drivers/rtc/rtc-ds1307.c

   1 /*
   2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
   3  *
   4  *  Copyright (C) 2005 James Chapman (ds1337 core)
   5  *  Copyright (C) 2006 David Brownell
   6  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/i2c.h>
  17 #include <linux/string.h>
  18 #include <linux/rtc.h>
  19 #include <linux/bcd.h>
  20
  21
  22
  23 /* We can't determine type by probing, but if we expect pre-Linux code
  24  * to have set the chip up as a clock (turning on the oscillator and
  25  * setting the date and time), Linux can ignore the non-clock features.
  26  * That's a natural job for a factory or repair bench.
  27  */
  28 enum ds_type {
  29         ds_1307,
  30         ds_1337,
  31         ds_1338,
  32         ds_1339,
  33         ds_1340,
  34         ds_1388,
  35         ds_3231,
  36         m41t00,
  37         rx_8025,
  38         // rs5c372 too?  different address...
  39 };
  40
  41
  42 /* RTC registers don't differ much, except for the century flag */
  43 #define DS1307_REG_SECS         0x00    /* 00-59 */
  44 #       define DS1307_BIT_CH            0x80
  45 #       define DS1340_BIT_nEOSC         0x80
  46 #define DS1307_REG_MIN          0x01    /* 00-59 */
  47 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  48 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  49 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  50 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  51 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  52 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  53 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  54 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  55 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  56 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  57
  58 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  59  * start at 7, and they differ a LOT. Only control and status matter for
  60  * basic RTC date and time functionality; be careful using them.
  61  */
  62 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  63 #       define DS1307_BIT_OUT           0x80
  64 #       define DS1338_BIT_OSF           0x20
  65 #       define DS1307_BIT_SQWE          0x10
  66 #       define DS1307_BIT_RS1           0x02
  67 #       define DS1307_BIT_RS0           0x01
  68 #define DS1337_REG_CONTROL      0x0e
  69 #       define DS1337_BIT_nEOSC         0x80
  70 #       define DS1339_BIT_BBSQI         0x20
  71 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  72 #       define DS1337_BIT_RS2           0x10
  73 #       define DS1337_BIT_RS1           0x08
  74 #       define DS1337_BIT_INTCN         0x04
  75 #       define DS1337_BIT_A2IE          0x02
  76 #       define DS1337_BIT_A1IE          0x01
  77 #define DS1340_REG_CONTROL      0x07
  78 #       define DS1340_BIT_OUT           0x80
  79 #       define DS1340_BIT_FT            0x40
  80 #       define DS1340_BIT_CALIB_SIGN    0x20
  81 #       define DS1340_M_CALIBRATION     0x1f
  82 #define DS1340_REG_FLAG         0x09
  83 #       define DS1340_BIT_OSF           0x80
  84 #define DS1337_REG_STATUS       0x0f
  85 #       define DS1337_BIT_OSF           0x80
  86 #       define DS1337_BIT_A2I           0x02
  87 #       define DS1337_BIT_A1I           0x01
  88 #define DS1339_REG_ALARM1_SECS  0x07
  89 #define DS1339_REG_TRICKLE      0x10
  90
  91 #define RX8025_REG_CTRL1        0x0e
  92 #       define RX8025_BIT_2412          0x20
  93 #define RX8025_REG_CTRL2        0x0f
  94 #       define RX8025_BIT_PON           0x10
  95 #       define RX8025_BIT_VDET          0x40
  96 #       define RX8025_BIT_XST           0x20
  97
  98
  99 struct ds1307 {
 100         u8                      offset; /* register's offset */
 101         u8                      regs[11];
 102         enum ds_type            type;
 103         unsigned long           flags;
 104 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 105 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 106         struct i2c_client       *client;
 107         struct rtc_device       *rtc;
 108         struct work_struct      work;
 109         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 110                                u8 length, u8 *values);
 111         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 112                                 u8 length, const u8 *values);
 113 };
 114
 115 struct chip_desc {
 116         unsigned                nvram56:1;
 117         unsigned                alarm:1;
 118 };
