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 #include <linux/module.h>
  27
  28 #define DRV_VERSION "0.6"
  29
  30 enum ds1511reg {
  31         DS1511_SEC = 0x0,
  32         DS1511_MIN = 0x1,
  33         DS1511_HOUR = 0x2,
  34         DS1511_DOW = 0x3,
  35         DS1511_DOM = 0x4,
  36         DS1511_MONTH = 0x5,
  37         DS1511_YEAR = 0x6,
  38         DS1511_CENTURY = 0x7,
  39         DS1511_AM1_SEC = 0x8,
  40         DS1511_AM2_MIN = 0x9,
  41         DS1511_AM3_HOUR = 0xa,
  42         DS1511_AM4_DATE = 0xb,
  43         DS1511_WD_MSEC = 0xc,
  44         DS1511_WD_SEC = 0xd,
  45         DS1511_CONTROL_A = 0xe,
  46         DS1511_CONTROL_B = 0xf,
  47         DS1511_RAMADDR_LSB = 0x10,
  48         DS1511_RAMDATA = 0x13
  49 };
  50
  51 #define DS1511_BLF1     0x80
  52 #define DS1511_BLF2     0x40
  53 #define DS1511_PRS      0x20
  54 #define DS1511_PAB      0x10
  55 #define DS1511_TDF      0x08
  56 #define DS1511_KSF      0x04
  57 #define DS1511_WDF      0x02
  58 #define DS1511_IRQF     0x01
  59 #define DS1511_TE       0x80
  60 #define DS1511_CS       0x40
  61 #define DS1511_BME      0x20
  62 #define DS1511_TPE      0x10
  63 #define DS1511_TIE      0x08
  64 #define DS1511_KIE      0x04
  65 #define DS1511_WDE      0x02
  66 #define DS1511_WDS      0x01
  67 #define DS1511_RAM_MAX  0xff
  68
  69 #define RTC_CMD         DS1511_CONTROL_B
  70 #define RTC_CMD1        DS1511_CONTROL_A
  71
  72 #define RTC_ALARM_SEC   DS1511_AM1_SEC
  73 #define RTC_ALARM_MIN   DS1511_AM2_MIN
  74 #define RTC_ALARM_HOUR  DS1511_AM3_HOUR
  75 #define RTC_ALARM_DATE  DS1511_AM4_DATE
  76
  77 #define RTC_SEC         DS1511_SEC
  78 #define RTC_MIN         DS1511_MIN
  79 #define RTC_HOUR        DS1511_HOUR
  80 #define RTC_DOW         DS1511_DOW
  81 #define RTC_DOM         DS1511_DOM
  82 #define RTC_MON         DS1511_MONTH
  83 #define RTC_YEAR        DS1511_YEAR
  84 #define RTC_CENTURY     DS1511_CENTURY
  85
  86 #define RTC_TIE DS1511_TIE
  87 #define RTC_TE  DS1511_TE
  88
  89 struct rtc_plat_data {
  90         struct rtc_device *rtc;
  91         void __iomem *ioaddr;           /* virtual base address */
  92         int size;                               /* amount of memory mapped */
  93         int irq;
  94         unsigned int irqen;
  95         int alrm_sec;
  96         int alrm_min;
  97         int alrm_hour;
  98         int alrm_mday;
  99         spinlock_t lock;
 100 };
 101
 102 static DEFINE_SPINLOCK(ds1511_lock);
 103
 104 static __iomem char *ds1511_base;
 105 static u32 reg_spacing = 1;
 106
 107  static noinline void
 108 rtc_write(uint8_t val, uint32_t reg)
 109 {
 110         writeb(val, ds1511_base + (reg * reg_spacing));
 111 }
 112
 113  static inline void
 114 rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 115 {
 116         rtc_write((val | 0x80), reg);
 117 }
 118
 119  static noinline uint8_t
 120 rtc_read(enum ds1511reg reg)
 121 {
 122         return readb(ds1511_base + (reg * reg_spacing));
 123 }
 124
 125  static inline void
 126 rtc_disable_update(void)
 127 {
 128         rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 129 }
 130
 131  static void
 132 rtc_enable_update(void)
 133 {
 134         rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
 135 }
 136
 137 /*
 138  * #define DS1511_WDOG_RESET_SUPPORT
 139  *
 140  * Uncomment this if you want to use these routines in
 141  * some platform code.
