sound/soc/codecs/cs4270.c

   1 /*
   2  * CS4270 ALSA SoC (ASoC) codec driver
   3  *
   4  * Author: Timur Tabi <timur@freescale.com>
   5  *
   6  * Copyright 2007-2009 Freescale Semiconductor, Inc.  This file is licensed
   7  * under the terms of the GNU General Public License version 2.  This
   8  * program is licensed "as is" without any warranty of any kind, whether
   9  * express or implied.
  10  *
  11  * This is an ASoC device driver for the Cirrus Logic CS4270 codec.
  12  *
  13  * Current features/limitations:
  14  *
  15  * - Software mode is supported.  Stand-alone mode is not supported.
  16  * - Only I2C is supported, not SPI
  17  * - Support for master and slave mode
  18  * - The machine driver's 'startup' function must call
  19  *   cs4270_set_dai_sysclk() with the value of MCLK.
  20  * - Only I2S and left-justified modes are supported
  21  * - Power management is supported
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <sound/core.h>
  27 #include <sound/soc.h>
  28 #include <sound/initval.h>
  29 #include <linux/i2c.h>
  30 #include <linux/delay.h>
  31
  32 #include "cs4270.h"
  33
  34 /*
  35  * The codec isn't really big-endian or little-endian, since the I2S
  36  * interface requires data to be sent serially with the MSbit first.
  37  * However, to support BE and LE I2S devices, we specify both here.  That
  38  * way, ALSA will always match the bit patterns.
  39  */
  40 #define CS4270_FORMATS (SNDRV_PCM_FMTBIT_S8      | \
  41                         SNDRV_PCM_FMTBIT_S16_LE  | SNDRV_PCM_FMTBIT_S16_BE  | \
  42                         SNDRV_PCM_FMTBIT_S18_3LE | SNDRV_PCM_FMTBIT_S18_3BE | \
  43                         SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S20_3BE | \
  44                         SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | \
  45                         SNDRV_PCM_FMTBIT_S24_LE  | SNDRV_PCM_FMTBIT_S24_BE)
  46
  47 /* CS4270 registers addresses */
  48 #define CS4270_CHIPID   0x01    /* Chip ID */
  49 #define CS4270_PWRCTL   0x02    /* Power Control */
  50 #define CS4270_MODE     0x03    /* Mode Control */
  51 #define CS4270_FORMAT   0x04    /* Serial Format, ADC/DAC Control */
  52 #define CS4270_TRANS    0x05    /* Transition Control */
  53 #define CS4270_MUTE     0x06    /* Mute Control */
  54 #define CS4270_VOLA     0x07    /* DAC Channel A Volume Control */
  55 #define CS4270_VOLB     0x08    /* DAC Channel B Volume Control */
  56
  57 #define CS4270_FIRSTREG 0x01
  58 #define CS4270_LASTREG  0x08
  59 #define CS4270_NUMREGS  (CS4270_LASTREG - CS4270_FIRSTREG + 1)
  60 #define CS4270_I2C_INCR 0x80
  61
  62 /* Bit masks for the CS4270 registers */
  63 #define CS4270_CHIPID_ID        0xF0
  64 #define CS4270_CHIPID_REV       0x0F
  65 #define CS4270_PWRCTL_FREEZE    0x80
  66 #define CS4270_PWRCTL_PDN_ADC   0x20
  67 #define CS4270_PWRCTL_PDN_DAC   0x02
  68 #define CS4270_PWRCTL_PDN       0x01
  69 #define CS4270_PWRCTL_PDN_ALL   \
  70         (CS4270_PWRCTL_PDN_ADC | CS4270_PWRCTL_PDN_DAC | CS4270_PWRCTL_PDN)
  71 #define CS4270_MODE_SPEED_MASK  0x30
  72 #define CS4270_MODE_1X          0x00
  73 #define CS4270_MODE_2X          0x10
  74 #define CS4270_MODE_4X          0x20
  75 #define CS4270_MODE_SLAVE       0x30
  76 #define CS4270_MODE_DIV_MASK    0x0E
  77 #define CS4270_MODE_DIV1        0x00
  78 #define CS4270_MODE_DIV15       0x02
  79 #define CS4270_MODE_DIV2        0x04
  80 #define CS4270_MODE_DIV3        0x06
  81 #define CS4270_MODE_DIV4        0x08
  82 #define CS4270_MODE_POPGUARD    0x01
  83 #define CS4270_FORMAT_FREEZE_A  0x80
  84 #define CS4270_FORMAT_FREEZE_B  0x40
  85 #define CS4270_FORMAT_LOOPBACK  0x20
  86 #define CS4270_FORMAT_DAC_MASK  0x18
