drivers/mfd/wm8994-core.c

   1 /*
   2  * wm8994-core.c  --  Device access for Wolfson WM8994
   3  *
   4  * Copyright 2009 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/i2c.h>
  19 #include <linux/err.h>
  20 #include <linux/delay.h>
  21 #include <linux/mfd/core.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/regmap.h>
  24 #include <linux/regulator/consumer.h>
  25 #include <linux/regulator/machine.h>
  26
  27 #include <linux/mfd/wm8994/core.h>
  28 #include <linux/mfd/wm8994/pdata.h>
  29 #include <linux/mfd/wm8994/registers.h>
  30
  31 static int wm8994_read(struct wm8994 *wm8994, unsigned short reg,
  32                        int bytes, void *dest)
  33 {
  34         return regmap_raw_read(wm8994->regmap, reg, dest, bytes);
  35 }
  36
  37 /**
  38  * wm8994_reg_read: Read a single WM8994 register.
  39  *
  40  * @wm8994: Device to read from.
  41  * @reg: Register to read.
  42  */
  43 int wm8994_reg_read(struct wm8994 *wm8994, unsigned short reg)
  44 {
  45         unsigned int val;
  46         int ret;
  47
  48         ret = regmap_read(wm8994->regmap, reg, &val);
  49
  50         if (ret < 0)
  51                 return ret;
  52         else
  53                 return val;
  54 }
  55 EXPORT_SYMBOL_GPL(wm8994_reg_read);
  56
  57 /**
  58  * wm8994_bulk_read: Read multiple WM8994 registers
  59  *
  60  * @wm8994: Device to read from
  61  * @reg: First register
  62  * @count: Number of registers
  63  * @buf: Buffer to fill.  The data will be returned big endian.
  64  */
  65 int wm8994_bulk_read(struct wm8994 *wm8994, unsigned short reg,
  66                      int count, u16 *buf)
  67 {
  68         return regmap_bulk_read(wm8994->regmap, reg, buf, count);
  69 }
  70
  71 static int wm8994_write(struct wm8994 *wm8994, unsigned short reg,
  72                         int bytes, const void *src)
  73 {
  74         return regmap_raw_write(wm8994->regmap, reg, src, bytes);
  75 }
  76
  77 /**
  78  * wm8994_reg_write: Write a single WM8994 register.
  79  *
  80  * @wm8994: Device to write to.
  81  * @reg: Register to write to.
  82  * @val: Value to write.
  83  */
  84 int wm8994_reg_write(struct wm8994 *wm8994, unsigned short reg,
  85                      unsigned short val)
  86 {
  87         return regmap_write(wm8994->regmap, reg, val);
  88 }
  89 EXPORT_SYMBOL_GPL(wm8994_reg_write);
  90
  91 /**
  92  * wm8994_bulk_write: Write multiple WM8994 registers
  93  *
  94  * @wm8994: Device to write to
  95  * @reg: First register
  96  * @count: Number of registers
  97  * @buf: Buffer to write from.  Data must be big-endian formatted.
  98  */
  99 int wm8994_bulk_write(struct wm8994 *wm8994, unsigned short reg,
 100                       int count, const u16 *buf)
 101 {
 102         return regmap_raw_write(wm8994->regmap, reg, buf, count * sizeof(u16));
 103 }
 104 EXPORT_SYMBOL_GPL(wm8994_bulk_write);
 105
 106 /**
 107  * wm8994_set_bits: Set the value of a bitfield in a WM8994 register
 108  *
 109  * @wm8994: Device to write to.
 110  * @reg: Register to write to.
 111  * @mask: Mask of bits to set.
