git.oblomov.eu Git - linux-2.6/blob - 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         m41t00,
  36         rx_8025,
  37         // rs5c372 too?  different address...
  38 };
  39
  40
  41 /* RTC registers don't differ much, except for the century flag */
  42 #define DS1307_REG_SECS         0x00    /* 00-59 */
  43 #       define DS1307_BIT_CH            0x80
  44 #       define DS1340_BIT_nEOSC         0x80
  45 #define DS1307_REG_MIN          0x01    /* 00-59 */
  46 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  47 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  48 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  49 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  50 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  51 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  52 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  53 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  54 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  55 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  56
  57 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  58  * start at 7, and they differ a LOT. Only control and status matter for
  59  * basic RTC date and time functionality; be careful using them.
  60  */
  61 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  62 #       define DS1307_BIT_OUT           0x80
  63 #       define DS1338_BIT_OSF           0x20
  64 #       define DS1307_BIT_SQWE          0x10
  65 #       define DS1307_BIT_RS1           0x02
  66 #       define DS1307_BIT_RS0           0x01
  67 #define DS1337_REG_CONTROL      0x0e
  68 #       define DS1337_BIT_nEOSC         0x80
  69 #       define DS1339_BIT_BBSQI         0x20
  70 #       define DS1337_BIT_RS2           0x10
  71 #       define DS1337_BIT_RS1           0x08
  72 #       define DS1337_BIT_INTCN         0x04
  73 #       define DS1337_BIT_A2IE          0x02
  74 #       define DS1337_BIT_A1IE          0x01
  75 #define DS1340_REG_CONTROL      0x07
  76 #       define DS1340_BIT_OUT           0x80
  77 #       define DS1340_BIT_FT            0x40
  78 #       define DS1340_BIT_CALIB_SIGN    0x20
  79 #       define DS1340_M_CALIBRATION     0x1f
  80 #define DS1340_REG_FLAG         0x09
  81 #       define DS1340_BIT_OSF           0x80
  82 #define DS1337_REG_STATUS       0x0f
  83 #       define DS1337_BIT_OSF           0x80
  84 #       define DS1337_BIT_A2I           0x02
  85 #       define DS1337_BIT_A1I           0x01
  86 #define DS1339_REG_ALARM1_SECS  0x07
  87 #define DS1339_REG_TRICKLE      0x10
  88
  89 #define RX8025_REG_CTRL1        0x0e
  90 #       define RX8025_BIT_2412          0x20
  91 #define RX8025_REG_CTRL2        0x0f
  92 #       define RX8025_BIT_PON           0x10
  93 #       define RX8025_BIT_VDET          0x40
  94 #       define RX8025_BIT_XST           0x20
  95
  96
  97 struct ds1307 {
  98         u8                      offset; /* register's offset */
  99         u8                      regs[11];
 100         enum ds_type            type;
 101         unsigned long           flags;
 102 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 103 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 104         struct i2c_client       *client;
 105         struct rtc_device       *rtc;
 106         struct work_struct      work;
 107         s32 (*read_block_data)(struct i2c_client *client, u8 command,
 108                                u8 length, u8 *values);
 109         s32 (*write_block_data)(struct i2c_client *client, u8 command,
 110                                 u8 length, const u8 *values);
 111 };
 112
 113 struct chip_desc {
 114         unsigned                nvram56:1;
 115         unsigned                alarm:1;
 116 };
 117
 118 static const struct chip_desc chips[] = {
 119 [ds_1307] = {
 120         .nvram56        = 1,
 121 },
 122 [ds_1337] = {
 123         .alarm          = 1,
 124 },
 125 [ds_1338] = {
 126         .nvram56        = 1,
 127 },
 128 [ds_1339] = {
 129         .alarm          = 1,
 130 },
 131 [ds_1340] = {
 132 },
 133 [m41t00] = {
 134 },
 135 [rx_8025] = {
 136 }, };
 137
 138 static const struct i2c_device_id ds1307_id[] = {
 139         { "ds1307", ds_1307 },
 140         { "ds1337", ds_1337 },
 141         { "ds1338", ds_1338 },
 142         { "ds1339", ds_1339 },
 143         { "ds1388", ds_1388 },
 144         { "ds1340", ds_1340 },
 145         { "m41t00", m41t00 },
 146         { "rx8025", rx_8025 },
 147         { }
 148 };
 149 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 150
 151 /*----------------------------------------------------------------------*/
 152
 153 #define BLOCK_DATA_MAX_TRIES 10
