LXR linux/drivers/rtc/rtc-ds1511.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * An rtc driver for the Dallas DS1511
   4 *
   5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   6 * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
   7 *
   8 * Real time clock driver for the Dallas 1511 chip, which also
   9 * contains a watchdog timer.  There is a tiny amount of code that
  10 * platform code could use to mess with the watchdog device a little
  11 * bit, but not a full watchdog driver.
  12 */
  13
  14#include <linux/bcd.h>
  15#include <linux/init.h>
  16#include <linux/kernel.h>
  17#include <linux/gfp.h>
  18#include <linux/delay.h>
  19#include <linux/interrupt.h>
  20#include <linux/rtc.h>
  21#include <linux/platform_device.h>
  22#include <linux/io.h>
  23#include <linux/module.h>
  24
  25enum ds1511reg {
  26        DS1511_SEC = 0x0,
  27        DS1511_MIN = 0x1,
  28        DS1511_HOUR = 0x2,
  29        DS1511_DOW = 0x3,
  30        DS1511_DOM = 0x4,
  31        DS1511_MONTH = 0x5,
  32        DS1511_YEAR = 0x6,
  33        DS1511_CENTURY = 0x7,
  34        DS1511_AM1_SEC = 0x8,
  35        DS1511_AM2_MIN = 0x9,
  36        DS1511_AM3_HOUR = 0xa,
  37        DS1511_AM4_DATE = 0xb,
  38        DS1511_WD_MSEC = 0xc,
  39        DS1511_WD_SEC = 0xd,
  40        DS1511_CONTROL_A = 0xe,
  41        DS1511_CONTROL_B = 0xf,
  42        DS1511_RAMADDR_LSB = 0x10,
  43        DS1511_RAMDATA = 0x13
  44};
  45
  46#define DS1511_BLF1     0x80
  47#define DS1511_BLF2     0x40
  48#define DS1511_PRS      0x20
  49#define DS1511_PAB      0x10
  50#define DS1511_TDF      0x08
  51#define DS1511_KSF      0x04
  52#define DS1511_WDF      0x02
  53#define DS1511_IRQF     0x01
  54#define DS1511_TE       0x80
  55#define DS1511_CS       0x40
  56#define DS1511_BME      0x20
  57#define DS1511_TPE      0x10
  58#define DS1511_TIE      0x08
  59#define DS1511_KIE      0x04
  60#define DS1511_WDE      0x02
  61#define DS1511_WDS      0x01
  62#define DS1511_RAM_MAX  0x100
  63
  64#define RTC_CMD         DS1511_CONTROL_B
  65#define RTC_CMD1        DS1511_CONTROL_A
  66
  67#define RTC_ALARM_SEC   DS1511_AM1_SEC
  68#define RTC_ALARM_MIN   DS1511_AM2_MIN
  69#define RTC_ALARM_HOUR  DS1511_AM3_HOUR
  70#define RTC_ALARM_DATE  DS1511_AM4_DATE
  71
  72#define RTC_SEC         DS1511_SEC
  73#define RTC_MIN         DS1511_MIN
  74#define RTC_HOUR        DS1511_HOUR
  75#define RTC_DOW         DS1511_DOW
  76#define RTC_DOM         DS1511_DOM
  77#define RTC_MON         DS1511_MONTH
  78#define RTC_YEAR        DS1511_YEAR
  79#define RTC_CENTURY     DS1511_CENTURY
  80
  81#define RTC_TIE DS1511_TIE
  82#define RTC_TE  DS1511_TE
  83
  84struct rtc_plat_data {
  85        struct rtc_device *rtc;
  86        void __iomem *ioaddr;           /* virtual base address */
  87        int irq;
  88        unsigned int irqen;
  89        int alrm_sec;
  90        int alrm_min;
  91        int alrm_hour;
  92        int alrm_mday;
  93        spinlock_t lock;
  94};
  95
  96static DEFINE_SPINLOCK(ds1511_lock);
  97
  98static __iomem char *ds1511_base;
  99static u32 reg_spacing = 1;
 100
 101static noinline void
 102rtc_write(uint8_t val, uint32_t reg)
 103{
 104        writeb(val, ds1511_base + (reg * reg_spacing));
 105}
 106
 107static inline void
 108rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 109{
 110        rtc_write((val | 0x80), reg);
 111}
 112
 113static noinline uint8_t
 114rtc_read(enum ds1511reg reg)
 115{
 116        return readb(ds1511_base + (reg * reg_spacing));
 117}
 118
 119static inline void
 120rtc_disable_update(void)
 121{
 122        rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 123}
 124
 125static void
 126rtc_enable_update(void)
 127{
 128        rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
 129}
 130
 131/*
 132 * #define DS1511_WDOG_RESET_SUPPORT
 133 *
 134 * Uncomment this if you want to use these routines in
 135 * some platform code.
