drivers/rtc/rtc-ds1374.c

   1 /*
   2  * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
   3  *
   4  * Based on code by Randy Vinson <rvinson@mvista.com>,
   5  * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
   6  *
   7  * Copyright (C) 2014 Rose Technology
   8  * Copyright (C) 2006-2007 Freescale Semiconductor
   9  *
  10  * 2005 (c) MontaVista Software, Inc. This file is licensed under
  11  * the terms of the GNU General Public License version 2. This program
  12  * is licensed "as is" without any warranty of any kind, whether express
  13  * or implied.
  14  */
  15 /*
  16  * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
  17  * recommened in .../Documentation/i2c/writing-clients section
  18  * "Sending and receiving", using SMBus level communication is preferred.
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/i2c.h>
  27 #include <linux/rtc.h>
  28 #include <linux/bcd.h>
  29 #include <linux/workqueue.h>
  30 #include <linux/slab.h>
  31 #include <linux/pm.h>
  32 #ifdef CONFIG_RTC_DRV_DS1374_WDT
  33 #include <linux/fs.h>
  34 #include <linux/ioctl.h>
  35 #include <linux/miscdevice.h>
  36 #include <linux/reboot.h>
  37 #include <linux/watchdog.h>
  38 #endif
  39
  40 #define DS1374_REG_TOD0         0x00 /* Time of Day */
  41 #define DS1374_REG_TOD1         0x01
  42 #define DS1374_REG_TOD2         0x02
  43 #define DS1374_REG_TOD3         0x03
  44 #define DS1374_REG_WDALM0       0x04 /* Watchdog/Alarm */
  45 #define DS1374_REG_WDALM1       0x05
  46 #define DS1374_REG_WDALM2       0x06
  47 #define DS1374_REG_CR           0x07 /* Control */
  48 #define DS1374_REG_CR_AIE       0x01 /* Alarm Int. Enable */
  49 #define DS1374_REG_CR_WDALM     0x20 /* 1=Watchdog, 0=Alarm */
  50 #define DS1374_REG_CR_WACE      0x40 /* WD/Alarm counter enable */
  51 #define DS1374_REG_SR           0x08 /* Status */
  52 #define DS1374_REG_SR_OSF       0x80 /* Oscillator Stop Flag */
  53 #define DS1374_REG_SR_AF        0x01 /* Alarm Flag */
  54 #define DS1374_REG_TCR          0x09 /* Trickle Charge */
  55
  56 static const struct i2c_device_id ds1374_id[] = {
  57         { "ds1374", 0 },
  58         { }
  59 };
  60 MODULE_DEVICE_TABLE(i2c, ds1374_id);
  61
  62 #ifdef CONFIG_OF
  63 static const struct of_device_id ds1374_of_match[] = {
  64         { .compatible = "dallas,ds1374" },
  65         { }
  66 };
  67 MODULE_DEVICE_TABLE(of, ds1374_of_match);
  68 #endif
  69
  70 struct ds1374 {
  71         struct i2c_client *client;
  72         struct rtc_device *rtc;
  73         struct work_struct work;
  74
  75         /* The mutex protects alarm operations, and prevents a race
  76          * between the enable_irq() in the workqueue and the free_irq()
  77          * in the remove function.
  78          */
  79         struct mutex mutex;
  80         int exiting;
  81 };
  82
  83 static struct i2c_driver ds1374_driver;
  84
  85 static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
  86                            int reg, int nbytes)
  87 {
  88         u8 buf[4];
  89         int ret;
  90         int i;
  91
  92         if (nbytes > 4) {
  93                 WARN_ON(1);
  94                 return -EINVAL;
  95         }
  96
  97         ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
  98
  99         if (ret < 0)
 100                 return ret;
 101         if (ret < nbytes)
 102                 return -EIO;
 103
 104         for (i = nbytes - 1, *time = 0; i >= 0; i--)
 105                 *time = (*time << 8) | buf[i];
 106
 107         return 0;
 108 }
 109
 110 static int ds1374_write_rtc(struct i2c_client *client, u32 time,
 111                             int reg, int nbytes)
 112 {
 113         u8 buf[4];
 114         int i;
 115
 116         if (nbytes > 4) {
 117                 WARN_ON(1);
 118                 return -EINVAL;
 119         }
 120
 121         for (i = 0; i < nbytes; i++) {
 122                 buf[i] = time & 0xff;
 123                 time >>= 8;
 124         }
 125
 126         return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
 127 }
 128
 129 static int ds1374_check_rtc_status(struct i2c_client *client)
 130 {
 131         int ret = 0;
 132         int control, stat;
 133
 134         stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
 135         if (stat < 0)
 136                 return stat;
 137
 138         if (stat & DS1374_REG_SR_OSF)
 139                 dev_warn(&client->dev,
 140                          "oscillator discontinuity flagged, time unreliable\n");
 141
 142         stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
 143
 144         ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
 145         if (ret < 0)
 146                 return ret;
 147
 148         /* If the alarm is pending, clear it before requesting
 149          * the interrupt, so an interrupt event isn't reported
 150          * before everything is initialized.
