ADC2 Switch", AD1938_ADC_CTRL0, AD1938_ADCL2_MUTE,
	AD1938_ADCR2_MUTE, 1, 1),

	/* DAC switch control */
	SOC_DOUBLE("DAC1 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL1_MUTE,
	AD1938_DACR1_MUTE, 1, 1),
	SOC_DOUBLE("DAC2 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL2_MUTE,
	AD1938_DACR2_MUTE, 1, 1),
	SOC_DOUBLE("DAC3 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL3_MUTE,
	AD1938_DACR3_MUTE, 1, 1),
	SOC_DOUBLE("DAC4 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL4_MUTE,
	AD1938_DACR4_MUTE, 1, 1),

	/* ADC high-pass filter */
	SOC_SINGLE("ADC High Pass Filter Switch", AD1938_ADC_CTRL0,
	AD1938_ADC_HIGHPASS_FILTER, 1, 0),

	/* DAC de-emphasis */
	SOC_ENUM("Playback Deemphasis", ad1938_deemp_enum),
	};

	static const struct snd_soc_dapm_widget ad1938_dapm_widgets[] = {
	SND_SOC_DAPM_DAC("DAC", "Playback", AD1938_DAC_CTRL0, 0, 1),
	SND_SOC_DAPM_ADC("ADC", "Capture", SND_SOC_NOPM, 0, 0),
	SND_SOC_DAPM_SUPPLY("ADC_PWR", AD1938_ADC_CTRL0, 0, 1, NULL, 0),
	SND_SOC_DAPM_OUTPUT("DAC1OUT"),
	SND_SOC_DAPM_OUTPUT("DAC2OUT"),
	SND_SOC_DAPM_OUTPUT("DAC3OUT"),
	SND_SOC_DAPM_OUTPUT("DAC4OUT"),
	SND_SOC_DAPM_INPUT("ADC1IN"),
	SND_SOC_DAPM_INPUT("ADC2IN"),
	};

	static const struct snd_soc_dapm_route audio_paths[] = {
	{ "DAC", NULL, "ADC_PWR" },
	{ "ADC", NULL, "ADC_PWR" },
	{ "DAC1OUT", "DAC1 Switch", "DAC" },
	{ "DAC2OUT", "DAC2 Switch", "DAC" },
	{ "DAC3OUT", "DAC3 Switch", "DAC" },
	{ "DAC4OUT", "DAC4 Switch", "DAC" },
	{ "ADC", "ADC1 Switch", "ADC1IN" },
	{ "ADC", "ADC2 Switch", "ADC2IN" },
	};

	/*
	* DAI ops entries
	*/

	static int ad1938_mute(struct snd_soc_dai *dai, int mute)
	{
	struct snd_soc_codec *codec = dai->codec;
	int reg;

	reg = codec->read(codec, AD1938_DAC_CTRL2);
	reg = (mute > 0) ? reg \| AD1938_DAC_MASTER_MUTE : reg &
	(~AD1938_DAC_MASTER_MUTE);
	codec->write(codec, AD1938_DAC_CTRL2, reg);

	return 0;
	}

	static inline int ad1938_pll_powerctrl(struct snd_soc_codec *codec, int cmd)
	{
	int reg = codec->read(codec, AD1938_PLL_CLK_CTRL0);
	reg = (cmd > 0) ? reg & (~AD1938_PLL_POWERDOWN) : reg \|
	AD1938_PLL_POWERDOWN;
	codec->write(codec, AD1938_PLL_CLK_CTRL0, reg);

	return 0;
	}

	static int ad1938_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx_mask,
	unsigned int mask, int slots, int width)
	{
	struct snd_soc_codec *codec = dai->codec;
	int dac_reg = codec->read(codec, AD1938_DAC_CTRL1);
	int adc_reg = codec->read(codec, AD1938_ADC_CTRL2);

	dac_reg &= ~AD1938_DAC_CHAN_MASK;
	adc_reg &= ~AD1938_ADC_CHAN_MASK;