 112  * @val: Value to set (unshifted)
 113  */
 114 int wm8994_set_bits(struct wm8994 *wm8994, unsigned short reg,
 115                     unsigned short mask, unsigned short val)
 116 {
 117         return regmap_update_bits(wm8994->regmap, reg, mask, val);
 118 }
 119 EXPORT_SYMBOL_GPL(wm8994_set_bits);
 120
 121 static struct mfd_cell wm8994_regulator_devs[] = {
 122         {
 123                 .name = "wm8994-ldo",
 124                 .id = 1,
 125                 .pm_runtime_no_callbacks = true,
 126         },
 127         {
 128                 .name = "wm8994-ldo",
 129                 .id = 2,
 130                 .pm_runtime_no_callbacks = true,
 131         },
 132 };
 133
 134 static struct resource wm8994_codec_resources[] = {
 135         {
 136                 .start = WM8994_IRQ_TEMP_SHUT,
 137                 .end   = WM8994_IRQ_TEMP_WARN,
 138                 .flags = IORESOURCE_IRQ,
 139         },
 140 };
 141
 142 static struct resource wm8994_gpio_resources[] = {
 143         {
 144                 .start = WM8994_IRQ_GPIO(1),
 145                 .end   = WM8994_IRQ_GPIO(11),
 146                 .flags = IORESOURCE_IRQ,
 147         },
 148 };
 149
 150 static struct mfd_cell wm8994_devs[] = {
 151         {
 152                 .name = "wm8994-codec",
 153                 .num_resources = ARRAY_SIZE(wm8994_codec_resources),
 154                 .resources = wm8994_codec_resources,
 155         },
 156
 157         {
 158                 .name = "wm8994-gpio",
 159                 .num_resources = ARRAY_SIZE(wm8994_gpio_resources),
 160                 .resources = wm8994_gpio_resources,
 161                 .pm_runtime_no_callbacks = true,
 162         },
 163 };
 164
 165 /*
 166  * Supplies for the main bulk of CODEC; the LDO supplies are ignored
 167  * and should be handled via the standard regulator API supply
 168  * management.
 169  */
 170 static const char *wm1811_main_supplies[] = {
 171         "DBVDD1",
 172         "DBVDD2",
 173         "DBVDD3",
 174         "DCVDD",
 175         "AVDD1",
 176         "AVDD2",
 177         "CPVDD",
 178         "SPKVDD1",
 179         "SPKVDD2",
 180 };
 181
 182 static const char *wm8994_main_supplies[] = {
 183         "DBVDD",
 184         "DCVDD",
 185         "AVDD1",
 186         "AVDD2",
 187         "CPVDD",
 188         "SPKVDD1",
 189         "SPKVDD2",
 190 };
 191
 192 static const char *wm8958_main_supplies[] = {
 193         "DBVDD1",
 194         "DBVDD2",
 195         "DBVDD3",
 196         "DCVDD",
 197         "AVDD1",
 198         "AVDD2",
 199         "CPVDD",
 200         "SPKVDD1",
 201         "SPKVDD2",
 202 };
 203
 204 #ifdef CONFIG_PM
 205 static int wm8994_suspend(struct device *dev)
 206 {
 207         struct wm8994 *wm8994 = dev_get_drvdata(dev);
 208         int ret;
 209
 210         /* Don't actually go through with the suspend if the CODEC is
 211          * still active (eg, for audio passthrough from CP. */
 212         ret = wm8994_reg_read(wm8994, WM8994_POWER_MANAGEMENT_1);
 213         if (ret < 0) {
 214                 dev_err(dev, "Failed to read power status: %d\n", ret);
 215         } else if (ret & WM8994_VMID_SEL_MASK) {
 216                 dev_dbg(dev, "CODEC still active, ignoring suspend\n");
 217                 return 0;
 218         }
 219
 220         ret = wm8994_reg_read(wm8994, WM8994_POWER_MANAGEMENT_4);
 221         if (ret < 0) {
 222                 dev_err(dev, "Failed to read power status: %d\n", ret);
 223         } else if (ret & (WM8994_AIF2ADCL_ENA | WM8994_AIF2ADCR_ENA |
 224                           WM8994_AIF1ADC2L_ENA | WM8994_AIF1ADC2R_ENA |
 225                           WM8994_AIF1ADC1L_ENA | WM8994_AIF1ADC1R_ENA)) {