 151          */
 152
 153         control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
 154         if (control < 0)
 155                 return control;
 156
 157         control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
 158         return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
 159 }
 160
 161 static int ds1374_read_time(struct device *dev, struct rtc_time *time)
 162 {
 163         struct i2c_client *client = to_i2c_client(dev);
 164         u32 itime;
 165         int ret;
 166
 167         ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
 168         if (!ret)
 169                 rtc_time_to_tm(itime, time);
 170
 171         return ret;
 172 }
 173
 174 static int ds1374_set_time(struct device *dev, struct rtc_time *time)
 175 {
 176         struct i2c_client *client = to_i2c_client(dev);
 177         unsigned long itime;
 178
 179         rtc_tm_to_time(time, &itime);
 180         return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
 181 }
 182
 183 #ifndef CONFIG_RTC_DRV_DS1374_WDT
 184 /* The ds1374 has a decrementer for an alarm, rather than a comparator.
 185  * If the time of day is changed, then the alarm will need to be
 186  * reset.
 187  */
 188 static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 189 {
 190         struct i2c_client *client = to_i2c_client(dev);
 191         struct ds1374 *ds1374 = i2c_get_clientdata(client);
 192         u32 now, cur_alarm;
 193         int cr, sr;
 194         int ret = 0;
 195
 196         if (client->irq <= 0)
 197                 return -EINVAL;
 198
 199         mutex_lock(&ds1374->mutex);
 200
 201         cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
 202         if (ret < 0)
 203                 goto out;
 204
 205         sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
 206         if (ret < 0)
 207                 goto out;
 208
 209         ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
 210         if (ret)
 211                 goto out;
 212
 213         ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
 214         if (ret)
 215                 goto out;
 216
 217         rtc_time_to_tm(now + cur_alarm, &alarm->time);
 218         alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
 219         alarm->pending = !!(sr & DS1374_REG_SR_AF);
 220
 221 out:
 222         mutex_unlock(&ds1374->mutex);
 223         return ret;
 224 }
 225
 226 static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 227 {
 228         struct i2c_client *client = to_i2c_client(dev);
 229         struct ds1374 *ds1374 = i2c_get_clientdata(client);
 230         struct rtc_time now;
 231         unsigned long new_alarm, itime;
 232         int cr;
 233         int ret = 0;
 234
 235         if (client->irq <= 0)
 236                 return -EINVAL;
 237
 238         ret = ds1374_read_time(dev, &now);
 239         if (ret < 0)
 240                 return ret;
 241
 242         rtc_tm_to_time(&alarm->time, &new_alarm);
 243         rtc_tm_to_time(&now, &itime);
 244
 245         /* This can happen due to races, in addition to dates that are
 246          * truly in the past.  To avoid requiring the caller to check for
 247          * races, dates in the past are assumed to be in the recent past
 248          * (i.e. not something that we'd rather the caller know about via
 249          * an error), and the alarm is set to go off as soon as possible.
