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
 107static noinline void
 108rtc_write(uint8_t val, uint32_t reg)
 109{
 110        writeb(val, ds1511_base + (reg * reg_spacing));
 111}
 112
 113static inline void
 114rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 115{
 116        rtc_write((val | 0x80), reg);
 117}
 118
 119static noinline uint8_t
 120rtc_read(enum ds1511reg reg)
 121{
 122        return readb(ds1511_base + (reg * reg_spacing));
 123}
 124
 125static inline void
 126rtc_disable_update(void)
 127{
 128        rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 129}
 130
 131static 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 */
 148void
 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
 166void
 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        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
 245static 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 */
 298static void
 299ds1511_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
 321static int
 322ds1511_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
 341static int
 342ds1511_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
 358static irqreturn_t
 359ds1511_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
 382static 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
 397static 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
 405static ssize_t
 406ds1511_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
 435static ssize_t
 436ds1511_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
 465static 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
 475static 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
 547static 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 */
 563MODULE_ALIAS("platform:ds1511");
 564
 565static 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
 574module_platform_driver(ds1511_rtc_driver);
 575
 576MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 577MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 578MODULE_LICENSE("GPL");
 579MODULE_VERSION(DRV_VERSION);
 580
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