 226                 dev_dbg(dev, "CODEC still active, ignoring suspend\n");
 227                 return 0;
 228         }
 229
 230         ret = wm8994_reg_read(wm8994, WM8994_POWER_MANAGEMENT_5);
 231         if (ret < 0) {
 232                 dev_err(dev, "Failed to read power status: %d\n", ret);
 233         } else if (ret & (WM8994_AIF2DACL_ENA | WM8994_AIF2DACR_ENA |
 234                           WM8994_AIF1DAC2L_ENA | WM8994_AIF1DAC2R_ENA |
 235                           WM8994_AIF1DAC1L_ENA | WM8994_AIF1DAC1R_ENA)) {
 236                 dev_dbg(dev, "CODEC still active, ignoring suspend\n");
 237                 return 0;
 238         }
 239
 240         switch (wm8994->type) {
 241         case WM8958:
 242         case WM1811:
 243                 ret = wm8994_reg_read(wm8994, WM8958_MIC_DETECT_1);
 244                 if (ret < 0) {
 245                         dev_err(dev, "Failed to read power status: %d\n", ret);
 246                 } else if (ret & WM8958_MICD_ENA) {
 247                         dev_dbg(dev, "CODEC still active, ignoring suspend\n");
 248                         return 0;
 249                 }
 250                 break;
 251         default:
 252                 break;
 253         }
 254
 255         /* Disable LDO pulldowns while the device is suspended if we
 256          * don't know that something will be driving them. */
 257         if (!wm8994->ldo_ena_always_driven)
 258                 wm8994_set_bits(wm8994, WM8994_PULL_CONTROL_2,
 259                                 WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD,
 260                                 WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD);
 261
 262         /* GPIO configuration state is saved here since we may be configuring
 263          * the GPIO alternate functions even if we're not using the gpiolib
 264          * driver for them.
 265          */
 266         ret = wm8994_read(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
 267                           &wm8994->gpio_regs);
 268         if (ret < 0)
 269                 dev_err(dev, "Failed to save GPIO registers: %d\n", ret);
 270
 271         /* For similar reasons we also stash the regulator states */
 272         ret = wm8994_read(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
 273                           &wm8994->ldo_regs);
 274         if (ret < 0)
 275                 dev_err(dev, "Failed to save LDO registers: %d\n", ret);
 276
 277         /* Explicitly put the device into reset in case regulators
 278          * don't get disabled in order to ensure consistent restart.
 279          */
 280         wm8994_reg_write(wm8994, WM8994_SOFTWARE_RESET, 0x8994);
 281
 282         wm8994->suspended = true;
 283
 284         ret = regulator_bulk_disable(wm8994->num_supplies,
 285                                      wm8994->supplies);
 286         if (ret != 0) {
 287                 dev_err(dev, "Failed to disable supplies: %d\n", ret);
 288                 return ret;
 289         }
 290
 291         return 0;
 292 }
 293
 294 static int wm8994_resume(struct device *dev)
 295 {
 296         struct wm8994 *wm8994 = dev_get_drvdata(dev);
 297         int ret, i;
 298
 299         /* We may have lied to the PM core about suspending */
 300         if (!wm8994->suspended)
 301                 return 0;
 302
 303         ret = regulator_bulk_enable(wm8994->num_supplies,
 304                                     wm8994->supplies);
 305         if (ret != 0) {
 306                 dev_err(dev, "Failed to enable supplies: %d\n", ret);
 307                 return ret;
 308         }
 309
 310         /* Write register at a time as we use the cache on the CPU so store
 311          * it in native endian.
