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 /*
  24  * We can't determine type by probing, but if we expect pre-Linux code
  25  * to have set the chip up as a clock (turning on the oscillator and
  26  * setting the date and time), Linux can ignore the non-clock features.
  27  * That's a natural job for a factory or repair bench.
  28  */
  29 enum ds_type {
  30         ds_1307,
  31         ds_1337,
  32         ds_1338,
  33         ds_1339,
  34         ds_1340,
  35         ds_1388,
  36         ds_3231,
  37         m41t00,
  38         mcp7941x,
  39         rx_8025,
  40         last_ds_type /* always last */
  41         /* rs5c372 too?  different address... */
  42 };
  43
  44
  45 /* RTC registers don't differ much, except for the century flag */
  46 #define DS1307_REG_SECS         0x00    /* 00-59 */
  47 #       define DS1307_BIT_CH            0x80
  48 #       define DS1340_BIT_nEOSC         0x80
  49 #       define MCP7941X_BIT_ST          0x80
  50 #define DS1307_REG_MIN          0x01    /* 00-59 */
  51 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  52 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  53 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  54 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  55 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  56 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  57 #       define MCP7941X_BIT_VBATEN      0x08
  58 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  59 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  60 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  61 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  62
  63 /*
  64  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  65  * start at 7, and they differ a LOT. Only control and status matter for
  66  * basic RTC date and time functionality; be careful using them.
  67  */
  68 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  69 #       define DS1307_BIT_OUT           0x80
  70 #       define DS1338_BIT_OSF           0x20
  71 #       define DS1307_BIT_SQWE          0x10
  72 #       define DS1307_BIT_RS1           0x02
  73 #       define DS1307_BIT_RS0           0x01
  74 #define DS1337_REG_CONTROL      0x0e
  75 #       define DS1337_BIT_nEOSC         0x80
  76 #       define DS1339_BIT_BBSQI         0x20
  77 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  78 #       define DS1337_BIT_RS2           0x10
  79 #       define DS1337_BIT_RS1           0x08
  80 #       define DS1337_BIT_INTCN         0x04
  81 #       define DS1337_BIT_A2IE          0x02
  82 #       define DS1337_BIT_A1IE          0x01
  83 #define DS1340_REG_CONTROL      0x07
  84 #       define DS1340_BIT_OUT           0x80
  85 #       define DS1340_BIT_FT            0x40
  86 #       define DS1340_BIT_CALIB_SIGN    0x20
  87 #       define DS1340_M_CALIBRATION     0x1f
  88 #define DS1340_REG_FLAG         0x09
  89 #       define DS1340_BIT_OSF           0x80
  90 #define DS1337_REG_STATUS       0x0f
  91 #       define DS1337_BIT_OSF           0x80
  92 #       define DS1337_BIT_A2I           0x02
  93 #       define DS1337_BIT_A1I           0x01
  94 #define DS1339_REG_ALARM1_SECS  0x07
  95 #define DS1339_REG_TRICKLE      0x10
  96
  97 #define RX8025_REG_CTRL1        0x0e
  98 #       define RX8025_BIT_2412          0x20
  99 #define RX8025_REG_CTRL2        0x0f
 100 #       define RX8025_BIT_PON           0x10
 101 #       define RX8025_BIT_VDET          0x40
 102 #       define RX8025_BIT_XST           0x20
 103
 104
 105 struct ds1307 {
 106         u8                      offset; /* register's offset */
 107         u8                      regs[11];
 108         enum ds_type            type;
 109         unsigned long           flags;
 110 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 111 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 112         struct i2c_client       *client;
 113         struct rtc_device       *rtc;
 114         struct work_struct      work;
 115         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 116                                u8 length, u8 *values);
 117         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 118                                 u8 length, const u8 *values);
 119 };
 120
 121 struct chip_desc {
 122         unsigned                nvram56:1;
 123         unsigned                alarm:1;
 124 };
 125
 126 static const struct chip_desc chips[last_ds_type] = {
 127         [ds_1307] = {
 128                 .nvram56        = 1,