 119
 120 static const struct chip_desc chips[] = {
 121 [ds_1307] = {
 122         .nvram56        = 1,
 123 },
 124 [ds_1337] = {
 125         .alarm          = 1,
 126 },
 127 [ds_1338] = {
 128         .nvram56        = 1,
 129 },
 130 [ds_1339] = {
 131         .alarm          = 1,
 132 },
 133 [ds_1340] = {
 134 },
 135 [ds_3231] = {
 136         .alarm          = 1,
 137 },
 138 [m41t00] = {
 139 },
 140 [rx_8025] = {
 141 }, };
 142
 143 static const struct i2c_device_id ds1307_id[] = {
 144         { "ds1307", ds_1307 },
 145         { "ds1337", ds_1337 },
 146         { "ds1338", ds_1338 },
 147         { "ds1339", ds_1339 },
 148         { "ds1388", ds_1388 },
 149         { "ds1340", ds_1340 },
 150         { "ds3231", ds_3231 },
 151         { "m41t00", m41t00 },
 152         { "pt7c4338", ds_1307 },
 153         { "rx8025", rx_8025 },
 154         { }
 155 };
 156 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 157
 158 /*----------------------------------------------------------------------*/
 159
 160 #define BLOCK_DATA_MAX_TRIES 10
 161
 162 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 163                                        u8 command, u8 length, u8 *values)
 164 {
 165         s32 i, data;
 166
 167         for (i = 0; i < length; i++) {
 168                 data = i2c_smbus_read_byte_data(client, command + i);
 169                 if (data < 0)
 170                         return data;
 171                 values[i] = data;
 172         }
 173         return i;
 174 }
 175
 176 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 177                                   u8 length, u8 *values)
 178 {
 179         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 180         s32 ret;
 181         int tries = 0;
 182
 183         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 184         ret = ds1307_read_block_data_once(client, command, length, values);
 185         if (ret < 0)
 186                 return ret;
 187         do {
 188                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 189                         dev_err(&client->dev,
 190                                 "ds1307_read_block_data failed\n");
 191                         return -EIO;
 192                 }
 193                 memcpy(oldvalues, values, length);
 194                 ret = ds1307_read_block_data_once(client, command, length,
 195                                                   values);
 196                 if (ret < 0)
 197                         return ret;
 198         } while (memcmp(oldvalues, values, length));
 199         return length;
 200 }
 201
 202 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 203                                    u8 length, const u8 *values)
 204 {
 205         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 206         int tries = 0;
 207
 208         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 209         do {
 210                 s32 i, ret;
 211
 212                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 213                         dev_err(&client->dev,
 214                                 "ds1307_write_block_data failed\n");
 215                         return -EIO;
 216                 }
 217                 for (i = 0; i < length; i++) {
 218                         ret = i2c_smbus_write_byte_data(client, command + i,
 219                                                         values[i]);
 220                         if (ret < 0)
 221                                 return ret;
 222                 }
 223                 ret = ds1307_read_block_data_once(client, command, length,
 224                                                   currvalues);
 225                 if (ret < 0)
 226                         return ret;
 227         } while (memcmp(currvalues, values, length));
 228         return length;
 229 }
 230
 231 /*----------------------------------------------------------------------*/
 232
 233 /*
 234  * The IRQ logic includes a "real" handler running in IRQ context just
 235  * long enough to schedule this workqueue entry.   We need a task context
 236  * to talk to the RTC, since I2C I/O calls require that; and disable the
 237  * IRQ until we clear its status on the chip, so that this handler can
 238  * work with any type of triggering (not just falling edge).
 239  *
 240  * The ds1337 and ds1339 both have two alarms, but we only use the first
 241  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 242  * signal; ds1339 chips have only one alarm signal.
