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         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         if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
 213                 return -EINVAL;
 214
 215         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 216                 return -EINVAL;
 217
 218         /*
 219          * each register is a different number of valid bits
 220          */
 221         sec = bin2bcd(sec) & 0x7f;
 222         min = bin2bcd(min) & 0x7f;
 223         hrs = bin2bcd(hrs) & 0x3f;
 224         day = bin2bcd(day) & 0x3f;
 225         mon = bin2bcd(mon) & 0x1f;
 226         yrs = bin2bcd(yrs) & 0xff;
 227         cen = bin2bcd(cen) & 0xff;
 228
 229         spin_lock_irqsave(&ds1511_lock, flags);
 230         rtc_disable_update();
 231         rtc_write(cen, RTC_CENTURY);
 232         rtc_write(yrs, RTC_YEAR);
 233         rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
 234         rtc_write(day, RTC_DOM);
 235         rtc_write(hrs, RTC_HOUR);
 236         rtc_write(min, RTC_MIN);
 237         rtc_write(sec, RTC_SEC);
 238         rtc_write(dow, RTC_DOW);
 239         rtc_enable_update();
 240         spin_unlock_irqrestore(&ds1511_lock, flags);
 241
 242         return 0;
 243 }
 244
 245 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 246 {
 247         unsigned int century;
 248         unsigned long flags;
 249
 250         spin_lock_irqsave(&ds1511_lock, flags);
 251         rtc_disable_update();
 252
 253         rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
 254         rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
 255         rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
 256         rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
 257         rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
 258         rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
 259         rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
 260         century = rtc_read(RTC_CENTURY);
 261
 262         rtc_enable_update();
 263         spin_unlock_irqrestore(&ds1511_lock, flags);
 264
 265         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 266         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 267         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 268         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 269         rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
 270         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 271         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 272         century = bcd2bin(century) * 100;
 273
 274         /*
 275          * Account for differences between how the RTC uses the values
 276          * and how they are defined in a struct rtc_time;
 277          */
 278         century += rtc_tm->tm_year;
 279         rtc_tm->tm_year = century - 1900;
 280
 281         rtc_tm->tm_mon--;
 282
 283         if (rtc_valid_tm(rtc_tm) < 0) {
 284                 dev_err(dev, "retrieved date/time is not valid.\n");
 285                 rtc_time_to_tm(0, rtc_tm);
 286         }
 287         return 0;
 288 }
 289
 290 /*
 291  * write the alarm register settings
 292  *
 293  * we only have the use to interrupt every second, otherwise
 294  * known as the update interrupt, or the interrupt if the whole
 295  * date/hours/mins/secs matches.  the ds1511 has many more
 296  * permutations, but the kernel doesn't.
 297  */
 298 static void
 299 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
 300 {
 301         unsigned long flags;
 302
 303         spin_lock_irqsave(&pdata->lock, flags);
 304         rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 305                0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
 306                RTC_ALARM_DATE);
 307         rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 308                0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
 309                RTC_ALARM_HOUR);
 310         rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 311                0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
 312                RTC_ALARM_MIN);
 313         rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 314                0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
 315                RTC_ALARM_SEC);
 316         rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
 317         rtc_read(RTC_CMD1);     /* clear interrupts */
 318         spin_unlock_irqrestore(&pdata->lock, flags);
 319 }
 320
 321 static int
 322 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 323 {
 324         struct platform_device *pdev = to_platform_device(dev);
 325         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 326
 327         if (pdata->irq <= 0)
 328                 return -EINVAL;
 329
 330         pdata->alrm_mday = alrm->time.tm_mday;
 331         pdata->alrm_hour = alrm->time.tm_hour;
 332         pdata->alrm_min = alrm->time.tm_min;
 333         pdata->alrm_sec = alrm->time.tm_sec;
 334         if (alrm->enabled)
 335                 pdata->irqen |= RTC_AF;
 336
 337         ds1511_rtc_update_alarm(pdata);
 338         return 0;
 339 }
 340
 341 static int
 342 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 343 {
 344         struct platform_device *pdev = to_platform_device(dev);
 345         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 346
 347         if (pdata->irq <= 0)
 348                 return -EINVAL;
 349
 350         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 351         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 352         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 353         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 354         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 355         return 0;
 356 }
 357
 358 static irqreturn_t
 359 ds1511_interrupt(int irq, void *dev_id)
 360 {
 361         struct platform_device *pdev = dev_id;
 362         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 363         unsigned long events = 0;
 364
 365         spin_lock(&pdata->lock);
 366         /*
 367          * read and clear interrupt
 368          */
 369         if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
 370                 events = RTC_IRQF;
 371                 if (rtc_read(RTC_ALARM_SEC) & 0x80)
 372                         events |= RTC_UF;
 373                 else
 374                         events |= RTC_AF;
 375                 if (likely(pdata->rtc))
 376                         rtc_update_irq(pdata->rtc, 1, events);
 377         }
 378         spin_unlock(&pdata->lock);
 379         return events ? IRQ_HANDLED : IRQ_NONE;
 380 }
 381
 382 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 383 {