 129         },
 130         [ds_1337] = {
 131                 .alarm          = 1,
 132         },
 133         [ds_1338] = {
 134                 .nvram56        = 1,
 135         },
 136         [ds_1339] = {
 137                 .alarm          = 1,
 138         },
 139         [ds_3231] = {
 140                 .alarm          = 1,
 141         },
 142 };
 143
 144 static const struct i2c_device_id ds1307_id[] = {
 145         { "ds1307", ds_1307 },
 146         { "ds1337", ds_1337 },
 147         { "ds1338", ds_1338 },
 148         { "ds1339", ds_1339 },
 149         { "ds1388", ds_1388 },
 150         { "ds1340", ds_1340 },
 151         { "ds3231", ds_3231 },
 152         { "m41t00", m41t00 },
 153         { "mcp7941x", mcp7941x },
 154         { "pt7c4338", ds_1307 },
 155         { "rx8025", rx_8025 },
 156         { }
 157 };
 158 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 159
 160 /*----------------------------------------------------------------------*/
 161
 162 #define BLOCK_DATA_MAX_TRIES 10
 163
 164 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 165                                        u8 command, u8 length, u8 *values)
 166 {
 167         s32 i, data;
 168
 169         for (i = 0; i < length; i++) {
 170                 data = i2c_smbus_read_byte_data(client, command + i);
 171                 if (data < 0)
 172                         return data;
 173                 values[i] = data;
 174         }
 175         return i;
 176 }
 177
 178 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 179                                   u8 length, u8 *values)
 180 {
 181         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 182         s32 ret;
 183         int tries = 0;
 184
 185         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 186         ret = ds1307_read_block_data_once(client, command, length, values);
 187         if (ret < 0)
 188                 return ret;
 189         do {
 190                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 191                         dev_err(&client->dev,
 192                                 "ds1307_read_block_data failed\n");
 193                         return -EIO;
 194                 }
 195                 memcpy(oldvalues, values, length);
 196                 ret = ds1307_read_block_data_once(client, command, length,
 197                                                   values);
 198                 if (ret < 0)
 199                         return ret;
 200         } while (memcmp(oldvalues, values, length));
 201         return length;
 202 }
 203
 204 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 205                                    u8 length, const u8 *values)
 206 {
 207         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 208         int tries = 0;
 209
 210         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 211         do {
 212                 s32 i, ret;
 213
 214                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 215                         dev_err(&client->dev,
 216                                 "ds1307_write_block_data failed\n");
 217                         return -EIO;
 218                 }
 219                 for (i = 0; i < length; i++) {
 220                         ret = i2c_smbus_write_byte_data(client, command + i,
 221                                                         values[i]);
 222                         if (ret < 0)
 223                                 return ret;
 224                 }
 225                 ret = ds1307_read_block_data_once(client, command, length,
 226                                                   currvalues);
 227                 if (ret < 0)
 228                         return ret;
 229         } while (memcmp(currvalues, values, length));
 230         return length;
 231 }
 232
 233 /*----------------------------------------------------------------------*/
 234
 235 /*
 236  * The IRQ logic includes a "real" handler running in IRQ context just
 237  * long enough to schedule this workqueue entry.   We need a task context
 238  * to talk to the RTC, since I2C I/O calls require that; and disable the
 239  * IRQ until we clear its status on the chip, so that this handler can
 240  * work with any type of triggering (not just falling edge).
 241  *
 242  * The ds1337 and ds1339 both have two alarms, but we only use the first
 243  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 244  * signal; ds1339 chips have only one alarm signal.