  87 #define CS4270_FORMAT_DAC_LJ    0x00
  88 #define CS4270_FORMAT_DAC_I2S   0x08
  89 #define CS4270_FORMAT_DAC_RJ16  0x18
  90 #define CS4270_FORMAT_DAC_RJ24  0x10
  91 #define CS4270_FORMAT_ADC_MASK  0x01
  92 #define CS4270_FORMAT_ADC_LJ    0x00
  93 #define CS4270_FORMAT_ADC_I2S   0x01
  94 #define CS4270_TRANS_ONE_VOL    0x80
  95 #define CS4270_TRANS_SOFT       0x40
  96 #define CS4270_TRANS_ZERO       0x20
  97 #define CS4270_TRANS_INV_ADC_A  0x08
  98 #define CS4270_TRANS_INV_ADC_B  0x10
  99 #define CS4270_TRANS_INV_DAC_A  0x02
 100 #define CS4270_TRANS_INV_DAC_B  0x04
 101 #define CS4270_TRANS_DEEMPH     0x01
 102 #define CS4270_MUTE_AUTO        0x20
 103 #define CS4270_MUTE_ADC_A       0x08
 104 #define CS4270_MUTE_ADC_B       0x10
 105 #define CS4270_MUTE_POLARITY    0x04
 106 #define CS4270_MUTE_DAC_A       0x01
 107 #define CS4270_MUTE_DAC_B       0x02
 108
 109 /* Private data for the CS4270 */
 110 struct cs4270_private {
 111         struct snd_soc_codec codec;
 112         u8 reg_cache[CS4270_NUMREGS];
 113         unsigned int mclk; /* Input frequency of the MCLK pin */
 114         unsigned int mode; /* The mode (I2S or left-justified) */
 115         unsigned int slave_mode;
 116         unsigned int manual_mute;
 117 };
 118
 119 /**
 120  * struct cs4270_mode_ratios - clock ratio tables
 121  * @ratio: the ratio of MCLK to the sample rate
 122  * @speed_mode: the Speed Mode bits to set in the Mode Control register for
 123  *              this ratio
 124  * @mclk: the Ratio Select bits to set in the Mode Control register for this
 125  *        ratio
 126  *
 127  * The data for this chart is taken from Table 5 of the CS4270 reference
 128  * manual.
 129  *
 130  * This table is used to determine how to program the Mode Control register.
 131  * It is also used by cs4270_set_dai_sysclk() to tell ALSA which sampling
 132  * rates the CS4270 currently supports.
 133  *
 134  * @speed_mode is the corresponding bit pattern to be written to the
 135  * MODE bits of the Mode Control Register
 136  *
 137  * @mclk is the corresponding bit pattern to be wirten to the MCLK bits of
 138  * the Mode Control Register.
 139  *
 140  * In situations where a single ratio is represented by multiple speed
 141  * modes, we favor the slowest speed.  E.g, for a ratio of 128, we pick
 142  * double-speed instead of quad-speed.  However, the CS4270 errata states
 143  * that divide-By-1.5 can cause failures, so we avoid that mode where
 144  * possible.
 145  *
 146  * Errata: There is an errata for the CS4270 where divide-by-1.5 does not
 147  * work if Vd is 3.3V.  If this effects you, select the
 148  * CONFIG_SND_SOC_CS4270_VD33_ERRATA Kconfig option, and the driver will
 149  * never select any sample rates that require divide-by-1.5.
 150  */
 151 struct cs4270_mode_ratios {
 152         unsigned int ratio;
 153         u8 speed_mode;
 154         u8 mclk;
 155 };
 156
 157 static struct cs4270_mode_ratios cs4270_mode_ratios[] = {
 158         {64, CS4270_MODE_4X, CS4270_MODE_DIV1},
 159 #ifndef CONFIG_SND_SOC_CS4270_VD33_ERRATA
 160         {96, CS4270_MODE_4X, CS4270_MODE_DIV15},
 161 #endif
 162         {128, CS4270_MODE_2X, CS4270_MODE_DIV1},
 163         {192, CS4270_MODE_4X, CS4270_MODE_DIV3},
 164         {256, CS4270_MODE_1X, CS4270_MODE_DIV1},
 165         {384, CS4270_MODE_2X, CS4270_MODE_DIV3},
 166         {512, CS4270_MODE_1X, CS4270_MODE_DIV2},
 167         {768, CS4270_MODE_1X, CS4270_MODE_DIV3},
 168         {1024, CS4270_MODE_1X, CS4270_MODE_DIV4}
 169 };
 170
 171 /* The number of MCLK/LRCK ratios supported by the CS4270 */
 172 #define NUM_MCLK_RATIOS         ARRAY_SIZE(cs4270_mode_ratios)
 173
 174 /**
 175  * cs4270_set_dai_sysclk - determine the CS4270 samples rates.
