sound/soc/codecs/ad1938.c

   1 /*
   2  * File:         sound/soc/codecs/ad1938.c
   3  * Author:       Barry Song <Barry.Song@analog.com>
   4  *
   5  * Created:      June 04 2009
   6  * Description:  Driver for AD1938 sound chip
   7  *
   8  * Modified:
   9  *               Copyright 2009 Analog Devices Inc.
  10  *
  11  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, see the file COPYING, or write
  25  * to the Free Software Foundation, Inc.,
  26  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  27  */
  28
  29 #include <linux/init.h>
  30 #include <linux/slab.h>
  31 #include <linux/module.h>
  32 #include <linux/kernel.h>
  33 #include <linux/device.h>
  34 #include <sound/core.h>
  35 #include <sound/pcm.h>
  36 #include <sound/pcm_params.h>
  37 #include <sound/initval.h>
  38 #include <sound/soc.h>
  39 #include <sound/tlv.h>
  40 #include <sound/soc-dapm.h>
  41 #include <linux/spi/spi.h>
  42 #include "ad1938.h"
  43
  44 /* codec private data */
  45 struct ad1938_priv {
  46         struct snd_soc_codec codec;
  47         u8 reg_cache[AD1938_NUM_REGS];
  48 };
  49
  50 /* ad1938 register cache & default register settings */
  51 static const u8 ad1938_reg[AD1938_NUM_REGS] = {
  52         0, 0, 0, 0, 0, 0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0,
  53 };
  54
  55 static struct snd_soc_codec *ad1938_codec;
  56 struct snd_soc_codec_device soc_codec_dev_ad1938;
  57 static int ad1938_register(struct ad1938_priv *ad1938);
  58 static void ad1938_unregister(struct ad1938_priv *ad1938);
  59
  60 /*
  61  * AD1938 volume/mute/de-emphasis etc. controls
  62  */
  63 static const char *ad1938_deemp[] = {"None", "48kHz", "44.1kHz", "32kHz"};
  64
  65 static const struct soc_enum ad1938_deemp_enum =
  66         SOC_ENUM_SINGLE(AD1938_DAC_CTRL2, 1, 4, ad1938_deemp);
  67
  68 static const struct snd_kcontrol_new ad1938_snd_controls[] = {
  69         /* DAC volume control */
  70         SOC_DOUBLE_R("DAC1  Volume", AD1938_DAC_L1_VOL,
  71                         AD1938_DAC_R1_VOL, 0, 0xFF, 1),
  72         SOC_DOUBLE_R("DAC2  Volume", AD1938_DAC_L2_VOL,
  73                         AD1938_DAC_R2_VOL, 0, 0xFF, 1),
  74         SOC_DOUBLE_R("DAC3  Volume", AD1938_DAC_L3_VOL,
  75                         AD1938_DAC_R3_VOL, 0, 0xFF, 1),
  76         SOC_DOUBLE_R("DAC4  Volume", AD1938_DAC_L4_VOL,
  77                         AD1938_DAC_R4_VOL, 0, 0xFF, 1),
  78
  79         /* ADC switch control */
  80         SOC_DOUBLE("ADC1 Switch", AD1938_ADC_CTRL0, AD1938_ADCL1_MUTE,
  81                 AD1938_ADCR1_MUTE, 1, 1),
  82         SOC_DOUBLE("ADC2 Switch", AD1938_ADC_CTRL0, AD1938_ADCL2_MUTE,
  83                 AD1938_ADCR2_MUTE, 1, 1),
  84
  85         /* DAC switch control */
  86         SOC_DOUBLE("DAC1 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL1_MUTE,
  87                 AD1938_DACR1_MUTE, 1, 1),
  88         SOC_DOUBLE("DAC2 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL2_MUTE,
  89                 AD1938_DACR2_MUTE, 1, 1),
  90         SOC_DOUBLE("DAC3 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL3_MUTE,
  91                 AD1938_DACR3_MUTE, 1, 1),
  92         SOC_DOUBLE("DAC4 Switch", AD1938_DAC_CHNL_MUTE, AD1938_DACL4_MUTE,