 245  */
 246 static void ds1307_work(struct work_struct *work)
 247 {
 248         struct ds1307           *ds1307;
 249         struct i2c_client       *client;
 250         struct mutex            *lock;
 251         int                     stat, control;
 252
 253         ds1307 = container_of(work, struct ds1307, work);
 254         client = ds1307->client;
 255         lock = &ds1307->rtc->ops_lock;
 256
 257         mutex_lock(lock);
 258         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 259         if (stat < 0)
 260                 goto out;
 261
 262         if (stat & DS1337_BIT_A1I) {
 263                 stat &= ~DS1337_BIT_A1I;
 264                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 265
 266                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 267                 if (control < 0)
 268                         goto out;
 269
 270                 control &= ~DS1337_BIT_A1IE;
 271                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 272
 273                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 274         }
 275
 276 out:
 277         if (test_bit(HAS_ALARM, &ds1307->flags))
 278                 enable_irq(client->irq);
 279         mutex_unlock(lock);
 280 }
 281
 282 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 283 {
 284         struct i2c_client       *client = dev_id;
 285         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 286
 287         disable_irq_nosync(irq);
 288         schedule_work(&ds1307->work);
 289         return IRQ_HANDLED;
 290 }
 291
 292 /*----------------------------------------------------------------------*/
 293
 294 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 295 {
 296         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 297         int             tmp;
 298
 299         /* read the RTC date and time registers all at once */
 300         tmp = ds1307->read_block_data(ds1307->client,
 301                 ds1307->offset, 7, ds1307->regs);
 302         if (tmp != 7) {
 303                 dev_err(dev, "%s error %d\n", "read", tmp);
 304                 return -EIO;
 305         }
 306
 307         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 308                         "read",
 309                         ds1307->regs[0], ds1307->regs[1],
 310                         ds1307->regs[2], ds1307->regs[3],
 311                         ds1307->regs[4], ds1307->regs[5],
 312                         ds1307->regs[6]);
 313
 314         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 315         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 316         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 317         t->tm_hour = bcd2bin(tmp);
 318         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 319         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 320         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 321         t->tm_mon = bcd2bin(tmp) - 1;
 322
 323         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 324         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 325
 326         dev_dbg(dev, "%s secs=%d, mins=%d, "
 327                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 328                 "read", t->tm_sec, t->tm_min,
 329                 t->tm_hour, t->tm_mday,
 330                 t->tm_mon, t->tm_year, t->tm_wday);
 331
 332         /* initial clock setting can be undefined */
 333         return rtc_valid_tm(t);
 334 }
 335
 336 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 337 {
 338         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 339         int             result;
 340         int             tmp;
 341         u8              *buf = ds1307->regs;
 342
 343         dev_dbg(dev, "%s secs=%d, mins=%d, "
 344                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 345                 "write", t->tm_sec, t->tm_min,
 346                 t->tm_hour, t->tm_mday,
 347                 t->tm_mon, t->tm_year, t->tm_wday);
 348
 349         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 350         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 351         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 352         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 353         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 354         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 355
 356         /* assume 20YY not 19YY */
 357         tmp = t->tm_year - 100;
 358         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 359
 360         switch (ds1307->type) {
 361         case ds_1337:
 362         case ds_1339:
 363         case ds_3231:
 364                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 365                 break;
 366         case ds_1340:
 367                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 368                                 | DS1340_BIT_CENTURY;
 369                 break;
 370         case mcp7941x:
 371                 /*
 372                  * these bits were cleared when preparing the date/time
 373                  * values and need to be set again before writing the
 374                  * buffer out to the device.
 375                  */
 376                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 377                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 378                 break;
 379         default:
 380                 break;
 381         }
 382
 383         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 384                 "write", buf[0], buf[1], buf[2], buf[3],
 385                 buf[4], buf[5], buf[6]);
 386
 387         result = ds1307->write_block_data(ds1307->client,
 388                 ds1307->offset, 7, buf);
 389         if (result < 0) {
 390                 dev_err(dev, "%s error %d\n", "write", result);
 391                 return result;
 392         }
 393         return 0;
 394 }
 395
 396 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 397 {
 398         struct i2c_client       *client = to_i2c_client(dev);
 399         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 400         int                     ret;
 401
 402         if (!test_bit(HAS_ALARM, &ds1307->flags))
 403                 return -EINVAL;
 404