 136 */
 137#ifdef DS1511_WDOG_RESET_SUPPORT
 138/*
 139 * just enough code to set the watchdog timer so that it
 140 * will reboot the system
 141 */
 142void
 143ds1511_wdog_set(unsigned long deciseconds)
 144{
 145        /*
 146         * the wdog timer can take 99.99 seconds
 147         */
 148        deciseconds %= 10000;
 149        /*
 150         * set the wdog values in the wdog registers
 151         */
 152        rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
 153        rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
 154        /*
 155         * set wdog enable and wdog 'steering' bit to issue a reset
 156         */
 157        rtc_write(rtc_read(RTC_CMD) | DS1511_WDE | DS1511_WDS, RTC_CMD);
 158}
 159
 160void
 161ds1511_wdog_disable(void)
 162{
 163        /*
 164         * clear wdog enable and wdog 'steering' bits
 165         */
 166        rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
 167        /*
 168         * clear the wdog counter
 169         */
 170        rtc_write(0, DS1511_WD_MSEC);
 171        rtc_write(0, DS1511_WD_SEC);
 172}
 173#endif
 174
 175/*
 176 * set the rtc chip's idea of the time.
 177 * stupidly, some callers call with year unmolested;
 178 * and some call with  year = year - 1900.  thanks.
 179 */
 180static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
 181{
 182        u8 mon, day, dow, hrs, min, sec, yrs, cen;
 183        unsigned long flags;
 184
 185        /*
 186         * won't have to change this for a while
 187         */
 188        if (rtc_tm->tm_year < 1900)
 189                rtc_tm->tm_year += 1900;
 190
 191        if (rtc_tm->tm_year < 1970)
 192                return -EINVAL;
 193
 194        yrs = rtc_tm->tm_year % 100;
 195        cen = rtc_tm->tm_year / 100;
 196        mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
 197        day = rtc_tm->tm_mday;
 198        dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
 199        hrs = rtc_tm->tm_hour;
 200        min = rtc_tm->tm_min;
 201        sec = rtc_tm->tm_sec;
 202
 203        if ((mon > 12) || (day == 0))
 204                return -EINVAL;
 205
 206        if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
 207                return -EINVAL;
 208
 209        if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 210                return -EINVAL;
 211
 212        /*
 213         * each register is a different number of valid bits
 214         */
 215        sec = bin2bcd(sec) & 0x7f;
 216        min = bin2bcd(min) & 0x7f;
 217        hrs = bin2bcd(hrs) & 0x3f;
 218        day = bin2bcd(day) & 0x3f;
 219        mon = bin2bcd(mon) & 0x1f;
 220        yrs = bin2bcd(yrs) & 0xff;
 221        cen = bin2bcd(cen) & 0xff;
 222
 223        spin_lock_irqsave(&ds1511_lock, flags);
 224        rtc_disable_update();
 225        rtc_write(cen, RTC_CENTURY);
 226        rtc_write(yrs, RTC_YEAR);
 227        rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
 228        rtc_write(day, RTC_DOM);
 229        rtc_write(hrs, RTC_HOUR);
 230        rtc_write(min, RTC_MIN);
 231        rtc_write(sec, RTC_SEC);
 232        rtc_write(dow, RTC_DOW);
 233        rtc_enable_update();
 234        spin_unlock_irqrestore(&ds1511_lock, flags);
 235
 236        return 0;
 237}
 238
 239static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 240{
 241        unsigned int century;
 242        unsigned long flags;
 243
 244        spin_lock_irqsave(&ds1511_lock, flags);
 245        rtc_disable_update();
 246
 247        rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
 248        rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
 249        rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
 250        rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
 251        rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
 252        rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
 253        rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
 254        century = rtc_read(RTC_CENTURY);
 255
 256        rtc_enable_update();
 257        spin_unlock_irqrestore(&ds1511_lock, flags);
 258