 312          */
 313         for (i = 0; i < ARRAY_SIZE(wm8994->irq_masks_cur); i++) {
 314                 ret = wm8994_reg_write(wm8994, WM8994_INTERRUPT_STATUS_1_MASK
 315                                        + i, wm8994->irq_masks_cur[i]);
 316                 if (ret < 0)
 317                         dev_err(dev, "Failed to restore interrupt masks: %d\n",
 318                                 ret);
 319         }
 320
 321         ret = wm8994_write(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
 322                            &wm8994->ldo_regs);
 323         if (ret < 0)
 324                 dev_err(dev, "Failed to restore LDO registers: %d\n", ret);
 325
 326         ret = wm8994_write(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
 327                            &wm8994->gpio_regs);
 328         if (ret < 0)
 329                 dev_err(dev, "Failed to restore GPIO registers: %d\n", ret);
 330
 331         /* Disable LDO pulldowns while the device is active */
 332         wm8994_set_bits(wm8994, WM8994_PULL_CONTROL_2,
 333                         WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD,
 334                         0);
 335
 336         wm8994->suspended = false;
 337
 338         return 0;
 339 }
 340 #endif
 341
 342 #ifdef CONFIG_REGULATOR
 343 static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
 344 {
 345         struct wm8994_ldo_pdata *ldo_pdata;
 346
 347         if (!pdata)
 348                 return 0;
 349
 350         ldo_pdata = &pdata->ldo[ldo];
 351
 352         if (!ldo_pdata->init_data)
 353                 return 0;
 354
 355         return ldo_pdata->init_data->num_consumer_supplies != 0;
 356 }
 357 #else
 358 static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
 359 {
 360         return 0;
 361 }
 362 #endif
 363
 364 static struct regmap_config wm8994_regmap_config = {
 365         .reg_bits = 16,
 366         .val_bits = 16,
 367 };
 368
 369 /*
 370  * Instantiate the generic non-control parts of the device.
 371  */
 372 static int wm8994_device_init(struct wm8994 *wm8994, int irq)
 373 {
 374         struct wm8994_pdata *pdata = wm8994->dev->platform_data;
 375         const char *devname;
 376         int ret, i;
 377
 378         dev_set_drvdata(wm8994->dev, wm8994);
 379
 380         /* Add the on-chip regulators first for bootstrapping */
 381         ret = mfd_add_devices(wm8994->dev, -1,
 382                               wm8994_regulator_devs,
 383                               ARRAY_SIZE(wm8994_regulator_devs),
 384                               NULL, 0);
 385         if (ret != 0) {
 386                 dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
 387                 goto err_regmap;
 388         }
 389
 390         switch (wm8994->type) {
 391         case WM1811:
 392                 wm8994->num_supplies = ARRAY_SIZE(wm1811_main_supplies);
 393                 break;
 394         case WM8994:
 395                 wm8994->num_supplies = ARRAY_SIZE(wm8994_main_supplies);
 396                 break;
 397         case WM8958:
 398                 wm8994->num_supplies = ARRAY_SIZE(wm8958_main_supplies);
 399                 break;
 400         default:
 401                 BUG();
 402                 goto err_regmap;
 403         }
 404
 405         wm8994->supplies = kzalloc(sizeof(struct regulator_bulk_data) *
 406                                    wm8994->num_supplies,
 407                                    GFP_KERNEL);
 408         if (!wm8994->supplies) {
 409                 ret = -ENOMEM;
 410                 goto err_regmap;
 411         }
 412
 413         switch (wm8994->type) {
 414         case WM1811:
 415                 for (i = 0; i < ARRAY_SIZE(wm1811_main_supplies); i++)
 416                         wm8994->supplies[i].supply = wm1811_main_supplies[i];
 417                 break;
 418         case WM8994:
 419                 for (i = 0; i < ARRAY_SIZE(wm8994_main_supplies); i++)
 420                         wm8994->supplies[i].supply = wm8994_main_supplies[i];
 421                 break;
 422         case WM8958:
 423                 for (i = 0; i < ARRAY_SIZE(wm8958_main_supplies); i++)
 424                         wm8994->supplies[i].supply = wm8958_main_supplies[i];
 425                 break;
 426         default:
 427                 BUG();