 250          */
 251         if (time_before_eq(new_alarm, itime))
 252                 new_alarm = 1;
 253         else
 254                 new_alarm -= itime;
 255
 256         mutex_lock(&ds1374->mutex);
 257
 258         ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
 259         if (ret < 0)
 260                 goto out;
 261
 262         /* Disable any existing alarm before setting the new one
 263          * (or lack thereof). */
 264         cr &= ~DS1374_REG_CR_WACE;
 265
 266         ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
 267         if (ret < 0)
 268                 goto out;
 269
 270         ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
 271         if (ret)
 272                 goto out;
 273
 274         if (alarm->enabled) {
 275                 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
 276                 cr &= ~DS1374_REG_CR_WDALM;
 277
 278                 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
 279         }
 280
 281 out:
 282         mutex_unlock(&ds1374->mutex);
 283         return ret;
 284 }
 285 #endif
 286
 287 static irqreturn_t ds1374_irq(int irq, void *dev_id)
 288 {
 289         struct i2c_client *client = dev_id;
 290         struct ds1374 *ds1374 = i2c_get_clientdata(client);
 291
 292         disable_irq_nosync(irq);
 293         schedule_work(&ds1374->work);
 294         return IRQ_HANDLED;
 295 }
 296
 297 static void ds1374_work(struct work_struct *work)
 298 {
 299         struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
 300         struct i2c_client *client = ds1374->client;
 301         int stat, control;
 302
 303         mutex_lock(&ds1374->mutex);
 304
 305         stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
 306         if (stat < 0)
 307                 goto unlock;
 308
 309         if (stat & DS1374_REG_SR_AF) {
 310                 stat &= ~DS1374_REG_SR_AF;
 311                 i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
 312
 313                 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
 314                 if (control < 0)
 315                         goto out;
 316
 317                 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
 318                 i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
 319
 320                 rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
 321         }
 322
 323 out:
 324         if (!ds1374->exiting)
 325                 enable_irq(client->irq);
 326 unlock:
 327         mutex_unlock(&ds1374->mutex);
 328 }
 329
 330 #ifndef CONFIG_RTC_DRV_DS1374_WDT
 331 static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
 332 {
 333         struct i2c_client *client = to_i2c_client(dev);
 334         struct ds1374 *ds1374 = i2c_get_clientdata(client);
 335         int ret;
 336
 337         mutex_lock(&ds1374->mutex);
 338
 339         ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
 340         if (ret < 0)
 341                 goto out;
 342
 343         if (enabled) {
 344                 ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
 345                 ret &= ~DS1374_REG_CR_WDALM;
 346         } else {
 347                 ret &= ~DS1374_REG_CR_WACE;
 348         }
 349         ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
 350
 351 out:
 352         mutex_unlock(&ds1374->mutex);
 353         return ret;
 354 }
 355 #endif
 356
 357 static const struct rtc_class_ops ds1374_rtc_ops = {
 358         .read_time = ds1374_read_time,
 359         .set_time = ds1374_set_time,
 360 #ifndef CONFIG_RTC_DRV_DS1374_WDT
 361         .read_alarm = ds1374_read_alarm,
 362         .set_alarm = ds1374_set_alarm,
 363         .alarm_irq_enable = ds1374_alarm_irq_enable,
 364 #endif
 365 };
 366
 367 #ifdef CONFIG_RTC_DRV_DS1374_WDT
 368 /*
 369  *****************************************************************************
 370  *
 371  * Watchdog Driver
 372  *
 373  *****************************************************************************
 374  */
 375 static struct i2c_client *save_client;
 376 /* Default margin */
 377 #define WD_TIMO 131762
 378
 379 #define DRV_NAME "DS1374 Watchdog"
 380
 381 static int wdt_margin = WD_TIMO;
 382 static unsigned long wdt_is_open;
 383 module_param(wdt_margin, int, 0);
 384 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
 385
 386 static const struct watchdog_info ds1374_wdt_info = {
 387         .identity       = "DS1374 WTD",
 388         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 389                                                 WDIOF_MAGICCLOSE,
 390 };
 391
 392 static int ds1374_wdt_settimeout(unsigned int timeout)
 393 {
 394         int ret = -ENOIOCTLCMD;
 395         int cr;
 396
 397         ret = cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
 398         if (ret < 0)
 399                 goto out;
 400
 401         /* Disable any existing watchdog/alarm before setting the new one */
 402         cr &= ~DS1374_REG_CR_WACE;
 403
 404         ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
 405         if (ret < 0)
 406                 goto out;
 407
 408         /* Set new watchdog time */
 409         ret = ds1374_write_rtc(save_client, timeout, DS1374_REG_WDALM0, 3);
 410         if (ret) {
 411                 pr_info("couldn't set new watchdog time\n");
 412                 goto out;
 413         }
 414
 415         /* Enable watchdog timer */
 416         cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
 417         cr &= ~DS1374_REG_CR_AIE;
 418
 419         ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
 420         if (ret < 0)
 421                 goto out;
 422
 423         return 0;
 424 out:
 425         return ret;
 426 }
 427
 428
 429 /*
 430  * Reload the watchdog timer.  (ie, pat the watchdog)
 431  */
 432 static void ds1374_wdt_ping(void)
 433 {
 434         u32 val;
 435         int ret = 0;
 436
 437         ret = ds1374_read_rtc(save_client, &val, DS1374_REG_WDALM0, 3);
 438         if (ret)
 439                 pr_info("WD TICK FAIL!!!!!!!!!! %i\n", ret);
 440 }
 441
 442 static void ds1374_wdt_disable(void)
 443 {
 444         int ret = -ENOIOCTLCMD;
 445         int cr;
 446
 447         cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
 448         /* Disable watchdog timer */
 449         cr &= ~DS1374_REG_CR_WACE;
 450
 451         ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
 452 }
 453
 454 /*
 455  * Watchdog device is opened, and watchdog starts running.