 142  */
 143 #ifdef DS1511_WDOG_RESET_SUPPORT
 144 /*
 145  * just enough code to set the watchdog timer so that it
 146  * will reboot the system
 147  */
 148  void
 149 ds1511_wdog_set(unsigned long deciseconds)
 150 {
 151         /*
 152          * the wdog timer can take 99.99 seconds
 153          */
 154         deciseconds %= 10000;
 155         /*
 156          * set the wdog values in the wdog registers
 157          */
 158         rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
 159         rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
 160         /*
 161          * set wdog enable and wdog 'steering' bit to issue a reset
 162          */
 163         rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
 164 }
 165
 166  void
 167 ds1511_wdog_disable(void)
 168 {
 169         /*
 170          * clear wdog enable and wdog 'steering' bits
 171          */
 172         rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
 173         /*
 174          * clear the wdog counter
 175          */
 176         rtc_write(0, DS1511_WD_MSEC);
 177         rtc_write(0, DS1511_WD_SEC);
 178 }
 179 #endif
 180
 181 /*
 182  * set the rtc chip's idea of the time.
 183  * stupidly, some callers call with year unmolested;
 184  * and some call with  year = year - 1900.  thanks.
 185  */
 186 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
 187 {
 188         u8 mon, day, dow, hrs, min, sec, yrs, cen;
 189         unsigned long flags;
 190
 191         /*
 192          * won't have to change this for a while
 193          */
 194         if (rtc_tm->tm_year < 1900) {
 195                 rtc_tm->tm_year += 1900;
 196         }
 197
 198         if (rtc_tm->tm_year < 1970) {
 199                 return -EINVAL;
 200         }
 201         yrs = rtc_tm->tm_year % 100;
 202         cen = rtc_tm->tm_year / 100;
 203         mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
 204         day = rtc_tm->tm_mday;
 205         dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
 206         hrs = rtc_tm->tm_hour;
 207         min = rtc_tm->tm_min;
 208         sec = rtc_tm->tm_sec;
 209
 210         if ((mon > 12) || (day == 0)) {
 211                 return -EINVAL;
 212         }
 213
 214         if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
 215                 return -EINVAL;
 216         }
 217
 218         if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
 219                 return -EINVAL;
 220         }
 221
 222         /*
 223          * each register is a different number of valid bits
 224          */
 225         sec = bin2bcd(sec) & 0x7f;
 226         min = bin2bcd(min) & 0x7f;
 227         hrs = bin2bcd(hrs) & 0x3f;
 228         day = bin2bcd(day) & 0x3f;
 229         mon = bin2bcd(mon) & 0x1f;
 230         yrs = bin2bcd(yrs) & 0xff;
 231         cen = bin2bcd(cen) & 0xff;
 232
 233         spin_lock_irqsave(&ds1511_lock, flags);
 234         rtc_disable_update();
 235         rtc_write(cen, RTC_CENTURY);
 236         rtc_write(yrs, RTC_YEAR);
 237         rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
 238         rtc_write(day, RTC_DOM);
 239         rtc_write(hrs, RTC_HOUR);
 240         rtc_write(min, RTC_MIN);
 241         rtc_write(sec, RTC_SEC);
 242         rtc_write(dow, RTC_DOW);
 243         rtc_enable_update();
 244         spin_unlock_irqrestore(&ds1511_lock, flags);
 245
 246         return 0;
 247 }
 248
 249 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 250 {
 251         unsigned int century;
 252         unsigned long 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->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->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 = 0;
 368
 369         spin_lock(&pdata->lock);
 370         /*
 371          * read and clear interrupt
 372          */
 373         if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
 374                 events = RTC_IRQF;
 375                 if (rtc_read(RTC_ALARM_SEC) & 0x80)
 376                         events |= RTC_UF;
 377                 else
 378                         events |= RTC_AF;
 379                 if (likely(pdata->rtc))
 380                         rtc_update_irq(pdata->rtc, 1, events);
 381         }
 382         spin_unlock(&pdata->lock);
 383         return events ? IRQ_HANDLED : IRQ_NONE;
 384 }
 385
 386 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 387 {