 428                 goto err_regmap;
 429         }
 430
 431         ret = regulator_bulk_get(wm8994->dev, wm8994->num_supplies,
 432                                  wm8994->supplies);
 433         if (ret != 0) {
 434                 dev_err(wm8994->dev, "Failed to get supplies: %d\n", ret);
 435                 goto err_supplies;
 436         }
 437
 438         ret = regulator_bulk_enable(wm8994->num_supplies,
 439                                     wm8994->supplies);
 440         if (ret != 0) {
 441                 dev_err(wm8994->dev, "Failed to enable supplies: %d\n", ret);
 442                 goto err_get;
 443         }
 444
 445         ret = wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET);
 446         if (ret < 0) {
 447                 dev_err(wm8994->dev, "Failed to read ID register\n");
 448                 goto err_enable;
 449         }
 450         switch (ret) {
 451         case 0x1811:
 452                 devname = "WM1811";
 453                 if (wm8994->type != WM1811)
 454                         dev_warn(wm8994->dev, "Device registered as type %d\n",
 455                                  wm8994->type);
 456                 wm8994->type = WM1811;
 457                 break;
 458         case 0x8994:
 459                 devname = "WM8994";
 460                 if (wm8994->type != WM8994)
 461                         dev_warn(wm8994->dev, "Device registered as type %d\n",
 462                                  wm8994->type);
 463                 wm8994->type = WM8994;
 464                 break;
 465         case 0x8958:
 466                 devname = "WM8958";
 467                 if (wm8994->type != WM8958)
 468                         dev_warn(wm8994->dev, "Device registered as type %d\n",
 469                                  wm8994->type);
 470                 wm8994->type = WM8958;
 471                 break;
 472         default:
 473                 dev_err(wm8994->dev, "Device is not a WM8994, ID is %x\n",
 474                         ret);
 475                 ret = -EINVAL;
 476                 goto err_enable;
 477         }
 478
 479         ret = wm8994_reg_read(wm8994, WM8994_CHIP_REVISION);
 480         if (ret < 0) {
 481                 dev_err(wm8994->dev, "Failed to read revision register: %d\n",
 482                         ret);
 483                 goto err_enable;
 484         }
 485
 486         switch (wm8994->type) {
 487         case WM8994:
 488                 switch (ret) {
 489                 case 0:
 490                 case 1:
 491                         dev_warn(wm8994->dev,
 492                                  "revision %c not fully supported\n",
 493                                  'A' + ret);
 494                         break;
 495                 default:
 496                         break;
 497                 }
 498                 break;
 499         default:
 500                 break;
 501         }
 502
 503         dev_info(wm8994->dev, "%s revision %c\n", devname, 'A' + ret);
 504
 505         if (pdata) {
 506                 wm8994->irq_base = pdata->irq_base;
 507                 wm8994->gpio_base = pdata->gpio_base;
 508
 509                 /* GPIO configuration is only applied if it's non-zero */
 510                 for (i = 0; i < ARRAY_SIZE(pdata->gpio_defaults); i++) {
 511                         if (pdata->gpio_defaults[i]) {
 512                                 wm8994_set_bits(wm8994, WM8994_GPIO_1 + i,
 513                                                 0xffff,
 514                                                 pdata->gpio_defaults[i]);
 515                         }
 516                 }
 517
 518                 wm8994->ldo_ena_always_driven = pdata->ldo_ena_always_driven;
 519         }
 520
 521         /* Disable LDO pulldowns while the device is active */
 522         wm8994_set_bits(wm8994, WM8994_PULL_CONTROL_2,
 523                         WM8994_LDO1ENA_PD | WM8994_LDO2ENA_PD,
 524                         0);
 525
 526         /* In some system designs where the regulators are not in use,
 527          * we can achieve a small reduction in leakage currents by
 528          * floating LDO outputs.  This bit makes no difference if the
 529          * LDOs are enabled, it only affects cases where the LDOs were
 530          * in operation and are then disabled.