 243  */
 244 static void ds1307_work(struct work_struct *work)
 245 {
 246         struct ds1307           *ds1307;
 247         struct i2c_client       *client;
 248         struct mutex            *lock;
 249         int                     stat, control;
 250
 251         ds1307 = container_of(work, struct ds1307, work);
 252         client = ds1307->client;
 253         lock = &ds1307->rtc->ops_lock;
 254
 255         mutex_lock(lock);
 256         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 257         if (stat < 0)
 258                 goto out;
 259
 260         if (stat & DS1337_BIT_A1I) {
 261                 stat &= ~DS1337_BIT_A1I;
 262                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 263
 264                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 265                 if (control < 0)
 266                         goto out;
 267
 268                 control &= ~DS1337_BIT_A1IE;
 269                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 270
 271                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 272         }
 273
 274 out:
 275         if (test_bit(HAS_ALARM, &ds1307->flags))
 276                 enable_irq(client->irq);
 277         mutex_unlock(lock);
 278 }
 279
 280 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 281 {
 282         struct i2c_client       *client = dev_id;
 283         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 284
 285         disable_irq_nosync(irq);
 286         schedule_work(&ds1307->work);
 287         return IRQ_HANDLED;
 288 }
 289
 290 /*----------------------------------------------------------------------*/
 291
 292 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 293 {
 294         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 295         int             tmp;
 296
 297         /* read the RTC date and time registers all at once */
 298         tmp = ds1307->read_block_data(ds1307->client,
 299                 ds1307->offset, 7, ds1307->regs);
 300         if (tmp != 7) {
 301                 dev_err(dev, "%s error %d\n", "read", tmp);
 302                 return -EIO;
 303         }
 304
 305         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 306                         "read",
 307                         ds1307->regs[0], ds1307->regs[1],
 308                         ds1307->regs[2], ds1307->regs[3],
 309                         ds1307->regs[4], ds1307->regs[5],
 310                         ds1307->regs[6]);
 311
 312         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 313         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 314         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 315         t->tm_hour = bcd2bin(tmp);
 316         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 317         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 318         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 319         t->tm_mon = bcd2bin(tmp) - 1;
 320
 321         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 322         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 323
 324         dev_dbg(dev, "%s secs=%d, mins=%d, "
 325                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 326                 "read", t->tm_sec, t->tm_min,
 327                 t->tm_hour, t->tm_mday,
 328                 t->tm_mon, t->tm_year, t->tm_wday);
 329
 330         /* initial clock setting can be undefined */
 331         return rtc_valid_tm(t);
 332 }
 333
 334 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 335 {
 336         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 337         int             result;
 338         int             tmp;
 339         u8              *buf = ds1307->regs;
 340
 341         dev_dbg(dev, "%s secs=%d, mins=%d, "
 342                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 343                 "write", t->tm_sec, t->tm_min,
 344                 t->tm_hour, t->tm_mday,
 345                 t->tm_mon, t->tm_year, t->tm_wday);
 346
 347         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 348         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 349         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 350         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 351         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 352         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 353
 354         /* assume 20YY not 19YY */
 355         tmp = t->tm_year - 100;
 356         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 357
 358         switch (ds1307->type) {
 359         case ds_1337:
 360         case ds_1339:
 361         case ds_3231:
 362                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 363                 break;
 364         case ds_1340:
 365                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 366                                 | DS1340_BIT_CENTURY;
 367                 break;
 368         default:
 369                 break;
 370         }
 371
 372         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 373                 "write", buf[0], buf[1], buf[2], buf[3],
 374                 buf[4], buf[5], buf[6]);
 375
 376         result = ds1307->write_block_data(ds1307->client,
 377                 ds1307->offset, 7, buf);
 378         if (result < 0) {
 379                 dev_err(dev, "%s error %d\n", "write", result);
 380                 return result;
 381         }