 388         struct platform_device *pdev = to_platform_device(dev);
 389         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 390
 391         if (pdata->irq <= 0)
 392                 return -EINVAL;
 393         if (enabled)
 394                 pdata->irqen |= RTC_AF;
 395         else
 396                 pdata->irqen &= ~RTC_AF;
 397         ds1511_rtc_update_alarm(pdata);
 398         return 0;
 399 }
 400
 401 static const struct rtc_class_ops ds1511_rtc_ops = {
 402         .read_time              = ds1511_rtc_read_time,
 403         .set_time               = ds1511_rtc_set_time,
 404         .read_alarm             = ds1511_rtc_read_alarm,
 405         .set_alarm              = ds1511_rtc_set_alarm,
 406         .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
 407 };
 408
 409  static ssize_t
 410 ds1511_nvram_read(struct file *filp, struct kobject *kobj,
 411                   struct bin_attribute *ba,
 412                   char *buf, loff_t pos, size_t size)
 413 {
 414         ssize_t count;
 415
 416         /*
 417          * if count is more than one, turn on "burst" mode
 418          * turn it off when you're done
 419          */
 420         if (size > 1) {
 421                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 422         }
 423         if (pos > DS1511_RAM_MAX) {
 424                 pos = DS1511_RAM_MAX;
 425         }
 426         if (size + pos > DS1511_RAM_MAX + 1) {
 427                 size = DS1511_RAM_MAX - pos + 1;
 428         }
 429         rtc_write(pos, DS1511_RAMADDR_LSB);
 430         for (count = 0; size > 0; count++, size--) {
 431                 *buf++ = rtc_read(DS1511_RAMDATA);
 432         }
 433         if (count > 1) {
 434                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 435         }
 436         return count;
 437 }
 438
 439  static ssize_t
 440 ds1511_nvram_write(struct file *filp, struct kobject *kobj,
 441                    struct bin_attribute *bin_attr,
 442                    char *buf, loff_t pos, size_t size)
 443 {
 444         ssize_t count;
 445
 446         /*
 447          * if count is more than one, turn on "burst" mode
 448          * turn it off when you're done
 449          */
 450         if (size > 1) {
 451                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 452         }
 453         if (pos > DS1511_RAM_MAX) {
 454                 pos = DS1511_RAM_MAX;
 455         }
 456         if (size + pos > DS1511_RAM_MAX + 1) {
 457                 size = DS1511_RAM_MAX - pos + 1;
 458         }
 459         rtc_write(pos, DS1511_RAMADDR_LSB);
 460         for (count = 0; size > 0; count++, size--) {
 461                 rtc_write(*buf++, DS1511_RAMDATA);
 462         }
 463         if (count > 1) {
 464                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 465         }
 466         return count;
 467 }
 468
 469 static struct bin_attribute ds1511_nvram_attr = {
 470         .attr = {
 471                 .name = "nvram",
 472                 .mode = S_IRUGO | S_IWUSR,
 473         },
 474         .size = DS1511_RAM_MAX,
 475         .read = ds1511_nvram_read,
 476         .write = ds1511_nvram_write,
 477 };
 478
 479 static int 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_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 ds1511_rtc_remove(struct platform_device *pdev)
 554 {
 555         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 556
 557         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 558         rtc_device_unregister(pdata->rtc);
 559         if (pdata->irq > 0) {
 560                 /*
 561                  * disable the alarm interrupt
 562                  */
 563                 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
 564                 rtc_read(RTC_CMD1);
 565         }
 566         return 0;
 567 }
 568
 569 /* work with hotplug and coldplug */
 570 MODULE_ALIAS("platform:ds1511");
 571
 572 static struct platform_driver ds1511_rtc_driver = {
 573         .probe          = ds1511_rtc_probe,
 574         .remove         = ds1511_rtc_remove,
 575         .driver         = {
 576                 .name   = "ds1511",
 577                 .owner  = THIS_MODULE,
 578         },
 579 };
 580
 581 module_platform_driver(ds1511_rtc_driver);
 582
 583 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 584 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 585 MODULE_LICENSE("GPL");
 586 MODULE_VERSION(DRV_VERSION);