 154
 155 static s32 ds1307_read_block_data_once(struct i2c_client *client, u8 command,
 156                                   u8 length, u8 *values)
 157 {
 158         s32 i, data;
 159
 160         for (i = 0; i < length; i++) {
 161                 data = i2c_smbus_read_byte_data(client, command + i);
 162                 if (data < 0)
 163                         return data;
 164                 values[i] = data;
 165         }
 166         return i;
 167 }
 168
 169 static s32 ds1307_read_block_data(struct i2c_client *client, u8 command,
 170                                   u8 length, u8 *values)
 171 {
 172         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 173         s32 ret;
 174         int tries = 0;
 175
 176         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 177         ret = ds1307_read_block_data_once(client, command, length, values);
 178         if (ret < 0)
 179                 return ret;
 180         do {
 181                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 182                         dev_err(&client->dev,
 183                                 "ds1307_read_block_data failed\n");
 184                         return -EIO;
 185                 }
 186                 memcpy(oldvalues, values, length);
 187                 ret = ds1307_read_block_data_once(client, command, length,
 188                                                   values);
 189                 if (ret < 0)
 190                         return ret;
 191         } while (memcmp(oldvalues, values, length));
 192         return length;
 193 }
 194
 195 static s32 ds1307_write_block_data(struct i2c_client *client, u8 command,
 196                                    u8 length, const u8 *values)
 197 {
 198         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 199         int tries = 0;
 200
 201         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 202         do {
 203                 s32 i, ret;
 204
 205                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 206                         dev_err(&client->dev,
 207                                 "ds1307_write_block_data failed\n");
 208                         return -EIO;
 209                 }
 210                 for (i = 0; i < length; i++) {
 211                         ret = i2c_smbus_write_byte_data(client, command + i,
 212                                                         values[i]);
 213                         if (ret < 0)
 214                                 return ret;
 215                 }
 216                 ret = ds1307_read_block_data_once(client, command, length,
 217                                                   currvalues);
 218                 if (ret < 0)
 219                         return ret;
 220         } while (memcmp(currvalues, values, length));
 221         return length;
 222 }
 223
 224 /*----------------------------------------------------------------------*/
 225
 226 /*
 227  * The IRQ logic includes a "real" handler running in IRQ context just
 228  * long enough to schedule this workqueue entry.   We need a task context
 229  * to talk to the RTC, since I2C I/O calls require that; and disable the
 230  * IRQ until we clear its status on the chip, so that this handler can
 231  * work with any type of triggering (not just falling edge).
 232  *
 233  * The ds1337 and ds1339 both have two alarms, but we only use the first
 234  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 235  * signal; ds1339 chips have only one alarm signal.
 236  */
 237 static void ds1307_work(struct work_struct *work)
 238 {
 239         struct ds1307           *ds1307;
 240         struct i2c_client       *client;
 241         struct mutex            *lock;
 242         int                     stat, control;
 243
 244         ds1307 = container_of(work, struct ds1307, work);
 245         client = ds1307->client;
 246         lock = &ds1307->rtc->ops_lock;
 247
 248         mutex_lock(lock);
 249         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 250         if (stat < 0)
 251                 goto out;
 252
 253         if (stat & DS1337_BIT_A1I) {
 254                 stat &= ~DS1337_BIT_A1I;
 255                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 256
 257                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 258                 if (control < 0)
 259                         goto out;
 260
 261                 control &= ~DS1337_BIT_A1IE;
 262                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 263
 264                 /* rtc_update_irq() assumes that it is called
 265                  * from IRQ-disabled context.
