drivers/rtc/rtc-ds1511.c

   1 /*
   2  * An rtc driver for the Dallas DS1511
   3  *
   4  * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   5  * Copyright (C) 2007 Andrew Sharp <andy.sharp@onstor.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Real time clock driver for the Dallas 1511 chip, which also
  12  * contains a watchdog timer.  There is a tiny amount of code that
  13  * platform code could use to mess with the watchdog device a little
  14  * bit, but not a full watchdog driver.
  15  */
  16
  17 #include <linux/bcd.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/delay.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/rtc.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/io.h>
  25
  26 #define DRV_VERSION "0.6"
  27
  28 enum ds1511reg {
  29         DS1511_SEC = 0x0,
  30         DS1511_MIN = 0x1,
  31         DS1511_HOUR = 0x2,
  32         DS1511_DOW = 0x3,
  33         DS1511_DOM = 0x4,
  34         DS1511_MONTH = 0x5,
  35         DS1511_YEAR = 0x6,
  36         DS1511_CENTURY = 0x7,
  37         DS1511_AM1_SEC = 0x8,
  38         DS1511_AM2_MIN = 0x9,
  39         DS1511_AM3_HOUR = 0xa,
  40         DS1511_AM4_DATE = 0xb,
  41         DS1511_WD_MSEC = 0xc,
  42         DS1511_WD_SEC = 0xd,
  43         DS1511_CONTROL_A = 0xe,
  44         DS1511_CONTROL_B = 0xf,
  45         DS1511_RAMADDR_LSB = 0x10,
  46         DS1511_RAMDATA = 0x13
  47 };
  48
  49 #define DS1511_BLF1     0x80
  50 #define DS1511_BLF2     0x40
  51 #define DS1511_PRS      0x20
  52 #define DS1511_PAB      0x10
  53 #define DS1511_TDF      0x08
  54 #define DS1511_KSF      0x04
  55 #define DS1511_WDF      0x02
  56 #define DS1511_IRQF     0x01
  57 #define DS1511_TE       0x80
  58 #define DS1511_CS       0x40
  59 #define DS1511_BME      0x20
  60 #define DS1511_TPE      0x10
  61 #define DS1511_TIE      0x08
  62 #define DS1511_KIE      0x04
  63 #define DS1511_WDE      0x02
  64 #define DS1511_WDS      0x01
  65 #define DS1511_RAM_MAX  0xff
  66
  67 #define RTC_CMD         DS1511_CONTROL_B
  68 #define RTC_CMD1        DS1511_CONTROL_A
  69
  70 #define RTC_ALARM_SEC   DS1511_AM1_SEC
  71 #define RTC_ALARM_MIN   DS1511_AM2_MIN
  72 #define RTC_ALARM_HOUR  DS1511_AM3_HOUR
  73 #define RTC_ALARM_DATE  DS1511_AM4_DATE
  74
  75 #define RTC_SEC         DS1511_SEC
  76 #define RTC_MIN         DS1511_MIN
  77 #define RTC_HOUR        DS1511_HOUR
  78 #define RTC_DOW         DS1511_DOW
  79 #define RTC_DOM         DS1511_DOM
  80 #define RTC_MON         DS1511_MONTH
  81 #define RTC_YEAR        DS1511_YEAR
  82 #define RTC_CENTURY     DS1511_CENTURY
  83
  84 #define RTC_TIE DS1511_TIE
  85 #define RTC_TE  DS1511_TE
  86
  87 struct rtc_plat_data {
  88         struct rtc_device *rtc;
  89         void __iomem *ioaddr;           /* virtual base address */
  90         unsigned long baseaddr;         /* physical base address */
  91         int size;                               /* amount of memory mapped */
  92         int irq;
  93         unsigned int irqen;
  94         int alrm_sec;
  95         int alrm_min;
  96         int alrm_hour;
  97         int alrm_mday;
  98 };
  99
 100 static DEFINE_SPINLOCK(ds1511_lock);
 101
 102 static __iomem char *ds1511_base;
 103 static u32 reg_spacing = 1;
 104
 105  static noinline void
 106 rtc_write(uint8_t val, uint32_t reg)
 107 {
 108         writeb(val, ds1511_base + (reg * reg_spacing));
 109 }
 110
 111  static inline void
 112 rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 113 {
 114         rtc_write((val | 0x80), reg);
 115 }
 116
 117  static noinline uint8_t
 118 rtc_read(enum ds1511reg reg)
 119 {
 120         return readb(ds1511_base + (reg * reg_spacing));
 121 }
 122
 123  static inline void
 124 rtc_disable_update(void)
 125 {
 126         rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 127 }
 128
 129  static void
 130 rtc_enable_update(void)
 131 {
 132         rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
 133 }
 134
 135 /*
 136  * #define DS1511_WDOG_RESET_SUPPORT
 137  *
 138  * Uncomment this if you want to use these routines in
 139  * some platform code.
