drivers/mfd/htc-i2cpld.c

   1 /*
   2  *  htc-i2cpld.c
   3  *  Chip driver for an unknown CPLD chip found on omap850 HTC devices like
   4  *  the HTC Wizard and HTC Herald.
   5  *  The cpld is located on the i2c bus and acts as an input/output GPIO
   6  *  extender.
   7  *
   8  *  Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
   9  *
  10  *  Based on work done in the linwizard project
  11  *  Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
  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, write to the Free Software
  25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/init.h>
  30 #include <linux/module.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/i2c.h>
  34 #include <linux/irq.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/htcpld.h>
  37 #include <linux/gpio.h>
  38 #include <linux/slab.h>
  39
  40 struct htcpld_chip {
  41         spinlock_t              lock;
  42
  43         /* chip info */
  44         u8                      reset;
  45         u8                      addr;
  46         struct device           *dev;
  47         struct i2c_client       *client;
  48
  49         /* Output details */
  50         u8                      cache_out;
  51         struct gpio_chip        chip_out;
  52
  53         /* Input details */
  54         u8                      cache_in;
  55         struct gpio_chip        chip_in;
  56
  57         u16                     irqs_enabled;
  58         uint                    irq_start;
  59         int                     nirqs;
  60
  61         unsigned int            flow_type;
  62         /*
  63          * Work structure to allow for setting values outside of any
  64          * possible interrupt context
  65          */
  66         struct work_struct set_val_work;
  67 };
  68
  69 struct htcpld_data {
  70         /* irq info */
  71         u16                irqs_enabled;
  72         uint               irq_start;
  73         int                nirqs;
  74         uint               chained_irq;
  75         unsigned int       int_reset_gpio_hi;
  76         unsigned int       int_reset_gpio_lo;
  77
  78         /* htcpld info */
  79         struct htcpld_chip *chip;
  80         unsigned int       nchips;
  81 };
  82
  83 /* There does not appear to be a way to proactively mask interrupts
  84  * on the htcpld chip itself.  So, we simply ignore interrupts that
  85  * aren't desired. */
  86 static void htcpld_mask(struct irq_data *data)
  87 {
  88         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  89         chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
  90         pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
  91 }
  92 static void htcpld_unmask(struct irq_data *data)
  93 {
  94         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  95         chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
  96         pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
  97 }
  98
  99 static int htcpld_set_type(struct irq_data *data, unsigned int flags)
 100 {
 101         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
 102
 103         if (flags & ~IRQ_TYPE_SENSE_MASK)
 104                 return -EINVAL;
 105
 106         /* We only allow edge triggering */
 107         if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
 108                 return -EINVAL;
 109
 110         chip->flow_type = flags;
 111         return 0;
 112 }
 113
 114 static struct irq_chip htcpld_muxed_chip = {
 115         .name         = "htcpld",
 116         .irq_mask     = htcpld_mask,
 117         .irq_unmask   = htcpld_unmask,
 118         .irq_set_type = htcpld_set_type,
 119 };
 120
 121 /* To properly dispatch IRQ events, we need to read from the
 122  * chip.  This is an I2C action that could possibly sleep
 123  * (which is bad in interrupt context) -- so we use a threaded
 124  * interrupt handler to get around that.
 125  */
 126 static irqreturn_t htcpld_handler(int irq, void *dev)
 127 {
 128         struct htcpld_data *htcpld = dev;
 129         unsigned int i;
 130         unsigned long flags;
 131         int irqpin;
 132
 133         if (!htcpld) {
 134                 pr_debug("htcpld is null in ISR\n");
 135                 return IRQ_HANDLED;
 136         }
 137
 138         /*
 139          * For each chip, do a read of the chip and trigger any interrupts
 140          * desired.  The interrupts will be triggered from LSB to MSB (i.e.
 141          * bit 0 first, then bit 1, etc.)
 142          *
 143          * For chips that have no interrupt range specified, just skip 'em.