  93                 AD1938_DACR4_MUTE, 1, 1),
  94
  95         /* ADC high-pass filter */
  96         SOC_SINGLE("ADC High Pass Filter Switch", AD1938_ADC_CTRL0,
  97                         AD1938_ADC_HIGHPASS_FILTER, 1, 0),
  98
  99         /* DAC de-emphasis */
 100         SOC_ENUM("Playback Deemphasis", ad1938_deemp_enum),
 101 };
 102
 103 static const struct snd_soc_dapm_widget ad1938_dapm_widgets[] = {
 104         SND_SOC_DAPM_DAC("DAC", "Playback", AD1938_DAC_CTRL0, 0, 1),
 105         SND_SOC_DAPM_ADC("ADC", "Capture", SND_SOC_NOPM, 0, 0),
 106         SND_SOC_DAPM_SUPPLY("PLL_PWR", AD1938_PLL_CLK_CTRL0, 0, 1, NULL, 0),
 107         SND_SOC_DAPM_SUPPLY("ADC_PWR", AD1938_ADC_CTRL0, 0, 1, NULL, 0),
 108         SND_SOC_DAPM_OUTPUT("DAC1OUT"),
 109         SND_SOC_DAPM_OUTPUT("DAC2OUT"),
 110         SND_SOC_DAPM_OUTPUT("DAC3OUT"),
 111         SND_SOC_DAPM_OUTPUT("DAC4OUT"),
 112         SND_SOC_DAPM_INPUT("ADC1IN"),
 113         SND_SOC_DAPM_INPUT("ADC2IN"),
 114 };
 115
 116 static const struct snd_soc_dapm_route audio_paths[] = {
 117         { "DAC", NULL, "PLL_PWR" },
 118         { "ADC", NULL, "PLL_PWR" },
 119         { "DAC", NULL, "ADC_PWR" },
 120         { "ADC", NULL, "ADC_PWR" },
 121         { "DAC1OUT", "DAC1 Switch", "DAC" },
 122         { "DAC2OUT", "DAC2 Switch", "DAC" },
 123         { "DAC3OUT", "DAC3 Switch", "DAC" },
 124         { "DAC4OUT", "DAC4 Switch", "DAC" },
 125         { "ADC", "ADC1 Switch", "ADC1IN" },
 126         { "ADC", "ADC2 Switch", "ADC2IN" },
 127 };
 128
 129 /*
 130  * DAI ops entries
 131  */
 132
 133 static int ad1938_mute(struct snd_soc_dai *dai, int mute)
 134 {
 135         struct snd_soc_codec *codec = dai->codec;
 136         int reg;
 137
 138         reg = snd_soc_read(codec, AD1938_DAC_CTRL2);
 139         reg = (mute > 0) ? reg | AD1938_DAC_MASTER_MUTE : reg &
 140                 (~AD1938_DAC_MASTER_MUTE);
 141         snd_soc_write(codec, AD1938_DAC_CTRL2, reg);
 142
 143         return 0;
 144 }
 145
 146 static int ad1938_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx_mask,
 147                                unsigned int rx_mask, int slots, int width)
 148 {
 149         struct snd_soc_codec *codec = dai->codec;
 150         int dac_reg = snd_soc_read(codec, AD1938_DAC_CTRL1);
 151         int adc_reg = snd_soc_read(codec, AD1938_ADC_CTRL2);
 152
 153         dac_reg &= ~AD1938_DAC_CHAN_MASK;
 154         adc_reg &= ~AD1938_ADC_CHAN_MASK;
 155
 156         switch (slots) {
 157         case 2:
 158                 dac_reg |= AD1938_DAC_2_CHANNELS << AD1938_DAC_CHAN_SHFT;
 159                 adc_reg |= AD1938_ADC_2_CHANNELS << AD1938_ADC_CHAN_SHFT;
 160                 break;
 161         case 4:
 162                 dac_reg |= AD1938_DAC_4_CHANNELS << AD1938_DAC_CHAN_SHFT;
 163                 adc_reg |= AD1938_ADC_4_CHANNELS << AD1938_ADC_CHAN_SHFT;
 164                 break;
 165         case 8:
 166                 dac_reg |= AD1938_DAC_8_CHANNELS << AD1938_DAC_CHAN_SHFT;
 167                 adc_reg |= AD1938_ADC_8_CHANNELS << AD1938_ADC_CHAN_SHFT;
 168                 break;
 169         case 16:
 170                 dac_reg |= AD1938_DAC_16_CHANNELS << AD1938_DAC_CHAN_SHFT;
 171                 adc_reg |= AD1938_ADC_16_CHANNELS << AD1938_ADC_CHAN_SHFT;