 266                  */
 267                 local_irq_disable();
 268                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 269                 local_irq_enable();
 270         }
 271
 272 out:
 273         if (test_bit(HAS_ALARM, &ds1307->flags))
 274                 enable_irq(client->irq);
 275         mutex_unlock(lock);
 276 }
 277
 278 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 279 {
 280         struct i2c_client       *client = dev_id;
 281         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 282
 283         disable_irq_nosync(irq);
 284         schedule_work(&ds1307->work);
 285         return IRQ_HANDLED;
 286 }
 287
 288 /*----------------------------------------------------------------------*/
 289
 290 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 291 {
 292         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 293         int             tmp;
 294
 295         /* read the RTC date and time registers all at once */
 296         tmp = ds1307->read_block_data(ds1307->client,
 297                 ds1307->offset, 7, ds1307->regs);
 298         if (tmp != 7) {
 299                 dev_err(dev, "%s error %d\n", "read", tmp);
 300                 return -EIO;
 301         }
 302
 303         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 304                         "read",
 305                         ds1307->regs[0], ds1307->regs[1],
 306                         ds1307->regs[2], ds1307->regs[3],
 307                         ds1307->regs[4], ds1307->regs[5],
 308                         ds1307->regs[6]);
 309
 310         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 311         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 312         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 313         t->tm_hour = bcd2bin(tmp);
 314         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 315         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 316         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 317         t->tm_mon = bcd2bin(tmp) - 1;
 318
 319         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 320         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 321
 322         dev_dbg(dev, "%s secs=%d, mins=%d, "
 323                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 324                 "read", t->tm_sec, t->tm_min,
 325                 t->tm_hour, t->tm_mday,
 326                 t->tm_mon, t->tm_year, t->tm_wday);
 327
 328         /* initial clock setting can be undefined */
 329         return rtc_valid_tm(t);
 330 }
 331
 332 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 333 {
 334         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 335         int             result;
 336         int             tmp;
 337         u8              *buf = ds1307->regs;
 338
 339         dev_dbg(dev, "%s secs=%d, mins=%d, "
 340                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 341                 "write", t->tm_sec, t->tm_min,
 342                 t->tm_hour, t->tm_mday,
 343                 t->tm_mon, t->tm_year, t->tm_wday);
 344
 345         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 346         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 347         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 348         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 349         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 350         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 351
 352         /* assume 20YY not 19YY */
 353         tmp = t->tm_year - 100;
 354         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 355
 356         switch (ds1307->type) {
 357         case ds_1337:
 358         case ds_1339:
 359                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 360                 break;
 361         case ds_1340:
 362                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 363                                 | DS1340_BIT_CENTURY;
 364                 break;
 365         default:
 366                 break;
 367         }
 368
 369         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 370                 "write", buf[0], buf[1], buf[2], buf[3],
 371                 buf[4], buf[5], buf[6]);
 372
 373         result = ds1307->write_block_data(ds1307->client,
 374                 ds1307->offset, 7, buf);
 375         if (result < 0) {
 376                 dev_err(dev, "%s error %d\n", "write", result);
 377                 return result;
 378         }
 379         return 0;
 380 }
 381
 382 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 383 {
 384         struct i2c_client       *client = to_i2c_client(dev);
 385         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 386         int                     ret;
 387
 388         if (!test_bit(HAS_ALARM, &ds1307->flags))
 389                 return -EINVAL;
 390
 391         /* read all ALARM1, ALARM2, and status registers at once */
 392         ret = ds1307->read_block_data(client,
 393                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 394         if (ret != 9) {
 395                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 396                 return -EIO;
 397         }
 398
 399         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 400                         "alarm read",