 259        rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 260        rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 261        rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 262        rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 263        rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
 264        rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 265        rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 266        century = bcd2bin(century) * 100;
 267
 268        /*
 269         * Account for differences between how the RTC uses the values
 270         * and how they are defined in a struct rtc_time;
 271         */
 272        century += rtc_tm->tm_year;
 273        rtc_tm->tm_year = century - 1900;
 274
 275        rtc_tm->tm_mon--;
 276
 277        return 0;
 278}
 279
 280/*
 281 * write the alarm register settings
 282 *
 283 * we only have the use to interrupt every second, otherwise
 284 * known as the update interrupt, or the interrupt if the whole
 285 * date/hours/mins/secs matches.  the ds1511 has many more
 286 * permutations, but the kernel doesn't.
 287 */
 288static void
 289ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
 290{
 291        unsigned long flags;
 292
 293        spin_lock_irqsave(&pdata->lock, flags);
 294        rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 295               0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
 296               RTC_ALARM_DATE);
 297        rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 298               0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
 299               RTC_ALARM_HOUR);
 300        rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 301               0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
 302               RTC_ALARM_MIN);
 303        rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 304               0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
 305               RTC_ALARM_SEC);
 306        rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
 307        rtc_read(RTC_CMD1);     /* clear interrupts */
 308        spin_unlock_irqrestore(&pdata->lock, flags);
 309}
 310
 311static int
 312ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 313{
 314        struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 315
 316        if (pdata->irq <= 0)
 317                return -EINVAL;
 318
 319        pdata->alrm_mday = alrm->time.tm_mday;
 320        pdata->alrm_hour = alrm->time.tm_hour;
 321        pdata->alrm_min = alrm->time.tm_min;
 322        pdata->alrm_sec = alrm->time.tm_sec;
 323        if (alrm->enabled)
 324                pdata->irqen |= RTC_AF;
 325
 326        ds1511_rtc_update_alarm(pdata);
 327        return 0;
 328}
 329
 330static int
 331ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 332{
 333        struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 334
 335        if (pdata->irq <= 0)
 336                return -EINVAL;
 337
 338        alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 339        alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 340        alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 341        alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 342        alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 343        return 0;
 344}
 345
 346static irqreturn_t
 347ds1511_interrupt(int irq, void *dev_id)
 348{
 349        struct platform_device *pdev = dev_id;
 350        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 351        unsigned long events = 0;
 352
 353        spin_lock(&pdata->lock);
 354        /*
 355         * read and clear interrupt
 356         */
 357        if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
 358                events = RTC_IRQF;
 359                if (rtc_read(RTC_ALARM_SEC) & 0x80)
 360                        events |= RTC_UF;
 361                else
 362                        events |= RTC_AF;
 363                rtc_update_irq(pdata->rtc, 1, events);
 364        }
 365        spin_unlock(&pdata->lock);
 366        return events ? IRQ_HANDLED : IRQ_NONE;
 367}
 368
 369static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 370{
 371        struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 372
 373        if (pdata->irq <= 0)
 374                return -EINVAL;
 375        if (enabled)