 176  * @codec_dai: the codec DAI
 177  * @clk_id: the clock ID (ignored)
 178  * @freq: the MCLK input frequency
 179  * @dir: the clock direction (ignored)
 180  *
 181  * This function is used to tell the codec driver what the input MCLK
 182  * frequency is.
 183  *
 184  * The value of MCLK is used to determine which sample rates are supported
 185  * by the CS4270.  The ratio of MCLK / Fs must be equal to one of nine
 186  * supported values - 64, 96, 128, 192, 256, 384, 512, 768, and 1024.
 187  *
 188  * This function calculates the nine ratios and determines which ones match
 189  * a standard sample rate.  If there's a match, then it is added to the list
 190  * of supported sample rates.
 191  *
 192  * This function must be called by the machine driver's 'startup' function,
 193  * otherwise the list of supported sample rates will not be available in
 194  * time for ALSA.
 195  */
 196 static int cs4270_set_dai_sysclk(struct snd_soc_dai *codec_dai,
 197                                  int clk_id, unsigned int freq, int dir)
 198 {
 199         struct snd_soc_codec *codec = codec_dai->codec;
 200         struct cs4270_private *cs4270 = codec->private_data;
 201         unsigned int rates = 0;
 202         unsigned int rate_min = -1;
 203         unsigned int rate_max = 0;
 204         unsigned int i;
 205
 206         cs4270->mclk = freq;
 207
 208         for (i = 0; i < NUM_MCLK_RATIOS; i++) {
 209                 unsigned int rate = freq / cs4270_mode_ratios[i].ratio;
 210                 rates |= snd_pcm_rate_to_rate_bit(rate);
 211                 if (rate < rate_min)
 212                         rate_min = rate;
 213                 if (rate > rate_max)
 214                         rate_max = rate;
 215         }
 216         /* FIXME: soc should support a rate list */
 217         rates &= ~SNDRV_PCM_RATE_KNOT;
 218
 219         if (!rates) {
 220                 dev_err(codec->dev, "could not find a valid sample rate\n");
 221                 return -EINVAL;
 222         }
 223
 224         codec_dai->playback.rates = rates;
 225         codec_dai->playback.rate_min = rate_min;
 226         codec_dai->playback.rate_max = rate_max;
 227
 228         codec_dai->capture.rates = rates;
 229         codec_dai->capture.rate_min = rate_min;
 230         codec_dai->capture.rate_max = rate_max;
 231
 232         return 0;
 233 }
 234
 235 /**
 236  * cs4270_set_dai_fmt - configure the codec for the selected audio format
 237  * @codec_dai: the codec DAI
 238  * @format: a SND_SOC_DAIFMT_x value indicating the data format
 239  *
 240  * This function takes a bitmask of SND_SOC_DAIFMT_x bits and programs the
 241  * codec accordingly.
 242  *
 243  * Currently, this function only supports SND_SOC_DAIFMT_I2S and
 244  * SND_SOC_DAIFMT_LEFT_J.  The CS4270 codec also supports right-justified
 245  * data for playback only, but ASoC currently does not support different
 246  * formats for playback vs. record.
 247  */
 248 static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
 249                               unsigned int format)
 250 {
 251         struct snd_soc_codec *codec = codec_dai->codec;
 252         struct cs4270_private *cs4270 = codec->private_data;
 253         int ret = 0;
 254
 255         /* set DAI format */
 256         switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
 257         case SND_SOC_DAIFMT_I2S:
 258         case SND_SOC_DAIFMT_LEFT_J:
 259                 cs4270->mode = format & SND_SOC_DAIFMT_FORMAT_MASK;
 260                 break;
 261         default:
 262                 dev_err(codec->dev, "invalid dai format\n");
 263                 ret = -EINVAL;
 264         }
 265
 266         /* set master/slave audio interface */
 267         switch (format & SND_SOC_DAIFMT_MASTER_MASK) {
 268         case SND_SOC_DAIFMT_CBS_CFS:
 269                 cs4270->slave_mode = 1;
 270                 break;
 271         case SND_SOC_DAIFMT_CBM_CFM:
 272                 cs4270->slave_mode = 0;
 273                 break;
 274         default:
 275                 /* all other modes are unsupported by the hardware */
 276                 ret = -EINVAL;
 277         }
 278
 279         return ret;
 280 }
 281
 282 /**
 283  * cs4270_fill_cache - pre-fill the CS4270 register cache.
 284  * @codec: the codec for this CS4270
 285  *
 286  * This function fills in the CS4270 register cache by reading the register
 287  * values from the hardware.
 288  *
 289  * This CS4270 registers are cached to avoid excessive I2C I/O operations.
 290  * After the initial read to pre-fill the cache, the CS4270 never updates
 291  * the register values, so we won't have a cache coherency problem.
