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@lsi.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/gfp.h>
  21 #include <linux/delay.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/rtc.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/io.h>
  26
  27 #define DRV_VERSION "0.6"
  28
  29 enum ds1511reg {
  30         DS1511_SEC = 0x0,
  31         DS1511_MIN = 0x1,
  32         DS1511_HOUR = 0x2,
  33         DS1511_DOW = 0x3,
  34         DS1511_DOM = 0x4,
  35         DS1511_MONTH = 0x5,
  36         DS1511_YEAR = 0x6,
  37         DS1511_CENTURY = 0x7,
  38         DS1511_AM1_SEC = 0x8,
  39         DS1511_AM2_MIN = 0x9,
  40         DS1511_AM3_HOUR = 0xa,
  41         DS1511_AM4_DATE = 0xb,
  42         DS1511_WD_MSEC = 0xc,
  43         DS1511_WD_SEC = 0xd,
  44         DS1511_CONTROL_A = 0xe,
  45         DS1511_CONTROL_B = 0xf,
  46         DS1511_RAMADDR_LSB = 0x10,
  47         DS1511_RAMDATA = 0x13
  48 };
  49
  50 #define DS1511_BLF1     0x80
  51 #define DS1511_BLF2     0x40
  52 #define DS1511_PRS      0x20
  53 #define DS1511_PAB      0x10
  54 #define DS1511_TDF      0x08
  55 #define DS1511_KSF      0x04
  56 #define DS1511_WDF      0x02
  57 #define DS1511_IRQF     0x01
  58 #define DS1511_TE       0x80
  59 #define DS1511_CS       0x40
  60 #define DS1511_BME      0x20
  61 #define DS1511_TPE      0x10
  62 #define DS1511_TIE      0x08
  63 #define DS1511_KIE      0x04
  64 #define DS1511_WDE      0x02
  65 #define DS1511_WDS      0x01
  66 #define DS1511_RAM_MAX  0xff
  67
  68 #define RTC_CMD         DS1511_CONTROL_B
  69 #define RTC_CMD1        DS1511_CONTROL_A
  70
  71 #define RTC_ALARM_SEC   DS1511_AM1_SEC
  72 #define RTC_ALARM_MIN   DS1511_AM2_MIN
  73 #define RTC_ALARM_HOUR  DS1511_AM3_HOUR
  74 #define RTC_ALARM_DATE  DS1511_AM4_DATE
  75
  76 #define RTC_SEC         DS1511_SEC
  77 #define RTC_MIN         DS1511_MIN
  78 #define RTC_HOUR        DS1511_HOUR
  79 #define RTC_DOW         DS1511_DOW
  80 #define RTC_DOM         DS1511_DOM
  81 #define RTC_MON         DS1511_MONTH
  82 #define RTC_YEAR        DS1511_YEAR
  83 #define RTC_CENTURY     DS1511_CENTURY
  84
  85 #define RTC_TIE DS1511_TIE
  86 #define RTC_TE  DS1511_TE
  87
  88 struct rtc_plat_data {
  89         struct rtc_device *rtc;
  90         void __iomem *ioaddr;           /* virtual 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         spinlock_t lock;
  99 };
 100
 101 static DEFINE_SPINLOCK(ds1511_lock);
 102
 103 static __iomem char *ds1511_base;
 104 static u32 reg_spacing = 1;
 105
 106  static noinline void
 107 rtc_write(uint8_t val, uint32_t reg)
 108 {
 109         writeb(val, ds1511_base + (reg * reg_spacing));
 110 }
 111
 112  static inline void
 113 rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 114 {
 115         rtc_write((val | 0x80), reg);
 116 }
 117
 118  static noinline uint8_t
 119 rtc_read(enum ds1511reg reg)
 120 {
 121         return readb(ds1511_base + (reg * reg_spacing));
 122 }
 123
 124  static inline void
 125 rtc_disable_update(void)
 126 {
 127         rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 128 }
 129
 130  static void
 131 rtc_enable_update(void)
 132 {
 133         rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
 134 }
 135
 136 /*
 137  * #define DS1511_WDOG_RESET_SUPPORT
 138  *
 139  * Uncomment this if you want to use these routines in
 140  * some platform code.