 376                pdata->irqen |= RTC_AF;
 377        else
 378                pdata->irqen &= ~RTC_AF;
 379        ds1511_rtc_update_alarm(pdata);
 380        return 0;
 381}
 382
 383static const struct rtc_class_ops ds1511_rtc_ops = {
 384        .read_time              = ds1511_rtc_read_time,
 385        .set_time               = ds1511_rtc_set_time,
 386        .read_alarm             = ds1511_rtc_read_alarm,
 387        .set_alarm              = ds1511_rtc_set_alarm,
 388        .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
 389};
 390
 391static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf,
 392                             size_t size)
 393{
 394        int i;
 395
 396        rtc_write(pos, DS1511_RAMADDR_LSB);
 397        for (i = 0; i < size; i++)
 398                *(char *)buf++ = rtc_read(DS1511_RAMDATA);
 399
 400        return 0;
 401}
 402
 403static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf,
 404                              size_t size)
 405{
 406        int i;
 407
 408        rtc_write(pos, DS1511_RAMADDR_LSB);
 409        for (i = 0; i < size; i++)
 410                rtc_write(*(char *)buf++, DS1511_RAMDATA);
 411
 412        return 0;
 413}
 414
 415static int ds1511_rtc_probe(struct platform_device *pdev)
 416{
 417        struct rtc_plat_data *pdata;
 418        int ret = 0;
 419        struct nvmem_config ds1511_nvmem_cfg = {
 420                .name = "ds1511_nvram",
 421                .word_size = 1,
 422                .stride = 1,
 423                .size = DS1511_RAM_MAX,
 424                .reg_read = ds1511_nvram_read,
 425                .reg_write = ds1511_nvram_write,
 426                .priv = &pdev->dev,
 427        };
 428
 429        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 430        if (!pdata)
 431                return -ENOMEM;
 432
 433        ds1511_base = devm_platform_ioremap_resource(pdev, 0);
 434        if (IS_ERR(ds1511_base))
 435                return PTR_ERR(ds1511_base);
 436        pdata->ioaddr = ds1511_base;
 437        pdata->irq = platform_get_irq(pdev, 0);
 438
 439        /*
 440         * turn on the clock and the crystal, etc.
 441         */
 442        rtc_write(DS1511_BME, RTC_CMD);
 443        rtc_write(0, RTC_CMD1);
 444        /*
 445         * clear the wdog counter
 446         */
 447        rtc_write(0, DS1511_WD_MSEC);
 448        rtc_write(0, DS1511_WD_SEC);
 449        /*
 450         * start the clock
 451         */
 452        rtc_enable_update();
 453
 454        /*
 455         * check for a dying bat-tree
 456         */
 457        if (rtc_read(RTC_CMD1) & DS1511_BLF1)
 458                dev_warn(&pdev->dev, "voltage-low detected.\n");
 459
 460        spin_lock_init(&pdata->lock);
 461        platform_set_drvdata(pdev, pdata);
 462
 463        pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
 464        if (IS_ERR(pdata->rtc))
 465                return PTR_ERR(pdata->rtc);
 466
 467        pdata->rtc->ops = &ds1511_rtc_ops;
 468
 469        ret = devm_rtc_register_device(pdata->rtc);
 470        if (ret)
 471                return ret;
 472
 473        devm_rtc_nvmem_register(pdata->rtc, &ds1511_nvmem_cfg);
 474
 475        /*
 476         * if the platform has an interrupt in mind for this device,
 477         * then by all means, set it
 478         */
 479        if (pdata->irq > 0) {
 480                rtc_read(RTC_CMD1);
 481                if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
 482                        IRQF_SHARED, pdev->name, pdev) < 0) {
 483
 484                        dev_warn(&pdev->dev, "interrupt not available.\n");
 485                        pdata->irq = 0;
 486                }
 487        }
 488
 489        return 0;
 490}
 491
 492/* work with hotplug and coldplug */
 493MODULE_ALIAS("platform:ds1511");
 494
 495static struct platform_driver ds1511_rtc_driver = {
 496        .probe          = ds1511_rtc_probe,
 497        .driver         = {
 498                .name   = "ds1511",
 499        },
 500};
 501
 502module_platform_driver(ds1511_rtc_driver);
 503
 504MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 505MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 506MODULE_LICENSE("GPL");
 507