 292  *
 293  * We use the auto-increment feature of the CS4270 to read all registers in
 294  * one shot.
 295  */
 296 static int cs4270_fill_cache(struct snd_soc_codec *codec)
 297 {
 298         u8 *cache = codec->reg_cache;
 299         struct i2c_client *i2c_client = codec->control_data;
 300         s32 length;
 301
 302         length = i2c_smbus_read_i2c_block_data(i2c_client,
 303                 CS4270_FIRSTREG | CS4270_I2C_INCR, CS4270_NUMREGS, cache);
 304
 305         if (length != CS4270_NUMREGS) {
 306                 dev_err(codec->dev, "i2c read failure, addr=0x%x\n",
 307                        i2c_client->addr);
 308                 return -EIO;
 309         }
 310
 311         return 0;
 312 }
 313
 314 /**
 315  * cs4270_read_reg_cache - read from the CS4270 register cache.
 316  * @codec: the codec for this CS4270
 317  * @reg: the register to read
 318  *
 319  * This function returns the value for a given register.  It reads only from
 320  * the register cache, not the hardware itself.
 321  *
 322  * This CS4270 registers are cached to avoid excessive I2C I/O operations.
 323  * After the initial read to pre-fill the cache, the CS4270 never updates
 324  * the register values, so we won't have a cache coherency problem.
 325  */
 326 static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
 327         unsigned int reg)
 328 {
 329         u8 *cache = codec->reg_cache;
 330
 331         if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
 332                 return -EIO;
 333
 334         return cache[reg - CS4270_FIRSTREG];
 335 }
 336
 337 /**
 338  * cs4270_i2c_write - write to a CS4270 register via the I2C bus.
 339  * @codec: the codec for this CS4270
 340  * @reg: the register to write
 341  * @value: the value to write to the register
 342  *
 343  * This function writes the given value to the given CS4270 register, and
 344  * also updates the register cache.
 345  *
 346  * Note that we don't use the hw_write function pointer of snd_soc_codec.
 347  * That's because it's too clunky: the hw_write_t prototype does not match
 348  * i2c_smbus_write_byte_data(), and it's just another layer of overhead.
 349  */
 350 static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
 351                             unsigned int value)
 352 {
 353         u8 *cache = codec->reg_cache;
 354
 355         if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
 356                 return -EIO;
 357
 358         /* Only perform an I2C operation if the new value is different */
 359         if (cache[reg - CS4270_FIRSTREG] != value) {
 360                 struct i2c_client *client = codec->control_data;
 361                 if (i2c_smbus_write_byte_data(client, reg, value)) {
 362                         dev_err(codec->dev, "i2c write failed\n");
 363                         return -EIO;
 364                 }
 365
 366                 /* We've written to the hardware, so update the cache */
 367                 cache[reg - CS4270_FIRSTREG] = value;
 368         }
 369
 370         return 0;
 371 }
 372
 373 /**
 374  * cs4270_hw_params - program the CS4270 with the given hardware parameters.
 375  * @substream: the audio stream
 376  * @params: the hardware parameters to set
 377  * @dai: the SOC DAI (ignored)
 378  *
 379  * This function programs the hardware with the values provided.
 380  * Specifically, the sample rate and the data format.
 381  *
 382  * The .ops functions are used to provide board-specific data, like input
 383  * frequencies, to this driver.  This function takes that information,
 384  * combines it with the hardware parameters provided, and programs the
 385  * hardware accordingly.