 144          */
 145         for (i = 0; i < htcpld->nchips; i++) {
 146                 struct htcpld_chip *chip = &htcpld->chip[i];
 147                 struct i2c_client *client;
 148                 int val;
 149                 unsigned long uval, old_val;
 150
 151                 if (!chip) {
 152                         pr_debug("chip %d is null in ISR\n", i);
 153                         continue;
 154                 }
 155
 156                 if (chip->nirqs == 0)
 157                         continue;
 158
 159                 client = chip->client;
 160                 if (!client) {
 161                         pr_debug("client %d is null in ISR\n", i);
 162                         continue;
 163                 }
 164
 165                 /* Scan the chip */
 166                 val = i2c_smbus_read_byte_data(client, chip->cache_out);
 167                 if (val < 0) {
 168                         /* Throw a warning and skip this chip */
 169                         dev_warn(chip->dev, "Unable to read from chip: %d\n",
 170                                  val);
 171                         continue;
 172                 }
 173
 174                 uval = (unsigned long)val;
 175
 176                 spin_lock_irqsave(&chip->lock, flags);
 177
 178                 /* Save away the old value so we can compare it */
 179                 old_val = chip->cache_in;
 180
 181                 /* Write the new value */
 182                 chip->cache_in = uval;
 183
 184                 spin_unlock_irqrestore(&chip->lock, flags);
 185
 186                 /*
 187                  * For each bit in the data (starting at bit 0), trigger
 188                  * associated interrupts.
 189                  */
 190                 for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
 191                         unsigned oldb, newb, type = chip->flow_type;
 192
 193                         irq = chip->irq_start + irqpin;
 194
 195                         /* Run the IRQ handler, but only if the bit value
 196                          * changed, and the proper flags are set */
 197                         oldb = (old_val >> irqpin) & 1;
 198                         newb = (uval >> irqpin) & 1;
 199
 200                         if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
 201                             (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
 202                                 pr_debug("fire IRQ %d\n", irqpin);
 203                                 generic_handle_irq(irq);
 204                         }
 205                 }
 206         }
 207
 208         /*
 209          * In order to continue receiving interrupts, the int_reset_gpio must
 210          * be asserted.
 211          */
 212         if (htcpld->int_reset_gpio_hi)
 213                 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 214         if (htcpld->int_reset_gpio_lo)
 215                 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 216
 217         return IRQ_HANDLED;
 218 }
 219
 220 /*
 221  * The GPIO set routines can be called from interrupt context, especially if,
 222  * for example they're attached to the led-gpio framework and a trigger is
 223  * enabled.  As such, we declared work above in the htcpld_chip structure,
 224  * and that work is scheduled in the set routine.  The kernel can then run
 225  * the I2C functions, which will sleep, in process context.
 226  */
 227 static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
 228 {
 229         struct i2c_client *client;
 230         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 231         unsigned long flags;
 232
 233         client = chip_data->client;
 234         if (!client)
 235                 return;
 236
 237         spin_lock_irqsave(&chip_data->lock, flags);
 238         if (val)
 239                 chip_data->cache_out |= (1 << offset);
 240         else
 241                 chip_data->cache_out &= ~(1 << offset);
 242         spin_unlock_irqrestore(&chip_data->lock, flags);
 243
 244         schedule_work(&(chip_data->set_val_work));
 245 }
 246
 247 static void htcpld_chip_set_ni(struct work_struct *work)
 248 {
 249         struct htcpld_chip *chip_data;
 250         struct i2c_client *client;
 251
 252         chip_data = container_of(work, struct htcpld_chip, set_val_work);
 253         client = chip_data->client;
 254         i2c_smbus_read_byte_data(client, chip_data->cache_out);
 255 }
 256
 257 static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
 258 {
 259         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 260         u8 cache;
 261
 262         if (!strncmp(chip->label, "htcpld-out", 10)) {
 263                 cache = chip_data->cache_out;
 264         } else if (!strncmp(chip->label, "htcpld-in", 9)) {
 265                 cache = chip_data->cache_in;
 266         } else
 267                 return -EINVAL;
 268
 269         return (cache >> offset) & 1;
 270 }
 271
 272 static int htcpld_direction_output(struct gpio_chip *chip,
 273                                         unsigned offset, int value)
 274 {
 275         htcpld_chip_set(chip, offset, value);
 276         return 0;
 277 }
 278
 279 static int htcpld_direction_input(struct gpio_chip *chip,
 280                                         unsigned offset)
 281 {
 282         /*
 283          * No-op: this function can only be called on the input chip.
 284          * We do however make sure the offset is within range.