 140  */
 141 #ifdef DS1511_WDOG_RESET_SUPPORT
 142 /*
 143  * just enough code to set the watchdog timer so that it
 144  * will reboot the system
 145  */
 146  void
 147 ds1511_wdog_set(unsigned long deciseconds)
 148 {
 149         /*
 150          * the wdog timer can take 99.99 seconds
 151          */
 152         deciseconds %= 10000;
 153         /*
 154          * set the wdog values in the wdog registers
 155          */
 156         rtc_write(BIN2BCD(deciseconds % 100), DS1511_WD_MSEC);
 157         rtc_write(BIN2BCD(deciseconds / 100), DS1511_WD_SEC);
 158         /*
 159          * set wdog enable and wdog 'steering' bit to issue a reset
 160          */
 161         rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
 162 }
 163
 164  void
 165 ds1511_wdog_disable(void)
 166 {
 167         /*
 168          * clear wdog enable and wdog 'steering' bits
 169          */
 170         rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
 171         /*
 172          * clear the wdog counter
 173          */
 174         rtc_write(0, DS1511_WD_MSEC);
 175         rtc_write(0, DS1511_WD_SEC);
 176 }
 177 #endif
 178
 179 /*
 180  * set the rtc chip's idea of the time.
 181  * stupidly, some callers call with year unmolested;
 182  * and some call with  year = year - 1900.  thanks.
 183  */
 184  int
 185 ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
 186 {
 187         u8 mon, day, dow, hrs, min, sec, yrs, cen;
 188         unsigned int flags;
 189
 190         /*
 191          * won't have to change this for a while
 192          */
 193         if (rtc_tm->tm_year < 1900) {
 194                 rtc_tm->tm_year += 1900;
 195         }
 196
 197         if (rtc_tm->tm_year < 1970) {
 198                 return -EINVAL;
 199         }
 200         yrs = rtc_tm->tm_year % 100;
 201         cen = rtc_tm->tm_year / 100;
 202         mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
 203         day = rtc_tm->tm_mday;
 204         dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
 205         hrs = rtc_tm->tm_hour;
 206         min = rtc_tm->tm_min;
 207         sec = rtc_tm->tm_sec;
 208
 209         if ((mon > 12) || (day == 0)) {
 210                 return -EINVAL;
 211         }
 212
 213         if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
 214                 return -EINVAL;
 215         }
 216
 217         if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
 218                 return -EINVAL;
 219         }
 220
 221         /*
 222          * each register is a different number of valid bits
 223          */
 224         sec = BIN2BCD(sec) & 0x7f;
 225         min = BIN2BCD(min) & 0x7f;
 226         hrs = BIN2BCD(hrs) & 0x3f;
 227         day = BIN2BCD(day) & 0x3f;
 228         mon = BIN2BCD(mon) & 0x1f;
 229         yrs = BIN2BCD(yrs) & 0xff;
 230         cen = BIN2BCD(cen) & 0xff;
 231
 232         spin_lock_irqsave(&ds1511_lock, flags);
 233         rtc_disable_update();
 234         rtc_write(cen, RTC_CENTURY);
 235         rtc_write(yrs, RTC_YEAR);
 236         rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
 237         rtc_write(day, RTC_DOM);
 238         rtc_write(hrs, RTC_HOUR);
 239         rtc_write(min, RTC_MIN);
 240         rtc_write(sec, RTC_SEC);
 241         rtc_write(dow, RTC_DOW);
 242         rtc_enable_update();
 243         spin_unlock_irqrestore(&ds1511_lock, flags);
 244
 245         return 0;
 246 }
 247
 248  int
 249 ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 250 {
 251         unsigned int century;
 252         unsigned int flags;
 253
 254         spin_lock_irqsave(&ds1511_lock, flags);
 255         rtc_disable_update();
 256
 257         rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
 258         rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
 259         rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
 260         rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
 261         rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
 262         rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
 263         rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
 264         century = rtc_read(RTC_CENTURY);
 265
 266         rtc_enable_update();
 267         spin_unlock_irqrestore(&ds1511_lock, flags);
 268
 269         rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
 270         rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
 271         rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
 272         rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
 273         rtc_tm->tm_wday = BCD2BIN(rtc_tm->tm_wday);
 274         rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
 275         rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