 401                         ds1307->regs[0], ds1307->regs[1],
 402                         ds1307->regs[2], ds1307->regs[3],
 403                         ds1307->regs[4], ds1307->regs[5],
 404                         ds1307->regs[6], ds1307->regs[7],
 405                         ds1307->regs[8]);
 406
 407         /* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 408          * and that all four fields are checked matches
 409          */
 410         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 411         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 412         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 413         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 414         t->time.tm_mon = -1;
 415         t->time.tm_year = -1;
 416         t->time.tm_wday = -1;
 417         t->time.tm_yday = -1;
 418         t->time.tm_isdst = -1;
 419
 420         /* ... and status */
 421         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 422         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 423
 424         dev_dbg(dev, "%s secs=%d, mins=%d, "
 425                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 426                 "alarm read", t->time.tm_sec, t->time.tm_min,
 427                 t->time.tm_hour, t->time.tm_mday,
 428                 t->enabled, t->pending);
 429
 430         return 0;
 431 }
 432
 433 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 434 {
 435         struct i2c_client       *client = to_i2c_client(dev);
 436         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 437         unsigned char           *buf = ds1307->regs;
 438         u8                      control, status;
 439         int                     ret;
 440
 441         if (!test_bit(HAS_ALARM, &ds1307->flags))
 442                 return -EINVAL;
 443
 444         dev_dbg(dev, "%s secs=%d, mins=%d, "
 445                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 446                 "alarm set", t->time.tm_sec, t->time.tm_min,
 447                 t->time.tm_hour, t->time.tm_mday,
 448                 t->enabled, t->pending);
 449
 450         /* read current status of both alarms and the chip */
 451         ret = ds1307->read_block_data(client,
 452                         DS1339_REG_ALARM1_SECS, 9, buf);
 453         if (ret != 9) {
 454                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 455                 return -EIO;
 456         }
 457         control = ds1307->regs[7];
 458         status = ds1307->regs[8];
 459
 460         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 461                         "alarm set (old status)",
 462                         ds1307->regs[0], ds1307->regs[1],
 463                         ds1307->regs[2], ds1307->regs[3],
 464                         ds1307->regs[4], ds1307->regs[5],
 465                         ds1307->regs[6], control, status);
 466
 467         /* set ALARM1, using 24 hour and day-of-month modes */
 468         buf[0] = bin2bcd(t->time.tm_sec);
 469         buf[1] = bin2bcd(t->time.tm_min);
 470         buf[2] = bin2bcd(t->time.tm_hour);
 471         buf[3] = bin2bcd(t->time.tm_mday);
 472
 473         /* set ALARM2 to non-garbage */
 474         buf[4] = 0;
 475         buf[5] = 0;
 476         buf[6] = 0;
 477
 478         /* optionally enable ALARM1 */
 479         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 480         if (t->enabled) {
 481                 dev_dbg(dev, "alarm IRQ armed\n");
 482                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 483         }
 484         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 485
 486         ret = ds1307->write_block_data(client,
 487                         DS1339_REG_ALARM1_SECS, 9, buf);
 488         if (ret < 0) {
 489                 dev_err(dev, "can't set alarm time\n");
 490                 return ret;
 491         }
 492
 493         return 0;
 494 }
 495
 496 static int ds1307_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 497 {
 498         struct i2c_client       *client = to_i2c_client(dev);
 499         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 500         int                     ret;
 501
 502         switch (cmd) {
 503         case RTC_AIE_OFF:
 504                 if (!test_bit(HAS_ALARM, &ds1307->flags))
 505                         return -ENOTTY;
 506
 507                 ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 508                 if (ret < 0)
 509                         return ret;
 510
 511                 ret &= ~DS1337_BIT_A1IE;
 512
 513                 ret = i2c_smbus_write_byte_data(client,
 514                                                 DS1337_REG_CONTROL, ret);
 515                 if (ret < 0)
 516                         return ret;
 517
 518                 break;
 519
 520         case RTC_AIE_ON:
 521                 if (!test_bit(HAS_ALARM, &ds1307->flags))
 522                         return -ENOTTY;
 523
 524                 ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 525                 if (ret < 0)
 526                         return ret;
 527
 528                 ret |= DS1337_BIT_A1IE;
 529
 530                 ret = i2c_smbus_write_byte_data(client,
 531                                                 DS1337_REG_CONTROL, ret);