 382         return 0;
 383 }
 384
 385 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 386 {
 387         struct i2c_client       *client = to_i2c_client(dev);
 388         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 389         int                     ret;
 390
 391         if (!test_bit(HAS_ALARM, &ds1307->flags))
 392                 return -EINVAL;
 393
 394         /* read all ALARM1, ALARM2, and status registers at once */
 395         ret = ds1307->read_block_data(client,
 396                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 397         if (ret != 9) {
 398                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 399                 return -EIO;
 400         }
 401
 402         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 403                         "alarm read",
 404                         ds1307->regs[0], ds1307->regs[1],
 405                         ds1307->regs[2], ds1307->regs[3],
 406                         ds1307->regs[4], ds1307->regs[5],
 407                         ds1307->regs[6], ds1307->regs[7],
 408                         ds1307->regs[8]);
 409
 410         /* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 411          * and that all four fields are checked matches
 412          */
 413         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 414         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 415         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 416         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 417         t->time.tm_mon = -1;
 418         t->time.tm_year = -1;
 419         t->time.tm_wday = -1;
 420         t->time.tm_yday = -1;
 421         t->time.tm_isdst = -1;
 422
 423         /* ... and status */
 424         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 425         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 426
 427         dev_dbg(dev, "%s secs=%d, mins=%d, "
 428                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 429                 "alarm read", t->time.tm_sec, t->time.tm_min,
 430                 t->time.tm_hour, t->time.tm_mday,
 431                 t->enabled, t->pending);
 432
 433         return 0;
 434 }
 435
 436 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 437 {
 438         struct i2c_client       *client = to_i2c_client(dev);
 439         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 440         unsigned char           *buf = ds1307->regs;
 441         u8                      control, status;
 442         int                     ret;
 443
 444         if (!test_bit(HAS_ALARM, &ds1307->flags))
 445                 return -EINVAL;
 446
 447         dev_dbg(dev, "%s secs=%d, mins=%d, "
 448                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 449                 "alarm set", t->time.tm_sec, t->time.tm_min,
 450                 t->time.tm_hour, t->time.tm_mday,
 451                 t->enabled, t->pending);
 452
 453         /* read current status of both alarms and the chip */
 454         ret = ds1307->read_block_data(client,
 455                         DS1339_REG_ALARM1_SECS, 9, buf);
 456         if (ret != 9) {
 457                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 458                 return -EIO;
 459         }
 460         control = ds1307->regs[7];
 461         status = ds1307->regs[8];
 462
 463         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 464                         "alarm set (old status)",
 465                         ds1307->regs[0], ds1307->regs[1],
 466                         ds1307->regs[2], ds1307->regs[3],
 467                         ds1307->regs[4], ds1307->regs[5],
 468                         ds1307->regs[6], control, status);
 469
 470         /* set ALARM1, using 24 hour and day-of-month modes */
 471         buf[0] = bin2bcd(t->time.tm_sec);
 472         buf[1] = bin2bcd(t->time.tm_min);
 473         buf[2] = bin2bcd(t->time.tm_hour);
 474         buf[3] = bin2bcd(t->time.tm_mday);
 475
 476         /* set ALARM2 to non-garbage */
 477         buf[4] = 0;
 478         buf[5] = 0;
 479         buf[6] = 0;
 480
 481         /* optionally enable ALARM1 */
 482         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 483         if (t->enabled) {
 484                 dev_dbg(dev, "alarm IRQ armed\n");
 485                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 486         }
 487         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 488
 489         ret = ds1307->write_block_data(client,
 490                         DS1339_REG_ALARM1_SECS, 9, buf);
 491         if (ret < 0) {
 492                 dev_err(dev, "can't set alarm time\n");
 493                 return ret;
 494         }
 495
 496         return 0;
 497 }
 498
 499 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 500 {
 501         struct i2c_client       *client = to_i2c_client(dev);
 502         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 503         int                     ret;
 504
 505         if (!test_bit(HAS_ALARM, &ds1307->flags))
 506                 return -ENOTTY;
 507
 508         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 509         if (ret < 0)
 510                 return ret;
 511
 512         if (enabled)
 513                 ret |= DS1337_BIT_A1IE;
 514         else
 515                 ret &= ~DS1337_BIT_A1IE;
 516
 517         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 518         if (ret < 0)