 276         century = BCD2BIN(century) * 100;
 277
 278         /*
 279          * Account for differences between how the RTC uses the values
 280          * and how they are defined in a struct rtc_time;
 281          */
 282         century += rtc_tm->tm_year;
 283         rtc_tm->tm_year = century - 1900;
 284
 285         rtc_tm->tm_mon--;
 286
 287         if (rtc_valid_tm(rtc_tm) < 0) {
 288                 dev_err(dev, "retrieved date/time is not valid.\n");
 289                 rtc_time_to_tm(0, rtc_tm);
 290         }
 291         return 0;
 292 }
 293
 294 /*
 295  * write the alarm register settings
 296  *
 297  * we only have the use to interrupt every second, otherwise
 298  * known as the update interrupt, or the interrupt if the whole
 299  * date/hours/mins/secs matches.  the ds1511 has many more
 300  * permutations, but the kernel doesn't.
 301  */
 302  static void
 303 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
 304 {
 305         unsigned long flags;
 306
 307         spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
 308         rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 309                0x80 : BIN2BCD(pdata->alrm_mday) & 0x3f,
 310                RTC_ALARM_DATE);
 311         rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 312                0x80 : BIN2BCD(pdata->alrm_hour) & 0x3f,
 313                RTC_ALARM_HOUR);
 314         rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 315                0x80 : BIN2BCD(pdata->alrm_min) & 0x7f,
 316                RTC_ALARM_MIN);
 317         rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 318                0x80 : BIN2BCD(pdata->alrm_sec) & 0x7f,
 319                RTC_ALARM_SEC);
 320         rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
 321         rtc_read(RTC_CMD1);     /* clear interrupts */
 322         spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
 323 }
 324
 325  static int
 326 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 327 {
 328         struct platform_device *pdev = to_platform_device(dev);
 329         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 330
 331         if (pdata->irq < 0) {
 332                 return -EINVAL;
 333         }
 334         pdata->alrm_mday = alrm->time.tm_mday;
 335         pdata->alrm_hour = alrm->time.tm_hour;
 336         pdata->alrm_min = alrm->time.tm_min;
 337         pdata->alrm_sec = alrm->time.tm_sec;
 338         if (alrm->enabled) {
 339                 pdata->irqen |= RTC_AF;
 340         }
 341         ds1511_rtc_update_alarm(pdata);
 342         return 0;
 343 }
 344
 345  static int
 346 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 347 {
 348         struct platform_device *pdev = to_platform_device(dev);
 349         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 350
 351         if (pdata->irq < 0) {
 352                 return -EINVAL;
 353         }
 354         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 355         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 356         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 357         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 358         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 359         return 0;
 360 }
 361
 362  static irqreturn_t
 363 ds1511_interrupt(int irq, void *dev_id)
 364 {
 365         struct platform_device *pdev = dev_id;
 366         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 367         unsigned long events = RTC_IRQF;
 368
 369         /*
 370          * read and clear interrupt
 371          */
 372         if (!(rtc_read(RTC_CMD1) & DS1511_IRQF)) {
 373                 return IRQ_NONE;
 374         }
 375         if (rtc_read(RTC_ALARM_SEC) & 0x80) {
 376                 events |= RTC_UF;
 377         } else {
 378                 events |= RTC_AF;
 379         }
 380         rtc_update_irq(pdata->rtc, 1, events);
 381         return IRQ_HANDLED;
 382 }
 383
 384  static void
 385 ds1511_rtc_release(struct device *dev)
 386 {
 387         struct platform_device *pdev = to_platform_device(dev);
 388         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 389
 390         if (pdata->irq >= 0) {
 391                 pdata->irqen = 0;
 392                 ds1511_rtc_update_alarm(pdata);
 393         }
 394 }
 395
 396  static int
 397 ds1511_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 398 {
 399         struct platform_device *pdev = to_platform_device(dev);
 400         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 401
 402         if (pdata->irq < 0) {
 403                 return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
 404         }