 172                 break;
 173         default:
 174                 return -EINVAL;
 175         }
 176
 177         snd_soc_write(codec, AD1938_DAC_CTRL1, dac_reg);
 178         snd_soc_write(codec, AD1938_ADC_CTRL2, adc_reg);
 179
 180         return 0;
 181 }
 182
 183 static int ad1938_set_dai_fmt(struct snd_soc_dai *codec_dai,
 184                 unsigned int fmt)
 185 {
 186         struct snd_soc_codec *codec = codec_dai->codec;
 187         int adc_reg, dac_reg;
 188
 189         adc_reg = snd_soc_read(codec, AD1938_ADC_CTRL2);
 190         dac_reg = snd_soc_read(codec, AD1938_DAC_CTRL1);
 191
 192         /* At present, the driver only support AUX ADC mode(SND_SOC_DAIFMT_I2S
 193          * with TDM) and ADC&DAC TDM mode(SND_SOC_DAIFMT_DSP_A)
 194          */
 195         switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
 196         case SND_SOC_DAIFMT_I2S:
 197                 adc_reg &= ~AD1938_ADC_SERFMT_MASK;
 198                 adc_reg |= AD1938_ADC_SERFMT_TDM;
 199                 break;
 200         case SND_SOC_DAIFMT_DSP_A:
 201                 adc_reg &= ~AD1938_ADC_SERFMT_MASK;
 202                 adc_reg |= AD1938_ADC_SERFMT_AUX;
 203                 break;
 204         default:
 205                 return -EINVAL;
 206         }
 207
 208         switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
 209         case SND_SOC_DAIFMT_NB_NF: /* normal bit clock + frame */
 210                 adc_reg &= ~AD1938_ADC_LEFT_HIGH;
 211                 adc_reg &= ~AD1938_ADC_BCLK_INV;
 212                 dac_reg &= ~AD1938_DAC_LEFT_HIGH;
 213                 dac_reg &= ~AD1938_DAC_BCLK_INV;
 214                 break;
 215         case SND_SOC_DAIFMT_NB_IF: /* normal bclk + invert frm */
 216                 adc_reg |= AD1938_ADC_LEFT_HIGH;
 217                 adc_reg &= ~AD1938_ADC_BCLK_INV;
 218                 dac_reg |= AD1938_DAC_LEFT_HIGH;
 219                 dac_reg &= ~AD1938_DAC_BCLK_INV;
 220                 break;
 221         case SND_SOC_DAIFMT_IB_NF: /* invert bclk + normal frm */
 222                 adc_reg &= ~AD1938_ADC_LEFT_HIGH;
 223                 adc_reg |= AD1938_ADC_BCLK_INV;
 224                 dac_reg &= ~AD1938_DAC_LEFT_HIGH;
 225                 dac_reg |= AD1938_DAC_BCLK_INV;
 226                 break;
 227
 228         case SND_SOC_DAIFMT_IB_IF: /* invert bclk + frm */
 229                 adc_reg |= AD1938_ADC_LEFT_HIGH;
 230                 adc_reg |= AD1938_ADC_BCLK_INV;
 231                 dac_reg |= AD1938_DAC_LEFT_HIGH;
 232                 dac_reg |= AD1938_DAC_BCLK_INV;
 233                 break;
 234         default:
 235                 return -EINVAL;
 236         }
 237
 238         switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 239         case SND_SOC_DAIFMT_CBM_CFM: /* codec clk & frm master */
 240                 adc_reg |= AD1938_ADC_LCR_MASTER;
 241                 adc_reg |= AD1938_ADC_BCLK_MASTER;
 242                 dac_reg |= AD1938_DAC_LCR_MASTER;
 243                 dac_reg |= AD1938_DAC_BCLK_MASTER;
 244                 break;
 245         case SND_SOC_DAIFMT_CBS_CFM: /* codec clk slave & frm master */
 246                 adc_reg |= AD1938_ADC_LCR_MASTER;
 247                 adc_reg &= ~AD1938_ADC_BCLK_MASTER;