 519                 return ret;
 520
 521         return 0;
 522 }
 523
 524 static const struct rtc_class_ops ds13xx_rtc_ops = {
 525         .read_time      = ds1307_get_time,
 526         .set_time       = ds1307_set_time,
 527         .read_alarm     = ds1337_read_alarm,
 528         .set_alarm      = ds1337_set_alarm,
 529         .alarm_irq_enable = ds1307_alarm_irq_enable,
 530 };
 531
 532 /*----------------------------------------------------------------------*/
 533
 534 #define NVRAM_SIZE      56
 535
 536 static ssize_t
 537 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 538                 struct bin_attribute *attr,
 539                 char *buf, loff_t off, size_t count)
 540 {
 541         struct i2c_client       *client;
 542         struct ds1307           *ds1307;
 543         int                     result;
 544
 545         client = kobj_to_i2c_client(kobj);
 546         ds1307 = i2c_get_clientdata(client);
 547
 548         if (unlikely(off >= NVRAM_SIZE))
 549                 return 0;
 550         if ((off + count) > NVRAM_SIZE)
 551                 count = NVRAM_SIZE - off;
 552         if (unlikely(!count))
 553                 return count;
 554
 555         result = ds1307->read_block_data(client, 8 + off, count, buf);
 556         if (result < 0)
 557                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 558         return result;
 559 }
 560
 561 static ssize_t
 562 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 563                 struct bin_attribute *attr,
 564                 char *buf, loff_t off, size_t count)
 565 {
 566         struct i2c_client       *client;
 567         struct ds1307           *ds1307;
 568         int                     result;
 569
 570         client = kobj_to_i2c_client(kobj);
 571         ds1307 = i2c_get_clientdata(client);
 572
 573         if (unlikely(off >= NVRAM_SIZE))
 574                 return -EFBIG;
 575         if ((off + count) > NVRAM_SIZE)
 576                 count = NVRAM_SIZE - off;
 577         if (unlikely(!count))
 578                 return count;
 579
 580         result = ds1307->write_block_data(client, 8 + off, count, buf);
 581         if (result < 0) {
 582                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 583                 return result;
 584         }
 585         return count;
 586 }
 587
 588 static struct bin_attribute nvram = {
 589         .attr = {
 590                 .name   = "nvram",
 591                 .mode   = S_IRUGO | S_IWUSR,
 592         },
 593
 594         .read   = ds1307_nvram_read,
 595         .write  = ds1307_nvram_write,
 596         .size   = NVRAM_SIZE,
 597 };
 598
 599 /*----------------------------------------------------------------------*/
 600
 601 static struct i2c_driver ds1307_driver;
 602
 603 static int __devinit ds1307_probe(struct i2c_client *client,
 604                                   const struct i2c_device_id *id)
 605 {
 606         struct ds1307           *ds1307;
 607         int                     err = -ENODEV;
 608         int                     tmp;
 609         const struct chip_desc  *chip = &chips[id->driver_data];
 610         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 611         int                     want_irq = false;
 612         unsigned char           *buf;
 613         static const int        bbsqi_bitpos[] = {
 614                 [ds_1337] = 0,
 615                 [ds_1339] = DS1339_BIT_BBSQI,
 616                 [ds_3231] = DS3231_BIT_BBSQW,
 617         };
 618
 619         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 620             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 621                 return -EIO;
 622
 623         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
 624                 return -ENOMEM;
 625
 626         i2c_set_clientdata(client, ds1307);
 627
 628         ds1307->client  = client;
 629         ds1307->type    = id->driver_data;
 630         ds1307->offset  = 0;
 631
 632         buf = ds1307->regs;
 633         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 634                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 635                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 636         } else {
 637                 ds1307->read_block_data = ds1307_read_block_data;
 638                 ds1307->write_block_data = ds1307_write_block_data;
 639         }
 640
 641         switch (ds1307->type) {
 642         case ds_1337:
 643         case ds_1339:
 644         case ds_3231:
 645                 /* has IRQ? */
 646                 if (ds1307->client->irq > 0 && chip->alarm) {
 647                         INIT_WORK(&ds1307->work, ds1307_work);
 648                         want_irq = true;
 649                 }
 650                 /* get registers that the "rtc" read below won't read... */
 651                 tmp = ds1307->read_block_data(ds1307->client,
 652                                 DS1337_REG_CONTROL, 2, buf);
 653                 if (tmp != 2) {
 654                         pr_debug("read error %d\n", tmp);
 655                         err = -EIO;
 656                         goto exit_free;
 657                 }
 658
 659                 /* oscillator off?  turn it on, so clock can tick. */
 660                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 661                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 662
 663                 /* Using IRQ?  Disable the square wave and both alarms.