 405         switch (cmd) {
 406         case RTC_AIE_OFF:
 407                 pdata->irqen &= ~RTC_AF;
 408                 ds1511_rtc_update_alarm(pdata);
 409                 break;
 410         case RTC_AIE_ON:
 411                 pdata->irqen |= RTC_AF;
 412                 ds1511_rtc_update_alarm(pdata);
 413                 break;
 414         case RTC_UIE_OFF:
 415                 pdata->irqen &= ~RTC_UF;
 416                 ds1511_rtc_update_alarm(pdata);
 417                 break;
 418         case RTC_UIE_ON:
 419                 pdata->irqen |= RTC_UF;
 420                 ds1511_rtc_update_alarm(pdata);
 421                 break;
 422         default:
 423                 return -ENOIOCTLCMD;
 424         }
 425         return 0;
 426 }
 427
 428 static const struct rtc_class_ops ds1511_rtc_ops = {
 429         .read_time      = ds1511_rtc_read_time,
 430         .set_time       = ds1511_rtc_set_time,
 431         .read_alarm     = ds1511_rtc_read_alarm,
 432         .set_alarm      = ds1511_rtc_set_alarm,
 433         .release        = ds1511_rtc_release,
 434         .ioctl          = ds1511_rtc_ioctl,
 435 };
 436
 437  static ssize_t
 438 ds1511_nvram_read(struct kobject *kobj, struct bin_attribute *ba,
 439                                 char *buf, loff_t pos, size_t size)
 440 {
 441         ssize_t count;
 442
 443         /*
 444          * if count is more than one, turn on "burst" mode
 445          * turn it off when you're done
 446          */
 447         if (size > 1) {
 448                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 449         }
 450         if (pos > DS1511_RAM_MAX) {
 451                 pos = DS1511_RAM_MAX;
 452         }
 453         if (size + pos > DS1511_RAM_MAX + 1) {
 454                 size = DS1511_RAM_MAX - pos + 1;
 455         }
 456         rtc_write(pos, DS1511_RAMADDR_LSB);
 457         for (count = 0; size > 0; count++, size--) {
 458                 *buf++ = rtc_read(DS1511_RAMDATA);
 459         }
 460         if (count > 1) {
 461                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 462         }
 463         return count;
 464 }
 465
 466  static ssize_t
 467 ds1511_nvram_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 468                                 char *buf, loff_t pos, size_t size)
 469 {
 470         ssize_t count;
 471
 472         /*
 473          * if count is more than one, turn on "burst" mode
 474          * turn it off when you're done
 475          */
 476         if (size > 1) {
 477                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 478         }
 479         if (pos > DS1511_RAM_MAX) {
 480                 pos = DS1511_RAM_MAX;
 481         }
 482         if (size + pos > DS1511_RAM_MAX + 1) {
 483                 size = DS1511_RAM_MAX - pos + 1;
 484         }
 485         rtc_write(pos, DS1511_RAMADDR_LSB);
 486         for (count = 0; size > 0; count++, size--) {
 487                 rtc_write(*buf++, DS1511_RAMDATA);
 488         }
 489         if (count > 1) {
 490                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 491         }
 492         return count;
 493 }
 494
 495 static struct bin_attribute ds1511_nvram_attr = {
 496         .attr = {
 497                 .name = "nvram",
 498                 .mode = S_IRUGO | S_IWUGO,
 499                 .owner = THIS_MODULE,
 500         },
 501         .size = DS1511_RAM_MAX,
 502         .read = ds1511_nvram_read,
 503         .write = ds1511_nvram_write,
 504 };
 505
 506  static int __devinit
 507 ds1511_rtc_probe(struct platform_device *pdev)
 508 {
 509         struct rtc_device *rtc;
 510         struct resource *res;
 511         struct rtc_plat_data *pdata = NULL;
 512         int ret = 0;
 513
 514         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 515         if (!res) {
 516                 return -ENODEV;
 517         }
 518         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 519         if (!pdata) {
 520                 return -ENOMEM;
 521         }
 522         pdata->irq = -1;
 523         pdata->size = res->end - res->start + 1;
 524         if (!request_mem_region(res->start, pdata->size, pdev->name)) {
 525                 ret = -EBUSY;
 526                 goto out;
 527         }
 528         pdata->baseaddr = res->start;
 529         pdata->size = pdata->size;
 530         ds1511_base = ioremap(pdata->baseaddr, pdata->size);
 531         if (!ds1511_base) {
 532                 ret = -ENOMEM;
 533                 goto out;
 534         }
 535         pdata->ioaddr = ds1511_base;
 536         pdata->irq = platform_get_irq(pdev, 0);
 537
 538         /*
 539          * turn on the clock and the crystal, etc.