 456  */
 457 static int ds1374_wdt_open(struct inode *inode, struct file *file)
 458 {
 459         struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
 460
 461         if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
 462                 mutex_lock(&ds1374->mutex);
 463                 if (test_and_set_bit(0, &wdt_is_open)) {
 464                         mutex_unlock(&ds1374->mutex);
 465                         return -EBUSY;
 466                 }
 467                 /*
 468                  *      Activate
 469                  */
 470                 wdt_is_open = 1;
 471                 mutex_unlock(&ds1374->mutex);
 472                 return nonseekable_open(inode, file);
 473         }
 474         return -ENODEV;
 475 }
 476
 477 /*
 478  * Close the watchdog device.
 479  */
 480 static int ds1374_wdt_release(struct inode *inode, struct file *file)
 481 {
 482         if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
 483                 clear_bit(0, &wdt_is_open);
 484
 485         return 0;
 486 }
 487
 488 /*
 489  * Pat the watchdog whenever device is written to.
 490  */
 491 static ssize_t ds1374_wdt_write(struct file *file, const char __user *data,
 492                                 size_t len, loff_t *ppos)
 493 {
 494         if (len) {
 495                 ds1374_wdt_ping();
 496                 return 1;
 497         }
 498         return 0;
 499 }
 500
 501 static ssize_t ds1374_wdt_read(struct file *file, char __user *data,
 502                                 size_t len, loff_t *ppos)
 503 {
 504         return 0;
 505 }
 506
 507 /*
 508  * Handle commands from user-space.
 509  */
 510 static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd,
 511                                                         unsigned long arg)
 512 {
 513         int new_margin, options;
 514
 515         switch (cmd) {
 516         case WDIOC_GETSUPPORT:
 517                 return copy_to_user((struct watchdog_info __user *)arg,
 518                 &ds1374_wdt_info, sizeof(ds1374_wdt_info)) ? -EFAULT : 0;
 519
 520         case WDIOC_GETSTATUS:
 521         case WDIOC_GETBOOTSTATUS:
 522                 return put_user(0, (int __user *)arg);
 523         case WDIOC_KEEPALIVE:
 524                 ds1374_wdt_ping();
 525                 return 0;
 526         case WDIOC_SETTIMEOUT:
 527                 if (get_user(new_margin, (int __user *)arg))
 528                         return -EFAULT;
 529
 530                 if (new_margin < 1 || new_margin > 16777216)
 531                         return -EINVAL;
 532
 533                 wdt_margin = new_margin;
 534                 ds1374_wdt_settimeout(new_margin);
 535                 ds1374_wdt_ping();
 536                 /* fallthrough */
 537         case WDIOC_GETTIMEOUT:
 538                 return put_user(wdt_margin, (int __user *)arg);
 539         case WDIOC_SETOPTIONS:
 540                 if (copy_from_user(&options, (int __user *)arg, sizeof(int)))
 541                         return -EFAULT;
 542
 543                 if (options & WDIOS_DISABLECARD) {
 544                         pr_info("disable watchdog\n");
 545                         ds1374_wdt_disable();
 546                 }
 547
 548                 if (options & WDIOS_ENABLECARD) {
 549                         pr_info("enable watchdog\n");
 550                         ds1374_wdt_settimeout(wdt_margin);
 551                         ds1374_wdt_ping();
 552                 }
 553
 554                 return -EINVAL;
 555         }
 556         return -ENOTTY;
 557 }
 558
 559 static long ds1374_wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
 560                         unsigned long arg)
 561 {
 562         int ret;
 563         struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
 564
 565         mutex_lock(&ds1374->mutex);
 566         ret = ds1374_wdt_ioctl(file, cmd, arg);
 567         mutex_unlock(&ds1374->mutex);
 568
 569         return ret;
 570 }
 571
 572 static int ds1374_wdt_notify_sys(struct notifier_block *this,
 573                         unsigned long code, void *unused)
 574 {
 575         if (code == SYS_DOWN || code == SYS_HALT)
 576                 /* Disable Watchdog */
 577                 ds1374_wdt_disable();
 578         return NOTIFY_DONE;
 579 }
 580
 581 static const struct file_operations ds1374_wdt_fops = {
 582         .owner                  = THIS_MODULE,
 583         .read                   = ds1374_wdt_read,
 584         .unlocked_ioctl         = ds1374_wdt_unlocked_ioctl,