 405         /* read all ALARM1, ALARM2, and status registers at once */
 406         ret = ds1307->read_block_data(client,
 407                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 408         if (ret != 9) {
 409                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 410                 return -EIO;
 411         }
 412
 413         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 414                         "alarm read",
 415                         ds1307->regs[0], ds1307->regs[1],
 416                         ds1307->regs[2], ds1307->regs[3],
 417                         ds1307->regs[4], ds1307->regs[5],
 418                         ds1307->regs[6], ds1307->regs[7],
 419                         ds1307->regs[8]);
 420
 421         /*
 422          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 423          * and that all four fields are checked matches
 424          */
 425         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 426         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 427         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 428         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 429         t->time.tm_mon = -1;
 430         t->time.tm_year = -1;
 431         t->time.tm_wday = -1;
 432         t->time.tm_yday = -1;
 433         t->time.tm_isdst = -1;
 434
 435         /* ... and status */
 436         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 437         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 438
 439         dev_dbg(dev, "%s secs=%d, mins=%d, "
 440                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 441                 "alarm read", t->time.tm_sec, t->time.tm_min,
 442                 t->time.tm_hour, t->time.tm_mday,
 443                 t->enabled, t->pending);
 444
 445         return 0;
 446 }
 447
 448 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 449 {
 450         struct i2c_client       *client = to_i2c_client(dev);
 451         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 452         unsigned char           *buf = ds1307->regs;
 453         u8                      control, status;
 454         int                     ret;
 455
 456         if (!test_bit(HAS_ALARM, &ds1307->flags))
 457                 return -EINVAL;
 458
 459         dev_dbg(dev, "%s secs=%d, mins=%d, "
 460                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 461                 "alarm set", t->time.tm_sec, t->time.tm_min,
 462                 t->time.tm_hour, t->time.tm_mday,
 463                 t->enabled, t->pending);
 464
 465         /* read current status of both alarms and the chip */
 466         ret = ds1307->read_block_data(client,
 467                         DS1339_REG_ALARM1_SECS, 9, buf);
 468         if (ret != 9) {
 469                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 470                 return -EIO;
 471         }
 472         control = ds1307->regs[7];
 473         status = ds1307->regs[8];
 474
 475         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 476                         "alarm set (old status)",
 477                         ds1307->regs[0], ds1307->regs[1],
 478                         ds1307->regs[2], ds1307->regs[3],
 479                         ds1307->regs[4], ds1307->regs[5],
 480                         ds1307->regs[6], control, status);
 481
 482         /* set ALARM1, using 24 hour and day-of-month modes */
 483         buf[0] = bin2bcd(t->time.tm_sec);
 484         buf[1] = bin2bcd(t->time.tm_min);
 485         buf[2] = bin2bcd(t->time.tm_hour);
 486         buf[3] = bin2bcd(t->time.tm_mday);
 487
 488         /* set ALARM2 to non-garbage */
 489         buf[4] = 0;
 490         buf[5] = 0;
 491         buf[6] = 0;
 492
 493         /* optionally enable ALARM1 */
 494         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 495         if (t->enabled) {
 496                 dev_dbg(dev, "alarm IRQ armed\n");
 497                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 498         }
 499         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 500
 501         ret = ds1307->write_block_data(client,
 502                         DS1339_REG_ALARM1_SECS, 9, buf);
 503         if (ret < 0) {
 504                 dev_err(dev, "can't set alarm time\n");
 505                 return ret;
 506         }
 507
 508         return 0;
 509 }
 510
 511 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 512 {
 513         struct i2c_client       *client = to_i2c_client(dev);
 514         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 515         int                     ret;
 516
 517         if (!test_bit(HAS_ALARM, &ds1307->flags))
 518                 return -ENOTTY;
 519
 520         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 521         if (ret < 0)
 522                 return ret;
 523
 524         if (enabled)
 525                 ret |= DS1337_BIT_A1IE;
 526         else
 527                 ret &= ~DS1337_BIT_A1IE;
 528
 529         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 530         if (ret < 0)
 531                 return ret;
 532
 533         return 0;
 534 }
 535
 536 static const struct rtc_class_ops ds13xx_rtc_ops = {
 537         .read_time      = ds1307_get_time,
 538         .set_time       = ds1307_set_time,
 539         .read_alarm     = ds1337_read_alarm,
 540         .set_alarm      = ds1337_set_alarm,
 541         .alarm_irq_enable = ds1307_alarm_irq_enable,
 542 };
 543
 544 /*----------------------------------------------------------------------*/
 545
 546 #define NVRAM_SIZE      56
 547
 548 static ssize_t
 549 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 550                 struct bin_attribute *attr,
 551                 char *buf, loff_t off, size_t count)
 552 {
 553         struct i2c_client       *client;
 554         struct ds1307           *ds1307;
 555         int                     result;
 556
 557         client = kobj_to_i2c_client(kobj);
 558         ds1307 = i2c_get_clientdata(client);
 559
 560         if (unlikely(off >= NVRAM_SIZE))
 561                 return 0;
 562         if ((off + count) > NVRAM_SIZE)
 563                 count = NVRAM_SIZE - off;
 564         if (unlikely(!count))
 565                 return count;
 566