	switch (slots) {
	case 2:
	dac_reg \|= AD1938_DAC_2_CHANNELS << AD1938_DAC_CHAN_SHFT;
	adc_reg \|= AD1938_ADC_2_CHANNELS << AD1938_ADC_CHAN_SHFT;
	break;
	case 4:
	dac_reg \|= AD1938_DAC_4_CHANNELS << AD1938_DAC_CHAN_SHFT;
	adc_reg \|= AD1938_ADC_4_CHANNELS << AD1938_ADC_CHAN_SHFT;
	break;
	case 8:
	dac_reg \|= AD1938_DAC_8_CHANNELS << AD1938_DAC_CHAN_SHFT;
	adc_reg \|= AD1938_ADC_8_CHANNELS << AD1938_ADC_CHAN_SHFT;
	break;
	case 16:
	dac_reg \|= AD1938_DAC_16_CHANNELS << AD1938_DAC_CHAN_SHFT;
	adc_reg \|= AD1938_ADC_16_CHANNELS << AD1938_ADC_CHAN_SHFT;
	break;
	default:
	return -EINVAL;
	}

	codec->write(codec, AD1938_DAC_CTRL1, dac_reg);
	codec->write(codec, AD1938_ADC_CTRL2, adc_reg);

	return 0;
	}

	static int ad1938_set_dai_fmt(struct snd_soc_dai *codec_dai,
	unsigned int fmt)
	{
	struct snd_soc_codec *codec = codec_dai->codec;
	int adc_reg, dac_reg;

	adc_reg = codec->read(codec, AD1938_ADC_CTRL2);
	dac_reg = codec->read(codec, AD1938_DAC_CTRL1);

	/* At present, the driver only support AUX ADC mode(SND_SOC_DAIFMT_I2S
	* with TDM) and ADC&DAC TDM mode(SND_SOC_DAIFMT_DSP_A)
	*/
	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
	adc_reg &= ~AD1938_ADC_SERFMT_MASK;
	adc_reg \|= AD1938_ADC_SERFMT_TDM;
	break;
	case SND_SOC_DAIFMT_DSP_A:
	adc_reg &= ~AD1938_ADC_SERFMT_MASK;
	adc_reg \|= AD1938_ADC_SERFMT_AUX;
	break;
	default:
	return -EINVAL;
	}

	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
	case SND_SOC_DAIFMT_NB_NF: /* normal bit clock + frame */
	adc_reg &= ~AD1938_ADC_LEFT_HIGH;
	adc_reg &= ~AD1938_ADC_BCLK_INV;
	dac_reg &= ~AD1938_DAC_LEFT_HIGH;
	dac_reg &= ~AD1938_DAC_BCLK_INV;
	break;
	case SND_SOC_DAIFMT_NB_IF: /* normal bclk + invert frm */
	adc_reg \|= AD1938_ADC_LEFT_HIGH;
	adc_reg &= ~AD1938_ADC_BCLK_INV;
	dac_reg \|= AD1938_DAC_LEFT_HIGH;
	dac_reg &= ~AD1938_DAC_BCLK_INV;
	break;
	case SND_SOC_DAIFMT_IB_NF: /* invert bclk + normal frm */
	adc_reg &= ~AD1938_ADC_LEFT_HIGH;
	adc_reg \|= AD1938_ADC_BCLK_INV;
	dac_reg &= ~AD1938_DAC_LEFT_HIGH;
	dac_reg \|= AD1938_DAC_BCLK_INV;
	break;

	case SND_SOC_DAIFMT_IB_IF: /* invert bclk + frm */
	adc_reg \|= AD1938_ADC_LEFT_HIGH;
	adc_reg \|= AD1938_ADC_BCLK_INV;
	dac_reg \|= AD1938_DAC_LEFT_HIGH;
	dac_reg \|= AD1938_DAC_BCLK_INV;
	break;
	default:
	return -EINVAL;
	}

	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBM_CFM: /* codec clk & frm master */
	adc_reg \|= AD1938_ADC_LCR_MASTER;
	adc_reg \|= AD1938_ADC_BCLK_MASTER;
	dac_reg \|= AD1938_DAC_LCR_MASTER;
	dac_reg \|= AD1938_DAC_BCLK_MASTER;
	break;
	case SND_SOC_DAIFMT_CBS_CFM: /* codec clk slave & frm master */
	adc_reg \|= AD1938_ADC_LCR_MASTER;
	adc_reg &= ~AD1938_ADC_BCLK_MASTER;
	dac_reg \|= AD1938_DAC_LCR_MASTER;
	dac_reg &= ~AD1938_DAC_BCLK_MASTER;
	break;
	case SND_SOC_DAIFMT_CBM_CFS: /* codec clk master & frame slave */
	adc_reg &= ~AD1938_ADC_LCR_MASTER;
	adc_reg \|= AD1938_ADC_BCLK_MASTER;
	dac_reg &= ~AD1938_DAC_LCR_MASTER;
	dac_reg \|= AD1938_DAC_BCLK_MASTER;
	break;
	case SND_SOC_DAIFMT_CBS_CFS: /* codec clk & frm slave */
	adc_reg &= ~AD1938_ADC_LCR_MASTER;
	adc_reg &= ~AD1938_ADC_BCLK_MASTER;
	dac_reg &= ~AD1938_DAC_LCR_MASTER;
	dac_reg &= ~AD1938_DAC_BCLK_MASTER;
	break;
	default:
	return -EINVAL;
	}