 532                 if (ret < 0)
 533                         return ret;
 534
 535                 break;
 536
 537         default:
 538                 return -ENOIOCTLCMD;
 539         }
 540
 541         return 0;
 542 }
 543
 544 static const struct rtc_class_ops ds13xx_rtc_ops = {
 545         .read_time      = ds1307_get_time,
 546         .set_time       = ds1307_set_time,
 547         .read_alarm     = ds1337_read_alarm,
 548         .set_alarm      = ds1337_set_alarm,
 549         .ioctl          = ds1307_ioctl,
 550 };
 551
 552 /*----------------------------------------------------------------------*/
 553
 554 #define NVRAM_SIZE      56
 555
 556 static ssize_t
 557 ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
 558                 char *buf, loff_t off, size_t count)
 559 {
 560         struct i2c_client       *client;
 561         struct ds1307           *ds1307;
 562         int                     result;
 563
 564         client = kobj_to_i2c_client(kobj);
 565         ds1307 = i2c_get_clientdata(client);
 566
 567         if (unlikely(off >= NVRAM_SIZE))
 568                 return 0;
 569         if ((off + count) > NVRAM_SIZE)
 570                 count = NVRAM_SIZE - off;
 571         if (unlikely(!count))
 572                 return count;
 573
 574         result = ds1307->read_block_data(client, 8 + off, count, buf);
 575         if (result < 0)
 576                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 577         return result;
 578 }
 579
 580 static ssize_t
 581 ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
 582                 char *buf, loff_t off, size_t count)
 583 {
 584         struct i2c_client       *client;
 585         struct ds1307           *ds1307;
 586         int                     result;
 587
 588         client = kobj_to_i2c_client(kobj);
 589         ds1307 = i2c_get_clientdata(client);
 590
 591         if (unlikely(off >= NVRAM_SIZE))
 592                 return -EFBIG;
 593         if ((off + count) > NVRAM_SIZE)
 594                 count = NVRAM_SIZE - off;
 595         if (unlikely(!count))
 596                 return count;
 597
 598         result = ds1307->write_block_data(client, 8 + off, count, buf);
 599         if (result < 0) {
 600                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 601                 return result;
 602         }
 603         return count;
 604 }
 605
 606 static struct bin_attribute nvram = {
 607         .attr = {
 608                 .name   = "nvram",
 609                 .mode   = S_IRUGO | S_IWUSR,
 610         },
 611
 612         .read   = ds1307_nvram_read,
 613         .write  = ds1307_nvram_write,
 614         .size   = NVRAM_SIZE,
 615 };
 616
 617 /*----------------------------------------------------------------------*/
 618
 619 static struct i2c_driver ds1307_driver;
 620
 621 static int __devinit ds1307_probe(struct i2c_client *client,
 622                                   const struct i2c_device_id *id)
 623 {
 624         struct ds1307           *ds1307;
 625         int                     err = -ENODEV;
 626         int                     tmp;
 627         const struct chip_desc  *chip = &chips[id->driver_data];
 628         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 629         int                     want_irq = false;
 630         unsigned char           *buf;
 631
 632         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 633             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 634                 return -EIO;
 635
 636         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
 637                 return -ENOMEM;
 638
 639         i2c_set_clientdata(client, ds1307);
 640
 641         ds1307->client  = client;
 642         ds1307->type    = id->driver_data;
 643         ds1307->offset  = 0;
 644
 645         buf = ds1307->regs;
 646         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 647                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 648                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 649         } else {
 650                 ds1307->read_block_data = ds1307_read_block_data;
 651                 ds1307->write_block_data = ds1307_write_block_data;
 652         }
 653
 654         switch (ds1307->type) {
 655         case ds_1337:
 656         case ds_1339:
 657                 /* has IRQ? */
 658                 if (ds1307->client->irq > 0 && chip->alarm) {
 659                         INIT_WORK(&ds1307->work, ds1307_work);
 660                         want_irq = true;
 661                 }
 662                 /* get registers that the "rtc" read below won't read... */
 663                 tmp = ds1307->read_block_data(ds1307->client,
 664                                 DS1337_REG_CONTROL, 2, buf);
 665                 if (tmp != 2) {
 666                         pr_debug("read error %d\n", tmp);
 667                         err = -EIO;
 668                         goto exit_free;
 669                 }
 670
 671                 /* oscillator off?  turn it on, so clock can tick. */
 672                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 673                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 674
 675                 /* Using IRQ?  Disable the square wave and both alarms.