 248                 dac_reg |= AD1938_DAC_LCR_MASTER;
 249                 dac_reg &= ~AD1938_DAC_BCLK_MASTER;
 250                 break;
 251         case SND_SOC_DAIFMT_CBM_CFS: /* codec clk master & frame slave */
 252                 adc_reg &= ~AD1938_ADC_LCR_MASTER;
 253                 adc_reg |= AD1938_ADC_BCLK_MASTER;
 254                 dac_reg &= ~AD1938_DAC_LCR_MASTER;
 255                 dac_reg |= AD1938_DAC_BCLK_MASTER;
 256                 break;
 257         case SND_SOC_DAIFMT_CBS_CFS: /* codec clk & frm slave */
 258                 adc_reg &= ~AD1938_ADC_LCR_MASTER;
 259                 adc_reg &= ~AD1938_ADC_BCLK_MASTER;
 260                 dac_reg &= ~AD1938_DAC_LCR_MASTER;
 261                 dac_reg &= ~AD1938_DAC_BCLK_MASTER;
 262                 break;
 263         default:
 264                 return -EINVAL;
 265         }
 266
 267         snd_soc_write(codec, AD1938_ADC_CTRL2, adc_reg);
 268         snd_soc_write(codec, AD1938_DAC_CTRL1, dac_reg);
 269
 270         return 0;
 271 }
 272
 273 static int ad1938_hw_params(struct snd_pcm_substream *substream,
 274                 struct snd_pcm_hw_params *params,
 275                 struct snd_soc_dai *dai)
 276 {
 277         int word_len = 0, reg = 0;
 278
 279         struct snd_soc_pcm_runtime *rtd = substream->private_data;
 280         struct snd_soc_device *socdev = rtd->socdev;
 281         struct snd_soc_codec *codec = socdev->card->codec;
 282
 283         /* bit size */
 284         switch (params_format(params)) {
 285         case SNDRV_PCM_FORMAT_S16_LE:
 286                 word_len = 3;
 287                 break;
 288         case SNDRV_PCM_FORMAT_S20_3LE:
 289                 word_len = 1;
 290                 break;
 291         case SNDRV_PCM_FORMAT_S24_LE:
 292         case SNDRV_PCM_FORMAT_S32_LE:
 293                 word_len = 0;
 294                 break;
 295         }
 296
 297         reg = snd_soc_read(codec, AD1938_DAC_CTRL2);
 298         reg = (reg & (~AD1938_DAC_WORD_LEN_MASK)) | word_len;
 299         snd_soc_write(codec, AD1938_DAC_CTRL2, reg);
 300
 301         reg = snd_soc_read(codec, AD1938_ADC_CTRL1);
 302         reg = (reg & (~AD1938_ADC_WORD_LEN_MASK)) | word_len;
 303         snd_soc_write(codec, AD1938_ADC_CTRL1, reg);
 304
 305         return 0;
 306 }
 307
 308 static int __devinit ad1938_spi_probe(struct spi_device *spi)
 309 {
 310         struct snd_soc_codec *codec;
 311         struct ad1938_priv *ad1938;
 312
 313         ad1938 = kzalloc(sizeof(struct ad1938_priv), GFP_KERNEL);
 314         if (ad1938 == NULL)
 315                 return -ENOMEM;
 316
 317         codec = &ad1938->codec;
 318         codec->control_data = spi;
 319         codec->dev = &spi->dev;
 320
 321         dev_set_drvdata(&spi->dev, ad1938);
 322
 323         return ad1938_register(ad1938);
 324 }
 325
 326 static int __devexit ad1938_spi_remove(struct spi_device *spi)
 327 {
 328         struct ad1938_priv *ad1938 = dev_get_drvdata(&spi->dev);
 329
 330         ad1938_unregister(ad1938);
 331         return 0;
 332 }
 333
 334 static struct spi_driver ad1938_spi_driver = {
 335         .driver = {
 336                 .name   = "ad1938",
 337                 .owner  = THIS_MODULE,
 338         },