 285          */
 286         return (offset < chip->ngpio) ? 0 : -EINVAL;
 287 }
 288
 289 static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
 290 {
 291         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 292
 293         if (offset < chip_data->nirqs)
 294                 return chip_data->irq_start + offset;
 295         else
 296                 return -EINVAL;
 297 }
 298
 299 static void htcpld_chip_reset(struct i2c_client *client)
 300 {
 301         struct htcpld_chip *chip_data = i2c_get_clientdata(client);
 302         if (!chip_data)
 303                 return;
 304
 305         i2c_smbus_read_byte_data(
 306                 client, (chip_data->cache_out = chip_data->reset));
 307 }
 308
 309 static int htcpld_setup_chip_irq(
 310                 struct platform_device *pdev,
 311                 int chip_index)
 312 {
 313         struct htcpld_data *htcpld;
 314         struct htcpld_chip *chip;
 315         unsigned int irq, irq_end;
 316
 317         /* Get the platform and driver data */
 318         htcpld = platform_get_drvdata(pdev);
 319         chip = &htcpld->chip[chip_index];
 320
 321         /* Setup irq handlers */
 322         irq_end = chip->irq_start + chip->nirqs;
 323         for (irq = chip->irq_start; irq < irq_end; irq++) {
 324                 irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
 325                                          handle_simple_irq);
 326                 irq_set_chip_data(irq, chip);
 327                 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
 328         }
 329
 330         return 0;
 331 }
 332
 333 static int htcpld_register_chip_i2c(
 334                 struct platform_device *pdev,
 335                 int chip_index)
 336 {
 337         struct htcpld_data *htcpld;
 338         struct device *dev = &pdev->dev;
 339         struct htcpld_core_platform_data *pdata;
 340         struct htcpld_chip *chip;
 341         struct htcpld_chip_platform_data *plat_chip_data;
 342         struct i2c_adapter *adapter;
 343         struct i2c_client *client;
 344         struct i2c_board_info info;
 345
 346         /* Get the platform and driver data */
 347         pdata = dev_get_platdata(dev);
 348         htcpld = platform_get_drvdata(pdev);
 349         chip = &htcpld->chip[chip_index];
 350         plat_chip_data = &pdata->chip[chip_index];
 351
 352         adapter = i2c_get_adapter(pdata->i2c_adapter_id);
 353         if (!adapter) {
 354                 /* Eek, no such I2C adapter!  Bail out. */
 355                 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
 356                          plat_chip_data->addr, pdata->i2c_adapter_id);
 357                 return -ENODEV;
 358         }
 359
 360         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
 361                 dev_warn(dev, "i2c adapter %d non-functional\n",
 362                          pdata->i2c_adapter_id);
 363                 return -EINVAL;
 364         }
 365
 366         memset(&info, 0, sizeof(struct i2c_board_info));
 367         info.addr = plat_chip_data->addr;
 368         strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
 369         info.platform_data = chip;
 370
 371         /* Add the I2C device.  This calls the probe() function. */
 372         client = i2c_new_device(adapter, &info);
 373         if (!client) {
 374                 /* I2C device registration failed, contineu with the next */
 375                 dev_warn(dev, "Unable to add I2C device for 0x%x\n",
 376                          plat_chip_data->addr);
 377                 return -ENODEV;
 378         }
 379
 380         i2c_set_clientdata(client, chip);
 381         snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr);
 382         chip->client = client;
 383
 384         /* Reset the chip */
 385         htcpld_chip_reset(client);
 386         chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
 387
 388         return 0;
 389 }
 390
 391 static void htcpld_unregister_chip_i2c(
 392                 struct platform_device *pdev,
 393                 int chip_index)
 394 {
 395         struct htcpld_data *htcpld;
 396         struct htcpld_chip *chip;
 397
 398         /* Get the platform and driver data */
 399         htcpld = platform_get_drvdata(pdev);
 400         chip = &htcpld->chip[chip_index];
 401
 402         if (chip->client)
 403                 i2c_unregister_device(chip->client);
 404 }
 405
 406 static int htcpld_register_chip_gpio(
 407                 struct platform_device *pdev,
 408                 int chip_index)
 409 {
 410         struct htcpld_data *htcpld;
 411         struct device *dev = &pdev->dev;
 412         struct htcpld_core_platform_data *pdata;
 413         struct htcpld_chip *chip;