 141  */
 142 #ifdef DS1511_WDOG_RESET_SUPPORT
 143 /*
 144  * just enough code to set the watchdog timer so that it
 145  * will reboot the system
 146  */
 147  void
 148 ds1511_wdog_set(unsigned long deciseconds)
 149 {
 150         /*
 151          * the wdog timer can take 99.99 seconds
 152          */
 153         deciseconds %= 10000;
 154         /*
 155          * set the wdog values in the wdog registers
 156          */
 157         rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
 158         rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
 159         /*
 160          * set wdog enable and wdog 'steering' bit to issue a reset
 161          */
 162         rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
 163 }
 164
 165  void
 166 ds1511_wdog_disable(void)
 167 {
 168         /*
 169          * clear wdog enable and wdog 'steering' bits
 170          */
 171         rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
 172         /*
 173          * clear the wdog counter
 174          */
 175         rtc_write(0, DS1511_WD_MSEC);
 176         rtc_write(0, DS1511_WD_SEC);
 177 }
 178 #endif
 179
 180 /*
 181  * set the rtc chip's idea of the time.
 182  * stupidly, some callers call with year unmolested;
 183  * and some call with  year = year - 1900.  thanks.
 184  */
 185 static int 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 long 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 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 249 {
 250         unsigned int century;
 251         unsigned long flags;
 252
 253         spin_lock_irqsave(&ds1511_lock, flags);
 254         rtc_disable_update();
 255
 256         rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
 257         rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
 258         rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
 259         rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
 260         rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
 261         rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
 262         rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
 263         century = rtc_read(RTC_CENTURY);
 264
 265         rtc_enable_update();
 266         spin_unlock_irqrestore(&ds1511_lock, flags);
 267
 268         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 269         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 270         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 271         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 272         rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
 273         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 274         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 275         century = bcd2bin(century) * 100;
 276
 277         /*
 278          * Account for differences between how the RTC uses the values
 279          * and how they are defined in a struct rtc_time;
 280          */
 281         century += rtc_tm->tm_year;
 282         rtc_tm->tm_year = century - 1900;
 283
 284         rtc_tm->tm_mon--;
 285
 286         if (rtc_valid_tm(rtc_tm) < 0) {
 287                 dev_err(dev, "retrieved date/time is not valid.\n");
 288                 rtc_time_to_tm(0, rtc_tm);
 289         }
 290         return 0;
 291 }
 292
 293 /*
 294  * write the alarm register settings
 295  *
 296  * we only have the use to interrupt every second, otherwise
 297  * known as the update interrupt, or the interrupt if the whole
 298  * date/hours/mins/secs matches.  the ds1511 has many more
 299  * permutations, but the kernel doesn't.