 540          */
 541         rtc_write(0, RTC_CMD);
 542         rtc_write(0, RTC_CMD1);
 543         /*
 544          * clear the wdog counter
 545          */
 546         rtc_write(0, DS1511_WD_MSEC);
 547         rtc_write(0, DS1511_WD_SEC);
 548         /*
 549          * start the clock
 550          */
 551         rtc_enable_update();
 552
 553         /*
 554          * check for a dying bat-tree
 555          */
 556         if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
 557                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 558         }
 559
 560         /*
 561          * if the platform has an interrupt in mind for this device,
 562          * then by all means, set it
 563          */
 564         if (pdata->irq >= 0) {
 565                 rtc_read(RTC_CMD1);
 566                 if (request_irq(pdata->irq, ds1511_interrupt,
 567                         IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
 568
 569                         dev_warn(&pdev->dev, "interrupt not available.\n");
 570                         pdata->irq = -1;
 571                 }
 572         }
 573
 574         rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
 575                 THIS_MODULE);
 576         if (IS_ERR(rtc)) {
 577                 ret = PTR_ERR(rtc);
 578                 goto out;
 579         }
 580         pdata->rtc = rtc;
 581         platform_set_drvdata(pdev, pdata);
 582         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 583         if (ret) {
 584                 goto out;
 585         }
 586         return 0;
 587  out:
 588         if (pdata->rtc) {
 589                 rtc_device_unregister(pdata->rtc);
 590         }
 591         if (pdata->irq >= 0) {
 592                 free_irq(pdata->irq, pdev);
 593         }
 594         if (ds1511_base) {
 595                 iounmap(ds1511_base);
 596                 ds1511_base = NULL;
 597         }
 598         if (pdata->baseaddr) {
 599                 release_mem_region(pdata->baseaddr, pdata->size);
 600         }
 601
 602         kfree(pdata);
 603         return ret;
 604 }
 605
 606  static int __devexit
 607 ds1511_rtc_remove(struct platform_device *pdev)
 608 {
 609         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 610
 611         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 612         rtc_device_unregister(pdata->rtc);
 613         pdata->rtc = NULL;
 614         if (pdata->irq >= 0) {
 615                 /*
 616                  * disable the alarm interrupt
 617                  */
 618                 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
 619                 rtc_read(RTC_CMD1);
 620                 free_irq(pdata->irq, pdev);
 621         }
 622         iounmap(pdata->ioaddr);
 623         ds1511_base = NULL;
 624         release_mem_region(pdata->baseaddr, pdata->size);
 625         kfree(pdata);
 626         return 0;
 627 }
 628
 629 /* work with hotplug and coldplug */
 630 MODULE_ALIAS("platform:ds1511");
 631
 632 static struct platform_driver ds1511_rtc_driver = {
 633         .probe          = ds1511_rtc_probe,
 634         .remove         = __devexit_p(ds1511_rtc_remove),
 635         .driver         = {
 636                 .name   = "ds1511",
 637                 .owner  = THIS_MODULE,
 638         },
 639 };
 640
 641  static int __init
 642 ds1511_rtc_init(void)
 643 {
 644         return platform_driver_register(&ds1511_rtc_driver);
 645 }
 646
 647  static void __exit
 648 ds1511_rtc_exit(void)
 649 {
 650         return platform_driver_unregister(&ds1511_rtc_driver);
 651 }
 652
 653 module_init(ds1511_rtc_init);
 654 module_exit(ds1511_rtc_exit);
 655
 656 MODULE_AUTHOR("Andrew Sharp <andy.sharp@onstor.com>");
 657 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 658 MODULE_LICENSE("GPL");
 659 MODULE_VERSION(DRV_VERSION);