 339         .probe          = ad1938_spi_probe,
 340         .remove         = __devexit_p(ad1938_spi_remove),
 341 };
 342
 343 static struct snd_soc_dai_ops ad1938_dai_ops = {
 344         .hw_params = ad1938_hw_params,
 345         .digital_mute = ad1938_mute,
 346         .set_tdm_slot = ad1938_set_tdm_slot,
 347         .set_fmt = ad1938_set_dai_fmt,
 348 };
 349
 350 /* codec DAI instance */
 351 struct snd_soc_dai ad1938_dai = {
 352         .name = "AD1938",
 353         .playback = {
 354                 .stream_name = "Playback",
 355                 .channels_min = 2,
 356                 .channels_max = 8,
 357                 .rates = SNDRV_PCM_RATE_48000,
 358                 .formats = SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S16_LE |
 359                         SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S24_LE,
 360         },
 361         .capture = {
 362                 .stream_name = "Capture",
 363                 .channels_min = 2,
 364                 .channels_max = 4,
 365                 .rates = SNDRV_PCM_RATE_48000,
 366                 .formats = SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S16_LE |
 367                         SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S24_LE,
 368         },
 369         .ops = &ad1938_dai_ops,
 370 };
 371 EXPORT_SYMBOL_GPL(ad1938_dai);
 372
 373 static int ad1938_register(struct ad1938_priv *ad1938)
 374 {
 375         int ret;
 376         struct snd_soc_codec *codec = &ad1938->codec;
 377
 378         if (ad1938_codec) {
 379                 dev_err(codec->dev, "Another ad1938 is registered\n");
 380                 return -EINVAL;
 381         }
 382
 383         mutex_init(&codec->mutex);
 384         INIT_LIST_HEAD(&codec->dapm_widgets);
 385         INIT_LIST_HEAD(&codec->dapm_paths);
 386         codec->private_data = ad1938;
 387         codec->reg_cache = ad1938->reg_cache;
 388         codec->reg_cache_size = AD1938_NUM_REGS;
 389         codec->name = "AD1938";
 390         codec->owner = THIS_MODULE;
 391         codec->dai = &ad1938_dai;
 392         codec->num_dai = 1;
 393         INIT_LIST_HEAD(&codec->dapm_widgets);
 394         INIT_LIST_HEAD(&codec->dapm_paths);
 395
 396         ad1938_dai.dev = codec->dev;
 397         ad1938_codec = codec;
 398
 399         memcpy(codec->reg_cache, ad1938_reg, AD1938_NUM_REGS);
 400
 401         ret = snd_soc_codec_set_cache_io(codec, 16, 8, SND_SOC_SPI);
 402         if (ret < 0) {
 403                 dev_err(codec->dev, "failed to set cache I/O: %d\n",
 404                                 ret);
 405                 kfree(ad1938);
 406                 return ret;
 407         }
 408
 409         /* default setting for ad1938 */
 410
 411         /* unmute dac channels */
 412         snd_soc_write(codec, AD1938_DAC_CHNL_MUTE, 0x0);
 413         /* de-emphasis: 48kHz, powedown dac */
 414         snd_soc_write(codec, AD1938_DAC_CTRL2, 0x1A);
 415         /* powerdown dac, dac in tdm mode */
 416         snd_soc_write(codec, AD1938_DAC_CTRL0, 0x41);
 417         /* high-pass filter enable */
 418         snd_soc_write(codec, AD1938_ADC_CTRL0, 0x3);
 419         /* sata delay=1, adc aux mode */
 420         snd_soc_write(codec, AD1938_ADC_CTRL1, 0x43);