 414         struct htcpld_chip_platform_data *plat_chip_data;
 415         struct gpio_chip *gpio_chip;
 416         int ret = 0;
 417
 418         /* Get the platform and driver data */
 419         pdata = dev_get_platdata(dev);
 420         htcpld = platform_get_drvdata(pdev);
 421         chip = &htcpld->chip[chip_index];
 422         plat_chip_data = &pdata->chip[chip_index];
 423
 424         /* Setup the GPIO chips */
 425         gpio_chip = &(chip->chip_out);
 426         gpio_chip->label           = "htcpld-out";
 427         gpio_chip->parent             = dev;
 428         gpio_chip->owner           = THIS_MODULE;
 429         gpio_chip->get             = htcpld_chip_get;
 430         gpio_chip->set             = htcpld_chip_set;
 431         gpio_chip->direction_input = NULL;
 432         gpio_chip->direction_output = htcpld_direction_output;
 433         gpio_chip->base            = plat_chip_data->gpio_out_base;
 434         gpio_chip->ngpio           = plat_chip_data->num_gpios;
 435
 436         gpio_chip = &(chip->chip_in);
 437         gpio_chip->label           = "htcpld-in";
 438         gpio_chip->parent             = dev;
 439         gpio_chip->owner           = THIS_MODULE;
 440         gpio_chip->get             = htcpld_chip_get;
 441         gpio_chip->set             = NULL;
 442         gpio_chip->direction_input = htcpld_direction_input;
 443         gpio_chip->direction_output = NULL;
 444         gpio_chip->to_irq          = htcpld_chip_to_irq;
 445         gpio_chip->base            = plat_chip_data->gpio_in_base;
 446         gpio_chip->ngpio           = plat_chip_data->num_gpios;
 447
 448         /* Add the GPIO chips */
 449         ret = gpiochip_add_data(&(chip->chip_out), chip);
 450         if (ret) {
 451                 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
 452                          plat_chip_data->addr, ret);
 453                 return ret;
 454         }
 455
 456         ret = gpiochip_add_data(&(chip->chip_in), chip);
 457         if (ret) {
 458                 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
 459                          plat_chip_data->addr, ret);
 460                 gpiochip_remove(&(chip->chip_out));
 461                 return ret;
 462         }
 463
 464         return 0;
 465 }
 466
 467 static int htcpld_setup_chips(struct platform_device *pdev)
 468 {
 469         struct htcpld_data *htcpld;
 470         struct device *dev = &pdev->dev;
 471         struct htcpld_core_platform_data *pdata;
 472         int i;
 473
 474         /* Get the platform and driver data */
 475         pdata = dev_get_platdata(dev);
 476         htcpld = platform_get_drvdata(pdev);
 477
 478         /* Setup each chip's output GPIOs */
 479         htcpld->nchips = pdata->num_chip;
 480         htcpld->chip = devm_kzalloc(dev, sizeof(struct htcpld_chip) * htcpld->nchips,
 481                                     GFP_KERNEL);
 482         if (!htcpld->chip) {
 483                 dev_warn(dev, "Unable to allocate memory for chips\n");
 484                 return -ENOMEM;
 485         }
 486
 487         /* Add the chips as best we can */
 488         for (i = 0; i < htcpld->nchips; i++) {
 489                 int ret;
 490
 491                 /* Setup the HTCPLD chips */
 492                 htcpld->chip[i].reset = pdata->chip[i].reset;
 493                 htcpld->chip[i].cache_out = pdata->chip[i].reset;
 494                 htcpld->chip[i].cache_in = 0;
 495                 htcpld->chip[i].dev = dev;
 496                 htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
 497                 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
 498
 499                 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
 500                 spin_lock_init(&(htcpld->chip[i].lock));
 501
 502                 /* Setup the interrupts for the chip */
 503                 if (htcpld->chained_irq) {
 504                         ret = htcpld_setup_chip_irq(pdev, i);
 505                         if (ret)
 506                                 continue;
 507                 }
 508
 509                 /* Register the chip with I2C */
 510                 ret = htcpld_register_chip_i2c(pdev, i);
 511                 if (ret)
 512                         continue;
 513
 514
 515                 /* Register the chips with the GPIO subsystem */
 516                 ret = htcpld_register_chip_gpio(pdev, i);
 517                 if (ret) {
 518                         /* Unregister the chip from i2c and continue */
 519                         htcpld_unregister_chip_i2c(pdev, i);
 520                         continue;
 521                 }
 522
 523                 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
 524         }
 525
 526         return 0;
 527 }
 528