 664                  * For some variants, be sure alarms can trigger when we're
 665                  * running on Vbackup (BBSQI/BBSQW)
 666                  */
 667                 if (want_irq) {
 668                         ds1307->regs[0] |= DS1337_BIT_INTCN
 669                                         | bbsqi_bitpos[ds1307->type];
 670                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 671                 }
 672
 673                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 674                                                         ds1307->regs[0]);
 675
 676                 /* oscillator fault?  clear flag, and warn */
 677                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 678                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 679                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 680                         dev_warn(&client->dev, "SET TIME!\n");
 681                 }
 682                 break;
 683
 684         case rx_8025:
 685                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 686                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 687                 if (tmp != 2) {
 688                         pr_debug("read error %d\n", tmp);
 689                         err = -EIO;
 690                         goto exit_free;
 691                 }
 692
 693                 /* oscillator off?  turn it on, so clock can tick. */
 694                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 695                         ds1307->regs[1] |= RX8025_BIT_XST;
 696                         i2c_smbus_write_byte_data(client,
 697                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 698                                                   ds1307->regs[1]);
 699                         dev_warn(&client->dev,
 700                                  "oscillator stop detected - SET TIME!\n");
 701                 }
 702
 703                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 704                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 705                         i2c_smbus_write_byte_data(client,
 706                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 707                                                   ds1307->regs[1]);
 708                         dev_warn(&client->dev, "power-on detected\n");
 709                 }
 710
 711                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 712                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 713                         i2c_smbus_write_byte_data(client,
 714                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 715                                                   ds1307->regs[1]);
 716                         dev_warn(&client->dev, "voltage drop detected\n");
 717                 }
 718
 719                 /* make sure we are running in 24hour mode */
 720                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 721                         u8 hour;
 722
 723                         /* switch to 24 hour mode */
 724                         i2c_smbus_write_byte_data(client,
 725                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 726                                                   ds1307->regs[0] |
 727                                                   RX8025_BIT_2412);
 728
 729                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 730                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 731                         if (tmp != 2) {
 732                                 pr_debug("read error %d\n", tmp);
 733                                 err = -EIO;
 734                                 goto exit_free;
 735                         }
 736
 737                         /* correct hour */
 738                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 739                         if (hour == 12)
 740                                 hour = 0;
 741                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 742                                 hour += 12;
 743
 744                         i2c_smbus_write_byte_data(client,
 745                                                   DS1307_REG_HOUR << 4 | 0x08,
 746                                                   hour);
 747                 }
 748                 break;
 749         case ds_1388:
 750                 ds1307->offset = 1; /* Seconds starts at 1 */
 751                 break;
 752         default:
 753                 break;
 754         }
 755
 756 read_rtc:
 757         /* read RTC registers */
 758         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 759         if (tmp != 8) {
 760                 pr_debug("read error %d\n", tmp);
 761                 err = -EIO;
 762                 goto exit_free;
 763         }
 764
 765         /* minimal sanity checking; some chips (like DS1340) don't
 766          * specify the extra bits as must-be-zero, but there are
 767          * still a few values that are clearly out-of-range.