 300  */
 301  static void
 302 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
 303 {
 304         unsigned long flags;
 305
 306         spin_lock_irqsave(&pdata->lock, flags);
 307         rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 308                0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
 309                RTC_ALARM_DATE);
 310         rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 311                0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
 312                RTC_ALARM_HOUR);
 313         rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 314                0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
 315                RTC_ALARM_MIN);
 316         rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 317                0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
 318                RTC_ALARM_SEC);
 319         rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
 320         rtc_read(RTC_CMD1);     /* clear interrupts */
 321         spin_unlock_irqrestore(&pdata->lock, flags);
 322 }
 323
 324  static int
 325 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 326 {
 327         struct platform_device *pdev = to_platform_device(dev);
 328         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 329
 330         if (pdata->irq <= 0)
 331                 return -EINVAL;
 332
 333         pdata->alrm_mday = alrm->time.tm_mday;
 334         pdata->alrm_hour = alrm->time.tm_hour;
 335         pdata->alrm_min = alrm->time.tm_min;
 336         pdata->alrm_sec = alrm->time.tm_sec;
 337         if (alrm->enabled) {
 338                 pdata->irqen |= RTC_AF;
 339         }
 340         ds1511_rtc_update_alarm(pdata);
 341         return 0;
 342 }
 343
 344  static int
 345 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 346 {
 347         struct platform_device *pdev = to_platform_device(dev);
 348         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 349
 350         if (pdata->irq <= 0)
 351                 return -EINVAL;
 352
 353         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 354         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 355         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 356         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 357         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 358         return 0;
 359 }
 360
 361  static irqreturn_t
 362 ds1511_interrupt(int irq, void *dev_id)
 363 {
 364         struct platform_device *pdev = dev_id;
 365         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 366         unsigned long events = 0;
 367
 368         spin_lock(&pdata->lock);
 369         /*
 370          * read and clear interrupt
 371          */
 372         if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
 373                 events = RTC_IRQF;
 374                 if (rtc_read(RTC_ALARM_SEC) & 0x80)
 375                         events |= RTC_UF;
 376                 else
 377                         events |= RTC_AF;
 378                 if (likely(pdata->rtc))
 379                         rtc_update_irq(pdata->rtc, 1, events);
 380         }
 381         spin_unlock(&pdata->lock);
 382         return events ? IRQ_HANDLED : IRQ_NONE;
 383 }
 384
 385 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 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                 return -EINVAL;
 392         if (enabled)
 393                 pdata->irqen |= RTC_AF;
 394         else
 395                 pdata->irqen &= ~RTC_AF;
 396         ds1511_rtc_update_alarm(pdata);
 397         return 0;
 398 }
 399
 400 static const struct rtc_class_ops ds1511_rtc_ops = {
 401         .read_time              = ds1511_rtc_read_time,
 402         .set_time               = ds1511_rtc_set_time,
 403         .read_alarm             = ds1511_rtc_read_alarm,
 404         .set_alarm              = ds1511_rtc_set_alarm,
 405         .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
 406 };
 407
 408  static ssize_t
 409 ds1511_nvram_read(struct file *filp, struct kobject *kobj,
 410                   struct bin_attribute *ba,
 411                   char *buf, loff_t pos, size_t size)
 412 {
 413         ssize_t count;
 414
 415         /*
 416          * if count is more than one, turn on "burst" mode
 417          * turn it off when you're done
 418          */
 419         if (size > 1) {
 420                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 421         }
 422         if (pos > DS1511_RAM_MAX) {
 423                 pos = DS1511_RAM_MAX;
 424         }
 425         if (size + pos > DS1511_RAM_MAX + 1) {
 426                 size = DS1511_RAM_MAX - pos + 1;
 427         }
 428         rtc_write(pos, DS1511_RAMADDR_LSB);
 429         for (count = 0; size > 0; count++, size--) {
 430                 *buf++ = rtc_read(DS1511_RAMDATA);
 431         }
 432         if (count > 1) {
 433                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 434         }
 435         return count;
 436 }
 437
 438  static ssize_t
 439 ds1511_nvram_write(struct file *filp, struct kobject *kobj,
 440                    struct bin_attribute *bin_attr,
 441                    char *buf, loff_t pos, size_t size)