 676                  * For ds1339, be sure alarms can trigger when we're
 677                  * running on Vbackup (BBSQI); we assume ds1337 will
 678                  * ignore that bit
 679                  */
 680                 if (want_irq) {
 681                         ds1307->regs[0] |= DS1337_BIT_INTCN | DS1339_BIT_BBSQI;
 682                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 683                 }
 684
 685                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 686                                                         ds1307->regs[0]);
 687
 688                 /* oscillator fault?  clear flag, and warn */
 689                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 690                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 691                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 692                         dev_warn(&client->dev, "SET TIME!\n");
 693                 }
 694                 break;
 695
 696         case rx_8025:
 697                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 698                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 699                 if (tmp != 2) {
 700                         pr_debug("read error %d\n", tmp);
 701                         err = -EIO;
 702                         goto exit_free;
 703                 }
 704
 705                 /* oscillator off?  turn it on, so clock can tick. */
 706                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 707                         ds1307->regs[1] |= RX8025_BIT_XST;
 708                         i2c_smbus_write_byte_data(client,
 709                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 710                                                   ds1307->regs[1]);
 711                         dev_warn(&client->dev,
 712                                  "oscillator stop detected - SET TIME!\n");
 713                 }
 714
 715                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 716                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 717                         i2c_smbus_write_byte_data(client,
 718                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 719                                                   ds1307->regs[1]);
 720                         dev_warn(&client->dev, "power-on detected\n");
 721                 }
 722
 723                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 724                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 725                         i2c_smbus_write_byte_data(client,
 726                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 727                                                   ds1307->regs[1]);
 728                         dev_warn(&client->dev, "voltage drop detected\n");
 729                 }
 730
 731                 /* make sure we are running in 24hour mode */
 732                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 733                         u8 hour;
 734
 735                         /* switch to 24 hour mode */
 736                         i2c_smbus_write_byte_data(client,
 737                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 738                                                   ds1307->regs[0] |
 739                                                   RX8025_BIT_2412);
 740
 741                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 742                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 743                         if (tmp != 2) {
 744                                 pr_debug("read error %d\n", tmp);
 745                                 err = -EIO;
 746                                 goto exit_free;
 747                         }
 748
 749                         /* correct hour */
 750                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 751                         if (hour == 12)
 752                                 hour = 0;
 753                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 754                                 hour += 12;
 755
 756                         i2c_smbus_write_byte_data(client,
 757                                                   DS1307_REG_HOUR << 4 | 0x08,
 758                                                   hour);
 759                 }
 760                 break;
 761         case ds_1388:
 762                 ds1307->offset = 1; /* Seconds starts at 1 */
 763                 break;
 764         default:
 765                 break;
 766         }
 767
 768 read_rtc:
 769         /* read RTC registers */
 770         tmp = ds1307->read_block_data(ds1307->client, 0, 8, buf);
 771         if (tmp != 8) {
 772                 pr_debug("read error %d\n", tmp);
 773                 err = -EIO;
 774                 goto exit_free;
 775         }
 776
 777         /* minimal sanity checking; some chips (like DS1340) don't
 778          * specify the extra bits as must-be-zero, but there are
 779          * still a few values that are clearly out-of-range.