 386  */
 387 static int cs4270_hw_params(struct snd_pcm_substream *substream,
 388                             struct snd_pcm_hw_params *params,
 389                             struct snd_soc_dai *dai)
 390 {
 391         struct snd_soc_pcm_runtime *rtd = substream->private_data;
 392         struct snd_soc_device *socdev = rtd->socdev;
 393         struct snd_soc_codec *codec = socdev->card->codec;
 394         struct cs4270_private *cs4270 = codec->private_data;
 395         int ret;
 396         unsigned int i;
 397         unsigned int rate;
 398         unsigned int ratio;
 399         int reg;
 400
 401         /* Figure out which MCLK/LRCK ratio to use */
 402
 403         rate = params_rate(params);     /* Sampling rate, in Hz */
 404         ratio = cs4270->mclk / rate;    /* MCLK/LRCK ratio */
 405
 406         for (i = 0; i < NUM_MCLK_RATIOS; i++) {
 407                 if (cs4270_mode_ratios[i].ratio == ratio)
 408                         break;
 409         }
 410
 411         if (i == NUM_MCLK_RATIOS) {
 412                 /* We did not find a matching ratio */
 413                 dev_err(codec->dev, "could not find matching ratio\n");
 414                 return -EINVAL;
 415         }
 416
 417         /* Set the sample rate */
 418
 419         reg = snd_soc_read(codec, CS4270_MODE);
 420         reg &= ~(CS4270_MODE_SPEED_MASK | CS4270_MODE_DIV_MASK);
 421         reg |= cs4270_mode_ratios[i].mclk;
 422
 423         if (cs4270->slave_mode)
 424                 reg |= CS4270_MODE_SLAVE;
 425         else
 426                 reg |= cs4270_mode_ratios[i].speed_mode;
 427
 428         ret = snd_soc_write(codec, CS4270_MODE, reg);
 429         if (ret < 0) {
 430                 dev_err(codec->dev, "i2c write failed\n");
 431                 return ret;
 432         }
 433
 434         /* Set the DAI format */
 435
 436         reg = snd_soc_read(codec, CS4270_FORMAT);
 437         reg &= ~(CS4270_FORMAT_DAC_MASK | CS4270_FORMAT_ADC_MASK);
 438
 439         switch (cs4270->mode) {
 440         case SND_SOC_DAIFMT_I2S:
 441                 reg |= CS4270_FORMAT_DAC_I2S | CS4270_FORMAT_ADC_I2S;
 442                 break;
 443         case SND_SOC_DAIFMT_LEFT_J:
 444                 reg |= CS4270_FORMAT_DAC_LJ | CS4270_FORMAT_ADC_LJ;
 445                 break;
 446         default:
 447                 dev_err(codec->dev, "unknown dai format\n");
 448                 return -EINVAL;
 449         }
 450
 451         ret = snd_soc_write(codec, CS4270_FORMAT, reg);
 452         if (ret < 0) {
 453                 dev_err(codec->dev, "i2c write failed\n");
 454                 return ret;
 455         }
 456
 457         return ret;
 458 }
 459
 460 /**
 461  * cs4270_dai_mute - enable/disable the CS4270 external mute
 462  * @dai: the SOC DAI
 463  * @mute: 0 = disable mute, 1 = enable mute
 464  *
 465  * This function toggles the mute bits in the MUTE register.  The CS4270's
 466  * mute capability is intended for external muting circuitry, so if the
 467  * board does not have the MUTEA or MUTEB pins connected to such circuitry,
 468  * then this function will do nothing.
 469  */
 470 static int cs4270_dai_mute(struct snd_soc_dai *dai, int mute)
 471 {
 472         struct snd_soc_codec *codec = dai->codec;
 473         struct cs4270_private *cs4270 = codec->private_data;
 474         int reg6;
 475
 476         reg6 = snd_soc_read(codec, CS4270_MUTE);
 477
 478         if (mute)
 479                 reg6 |= CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B;
 480         else {
 481                 reg6 &= ~(CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B);
 482                 reg6 |= cs4270->manual_mute;
 483         }
 484
 485         return snd_soc_write(codec, CS4270_MUTE, reg6);
 486 }
 487
 488 /**
 489  * cs4270_soc_put_mute - put callback for the 'Master Playback switch'
 490  *                       alsa control.
 491  * @kcontrol: mixer control
 492  * @ucontrol: control element information
 493  *
 494  * This function basically passes the arguments on to the generic
 495  * snd_soc_put_volsw() function and saves the mute information in
 496  * our private data structure. This is because we want to prevent
 497  * cs4270_dai_mute() neglecting the user's decision to manually
 498  * mute the codec's output.
 499  *
 500  * Returns 0 for success.
 501  */
 502 static int cs4270_soc_put_mute(struct snd_kcontrol *kcontrol,
 503                                 struct snd_ctl_elem_value *ucontrol)
 504 {
 505         struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
 506         struct cs4270_private *cs4270 = codec->private_data;
 507         int left = !ucontrol->value.integer.value[0];
 508         int right = !ucontrol->value.integer.value[1];
 509
 510         cs4270->manual_mute = (left ? CS4270_MUTE_DAC_A : 0) |
 511                               (right ? CS4270_MUTE_DAC_B : 0);
 512
 513         return snd_soc_put_volsw(kcontrol, ucontrol);
 514 }
 515
 516 /* A list of non-DAPM controls that the CS4270 supports */
 517 static const struct snd_kcontrol_new cs4270_snd_controls[] = {
 518         SOC_DOUBLE_R("Master Playback Volume",
 519                 CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 1),
 520         SOC_SINGLE("Digital Sidetone Switch", CS4270_FORMAT, 5, 1, 0),
 521         SOC_SINGLE("Soft Ramp Switch", CS4270_TRANS, 6, 1, 0),
 522         SOC_SINGLE("Zero Cross Switch", CS4270_TRANS, 5, 1, 0),
 523         SOC_SINGLE("De-emphasis filter", CS4270_TRANS, 0, 1, 0),
 524         SOC_SINGLE("Popguard Switch", CS4270_MODE, 0, 1, 1),
 525         SOC_SINGLE("Auto-Mute Switch", CS4270_MUTE, 5, 1, 0),
 526         SOC_DOUBLE("Master Capture Switch", CS4270_MUTE, 3, 4, 1, 1),
 527         SOC_DOUBLE_EXT("Master Playback Switch", CS4270_MUTE, 0, 1, 1, 1,
 528                 snd_soc_get_volsw, cs4270_soc_put_mute),
 529 };
 530
 531 /*
 532  * cs4270_codec - global variable to store codec for the ASoC probe function
 533  *
 534  * If struct i2c_driver had a private_data field, we wouldn't need to use
 535  * cs4270_codec.  This is the only way to pass the codec structure from
 536  * cs4270_i2c_probe() to cs4270_probe().  Unfortunately, there is no good
 537  * way to synchronize these two functions.  cs4270_i2c_probe() can be called
 538  * multiple times before cs4270_probe() is called even once.  So for now, we
 539  * also only allow cs4270_i2c_probe() to be run once.  That means that we do
 540  * not support more than one cs4270 device in the system, at least for now.