	codec->write(codec, AD1938_ADC_CTRL2, adc_reg);
	codec->write(codec, AD1938_DAC_CTRL1, dac_reg);

	return 0;
	}

	static int ad1938_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params,
	struct snd_soc_dai *dai)
	{
	int word_len = 0, reg = 0;

	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct snd_soc_device *socdev = rtd->socdev;
	struct snd_soc_codec *codec = socdev->card->codec;

	/* bit size */
	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S16_LE:
	word_len = 3;
	break;
	case SNDRV_PCM_FORMAT_S20_3LE:
	word_len = 1;
	break;
	case SNDRV_PCM_FORMAT_S24_LE:
	case SNDRV_PCM_FORMAT_S32_LE:
	word_len = 0;
	break;
	}

	reg = codec->read(codec, AD1938_DAC_CTRL2);
	reg = (reg & (~AD1938_DAC_WORD_LEN_MASK)) \| word_len;
	codec->write(codec, AD1938_DAC_CTRL2, reg);

	reg = codec->read(codec, AD1938_ADC_CTRL1);
	reg = (reg & (~AD1938_ADC_WORD_LEN_MASK)) \| word_len;
	codec->write(codec, AD1938_ADC_CTRL1, reg);

	return 0;
	}

	static int ad1938_set_bias_level(struct snd_soc_codec *codec,
	enum snd_soc_bias_level level)
	{
	switch (level) {
	case SND_SOC_BIAS_ON:
	ad1938_pll_powerctrl(codec, 1);
	break;
	case SND_SOC_BIAS_PREPARE:
	break;
	case SND_SOC_BIAS_STANDBY:
	case SND_SOC_BIAS_OFF:
	ad1938_pll_powerctrl(codec, 0);
	break;
	}
	codec->bias_level = level;
	return 0;
	}

	/*
	* interface to read/write ad1938 register
	*/

	#define AD1938_SPI_ADDR 0x4
	#define AD1938_SPI_READ 0x1
	#define AD1938_SPI_BUFLEN 3

	/*
	* write to the ad1938 register space
	*/

	static int ad1938_write_reg(struct snd_soc_codec *codec, unsigned int reg,
	unsigned int value)
	{
	u8 *reg_cache = codec->reg_cache;
	int ret = 0;

	if (value != reg_cache[reg]) {
	uint8_t buf[AD1938_SPI_BUFLEN];
	struct spi_transfer t = {
	.tx_buf = buf,
	.len = AD1938_SPI_BUFLEN,
	};
	struct spi_message m;

	buf[0] = AD1938_SPI_ADDR << 1;
	buf[1] = reg;
	buf[2] = value;
	spi_message_init(&m);
	spi_message_add_tail(&t, &m);
	ret = spi_sync(codec->control_data, &m);
	if (ret == 0)
	reg_cache[reg] = value;
	}

	return ret;
	}

	/*
	* read from the ad1938 register space cache
	*/

	static unsigned int ad1938_read_reg_cache(struct snd_soc_codec *codec,
	unsigned int reg)
	{
	u8 *reg_cache = codec->reg_cache;

	if (reg >= codec->reg_cache_size)
	return -EINVAL;

	return reg_cache[reg];
	}

	/*
	* read from the ad1938 register space
	*/

	static unsigned int ad1938_read_reg(struct snd_soc_codec *codec,
	unsigned int reg)
	{
	char w_buf[AD1938_SPI_BUFLEN];
	char r_buf[AD1938_SPI_BUFLEN];
	int ret;

	struct spi_transfer t = {
	.tx_buf = w_buf,
	.rx_buf = r_buf,
	.len = AD1938_SPI_BUFLEN,
	};
	struct spi_message m;

