drivers/rtc/rtc-ds1511.c

   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
  30 enum 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
  89 struct 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
 101 static DEFINE_SPINLOCK(ds1511_lock);
 102
 103 static __iomem char *ds1511_base;
 104 static u32 reg_spacing = 1;
 105
 106 static noinline void
 107 rtc_write(uint8_t val, uint32_t reg)
 108 {
 109         writeb(val, ds1511_base + (reg * reg_spacing));
 110 }
 111
 112 static inline void
 113 rtc_write_alarm(uint8_t val, enum ds1511reg reg)
 114 {
 115         rtc_write((val | 0x80), reg);
 116 }
 117
 118 static noinline uint8_t
 119 rtc_read(enum ds1511reg reg)
 120 {
 121         return readb(ds1511_base + (reg * reg_spacing));
 122 }
 123
 124 static inline void
 125 rtc_disable_update(void)
 126 {
 127         rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
 128 }
 129
 130 static void
 131 rtc_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  */
 147 void
 148 ds1511_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
 165 void
 166 ds1511_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  */
 185 static 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
 244 static 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  */
 297 static void
 298 ds1511_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
 320 static int
 321 ds1511_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
 340 static int
 341 ds1511_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
 357 static irqreturn_t
 358 ds1511_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
 381 static 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
 396 static 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
 404 static ssize_t
 405 ds1511_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
 434 static ssize_t
 435 ds1511_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
 464 static 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
 474 static 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
 540 static 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 */
 556 MODULE_ALIAS("platform:ds1511");
 557
 558 static 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
 567 module_platform_driver(ds1511_rtc_driver);
 568
 569 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 570 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 571 MODULE_LICENSE("GPL");
 572 MODULE_VERSION(DRV_VERSION);