 768          */
 769         tmp = ds1307->regs[DS1307_REG_SECS];
 770         switch (ds1307->type) {
 771         case ds_1307:
 772         case m41t00:
 773                 /* clock halted?  turn it on, so clock can tick. */
 774                 if (tmp & DS1307_BIT_CH) {
 775                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 776                         dev_warn(&client->dev, "SET TIME!\n");
 777                         goto read_rtc;
 778                 }
 779                 break;
 780         case ds_1338:
 781                 /* clock halted?  turn it on, so clock can tick. */
 782                 if (tmp & DS1307_BIT_CH)
 783                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 784
 785                 /* oscillator fault?  clear flag, and warn */
 786                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 787                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 788                                         ds1307->regs[DS1307_REG_CONTROL]
 789                                         & ~DS1338_BIT_OSF);
 790                         dev_warn(&client->dev, "SET TIME!\n");
 791                         goto read_rtc;
 792                 }
 793                 break;
 794         case ds_1340:
 795                 /* clock halted?  turn it on, so clock can tick. */
 796                 if (tmp & DS1340_BIT_nEOSC)
 797                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 798
 799                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 800                 if (tmp < 0) {
 801                         pr_debug("read error %d\n", tmp);
 802                         err = -EIO;
 803                         goto exit_free;
 804                 }
 805
 806                 /* oscillator fault?  clear flag, and warn */
 807                 if (tmp & DS1340_BIT_OSF) {
 808                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 809                         dev_warn(&client->dev, "SET TIME!\n");
 810                 }
 811                 break;
 812         case rx_8025:
 813         case ds_1337:
 814         case ds_1339:
 815         case ds_1388:
 816         case ds_3231:
 817                 break;
 818         }
 819
 820         tmp = ds1307->regs[DS1307_REG_HOUR];
 821         switch (ds1307->type) {
 822         case ds_1340:
 823         case m41t00:
 824                 /* NOTE: ignores century bits; fix before deploying
 825                  * systems that will run through year 2100.
 826                  */
 827                 break;
 828         case rx_8025:
 829                 break;
 830         default:
 831                 if (!(tmp & DS1307_BIT_12HR))
 832                         break;
 833
 834                 /* Be sure we're in 24 hour mode.  Multi-master systems
 835                  * take note...
 836                  */
 837                 tmp = bcd2bin(tmp & 0x1f);
 838                 if (tmp == 12)
 839                         tmp = 0;
 840                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 841                         tmp += 12;
 842                 i2c_smbus_write_byte_data(client,
 843                                 ds1307->offset + DS1307_REG_HOUR,
 844                                 bin2bcd(tmp));
 845         }
 846
 847         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 848                                 &ds13xx_rtc_ops, THIS_MODULE);
 849         if (IS_ERR(ds1307->rtc)) {
 850                 err = PTR_ERR(ds1307->rtc);
 851                 dev_err(&client->dev,
 852                         "unable to register the class device\n");
 853                 goto exit_free;
 854         }
 855
 856         if (want_irq) {
 857                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 858                           ds1307->rtc->name, client);
 859                 if (err) {
 860                         dev_err(&client->dev,
 861                                 "unable to request IRQ!\n");
 862                         goto exit_irq;
 863                 }
 864
 865                 device_set_wakeup_capable(&client->dev, 1);
 866                 set_bit(HAS_ALARM, &ds1307->flags);
 867                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 868         }
 869
 870         if (chip->nvram56) {
 871                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
 872                 if (err == 0) {
 873                         set_bit(HAS_NVRAM, &ds1307->flags);
 874                         dev_info(&client->dev, "56 bytes nvram\n");
 875                 }
 876         }
 877
 878         return 0;
 879
 880 exit_irq:
 881         rtc_device_unregister(ds1307->rtc);
 882 exit_free:
 883         kfree(ds1307);
 884         return err;
 885 }
 886
 887 static int __devexit ds1307_remove(struct i2c_client *client)
 888 {
 889         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 890
 891         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 892                 free_irq(client->irq, client);
 893                 cancel_work_sync(&ds1307->work);
 894         }
 895
 896         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
 897                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
 898
 899         rtc_device_unregister(ds1307->rtc);
 900         kfree(ds1307);
 901         return 0;
 902 }
 903
 904 static struct i2c_driver ds1307_driver = {
 905         .driver = {
 906                 .name   = "rtc-ds1307",
 907                 .owner  = THIS_MODULE,
 908         },
 909         .probe          = ds1307_probe,
 910         .remove         = __devexit_p(ds1307_remove),
 911         .id_table       = ds1307_id,
 912 };
 913
 914 static int __init ds1307_init(void)
 915 {
 916         return i2c_add_driver(&ds1307_driver);
 917 }
 918 module_init(ds1307_init);
 919
 920 static void __exit ds1307_exit(void)
 921 {
 922         i2c_del_driver(&ds1307_driver);
 923 }
 924 module_exit(ds1307_exit);
 925
 926 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 927 MODULE_LICENSE("GPL");