 384         struct platform_device *pdev = to_platform_device(dev);
 385         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 386
 387         if (pdata->irq <= 0)
 388                 return -EINVAL;
 389         if (enabled)
 390                 pdata->irqen |= RTC_AF;
 391         else
 392                 pdata->irqen &= ~RTC_AF;
 393         ds1511_rtc_update_alarm(pdata);
 394         return 0;
 395 }
 396
 397 static const struct rtc_class_ops ds1511_rtc_ops = {
 398         .read_time              = ds1511_rtc_read_time,
 399         .set_time               = ds1511_rtc_set_time,
 400         .read_alarm             = ds1511_rtc_read_alarm,
 401         .set_alarm              = ds1511_rtc_set_alarm,
 402         .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
 403 };
 404
 405 static ssize_t
 406 ds1511_nvram_read(struct file *filp, struct kobject *kobj,
 407                   struct bin_attribute *ba,
 408                   char *buf, loff_t pos, size_t size)
 409 {
 410         ssize_t count;
 411
 412         /*
 413          * if count is more than one, turn on "burst" mode
 414          * turn it off when you're done
 415          */
 416         if (size > 1)
 417                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 418
 419         if (pos > DS1511_RAM_MAX)
 420                 pos = DS1511_RAM_MAX;
 421
 422         if (size + pos > DS1511_RAM_MAX + 1)
 423                 size = DS1511_RAM_MAX - pos + 1;
 424
 425         rtc_write(pos, DS1511_RAMADDR_LSB);
 426         for (count = 0; size > 0; count++, size--)
 427                 *buf++ = rtc_read(DS1511_RAMDATA);
 428
 429         if (count > 1)
 430                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 431
 432         return count;
 433 }
 434
 435 static ssize_t
 436 ds1511_nvram_write(struct file *filp, struct kobject *kobj,
 437                    struct bin_attribute *bin_attr,
 438                    char *buf, loff_t pos, size_t size)
 439 {
 440         ssize_t count;
 441
 442         /*
 443          * if count is more than one, turn on "burst" mode
 444          * turn it off when you're done
 445          */
 446         if (size > 1)
 447                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 448
 449         if (pos > DS1511_RAM_MAX)
 450                 pos = DS1511_RAM_MAX;
 451
 452         if (size + pos > DS1511_RAM_MAX + 1)
 453                 size = DS1511_RAM_MAX - pos + 1;
 454
 455         rtc_write(pos, DS1511_RAMADDR_LSB);
 456         for (count = 0; size > 0; count++, size--)
 457                 rtc_write(*buf++, DS1511_RAMDATA);
 458
 459         if (count > 1)
 460                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 461
 462         return count;
 463 }
 464
 465 static struct bin_attribute ds1511_nvram_attr = {
 466         .attr = {
 467                 .name = "nvram",
 468                 .mode = S_IRUGO | S_IWUSR,
 469         },
 470         .size = DS1511_RAM_MAX,
 471         .read = ds1511_nvram_read,
 472         .write = ds1511_nvram_write,
 473 };
 474
 475 static int ds1511_rtc_probe(struct platform_device *pdev)
 476 {
 477         struct rtc_device *rtc;
 478         struct resource *res;
 479         struct rtc_plat_data *pdata;
 480         int ret = 0;
 481
 482         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 483         if (!res)
 484                 return -ENODEV;
 485
 486         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 487         if (!pdata)
 488                 return -ENOMEM;
 489         pdata->size = resource_size(res);
 490         if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
 491                         pdev->name))
 492                 return -EBUSY;
 493         ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size);
 494         if (!ds1511_base)
 495                 return -ENOMEM;
 496         pdata->ioaddr = ds1511_base;
 497         pdata->irq = platform_get_irq(pdev, 0);
 498
 499         /*
 500          * turn on the clock and the crystal, etc.
 501          */
 502         rtc_write(0, RTC_CMD);
 503         rtc_write(0, RTC_CMD1);
 504         /*
 505          * clear the wdog counter
 506          */
 507         rtc_write(0, DS1511_WD_MSEC);
 508         rtc_write(0, DS1511_WD_SEC);
 509         /*
 510          * start the clock
 511          */
 512         rtc_enable_update();
 513
 514         /*
 515          * check for a dying bat-tree
 516          */
 517         if (rtc_read(RTC_CMD1) & DS1511_BLF1)
 518                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 519
 520         spin_lock_init(&pdata->lock);
 521         platform_set_drvdata(pdev, pdata);
 522         /*
 523          * if the platform has an interrupt in mind for this device,
 524          * then by all means, set it
 525          */
 526         if (pdata->irq > 0) {
 527                 rtc_read(RTC_CMD1);
 528                 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
 529                         IRQF_SHARED, pdev->name, pdev) < 0) {
 530
 531                         dev_warn(&pdev->dev, "interrupt not available.\n");
 532                         pdata->irq = 0;
 533                 }
 534         }
 535
 536         rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &ds1511_rtc_ops,
 537                                         THIS_MODULE);
 538         if (IS_ERR(rtc))
 539                 return PTR_ERR(rtc);
 540         pdata->rtc = rtc;
 541
 542         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 543
 544         return ret;
 545 }
 546
 547 static int ds1511_rtc_remove(struct platform_device *pdev)
 548 {
 549         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 550
 551         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 552         if (pdata->irq > 0) {
 553                 /*
 554                  * disable the alarm interrupt
 555                  */
 556                 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
 557                 rtc_read(RTC_CMD1);
 558         }
 559         return 0;
 560 }
 561
 562 /* work with hotplug and coldplug */
 563 MODULE_ALIAS("platform:ds1511");
 564
 565 static struct platform_driver ds1511_rtc_driver = {
 566         .probe          = ds1511_rtc_probe,
 567         .remove         = ds1511_rtc_remove,
 568         .driver         = {
 569                 .name   = "ds1511",
 570                 .owner  = THIS_MODULE,
 571         },
 572 };
 573
 574 module_platform_driver(ds1511_rtc_driver);
 575
 576 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 577 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 578 MODULE_LICENSE("GPL");
 579 MODULE_VERSION(DRV_VERSION);