	w_buf[0] = (AD1938_SPI_ADDR << 1) \| AD1938_SPI_READ;
	w_buf[1] = reg;
	w_buf[2] = 0;

	spi_message_init(&m);
	spi_message_add_tail(&t, &m);
	ret = spi_sync(codec->control_data, &m);
	if (ret == 0)
	return r_buf[2];
	else
	return -EIO;
	}

	static int ad1938_fill_cache(struct snd_soc_codec *codec)
	{
	int i;
	u8 *reg_cache = codec->reg_cache;
	struct spi_device *spi = codec->control_data;

	for (i = 0; i < codec->reg_cache_size; i++) {
	int ret = ad1938_read_reg(codec, i);
	if (ret == -EIO) {
	dev_err(&spi->dev, "AD1938 SPI read failure\n");
	return ret;
	}
	reg_cache[i] = ret;
	}

	return 0;
	}

	static int __devinit ad1938_spi_probe(struct spi_device *spi)
	{
	struct snd_soc_codec *codec;
	struct ad1938_priv *ad1938;

	ad1938 = kzalloc(sizeof(struct ad1938_priv), GFP_KERNEL);
	if (ad1938 == NULL)
	return -ENOMEM;

	codec = &ad1938->codec;
	codec->control_data = spi;
	codec->dev = &spi->dev;

	dev_set_drvdata(&spi->dev, ad1938);

	return ad1938_register(ad1938);
	}

	static int __devexit ad1938_spi_remove(struct spi_device *spi)
	{
	struct ad1938_priv *ad1938 = dev_get_drvdata(&spi->dev);

	ad1938_unregister(ad1938);
	return 0;
	}

	static struct spi_driver ad1938_spi_driver = {
	.driver = {
	.name = "ad1938",
	.owner = THIS_MODULE,
	},
	.probe = ad1938_spi_probe,
	.remove = __devexit_p(ad1938_spi_remove),
	};

	static struct snd_soc_dai_ops ad1938_dai_ops = {
	.hw_params = ad1938_hw_params,
	.digital_mute = ad1938_mute,
	.set_tdm_slot = ad1938_set_tdm_slot,
	.set_fmt = ad1938_set_dai_fmt,
	};

	/* codec DAI instance */
	struct snd_soc_dai ad1938_dai = {
	.name = "AD1938",
	.playback = {
	.stream_name = "Playback",
	.channels_min = 2,
	.channels_max = 8,
	.rates = SNDRV_PCM_RATE_48000,
	.formats = SNDRV_PCM_FMTBIT_S32_LE \| SNDRV_PCM_FMTBIT_S16_LE \|
	SNDRV_PCM_FMTBIT_S20_3LE \| SNDRV_PCM_FMTBIT_S24_LE,
	},
	.capture = {
	.stream_name = "Capture",
	.channels_min = 2,
	.channels_max = 4,
	.rates = SNDRV_PCM_RATE_48000,
	.formats = SNDRV_PCM_FMTBIT_S32_LE \| SNDRV_PCM_FMTBIT_S16_LE \|
	SNDRV_PCM_FMTBIT_S20_3LE \| SNDRV_PCM_FMTBIT_S24_LE,
	},
	.ops = &ad1938_dai_ops,
	};
	EXPORT_SYMBOL_GPL(ad1938_dai);

	static int ad1938_register(struct ad1938_priv *ad1938)
	{
	int ret;
	struct snd_soc_codec *codec = &ad1938->codec;

	if (ad1938_codec) {
	dev_err(codec->dev, "Another ad1938 is registered\n");
	return -EINVAL;
	}

	mutex_init(&codec->mutex);
	INIT_LIST_HEAD(&codec->dapm_widgets);
	INIT_LIST_HEAD(&codec->dapm_paths);
	codec->private_data = ad1938;
	codec->reg_cache = ad1938->reg_cache;
	codec->reg_cache_size = AD1938_NUM_REGS;
	codec->name = "AD1938";
	codec->owner = THIS_MODULE;
	codec->dai = &ad1938_dai;
	codec->num_dai = 1;
	codec->write = ad1938_write_reg;
	codec->read = ad1938_read_reg_cache;
	codec->set_bias_level = ad1938_set_bias_level;
	INIT_LIST_HEAD(&codec->dapm_widgets);
	INIT_LIST_HEAD(&codec->dapm_paths);

	ad1938_dai.dev = codec->dev;
	ad1938_codec = codec;

