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