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 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
 185 {
 186         u8 mon, day, dow, hrs, min, sec, yrs, cen;
 187         unsigned long flags;
 188
 189         /*
 190          * won't have to change this for a while
 191          */
 192         if (rtc_tm->tm_year < 1900) {
 193                 rtc_tm->tm_year += 1900;
 194         }
 195
 196         if (rtc_tm->tm_year < 1970) {
 197                 return -EINVAL;
 198         }
 199         yrs = rtc_tm->tm_year % 100;
 200         cen = rtc_tm->tm_year / 100;
 201         mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
 202         day = rtc_tm->tm_mday;
 203         dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
 204         hrs = rtc_tm->tm_hour;
 205         min = rtc_tm->tm_min;
 206         sec = rtc_tm->tm_sec;
 207
 208         if ((mon > 12) || (day == 0)) {
 209                 return -EINVAL;
 210         }
 211
 212         if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
 213                 return -EINVAL;
 214         }
 215
 216         if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
 217                 return -EINVAL;
 218         }
 219
 220         /*
 221          * each register is a different number of valid bits
 222          */
 223         sec = BIN2BCD(sec) & 0x7f;
 224         min = BIN2BCD(min) & 0x7f;
 225         hrs = BIN2BCD(hrs) & 0x3f;
 226         day = BIN2BCD(day) & 0x3f;
 227         mon = BIN2BCD(mon) & 0x1f;
 228         yrs = BIN2BCD(yrs) & 0xff;
 229         cen = BIN2BCD(cen) & 0xff;
 230
 231         spin_lock_irqsave(&ds1511_lock, flags);
 232         rtc_disable_update();
 233         rtc_write(cen, RTC_CENTURY);
 234         rtc_write(yrs, RTC_YEAR);
 235         rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
 236         rtc_write(day, RTC_DOM);
 237         rtc_write(hrs, RTC_HOUR);
 238         rtc_write(min, RTC_MIN);
 239         rtc_write(sec, RTC_SEC);
 240         rtc_write(dow, RTC_DOW);
 241         rtc_enable_update();
 242         spin_unlock_irqrestore(&ds1511_lock, flags);
 243
 244         return 0;
 245 }
 246
 247 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 248 {
 249         unsigned int century;
 250         unsigned long flags;
 251
 252         spin_lock_irqsave(&ds1511_lock, flags);
 253         rtc_disable_update();
 254
 255         rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
 256         rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
 257         rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
 258         rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
 259         rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
 260         rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
 261         rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
 262         century = rtc_read(RTC_CENTURY);
 263
 264         rtc_enable_update();
 265         spin_unlock_irqrestore(&ds1511_lock, flags);
 266
 267         rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
 268         rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
 269         rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
 270         rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
 271         rtc_tm->tm_wday = BCD2BIN(rtc_tm->tm_wday);
 272         rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
 273         rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
 274         century = BCD2BIN(century) * 100;
 275
 276         /*
 277          * Account for differences between how the RTC uses the values
 278          * and how they are defined in a struct rtc_time;
 279          */
 280         century += rtc_tm->tm_year;
 281         rtc_tm->tm_year = century - 1900;
 282
 283         rtc_tm->tm_mon--;
 284
 285         if (rtc_valid_tm(rtc_tm) < 0) {
 286                 dev_err(dev, "retrieved date/time is not valid.\n");
 287                 rtc_time_to_tm(0, rtc_tm);
 288         }
 289         return 0;
 290 }
 291
 292 /*
 293  * write the alarm register settings
 294  *
 295  * we only have the use to interrupt every second, otherwise
 296  * known as the update interrupt, or the interrupt if the whole
 297  * date/hours/mins/secs matches.  the ds1511 has many more
 298  * permutations, but the kernel doesn't.