 780          */
 781         tmp = ds1307->regs[DS1307_REG_SECS];
 782         switch (ds1307->type) {
 783         case ds_1307:
 784         case m41t00:
 785                 /* clock halted?  turn it on, so clock can tick. */
 786                 if (tmp & DS1307_BIT_CH) {
 787                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 788                         dev_warn(&client->dev, "SET TIME!\n");
 789                         goto read_rtc;
 790                 }
 791                 break;
 792         case ds_1338:
 793                 /* clock halted?  turn it on, so clock can tick. */
 794                 if (tmp & DS1307_BIT_CH)
 795                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 796
 797                 /* oscillator fault?  clear flag, and warn */
 798                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 799                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 800                                         ds1307->regs[DS1307_REG_CONTROL]
 801                                         & ~DS1338_BIT_OSF);
 802                         dev_warn(&client->dev, "SET TIME!\n");
 803                         goto read_rtc;
 804                 }
 805                 break;
 806         case ds_1340:
 807                 /* clock halted?  turn it on, so clock can tick. */
 808                 if (tmp & DS1340_BIT_nEOSC)
 809                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 810
 811                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 812                 if (tmp < 0) {
 813                         pr_debug("read error %d\n", tmp);
 814                         err = -EIO;
 815                         goto exit_free;
 816                 }
 817
 818                 /* oscillator fault?  clear flag, and warn */
 819                 if (tmp & DS1340_BIT_OSF) {
 820                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 821                         dev_warn(&client->dev, "SET TIME!\n");
 822                 }
 823                 break;
 824         case rx_8025:
 825         case ds_1337:
 826         case ds_1339:
 827         case ds_1388:
 828                 break;
 829         }
 830
 831         tmp = ds1307->regs[DS1307_REG_HOUR];
 832         switch (ds1307->type) {
 833         case ds_1340:
 834         case m41t00:
 835                 /* NOTE: ignores century bits; fix before deploying
 836                  * systems that will run through year 2100.
 837                  */
 838                 break;
 839         case rx_8025:
 840                 break;
 841         default:
 842                 if (!(tmp & DS1307_BIT_12HR))
 843                         break;
 844
 845                 /* Be sure we're in 24 hour mode.  Multi-master systems
 846                  * take note...
 847                  */
 848                 tmp = bcd2bin(tmp & 0x1f);
 849                 if (tmp == 12)
 850                         tmp = 0;
 851                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 852                         tmp += 12;
 853                 i2c_smbus_write_byte_data(client,
 854                                 DS1307_REG_HOUR,
 855                                 bin2bcd(tmp));
 856         }
 857
 858         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 859                                 &ds13xx_rtc_ops, THIS_MODULE);
 860         if (IS_ERR(ds1307->rtc)) {
 861                 err = PTR_ERR(ds1307->rtc);
 862                 dev_err(&client->dev,
 863                         "unable to register the class device\n");
 864                 goto exit_free;
 865         }
 866
 867         if (want_irq) {
 868                 err = request_irq(client->irq, ds1307_irq, 0,
 869                           ds1307->rtc->name, client);
 870                 if (err) {
 871                         dev_err(&client->dev,
 872                                 "unable to request IRQ!\n");
 873                         goto exit_irq;
 874                 }
 875                 set_bit(HAS_ALARM, &ds1307->flags);
 876                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 877         }
 878
 879         if (chip->nvram56) {
 880                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
 881                 if (err == 0) {
 882                         set_bit(HAS_NVRAM, &ds1307->flags);
 883                         dev_info(&client->dev, "56 bytes nvram\n");
 884                 }
 885         }
 886
 887         return 0;
 888
 889 exit_irq:
 890         if (ds1307->rtc)
 891                 rtc_device_unregister(ds1307->rtc);
 892 exit_free:
 893         kfree(ds1307);
 894         return err;
 895 }
 896
 897 static int __devexit ds1307_remove(struct i2c_client *client)
 898 {
 899         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 900
 901         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 902                 free_irq(client->irq, client);
 903                 cancel_work_sync(&ds1307->work);
 904         }
 905
 906         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
 907                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
 908
 909         rtc_device_unregister(ds1307->rtc);
 910         kfree(ds1307);
 911         return 0;
 912 }
 913
 914 static struct i2c_driver ds1307_driver = {
 915         .driver = {
 916                 .name   = "rtc-ds1307",
 917                 .owner  = THIS_MODULE,
 918         },
 919         .probe          = ds1307_probe,
 920         .remove         = __devexit_p(ds1307_remove),
 921         .id_table       = ds1307_id,
 922 };
 923
 924 static int __init ds1307_init(void)
 925 {
 926         return i2c_add_driver(&ds1307_driver);
 927 }
 928 module_init(ds1307_init);
 929
 930 static void __exit ds1307_exit(void)
 931 {
 932         i2c_del_driver(&ds1307_driver);
 933 }
 934 module_exit(ds1307_exit);
 935
 936 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 937 MODULE_LICENSE("GPL");