 529 static int htcpld_core_probe(struct platform_device *pdev)
 530 {
 531         struct htcpld_data *htcpld;
 532         struct device *dev = &pdev->dev;
 533         struct htcpld_core_platform_data *pdata;
 534         struct resource *res;
 535         int ret = 0;
 536
 537         if (!dev)
 538                 return -ENODEV;
 539
 540         pdata = dev_get_platdata(dev);
 541         if (!pdata) {
 542                 dev_warn(dev, "Platform data not found for htcpld core!\n");
 543                 return -ENXIO;
 544         }
 545
 546         htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
 547         if (!htcpld)
 548                 return -ENOMEM;
 549
 550         /* Find chained irq */
 551         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 552         if (res) {
 553                 int flags;
 554                 htcpld->chained_irq = res->start;
 555
 556                 /* Setup the chained interrupt handler */
 557                 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
 558                         IRQF_ONESHOT;
 559                 ret = request_threaded_irq(htcpld->chained_irq,
 560                                            NULL, htcpld_handler,
 561                                            flags, pdev->name, htcpld);
 562                 if (ret) {
 563                         dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
 564                         return ret;
 565                 } else
 566                         device_init_wakeup(dev, 0);
 567         }
 568
 569         /* Set the driver data */
 570         platform_set_drvdata(pdev, htcpld);
 571
 572         /* Setup the htcpld chips */
 573         ret = htcpld_setup_chips(pdev);
 574         if (ret)
 575                 return ret;
 576
 577         /* Request the GPIO(s) for the int reset and set them up */
 578         if (pdata->int_reset_gpio_hi) {
 579                 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
 580                 if (ret) {
 581                         /*
 582                          * If it failed, that sucks, but we can probably
 583                          * continue on without it.
 584                          */
 585                         dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
 586                         htcpld->int_reset_gpio_hi = 0;
 587                 } else {
 588                         htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
 589                         gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 590                 }
 591         }
 592
 593         if (pdata->int_reset_gpio_lo) {
 594                 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
 595                 if (ret) {
 596                         /*
 597                          * If it failed, that sucks, but we can probably
 598                          * continue on without it.
 599                          */
 600                         dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
 601                         htcpld->int_reset_gpio_lo = 0;
 602                 } else {
 603                         htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
 604                         gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 605                 }
 606         }
 607
 608         dev_info(dev, "Initialized successfully\n");
 609         return 0;
 610 }
 611
 612 /* The I2C Driver -- used internally */
 613 static const struct i2c_device_id htcpld_chip_id[] = {
 614         { "htcpld-chip", 0 },
 615         { }
 616 };
 617 MODULE_DEVICE_TABLE(i2c, htcpld_chip_id);
 618
 619
 620 static struct i2c_driver htcpld_chip_driver = {
 621         .driver = {
 622                 .name   = "htcpld-chip",
 623         },
 624         .id_table = htcpld_chip_id,
 625 };
 626
 627 /* The Core Driver */
 628 static struct platform_driver htcpld_core_driver = {
 629         .driver = {
 630                 .name = "i2c-htcpld",
 631         },
 632 };
 633
 634 static int __init htcpld_core_init(void)
 635 {
 636         int ret;
 637
 638         /* Register the I2C Chip driver */
 639         ret = i2c_add_driver(&htcpld_chip_driver);
 640         if (ret)
 641                 return ret;
 642
 643         /* Probe for our chips */
 644         return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
 645 }
 646
 647 static void __exit htcpld_core_exit(void)
 648 {
 649         i2c_del_driver(&htcpld_chip_driver);
 650         platform_driver_unregister(&htcpld_core_driver);
 651 }
 652
 653 module_init(htcpld_core_init);
 654 module_exit(htcpld_core_exit);
 655
 656 MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>");
 657 MODULE_DESCRIPTION("I2C HTC PLD Driver");
 658 MODULE_LICENSE("GPL");
 659