linux/drivers/rtc/rtc-ds1511.c
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   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
  30enum 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
  89struct 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
 102static DEFINE_SPINLOCK(ds1511_lock);
 103
 104static __iomem char *ds1511_base;
 105static u32 reg_spacing = 1;
 106
 107 static noinline void
 108rtc_write(uint8_t val, uint32_t reg)
 109{
 110        writeb(val, ds1511_base + (reg * reg_spacing));
 111}
 112
 113 static inline void
 114rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 115{
 116        rtc_write((val | 0x80), reg);
 117}
 118
 119 static noinline uint8_t
 120rtc_read(enum ds1511reg reg)
 121{
 122        return readb(ds1511_base + (reg * reg_spacing));
 123}
 124
 125 static inline void
 126rtc_disable_update(void)
 127{
 128        rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 129}
 130
 131 static void
 132rtc_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
 149ds1511_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
 167ds1511_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 */
 186static 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
 249static 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
 303ds1511_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
 326ds1511_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
 346ds1511_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
 363ds1511_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
 386static 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
 401static 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
 410ds1511_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
 440ds1511_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
 469static 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
 479static 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
 553static 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 */
 570MODULE_ALIAS("platform:ds1511");
 571
 572static 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
 581module_platform_driver(ds1511_rtc_driver);
 582
 583MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 584MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 585MODULE_LICENSE("GPL");
 586MODULE_VERSION(DRV_VERSION);
 587
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