	/* default setting for ad1938 */

	/* unmute dac channels */
	codec->write(codec, AD1938_DAC_CHNL_MUTE, 0x0);
	/* de-emphasis: 48kHz, powedown dac */
	codec->write(codec, AD1938_DAC_CTRL2, 0x1A);
	/* powerdown dac, dac in tdm mode */
	codec->write(codec, AD1938_DAC_CTRL0, 0x41);
	/* high-pass filter enable */
	codec->write(codec, AD1938_ADC_CTRL0, 0x3);
	/* sata delay=1, adc aux mode */
	codec->write(codec, AD1938_ADC_CTRL1, 0x43);
	/* pll input: mclki/xi */
	codec->write(codec, AD1938_PLL_CLK_CTRL0, 0x9D);
	codec->write(codec, AD1938_PLL_CLK_CTRL1, 0x04);

	ad1938_fill_cache(codec);

	ret = snd_soc_register_codec(codec);
	if (ret != 0) {
	dev_err(codec->dev, "Failed to register codec: %d\n", ret);
	kfree(ad1938);
	return ret;
	}

	ret = snd_soc_register_dai(&ad1938_dai);
	if (ret != 0) {
	dev_err(codec->dev, "Failed to register DAI: %d\n", ret);
	snd_soc_unregister_codec(codec);
	kfree(ad1938);
	return ret;
	}

	return 0;
	}

	static void ad1938_unregister(struct ad1938_priv *ad1938)
	{
	ad1938_set_bias_level(&ad1938->codec, SND_SOC_BIAS_OFF);
	snd_soc_unregister_dai(&ad1938_dai);
	snd_soc_unregister_codec(&ad1938->codec);
	kfree(ad1938);
	ad1938_codec = NULL;
	}

	static int ad1938_probe(struct platform_device *pdev)
	{
	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
	struct snd_soc_codec *codec;
	int ret = 0;

	if (ad1938_codec == NULL) {
	dev_err(&pdev->dev, "Codec device not registered\n");
	return -ENODEV;
	}

	socdev->card->codec = ad1938_codec;
	codec = ad1938_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, ad1938_snd_controls,
	ARRAY_SIZE(ad1938_snd_controls));
	snd_soc_dapm_new_controls(codec, ad1938_dapm_widgets,
	ARRAY_SIZE(ad1938_dapm_widgets));
	snd_soc_dapm_add_routes(codec, audio_paths, ARRAY_SIZE(audio_paths));
	snd_soc_dapm_new_widgets(codec);

	ad1938_set_bias_level(codec, SND_SOC_BIAS_STANDBY);

	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;
	}

	/* power down chip */
	static int ad1938_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;
	}

	#ifdef CONFIG_PM
	static int ad1938_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;

	ad1938_set_bias_level(codec, SND_SOC_BIAS_OFF);
	return 0;
	}

	static int ad1938_resume(struct platform_device *pdev)
	{
	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
	struct snd_soc_codec *codec = socdev->card->codec;

	if (codec->suspend_bias_level == SND_SOC_BIAS_ON)
	ad1938_set_bias_level(codec, SND_SOC_BIAS_ON);

	return 0;
	}
	#else
	#define ad1938_suspend NULL
	#define ad1938_resume NULL
	#endif

	struct snd_soc_codec_device soc_codec_dev_ad1938 = {
	.probe = ad1938_probe,
	.remove = ad1938_remove,
	.suspend = ad1938_suspend,
	.resume = ad1938_resume,
	};
	EXPORT_SYMBOL_GPL(soc_codec_dev_ad1938);

	static int __init ad1938_init(void)
	{
	int ret;

	ret = spi_register_driver(&ad1938_spi_driver);
	if (ret != 0) {
	printk(KERN_ERR "Failed to register ad1938 SPI driver: %d\n",
	ret);
	}

	return ret;
	}
	module_init(ad1938_init);

	static void __exit ad1938_exit(void)
	{
	spi_unregister_driver(&ad1938_spi_driver);
	}
	module_exit(ad1938_exit);

	MODULE_DESCRIPTION("ASoC ad1938 driver");
	MODULE_AUTHOR("Barry Song ");
	MODULE_LICENSE("GPL");