 585         .write                  = ds1374_wdt_write,
 586         .open                   = ds1374_wdt_open,
 587         .release                = ds1374_wdt_release,
 588         .llseek                 = no_llseek,
 589 };
 590
 591 static struct miscdevice ds1374_miscdev = {
 592         .minor          = WATCHDOG_MINOR,
 593         .name           = "watchdog",
 594         .fops           = &ds1374_wdt_fops,
 595 };
 596
 597 static struct notifier_block ds1374_wdt_notifier = {
 598         .notifier_call = ds1374_wdt_notify_sys,
 599 };
 600
 601 #endif /*CONFIG_RTC_DRV_DS1374_WDT*/
 602 /*
 603  *****************************************************************************
 604  *
 605  *      Driver Interface
 606  *
 607  *****************************************************************************
 608  */
 609 static int ds1374_probe(struct i2c_client *client,
 610                         const struct i2c_device_id *id)
 611 {
 612         struct ds1374 *ds1374;
 613         int ret;
 614
 615         ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
 616         if (!ds1374)
 617                 return -ENOMEM;
 618
 619         ds1374->client = client;
 620         i2c_set_clientdata(client, ds1374);
 621
 622         INIT_WORK(&ds1374->work, ds1374_work);
 623         mutex_init(&ds1374->mutex);
 624
 625         ret = ds1374_check_rtc_status(client);
 626         if (ret)
 627                 return ret;
 628
 629         if (client->irq > 0) {
 630                 ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
 631                                         "ds1374", client);
 632                 if (ret) {
 633                         dev_err(&client->dev, "unable to request IRQ\n");
 634                         return ret;
 635                 }
 636
 637                 device_set_wakeup_capable(&client->dev, 1);
 638         }
 639
 640         ds1374->rtc = devm_rtc_device_register(&client->dev, client->name,
 641                                                 &ds1374_rtc_ops, THIS_MODULE);
 642         if (IS_ERR(ds1374->rtc)) {
 643                 dev_err(&client->dev, "unable to register the class device\n");
 644                 return PTR_ERR(ds1374->rtc);
 645         }
 646
 647 #ifdef CONFIG_RTC_DRV_DS1374_WDT
 648         save_client = client;
 649         ret = misc_register(&ds1374_miscdev);
 650         if (ret)
 651                 return ret;
 652         ret = register_reboot_notifier(&ds1374_wdt_notifier);
 653         if (ret) {
 654                 misc_deregister(&ds1374_miscdev);
 655                 return ret;
 656         }
 657         ds1374_wdt_settimeout(131072);
 658 #endif
 659
 660         return 0;
 661 }
 662
 663 static int ds1374_remove(struct i2c_client *client)
 664 {
 665         struct ds1374 *ds1374 = i2c_get_clientdata(client);
 666 #ifdef CONFIG_RTC_DRV_DS1374_WDT
 667         misc_deregister(&ds1374_miscdev);
 668         ds1374_miscdev.parent = NULL;
 669         unregister_reboot_notifier(&ds1374_wdt_notifier);
 670 #endif
 671
 672         if (client->irq > 0) {
 673                 mutex_lock(&ds1374->mutex);
 674                 ds1374->exiting = 1;
 675                 mutex_unlock(&ds1374->mutex);
 676
 677                 devm_free_irq(&client->dev, client->irq, client);
 678                 cancel_work_sync(&ds1374->work);
 679         }
 680
 681         return 0;
 682 }
 683
 684 #ifdef CONFIG_PM_SLEEP
 685 static int ds1374_suspend(struct device *dev)
 686 {
 687         struct i2c_client *client = to_i2c_client(dev);
 688
 689         if (client->irq > 0 && device_may_wakeup(&client->dev))
 690                 enable_irq_wake(client->irq);
 691         return 0;
 692 }
 693
 694 static int ds1374_resume(struct device *dev)
 695 {
 696         struct i2c_client *client = to_i2c_client(dev);
 697
 698         if (client->irq > 0 && device_may_wakeup(&client->dev))
 699                 disable_irq_wake(client->irq);
 700         return 0;
 701 }
 702 #endif
 703
 704 static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
 705
 706 static struct i2c_driver ds1374_driver = {
 707         .driver = {
 708                 .name = "rtc-ds1374",
 709                 .pm = &ds1374_pm,
 710         },
 711         .probe = ds1374_probe,
 712         .remove = ds1374_remove,
 713         .id_table = ds1374_id,
 714 };
 715
 716 module_i2c_driver(ds1374_driver);
 717
 718 MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
 719 MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
 720 MODULE_LICENSE("GPL");