 442 {
 443         ssize_t count;
 444
 445         /*
 446          * if count is more than one, turn on "burst" mode
 447          * turn it off when you're done
 448          */
 449         if (size > 1) {
 450                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 451         }
 452         if (pos > DS1511_RAM_MAX) {
 453                 pos = DS1511_RAM_MAX;
 454         }
 455         if (size + pos > DS1511_RAM_MAX + 1) {
 456                 size = DS1511_RAM_MAX - pos + 1;
 457         }
 458         rtc_write(pos, DS1511_RAMADDR_LSB);
 459         for (count = 0; size > 0; count++, size--) {
 460                 rtc_write(*buf++, DS1511_RAMDATA);
 461         }
 462         if (count > 1) {
 463                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 464         }
 465         return count;
 466 }
 467
 468 static struct bin_attribute ds1511_nvram_attr = {
 469         .attr = {
 470                 .name = "nvram",
 471                 .mode = S_IRUGO | S_IWUSR,
 472         },
 473         .size = DS1511_RAM_MAX,
 474         .read = ds1511_nvram_read,
 475         .write = ds1511_nvram_write,
 476 };
 477
 478  static int __devinit
 479 ds1511_rtc_probe(struct platform_device *pdev)
 480 {
 481         struct rtc_device *rtc;
 482         struct resource *res;
 483         struct rtc_plat_data *pdata;
 484         int ret = 0;
 485
 486         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 487         if (!res) {
 488                 return -ENODEV;
 489         }
 490         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 491         if (!pdata)
 492                 return -ENOMEM;
 493         pdata->size = resource_size(res);
 494         if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
 495                         pdev->name))
 496                 return -EBUSY;
 497         ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size);
 498         if (!ds1511_base)
 499                 return -ENOMEM;
 500         pdata->ioaddr = ds1511_base;
 501         pdata->irq = platform_get_irq(pdev, 0);
 502
 503         /*
 504          * turn on the clock and the crystal, etc.
 505          */
 506         rtc_write(0, RTC_CMD);
 507         rtc_write(0, RTC_CMD1);
 508         /*
 509          * clear the wdog counter
 510          */
 511         rtc_write(0, DS1511_WD_MSEC);
 512         rtc_write(0, DS1511_WD_SEC);
 513         /*
 514          * start the clock
 515          */
 516         rtc_enable_update();
 517
 518         /*
 519          * check for a dying bat-tree
 520          */
 521         if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
 522                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 523         }
 524
 525         spin_lock_init(&pdata->lock);
 526         platform_set_drvdata(pdev, pdata);
 527         /*
 528          * if the platform has an interrupt in mind for this device,
 529          * then by all means, set it
 530          */
 531         if (pdata->irq > 0) {
 532                 rtc_read(RTC_CMD1);
 533                 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
 534                         IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
 535
 536                         dev_warn(&pdev->dev, "interrupt not available.\n");
 537                         pdata->irq = 0;
 538                 }
 539         }
 540
 541         rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
 542                 THIS_MODULE);
 543         if (IS_ERR(rtc))
 544                 return PTR_ERR(rtc);
 545         pdata->rtc = rtc;
 546
 547         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 548         if (ret)
 549                 rtc_device_unregister(pdata->rtc);
 550         return ret;
 551 }
 552
 553  static int __devexit
 554 ds1511_rtc_remove(struct platform_device *pdev)
 555 {
 556         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 557
 558         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 559         rtc_device_unregister(pdata->rtc);
 560         if (pdata->irq > 0) {
 561                 /*
 562                  * disable the alarm interrupt
 563                  */
 564                 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
 565                 rtc_read(RTC_CMD1);
 566         }
 567         return 0;
 568 }
 569
 570 /* work with hotplug and coldplug */
 571 MODULE_ALIAS("platform:ds1511");
 572
 573 static struct platform_driver ds1511_rtc_driver = {
 574         .probe          = ds1511_rtc_probe,
 575         .remove         = __devexit_p(ds1511_rtc_remove),
 576         .driver         = {
 577                 .name   = "ds1511",
 578                 .owner  = THIS_MODULE,
 579         },
 580 };
 581
 582  static int __init
 583 ds1511_rtc_init(void)
 584 {
 585         return platform_driver_register(&ds1511_rtc_driver);
 586 }
 587
 588  static void __exit
 589 ds1511_rtc_exit(void)
 590 {
 591         platform_driver_unregister(&ds1511_rtc_driver);
 592 }
 593
 594 module_init(ds1511_rtc_init);
 595 module_exit(ds1511_rtc_exit);
 596
 597 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 598 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 599 MODULE_LICENSE("GPL");
 600 MODULE_VERSION(DRV_VERSION);