 421         /* pll input: mclki/xi */
 422         snd_soc_write(codec, AD1938_PLL_CLK_CTRL0, 0x9D);
 423         snd_soc_write(codec, AD1938_PLL_CLK_CTRL1, 0x04);
 424
 425         ret = snd_soc_register_codec(codec);
 426         if (ret != 0) {
 427                 dev_err(codec->dev, "Failed to register codec: %d\n", ret);
 428                 kfree(ad1938);
 429                 return ret;
 430         }
 431
 432         ret = snd_soc_register_dai(&ad1938_dai);
 433         if (ret != 0) {
 434                 dev_err(codec->dev, "Failed to register DAI: %d\n", ret);
 435                 snd_soc_unregister_codec(codec);
 436                 kfree(ad1938);
 437                 return ret;
 438         }
 439
 440         return 0;
 441 }
 442
 443 static void ad1938_unregister(struct ad1938_priv *ad1938)
 444 {
 445         snd_soc_unregister_dai(&ad1938_dai);
 446         snd_soc_unregister_codec(&ad1938->codec);
 447         kfree(ad1938);
 448         ad1938_codec = NULL;
 449 }
 450
 451 static int ad1938_probe(struct platform_device *pdev)
 452 {
 453         struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 454         struct snd_soc_codec *codec;
 455         int ret = 0;
 456
 457         if (ad1938_codec == NULL) {
 458                 dev_err(&pdev->dev, "Codec device not registered\n");
 459                 return -ENODEV;
 460         }
 461
 462         socdev->card->codec = ad1938_codec;
 463         codec = ad1938_codec;
 464
 465         /* register pcms */
 466         ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
 467         if (ret < 0) {
 468                 dev_err(codec->dev, "failed to create pcms: %d\n", ret);
 469                 goto pcm_err;
 470         }
 471
 472         snd_soc_add_controls(codec, ad1938_snd_controls,
 473                              ARRAY_SIZE(ad1938_snd_controls));
 474         snd_soc_dapm_new_controls(codec, ad1938_dapm_widgets,
 475                                   ARRAY_SIZE(ad1938_dapm_widgets));
 476         snd_soc_dapm_add_routes(codec, audio_paths, ARRAY_SIZE(audio_paths));
 477
 478
 479 pcm_err:
 480         return ret;
 481 }
 482
 483 /* power down chip */
 484 static int ad1938_remove(struct platform_device *pdev)
 485 {
 486         struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 487
 488         snd_soc_free_pcms(socdev);
 489         snd_soc_dapm_free(socdev);
 490
 491         return 0;
 492 }
 493
 494 struct snd_soc_codec_device soc_codec_dev_ad1938 = {
 495         .probe =        ad1938_probe,
 496         .remove =       ad1938_remove,
 497 };
 498 EXPORT_SYMBOL_GPL(soc_codec_dev_ad1938);
 499
 500 static int __init ad1938_init(void)
 501 {
 502         int ret;
 503
 504         ret = spi_register_driver(&ad1938_spi_driver);
 505         if (ret != 0) {
 506                 printk(KERN_ERR "Failed to register ad1938 SPI driver: %d\n",
 507                                 ret);
 508         }
 509
 510         return ret;
 511 }
 512 module_init(ad1938_init);
 513
 514 static void __exit ad1938_exit(void)
 515 {
 516         spi_unregister_driver(&ad1938_spi_driver);
 517 }
 518 module_exit(ad1938_exit);
 519
 520 MODULE_DESCRIPTION("ASoC ad1938 driver");
 521 MODULE_AUTHOR("Barry Song ");
 522 MODULE_LICENSE("GPL");