 541  */
 542 static struct snd_soc_codec *cs4270_codec;
 543
 544 static struct snd_soc_dai_ops cs4270_dai_ops = {
 545         .hw_params      = cs4270_hw_params,
 546         .set_sysclk     = cs4270_set_dai_sysclk,
 547         .set_fmt        = cs4270_set_dai_fmt,
 548         .digital_mute   = cs4270_dai_mute,
 549 };
 550
 551 struct snd_soc_dai cs4270_dai = {
 552         .name = "cs4270",
 553         .playback = {
 554                 .stream_name = "Playback",
 555                 .channels_min = 1,
 556                 .channels_max = 2,
 557                 .rates = 0,
 558                 .formats = CS4270_FORMATS,
 559         },
 560         .capture = {
 561                 .stream_name = "Capture",
 562                 .channels_min = 1,
 563                 .channels_max = 2,
 564                 .rates = 0,
 565                 .formats = CS4270_FORMATS,
 566         },
 567         .ops = &cs4270_dai_ops,
 568 };
 569 EXPORT_SYMBOL_GPL(cs4270_dai);
 570
 571 /**
 572  * cs4270_probe - ASoC probe function
 573  * @pdev: platform device
 574  *
 575  * This function is called when ASoC has all the pieces it needs to
 576  * instantiate a sound driver.
 577  */
 578 static int cs4270_probe(struct platform_device *pdev)
 579 {
 580         struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 581         struct snd_soc_codec *codec = cs4270_codec;
 582         int ret;
 583
 584         /* Connect the codec to the socdev.  snd_soc_new_pcms() needs this. */
 585         socdev->card->codec = codec;
 586
 587         /* Register PCMs */
 588         ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
 589         if (ret < 0) {
 590                 dev_err(codec->dev, "failed to create pcms\n");
 591                 return ret;
 592         }
 593
 594         /* Add the non-DAPM controls */
 595         ret = snd_soc_add_controls(codec, cs4270_snd_controls,
 596                                 ARRAY_SIZE(cs4270_snd_controls));
 597         if (ret < 0) {
 598                 dev_err(codec->dev, "failed to add controls\n");
 599                 goto error_free_pcms;
 600         }
 601
 602         return 0;
 603
 604 error_free_pcms:
 605         snd_soc_free_pcms(socdev);
 606
 607         return ret;
 608 }
 609
 610 /**
 611  * cs4270_remove - ASoC remove function
 612  * @pdev: platform device
 613  *
 614  * This function is the counterpart to cs4270_probe().
 615  */
 616 static int cs4270_remove(struct platform_device *pdev)
 617 {
 618         struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 619
 620         snd_soc_free_pcms(socdev);
 621
 622         return 0;
 623 };
 624
 625 /**
 626  * cs4270_i2c_probe - initialize the I2C interface of the CS4270
 627  * @i2c_client: the I2C client object
 628  * @id: the I2C device ID (ignored)
 629  *
 630  * This function is called whenever the I2C subsystem finds a device that
 631  * matches the device ID given via a prior call to i2c_add_driver().
 632  */
 633 static int cs4270_i2c_probe(struct i2c_client *i2c_client,
 634         const struct i2c_device_id *id)
 635 {
 636         struct snd_soc_codec *codec;
 637         struct cs4270_private *cs4270;
 638         unsigned int reg;
 639         int ret;
 640
 641         /* For now, we only support one cs4270 device in the system.  See the
 642          * comment for cs4270_codec.
