linux/drivers/rtc/rtc-ds1511.c
<<
>>
Prefs
   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 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
 101static DEFINE_SPINLOCK(ds1511_lock);
 102
 103static __iomem char *ds1511_base;
 104static u32 reg_spacing = 1;
 105
 106static noinline void
 107rtc_write(uint8_t val, uint32_t reg)
 108{
 109        writeb(val, ds1511_base + (reg * reg_spacing));
 110}
 111
 112static inline void
 113rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 114{
 115        rtc_write((val | 0x80), reg);
 116}
 117
 118static noinline uint8_t
 119rtc_read(enum ds1511reg reg)
 120{
 121        return readb(ds1511_base + (reg * reg_spacing));
 122}
 123
 124static inline void
 125rtc_disable_update(void)
 126{
 127        rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 128}
 129
 130static void
 131rtc_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 */
 147void
 148ds1511_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
 165void
 166ds1511_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 */
 185static 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        if (rtc_tm->tm_year < 1970)
 197                return -EINVAL;
 198
 199        yrs = rtc_tm->tm_year % 100;
 200        cen = rtc_tm->tm_year / 100;
 201        mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
 202        day = rtc_tm->tm_mday;
 203        dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
 204        hrs = rtc_tm->tm_hour;
 205        min = rtc_tm->tm_min;
 206        sec = rtc_tm->tm_sec;
 207
 208        if ((mon > 12) || (day == 0))
 209                return -EINVAL;
 210
 211        if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
 212                return -EINVAL;
 213
 214        if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 215                return -EINVAL;
 216
 217        /*
 218         * each register is a different number of valid bits
 219         */
 220        sec = bin2bcd(sec) & 0x7f;
 221        min = bin2bcd(min) & 0x7f;
 222        hrs = bin2bcd(hrs) & 0x3f;
 223        day = bin2bcd(day) & 0x3f;
 224        mon = bin2bcd(mon) & 0x1f;
 225        yrs = bin2bcd(yrs) & 0xff;
 226        cen = bin2bcd(cen) & 0xff;
 227
 228        spin_lock_irqsave(&ds1511_lock, flags);
 229        rtc_disable_update();
 230        rtc_write(cen, RTC_CENTURY);
 231        rtc_write(yrs, RTC_YEAR);
 232        rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
 233        rtc_write(day, RTC_DOM);
 234        rtc_write(hrs, RTC_HOUR);
 235        rtc_write(min, RTC_MIN);
 236        rtc_write(sec, RTC_SEC);
 237        rtc_write(dow, RTC_DOW);
 238        rtc_enable_update();
 239        spin_unlock_irqrestore(&ds1511_lock, flags);
 240
 241        return 0;
 242}
 243
 244static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 245{
 246        unsigned int century;
 247        unsigned long flags;
 248
 249        spin_lock_irqsave(&ds1511_lock, flags);
 250        rtc_disable_update();
 251
 252        rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
 253        rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
 254        rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
 255        rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
 256        rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
 257        rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
 258        rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
 259        century = rtc_read(RTC_CENTURY);
 260
 261        rtc_enable_update();
 262        spin_unlock_irqrestore(&ds1511_lock, flags);
 263
 264        rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 265        rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 266        rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 267        rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 268        rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
 269        rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 270        rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 271        century = bcd2bin(century) * 100;
 272
 273        /*
 274         * Account for differences between how the RTC uses the values
 275         * and how they are defined in a struct rtc_time;
 276         */
 277        century += rtc_tm->tm_year;
 278        rtc_tm->tm_year = century - 1900;
 279
 280        rtc_tm->tm_mon--;
 281
 282        if (rtc_valid_tm(rtc_tm) < 0) {
 283                dev_err(dev, "retrieved date/time is not valid.\n");
 284                rtc_time_to_tm(0, rtc_tm);
 285        }
 286        return 0;
 287}
 288
 289/*
 290 * write the alarm register settings
 291 *
 292 * we only have the use to interrupt every second, otherwise
 293 * known as the update interrupt, or the interrupt if the whole
 294 * date/hours/mins/secs matches.  the ds1511 has many more
 295 * permutations, but the kernel doesn't.