 531          */
 532         for (i = 0; i < WM8994_NUM_LDO_REGS; i++) {
 533                 if (wm8994_ldo_in_use(pdata, i))
 534                         wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
 535                                         WM8994_LDO1_DISCH, WM8994_LDO1_DISCH);
 536                 else
 537                         wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
 538                                         WM8994_LDO1_DISCH, 0);
 539         }
 540
 541         wm8994_irq_init(wm8994);
 542
 543         ret = mfd_add_devices(wm8994->dev, -1,
 544                               wm8994_devs, ARRAY_SIZE(wm8994_devs),
 545                               NULL, 0);
 546         if (ret != 0) {
 547                 dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
 548                 goto err_irq;
 549         }
 550
 551         pm_runtime_enable(wm8994->dev);
 552         pm_runtime_resume(wm8994->dev);
 553
 554         return 0;
 555
 556 err_irq:
 557         wm8994_irq_exit(wm8994);
 558 err_enable:
 559         regulator_bulk_disable(wm8994->num_supplies,
 560                                wm8994->supplies);
 561 err_get:
 562         regulator_bulk_free(wm8994->num_supplies, wm8994->supplies);
 563 err_supplies:
 564         kfree(wm8994->supplies);
 565 err_regmap:
 566         regmap_exit(wm8994->regmap);
 567         mfd_remove_devices(wm8994->dev);
 568         kfree(wm8994);
 569         return ret;
 570 }
 571
 572 static void wm8994_device_exit(struct wm8994 *wm8994)
 573 {
 574         pm_runtime_disable(wm8994->dev);
 575         mfd_remove_devices(wm8994->dev);
 576         wm8994_irq_exit(wm8994);
 577         regulator_bulk_disable(wm8994->num_supplies,
 578                                wm8994->supplies);
 579         regulator_bulk_free(wm8994->num_supplies, wm8994->supplies);
 580         kfree(wm8994->supplies);
 581         regmap_exit(wm8994->regmap);
 582         kfree(wm8994);
 583 }
 584
 585 static int wm8994_i2c_probe(struct i2c_client *i2c,
 586                             const struct i2c_device_id *id)
 587 {
 588         struct wm8994 *wm8994;
 589         int ret;
 590
 591         wm8994 = kzalloc(sizeof(struct wm8994), GFP_KERNEL);
 592         if (wm8994 == NULL)
 593                 return -ENOMEM;
 594
 595         i2c_set_clientdata(i2c, wm8994);
 596         wm8994->dev = &i2c->dev;
 597         wm8994->irq = i2c->irq;
 598         wm8994->type = id->driver_data;
 599
 600         wm8994->regmap = regmap_init_i2c(i2c, &wm8994_regmap_config);
 601         if (IS_ERR(wm8994->regmap)) {
 602                 ret = PTR_ERR(wm8994->regmap);
 603                 dev_err(wm8994->dev, "Failed to allocate register map: %d\n",
 604                         ret);
 605                 kfree(wm8994);
 606                 return ret;
 607         }
 608
 609         return wm8994_device_init(wm8994, i2c->irq);
 610 }
 611
 612 static int wm8994_i2c_remove(struct i2c_client *i2c)
 613 {
 614         struct wm8994 *wm8994 = i2c_get_clientdata(i2c);
 615
 616         wm8994_device_exit(wm8994);
 617
 618         return 0;
 619 }
 620
 621 static const struct i2c_device_id wm8994_i2c_id[] = {
 622         { "wm1811", WM1811 },
 623         { "wm8994", WM8994 },
 624         { "wm8958", WM8958 },
 625         { }
 626 };
 627 MODULE_DEVICE_TABLE(i2c, wm8994_i2c_id);
 628
 629 static UNIVERSAL_DEV_PM_OPS(wm8994_pm_ops, wm8994_suspend, wm8994_resume,
 630                             NULL);
 631
 632 static struct i2c_driver wm8994_i2c_driver = {
 633         .driver = {
 634                 .name = "wm8994",
 635                 .owner = THIS_MODULE,
 636                 .pm = &wm8994_pm_ops,
 637         },
 638         .probe = wm8994_i2c_probe,
 639         .remove = wm8994_i2c_remove,
 640         .id_table = wm8994_i2c_id,
 641 };
 642
 643 static int __init wm8994_i2c_init(void)
 644 {
 645         int ret;
 646
 647         ret = i2c_add_driver(&wm8994_i2c_driver);
 648         if (ret != 0)
 649                 pr_err("Failed to register wm8994 I2C driver: %d\n", ret);
 650
 651         return ret;
 652 }
 653 module_init(wm8994_i2c_init);
 654
 655 static void __exit wm8994_i2c_exit(void)
 656 {
 657         i2c_del_driver(&wm8994_i2c_driver);
 658 }
 659 module_exit(wm8994_i2c_exit);
 660
 661 MODULE_DESCRIPTION("Core support for the WM8994 audio CODEC");
 662 MODULE_LICENSE("GPL");
 663 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");