 643          */
 644         if (cs4270_codec) {
 645                 dev_err(&i2c_client->dev, "ignoring CS4270 at addr %X\n",
 646                        i2c_client->addr);
 647                 dev_err(&i2c_client->dev, "only one per board allowed\n");
 648                 /* Should we return something other than ENODEV here? */
 649                 return -ENODEV;
 650         }
 651
 652         /* Verify that we have a CS4270 */
 653
 654         ret = i2c_smbus_read_byte_data(i2c_client, CS4270_CHIPID);
 655         if (ret < 0) {
 656                 dev_err(&i2c_client->dev, "failed to read i2c at addr %X\n",
 657                        i2c_client->addr);
 658                 return ret;
 659         }
 660         /* The top four bits of the chip ID should be 1100. */
 661         if ((ret & 0xF0) != 0xC0) {
 662                 dev_err(&i2c_client->dev, "device at addr %X is not a CS4270\n",
 663                        i2c_client->addr);
 664                 return -ENODEV;
 665         }
 666
 667         dev_info(&i2c_client->dev, "found device at i2c address %X\n",
 668                 i2c_client->addr);
 669         dev_info(&i2c_client->dev, "hardware revision %X\n", ret & 0xF);
 670
 671         /* Allocate enough space for the snd_soc_codec structure
 672            and our private data together. */
 673         cs4270 = kzalloc(sizeof(struct cs4270_private), GFP_KERNEL);
 674         if (!cs4270) {
 675                 dev_err(&i2c_client->dev, "could not allocate codec\n");
 676                 return -ENOMEM;
 677         }
 678         codec = &cs4270->codec;
 679
 680         mutex_init(&codec->mutex);
 681         INIT_LIST_HEAD(&codec->dapm_widgets);
 682         INIT_LIST_HEAD(&codec->dapm_paths);
 683
 684         codec->dev = &i2c_client->dev;
 685         codec->name = "CS4270";
 686         codec->owner = THIS_MODULE;
 687         codec->dai = &cs4270_dai;
 688         codec->num_dai = 1;
 689         codec->private_data = cs4270;
 690         codec->control_data = i2c_client;
 691         codec->read = cs4270_read_reg_cache;
 692         codec->write = cs4270_i2c_write;
 693         codec->reg_cache = cs4270->reg_cache;
 694         codec->reg_cache_size = CS4270_NUMREGS;
 695
 696         /* The I2C interface is set up, so pre-fill our register cache */
 697
 698         ret = cs4270_fill_cache(codec);
 699         if (ret < 0) {
 700                 dev_err(&i2c_client->dev, "failed to fill register cache\n");
 701                 goto error_free_codec;
 702         }
 703
 704         /* Disable auto-mute.  This feature appears to be buggy.  In some
 705          * situations, auto-mute will not deactivate when it should, so we want
 706          * this feature disabled by default.  An application (e.g. alsactl) can
 707          * re-enabled it by using the controls.
 708          */
 709
 710         reg = cs4270_read_reg_cache(codec, CS4270_MUTE);
 711         reg &= ~CS4270_MUTE_AUTO;
 712         ret = cs4270_i2c_write(codec, CS4270_MUTE, reg);
 713         if (ret < 0) {
 714                 dev_err(&i2c_client->dev, "i2c write failed\n");
 715                 return ret;
 716         }
 717
 718         /* Disable automatic volume control.  The hardware enables, and it
 719          * causes volume change commands to be delayed, sometimes until after
 720          * playback has started.  An application (e.g. alsactl) can
 721          * re-enabled it by using the controls.
 722          */
 723
 724         reg = cs4270_read_reg_cache(codec, CS4270_TRANS);
 725         reg &= ~(CS4270_TRANS_SOFT | CS4270_TRANS_ZERO);
 726         ret = cs4270_i2c_write(codec, CS4270_TRANS, reg);
 727         if (ret < 0) {
 728                 dev_err(&i2c_client->dev, "i2c write failed\n");
 729                 return ret;
 730         }
 731
 732         /* Initialize the DAI. Normally, we'd prefer to have a kmalloc'd DAI
 733          * structure for each CS4270 device, but the machine driver needs to
 734          * have a pointer to the DAI structure, so for now it must be a global
 735          * variable.
 736          */
 737         cs4270_dai.dev = &i2c_client->dev;
 738
 739         /* Register the DAI.  If all the other ASoC driver have already
 740          * registered, then this will call our probe function, so
 741          * cs4270_codec needs to be ready.
 742          */
 743         cs4270_codec = codec;
 744         ret = snd_soc_register_dai(&cs4270_dai);
 745         if (ret < 0) {
 746                 dev_err(&i2c_client->dev, "failed to register DAIe\n");
 747                 goto error_free_codec;
 748         }
 749
 750         i2c_set_clientdata(i2c_client, cs4270);
 751
 752         return 0;
 753
 754 error_free_codec:
 755         kfree(cs4270);
 756         cs4270_codec = NULL;
 757         cs4270_dai.dev = NULL;
 758
 759         return ret;
 760 }
 761
 762 /**
 763  * cs4270_i2c_remove - remove an I2C device
 764  * @i2c_client: the I2C client object
 765  *
 766  * This function is the counterpart to cs4270_i2c_probe().