 296 */
 297static void
 298ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
 299{
 300        unsigned long flags;
 301
 302        spin_lock_irqsave(&pdata->lock, flags);
 303        rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 304               0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
 305               RTC_ALARM_DATE);
 306        rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 307               0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
 308               RTC_ALARM_HOUR);
 309        rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 310               0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
 311               RTC_ALARM_MIN);
 312        rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 313               0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
 314               RTC_ALARM_SEC);
 315        rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
 316        rtc_read(RTC_CMD1);     /* clear interrupts */
 317        spin_unlock_irqrestore(&pdata->lock, flags);
 318}
 319
 320static int
 321ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 322{
 323        struct platform_device *pdev = to_platform_device(dev);
 324        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 325
 326        if (pdata->irq <= 0)
 327                return -EINVAL;
 328
 329        pdata->alrm_mday = alrm->time.tm_mday;
 330        pdata->alrm_hour = alrm->time.tm_hour;
 331        pdata->alrm_min = alrm->time.tm_min;
 332        pdata->alrm_sec = alrm->time.tm_sec;
 333        if (alrm->enabled)
 334                pdata->irqen |= RTC_AF;
 335
 336        ds1511_rtc_update_alarm(pdata);
 337        return 0;
 338}
 339
 340static int
 341ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 342{
 343        struct platform_device *pdev = to_platform_device(dev);
 344        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 345
 346        if (pdata->irq <= 0)
 347                return -EINVAL;
 348
 349        alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 350        alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 351        alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 352        alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 353        alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 354        return 0;
 355}
 356
 357static irqreturn_t
 358ds1511_interrupt(int irq, void *dev_id)
 359{
 360        struct platform_device *pdev = dev_id;
 361        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 362        unsigned long events = 0;
 363
 364        spin_lock(&pdata->lock);
 365        /*
 366         * read and clear interrupt
 367         */
 368        if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
 369                events = RTC_IRQF;
 370                if (rtc_read(RTC_ALARM_SEC) & 0x80)
 371                        events |= RTC_UF;
 372                else
 373                        events |= RTC_AF;
 374                if (likely(pdata->rtc))
 375                        rtc_update_irq(pdata->rtc, 1, events);
 376        }
 377        spin_unlock(&pdata->lock);
 378        return events ? IRQ_HANDLED : IRQ_NONE;
 379}
 380
 381static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 382{
 383        struct platform_device *pdev = to_platform_device(dev);
 384        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 385
 386        if (pdata->irq <= 0)
 387                return -EINVAL;
 388        if (enabled)
 389                pdata->irqen |= RTC_AF;
 390        else
 391                pdata->irqen &= ~RTC_AF;
 392        ds1511_rtc_update_alarm(pdata);
 393        return 0;
 394}
 395
 396static const struct rtc_class_ops ds1511_rtc_ops = {
 397        .read_time              = ds1511_rtc_read_time,
 398        .set_time               = ds1511_rtc_set_time,
 399        .read_alarm             = ds1511_rtc_read_alarm,
 400        .set_alarm              = ds1511_rtc_set_alarm,
 401        .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
 402};
 403
 404static ssize_t
 405ds1511_nvram_read(struct file *filp, struct kobject *kobj,
 406                  struct bin_attribute *ba,
 407                  char *buf, loff_t pos, size_t size)
 408{
 409        ssize_t count;
 410
 411        /*
 412         * if count is more than one, turn on "burst" mode
 413         * turn it off when you're done
 414         */
 415        if (size > 1)
 416                rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 417
 418        if (pos > DS1511_RAM_MAX)
 419                pos = DS1511_RAM_MAX;
 420
 421        if (size + pos > DS1511_RAM_MAX + 1)
 422                size = DS1511_RAM_MAX - pos + 1;
 423
 424        rtc_write(pos, DS1511_RAMADDR_LSB);
 425        for (count = 0; size > 0; count++, size--)
