ASoC: new ad1938 codec driver based on asoc

Signed-off-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 652 insertions, 0 deletions

diff --git a/sound/soc/codecs/ad1938.c b/sound/soc/codecs/ad1938.c
new file mode 100644
index 00000000000..3dc80910318
--- /dev/null
+++ b/sound/soc/codecs/ad1938.c
@@ -0,0 +1,652 @@
+/*
+ * 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/version.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),
+};
+
+static const struct snd_soc_dapm_route audio_paths[] = {
+	{ "DAC", NULL, "ADC_PWR" },
+	{ "ADC", NULL, "ADC_PWR" },
+};
+
+/*
+ * 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 mask, int slots)
+{
+	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);
+		if((ret = spi_sync(codec->control_data, &m)) == 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;
+
+	spi->dev.driver_data = ad1938;
+
+	return ad1938_register(ad1938);
+}
+
+static int __devexit ad1938_spi_remove(struct spi_device *spi)
+{
+	struct ad1938_priv *ad1938 = spi->dev.driver_data;
+
+	ad1938_unregister(ad1938);
+	return 0;
+}
+
+static struct spi_driver ad1938_spi_driver = {
+	.driver = {
+		.name	= "ad1938-spi",
+		.bus	= &spi_bus_type,
+		.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;
+	INIT_LIST_HEAD(&codec->dapm_widgets);
+	INIT_LIST_HEAD(&codec->dapm_paths);
+
+        ad1938_dai.dev = codec->dev;
+        ad1938_codec = codec;
+
+	/* default setting for ad1938 */
+	codec->write(codec, AD1938_DAC_CHNL_MUTE, 0x0); /* unmute dac channels */
+	codec->write(codec, AD1938_DAC_CTRL2, 0x1A); /* de-emphasis: 48kHz, powedown dac */
+	codec->write(codec, AD1938_DAC_CTRL0, 0x21); /* powerdown dac, dac tdm mode */
+	codec->write(codec, AD1938_ADC_CTRL0, 0x3); /* high-pass filter enable */
+	codec->write(codec, AD1938_ADC_CTRL1, 0x43); /* sata delay=1, adc aux mode */
+	codec->write(codec, AD1938_PLL_CLK_CTRL0, 0x9D); /* pll input:mclki/xi */
+	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);
+                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);
+                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");