 299  */
 300  static void
 301 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
 302 {
 303         unsigned long flags;
 304
 305         spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
 306         rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 307                0x80 : BIN2BCD(pdata->alrm_mday) & 0x3f,
 308                RTC_ALARM_DATE);
 309         rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 310                0x80 : BIN2BCD(pdata->alrm_hour) & 0x3f,
 311                RTC_ALARM_HOUR);
 312         rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 313                0x80 : BIN2BCD(pdata->alrm_min) & 0x7f,
 314                RTC_ALARM_MIN);
 315         rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 316                0x80 : BIN2BCD(pdata->alrm_sec) & 0x7f,
 317                RTC_ALARM_SEC);
 318         rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
 319         rtc_read(RTC_CMD1);     /* clear interrupts */
 320         spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
 321 }
 322
 323  static int
 324 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 325 {
 326         struct platform_device *pdev = to_platform_device(dev);
 327         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 328
 329         if (pdata->irq < 0) {
 330                 return -EINVAL;
 331         }
 332         pdata->alrm_mday = alrm->time.tm_mday;
 333         pdata->alrm_hour = alrm->time.tm_hour;
 334         pdata->alrm_min = alrm->time.tm_min;
 335         pdata->alrm_sec = alrm->time.tm_sec;
 336         if (alrm->enabled) {
 337                 pdata->irqen |= RTC_AF;
 338         }
 339         ds1511_rtc_update_alarm(pdata);
 340         return 0;
 341 }
 342
 343  static int
 344 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 345 {
 346         struct platform_device *pdev = to_platform_device(dev);
 347         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 348
 349         if (pdata->irq < 0) {
 350                 return -EINVAL;
 351         }
 352         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 353         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 354         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 355         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 356         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 357         return 0;
 358 }
 359
 360  static irqreturn_t
 361 ds1511_interrupt(int irq, void *dev_id)
 362 {
 363         struct platform_device *pdev = dev_id;
 364         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 365         unsigned long events = RTC_IRQF;
 366
 367         /*
 368          * read and clear interrupt
 369          */
 370         if (!(rtc_read(RTC_CMD1) & DS1511_IRQF)) {
 371                 return IRQ_NONE;
 372         }
 373         if (rtc_read(RTC_ALARM_SEC) & 0x80) {
 374                 events |= RTC_UF;
 375         } else {
 376                 events |= RTC_AF;
 377         }
 378         rtc_update_irq(pdata->rtc, 1, events);
 379         return IRQ_HANDLED;
 380 }
 381
 382  static void
 383 ds1511_rtc_release(struct device *dev)
 384 {
 385         struct platform_device *pdev = to_platform_device(dev);
 386         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 387
 388         if (pdata->irq >= 0) {
 389                 pdata->irqen = 0;
 390                 ds1511_rtc_update_alarm(pdata);
 391         }
 392 }
 393
 394  static int
 395 ds1511_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 396 {
 397         struct platform_device *pdev = to_platform_device(dev);
 398         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 399
 400         if (pdata->irq < 0) {
 401                 return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
 402         }
 403         switch (cmd) {
 404         case RTC_AIE_OFF:
 405                 pdata->irqen &= ~RTC_AF;
 406                 ds1511_rtc_update_alarm(pdata);
 407                 break;
 408         case RTC_AIE_ON:
 409                 pdata->irqen |= RTC_AF;
 410                 ds1511_rtc_update_alarm(pdata);
 411                 break;
 412         case RTC_UIE_OFF:
 413                 pdata->irqen &= ~RTC_UF;
 414                 ds1511_rtc_update_alarm(pdata);
 415                 break;
 416         case RTC_UIE_ON:
 417                 pdata->irqen |= RTC_UF;
 418                 ds1511_rtc_update_alarm(pdata);
 419                 break;
 420         default:
 421                 return -ENOIOCTLCMD;
 422         }
 423         return 0;
 424 }
 425
 426 static const struct rtc_class_ops ds1511_rtc_ops = {
 427         .read_time      = ds1511_rtc_read_time,
 428         .set_time       = ds1511_rtc_set_time,
 429         .read_alarm     = ds1511_rtc_read_alarm,
 430         .set_alarm      = ds1511_rtc_set_alarm,
 431         .release        = ds1511_rtc_release,
 432         .ioctl          = ds1511_rtc_ioctl,
 433 };
 434
 435  static ssize_t
 436 ds1511_nvram_read(struct kobject *kobj, struct bin_attribute *ba,
 437                                 char *buf, loff_t pos, size_t size)
 438 {
 439         ssize_t count;
 440
 441         /*
 442          * if count is more than one, turn on "burst" mode
 443          * turn it off when you're done
 444          */
 445         if (size > 1) {
 446                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 447         }
 448         if (pos > DS1511_RAM_MAX) {
 449                 pos = DS1511_RAM_MAX;
 450         }
 451         if (size + pos > DS1511_RAM_MAX + 1) {
 452                 size = DS1511_RAM_MAX - pos + 1;
 453         }
 454         rtc_write(pos, DS1511_RAMADDR_LSB);
 455         for (count = 0; size > 0; count++, size--) {
 456                 *buf++ = rtc_read(DS1511_RAMDATA);
 457         }
 458         if (count > 1) {
 459                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 460         }
 461         return count;
 462 }
 463
 464  static ssize_t
 465 ds1511_nvram_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 466                                 char *buf, loff_t pos, size_t size)
 467 {
 468         ssize_t count;
 469
 470         /*
 471          * if count is more than one, turn on "burst" mode
 472          * turn it off when you're done
 473          */
 474         if (size > 1) {
 475                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 476         }
 477         if (pos > DS1511_RAM_MAX) {
 478                 pos = DS1511_RAM_MAX;
 479         }
 480         if (size + pos > DS1511_RAM_MAX + 1) {
 481                 size = DS1511_RAM_MAX - pos + 1;
 482         }
 483         rtc_write(pos, DS1511_RAMADDR_LSB);
 484         for (count = 0; size > 0; count++, size--) {
 485                 rtc_write(*buf++, DS1511_RAMDATA);
 486         }
 487         if (count > 1) {
 488                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 489         }
 490         return count;
 491 }
 492
 493 static struct bin_attribute ds1511_nvram_attr = {
 494         .attr = {
 495                 .name = "nvram",
 496                 .mode = S_IRUGO | S_IWUGO,
 497                 .owner = THIS_MODULE,
 498         },
 499         .size = DS1511_RAM_MAX,
 500         .read = ds1511_nvram_read,
 501         .write = ds1511_nvram_write,
 502 };
 503
 504  static int __devinit
 505 ds1511_rtc_probe(struct platform_device *pdev)
 506 {
 507         struct rtc_device *rtc;
 508         struct resource *res;
 509         struct rtc_plat_data *pdata = NULL;
 510         int ret = 0;
 511
 512         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 513         if (!res) {
 514                 return -ENODEV;
 515         }
 516         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 517         if (!pdata) {
 518                 return -ENOMEM;
 519         }
 520         pdata->irq = -1;
 521         pdata->size = res->end - res->start + 1;
 522         if (!request_mem_region(res->start, pdata->size, pdev->name)) {
 523                 ret = -EBUSY;
 524                 goto out;
 525         }
 526         pdata->baseaddr = res->start;
 527         pdata->size = pdata->size;
 528         ds1511_base = ioremap(pdata->baseaddr, pdata->size);
 529         if (!ds1511_base) {
 530                 ret = -ENOMEM;
 531                 goto out;
 532         }
 533         pdata->ioaddr = ds1511_base;
 534         pdata->irq = platform_get_irq(pdev, 0);
 535
 536         /*
 537          * turn on the clock and the crystal, etc.