 767  */
 768 static int cs4270_i2c_remove(struct i2c_client *i2c_client)
 769 {
 770         struct cs4270_private *cs4270 = i2c_get_clientdata(i2c_client);
 771
 772         kfree(cs4270);
 773         cs4270_codec = NULL;
 774         cs4270_dai.dev = NULL;
 775
 776         return 0;
 777 }
 778
 779 /*
 780  * cs4270_id - I2C device IDs supported by this driver
 781  */
 782 static struct i2c_device_id cs4270_id[] = {
 783         {"cs4270", 0},
 784         {}
 785 };
 786 MODULE_DEVICE_TABLE(i2c, cs4270_id);
 787
 788 #ifdef CONFIG_PM
 789
 790 /* This suspend/resume implementation can handle both - a simple standby
 791  * where the codec remains powered, and a full suspend, where the voltage
 792  * domain the codec is connected to is teared down and/or any other hardware
 793  * reset condition is asserted.
 794  *
 795  * The codec's own power saving features are enabled in the suspend callback,
 796  * and all registers are written back to the hardware when resuming.
 797  */
 798
 799 static int cs4270_soc_suspend(struct platform_device *pdev, pm_message_t mesg)
 800 {
 801         struct snd_soc_codec *codec = cs4270_codec;
 802         int reg = snd_soc_read(codec, CS4270_PWRCTL) | CS4270_PWRCTL_PDN_ALL;
 803
 804         return snd_soc_write(codec, CS4270_PWRCTL, reg);
 805 }
 806
 807 static int cs4270_soc_resume(struct platform_device *pdev)
 808 {
 809         struct snd_soc_codec *codec = cs4270_codec;
 810         struct i2c_client *i2c_client = codec->control_data;
 811         int reg;
 812
 813         /* In case the device was put to hard reset during sleep, we need to
 814          * wait 500ns here before any I2C communication. */
 815         ndelay(500);
 816
 817         /* first restore the entire register cache ... */
 818         for (reg = CS4270_FIRSTREG; reg <= CS4270_LASTREG; reg++) {
 819                 u8 val = snd_soc_read(codec, reg);
 820
 821                 if (i2c_smbus_write_byte_data(i2c_client, reg, val)) {
 822                         dev_err(codec->dev, "i2c write failed\n");
 823                         return -EIO;
 824                 }
 825         }
 826
 827         /* ... then disable the power-down bits */
 828         reg = snd_soc_read(codec, CS4270_PWRCTL);
 829         reg &= ~CS4270_PWRCTL_PDN_ALL;
 830
 831         return snd_soc_write(codec, CS4270_PWRCTL, reg);
 832 }
 833 #else
 834 #define cs4270_soc_suspend      NULL
 835 #define cs4270_soc_resume       NULL
 836 #endif /* CONFIG_PM */
 837
 838 /*
 839  * cs4270_i2c_driver - I2C device identification
 840  *
 841  * This structure tells the I2C subsystem how to identify and support a
 842  * given I2C device type.
 843  */
 844 static struct i2c_driver cs4270_i2c_driver = {
 845         .driver = {
 846                 .name = "cs4270",
 847                 .owner = THIS_MODULE,
 848         },
 849         .id_table = cs4270_id,
 850         .probe = cs4270_i2c_probe,
 851         .remove = cs4270_i2c_remove,
 852 };
 853
 854 /*
 855  * ASoC codec device structure
 856  *
 857  * Assign this variable to the codec_dev field of the machine driver's
 858  * snd_soc_device structure.
 859  */
 860 struct snd_soc_codec_device soc_codec_device_cs4270 = {
 861         .probe =        cs4270_probe,
 862         .remove =       cs4270_remove,
 863         .suspend =      cs4270_soc_suspend,
 864         .resume =       cs4270_soc_resume,
 865 };
 866 EXPORT_SYMBOL_GPL(soc_codec_device_cs4270);
 867
 868 static int __init cs4270_init(void)
 869 {
 870         pr_info("Cirrus Logic CS4270 ALSA SoC Codec Driver\n");
 871
 872         return i2c_add_driver(&cs4270_i2c_driver);
 873 }
 874 module_init(cs4270_init);
 875
 876 static void __exit cs4270_exit(void)
 877 {
 878         i2c_del_driver(&cs4270_i2c_driver);
 879 }
 880 module_exit(cs4270_exit);
 881
 882 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
 883 MODULE_DESCRIPTION("Cirrus Logic CS4270 ALSA SoC Codec Driver");
 884 MODULE_LICENSE("GPL");