 426                *buf++ = rtc_read(DS1511_RAMDATA);
 427
 428        if (count > 1)
 429                rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 430
 431        return count;
 432}
 433
 434static ssize_t
 435ds1511_nvram_write(struct file *filp, struct kobject *kobj,
 436                   struct bin_attribute *bin_attr,
 437                   char *buf, loff_t pos, size_t size)
 438{
 439        ssize_t count;
 440
 441        /*
 442         * if count is more than one, turn on "burst" mode
 443         * turn it off when you're done
 444         */
 445        if (size > 1)
 446                rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
 447
 448        if (pos > DS1511_RAM_MAX)
 449                pos = DS1511_RAM_MAX;
 450
 451        if (size + pos > DS1511_RAM_MAX + 1)
 452                size = DS1511_RAM_MAX - pos + 1;
 453
 454        rtc_write(pos, DS1511_RAMADDR_LSB);
 455        for (count = 0; size > 0; count++, size--)
 456                rtc_write(*buf++, DS1511_RAMDATA);
 457
 458        if (count > 1)
 459                rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
 460
 461        return count;
 462}
 463
 464static struct bin_attribute ds1511_nvram_attr = {
 465        .attr = {
 466                .name = "nvram",
 467                .mode = S_IRUGO | S_IWUSR,
 468        },
 469        .size = DS1511_RAM_MAX,
 470        .read = ds1511_nvram_read,
 471        .write = ds1511_nvram_write,
 472};
 473
 474static int ds1511_rtc_probe(struct platform_device *pdev)
 475{
 476        struct rtc_device *rtc;
 477        struct resource *res;
 478        struct rtc_plat_data *pdata;
 479        int ret = 0;
 480
 481        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 482        if (!pdata)
 483                return -ENOMEM;
 484
 485        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 486        ds1511_base = devm_ioremap_resource(&pdev->dev, res);
 487        if (IS_ERR(ds1511_base))
 488                return PTR_ERR(ds1511_base);
 489        pdata->ioaddr = ds1511_base;
 490        pdata->irq = platform_get_irq(pdev, 0);
 491
 492        /*
 493         * turn on the clock and the crystal, etc.
 494         */
 495        rtc_write(0, RTC_CMD);
 496        rtc_write(0, RTC_CMD1);
 497        /*
 498         * clear the wdog counter
 499         */
 500        rtc_write(0, DS1511_WD_MSEC);
 501        rtc_write(0, DS1511_WD_SEC);
 502        /*
 503         * start the clock
 504         */
 505        rtc_enable_update();
 506
 507        /*
 508         * check for a dying bat-tree
 509         */
 510        if (rtc_read(RTC_CMD1) & DS1511_BLF1)
 511                dev_warn(&pdev->dev, "voltage-low detected.\n");
 512
 513        spin_lock_init(&pdata->lock);
 514        platform_set_drvdata(pdev, pdata);
 515        /*
 516         * if the platform has an interrupt in mind for this device,
 517         * then by all means, set it
 518         */
 519        if (pdata->irq > 0) {
 520                rtc_read(RTC_CMD1);
 521                if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
 522                        IRQF_SHARED, pdev->name, pdev) < 0) {
 523
 524                        dev_warn(&pdev->dev, "interrupt not available.\n");
 525                        pdata->irq = 0;
 526                }
 527        }
 528
 529        rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &ds1511_rtc_ops,
 530                                        THIS_MODULE);
 531        if (IS_ERR(rtc))
 532                return PTR_ERR(rtc);
 533        pdata->rtc = rtc;
 534
 535        ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 536
 537        return ret;
 538}
 539
 540static int ds1511_rtc_remove(struct platform_device *pdev)
 541{
 542        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 543
 544        sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
 545        if (pdata->irq > 0) {
 546                /*
 547                 * disable the alarm interrupt
 548                 */
 549                rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
 550                rtc_read(RTC_CMD1);
 551        }
 552        return 0;
 553}
 554
 555/* work with hotplug and coldplug */
 556MODULE_ALIAS("platform:ds1511");
 557
 558static struct platform_driver ds1511_rtc_driver = {
 559        .probe          = ds1511_rtc_probe,
 560        .remove         = ds1511_rtc_remove,
 561        .driver         = {
 562                .name   = "ds1511",
 563                .owner  = THIS_MODULE,
 564        },
 565};
 566
 567module_platform_driver(ds1511_rtc_driver);
 568
 569MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 570MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 571MODULE_LICENSE("GPL");
 572MODULE_VERSION(DRV_VERSION);
 573
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.