 538          */
 539         rtc_write(0, RTC_CMD);
 540         rtc_write(0, RTC_CMD1);
 541         /*
 542          * clear the wdog counter
 543          */
 544         rtc_write(0, DS1511_WD_MSEC);
 545         rtc_write(0, DS1511_WD_SEC);
 546         /*
 547          * start the clock
 548          */
 549         rtc_enable_update();
 550
 551         /*
 552          * check for a dying bat-tree
 553          */
 554         if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
 555                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 556         }
 557
 558         /*
 559          * if the platform has an interrupt in mind for this device,
 560          * then by all means, set it
 561          */
 562         if (pdata->irq >= 0) {
 563                 rtc_read(RTC_CMD1);
 564                 if (request_irq(pdata->irq, ds1511_interrupt,
 565                         IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
 566
 567                         dev_warn(&pdev->dev, "interrupt not available.\n");
 568                         pdata->irq = -1;
 569                 }
 570         }
 571
 572         rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
 573                 THIS_MODULE);
 574         if (IS_ERR(rtc)) {
 575                 ret = PTR_ERR(rtc);
 576                 goto out;
 577         }
 578         pdata->rtc = rtc;
 579         platform_set_drvdata(pdev, pdata);
 580         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 581         if (ret) {
 582                 goto out;
 583         }
 584         return 0;
 585  out:
 586         if (pdata->rtc) {
 587                 rtc_device_unregister(pdata->rtc);
 588         }
 589         if (pdata->irq >= 0) {
 590                 free_irq(pdata->irq, pdev);
 591         }
 592         if (ds1511_base) {
 593                 iounmap(ds1511_base);
 594                 ds1511_base = NULL;
 595         }
 596         if (pdata->baseaddr) {
 597                 release_mem_region(pdata->baseaddr, pdata->size);
 598         }
 599
 600         kfree(pdata);
 601         return ret;
 602 }
 603
 604  static int __devexit
 605 ds1511_rtc_remove(struct platform_device *pdev)
 606 {
 607         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 608
 609         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 610         rtc_device_unregister(pdata->rtc);
 611         pdata->rtc = NULL;
 612         if (pdata->irq >= 0) {
 613                 /*
 614                  * disable the alarm interrupt
 615                  */
 616                 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
 617                 rtc_read(RTC_CMD1);
 618                 free_irq(pdata->irq, pdev);
 619         }
 620         iounmap(pdata->ioaddr);
 621         ds1511_base = NULL;
 622         release_mem_region(pdata->baseaddr, pdata->size);
 623         kfree(pdata);
 624         return 0;
 625 }
 626
 627 /* work with hotplug and coldplug */
 628 MODULE_ALIAS("platform:ds1511");
 629
 630 static struct platform_driver ds1511_rtc_driver = {
 631         .probe          = ds1511_rtc_probe,
 632         .remove         = __devexit_p(ds1511_rtc_remove),
 633         .driver         = {
 634                 .name   = "ds1511",
 635                 .owner  = THIS_MODULE,
 636         },
 637 };
 638
 639  static int __init
 640 ds1511_rtc_init(void)
 641 {
 642         return platform_driver_register(&ds1511_rtc_driver);
 643 }
 644
 645  static void __exit
 646 ds1511_rtc_exit(void)
 647 {
 648         return platform_driver_unregister(&ds1511_rtc_driver);
 649 }
 650
 651 module_init(ds1511_rtc_init);
 652 module_exit(ds1511_rtc_exit);
 653
 654 MODULE_AUTHOR("Andrew Sharp <andy.sharp@onstor.com>");
 655 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 656 MODULE_LICENSE("GPL");
 657 MODULE_VERSION(DRV_VERSION);