 567         result = ds1307->read_block_data(client, 8 + off, count, buf);
 568         if (result < 0)
 569                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 570         return result;
 571 }
 572
 573 static ssize_t
 574 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 575                 struct bin_attribute *attr,
 576                 char *buf, loff_t off, size_t count)
 577 {
 578         struct i2c_client       *client;
 579         struct ds1307           *ds1307;
 580         int                     result;
 581
 582         client = kobj_to_i2c_client(kobj);
 583         ds1307 = i2c_get_clientdata(client);
 584
 585         if (unlikely(off >= NVRAM_SIZE))
 586                 return -EFBIG;
 587         if ((off + count) > NVRAM_SIZE)
 588                 count = NVRAM_SIZE - off;
 589         if (unlikely(!count))
 590                 return count;
 591
 592         result = ds1307->write_block_data(client, 8 + off, count, buf);
 593         if (result < 0) {
 594                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 595                 return result;
 596         }
 597         return count;
 598 }
 599
 600 static struct bin_attribute nvram = {
 601         .attr = {
 602                 .name   = "nvram",
 603                 .mode   = S_IRUGO | S_IWUSR,
 604         },
 605
 606         .read   = ds1307_nvram_read,
 607         .write  = ds1307_nvram_write,
 608         .size   = NVRAM_SIZE,
 609 };
 610
 611 /*----------------------------------------------------------------------*/
 612
 613 static int __devinit ds1307_probe(struct i2c_client *client,
 614                                   const struct i2c_device_id *id)
 615 {
 616         struct ds1307           *ds1307;
 617         int                     err = -ENODEV;
 618         int                     tmp;
 619         const struct chip_desc  *chip = &chips[id->driver_data];
 620         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 621         int                     want_irq = false;
 622         unsigned char           *buf;
 623         static const int        bbsqi_bitpos[] = {
 624                 [ds_1337] = 0,
 625                 [ds_1339] = DS1339_BIT_BBSQI,
 626                 [ds_3231] = DS3231_BIT_BBSQW,
 627         };
 628
 629         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 630             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 631                 return -EIO;
 632
 633         ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
 634         if (!ds1307)
 635                 return -ENOMEM;
 636
 637         i2c_set_clientdata(client, ds1307);
 638
 639         ds1307->client  = client;
 640         ds1307->type    = id->driver_data;
 641         ds1307->offset  = 0;
 642
 643         buf = ds1307->regs;
 644         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 645                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 646                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 647         } else {
 648                 ds1307->read_block_data = ds1307_read_block_data;
 649                 ds1307->write_block_data = ds1307_write_block_data;
 650         }
 651
 652         switch (ds1307->type) {
 653         case ds_1337:
 654         case ds_1339:
 655         case ds_3231:
 656                 /* get registers that the "rtc" read below won't read... */
 657                 tmp = ds1307->read_block_data(ds1307->client,
 658                                 DS1337_REG_CONTROL, 2, buf);
 659                 if (tmp != 2) {
 660                         pr_debug("read error %d\n", tmp);
 661                         err = -EIO;
 662                         goto exit_free;
 663                 }
 664
 665                 /* oscillator off?  turn it on, so clock can tick. */
 666                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 667                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 668
 669                 /*
 670                  * Using IRQ?  Disable the square wave and both alarms.
 671                  * For some variants, be sure alarms can trigger when we're
 672                  * running on Vbackup (BBSQI/BBSQW)
 673                  */
 674                 if (ds1307->client->irq > 0 && chip->alarm) {
 675                         INIT_WORK(&ds1307->work, ds1307_work);
 676
 677                         ds1307->regs[0] |= DS1337_BIT_INTCN
 678                                         | bbsqi_bitpos[ds1307->type];
 679                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 680
 681                         want_irq = true;
 682                 }
 683
 684                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 685                                                         ds1307->regs[0]);
 686
 687                 /* oscillator fault?  clear flag, and warn */
 688                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 689                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 690                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 691                         dev_warn(&client->dev, "SET TIME!\n");
 692                 }
 693                 break;
 694
 695         case rx_8025:
 696                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 697                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 698                 if (tmp != 2) {
 699                         pr_debug("read error %d\n", tmp);
 700                         err = -EIO;
 701                         goto exit_free;
 702                 }
 703
 704                 /* oscillator off?  turn it on, so clock can tick. */
 705                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 706                         ds1307->regs[1] |= RX8025_BIT_XST;
 707                         i2c_smbus_write_byte_data(client,
 708                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 709                                                   ds1307->regs[1]);
 710                         dev_warn(&client->dev,
 711                                  "oscillator stop detected - SET TIME!\n");
 712                 }
 713
 714                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 715                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 716                         i2c_smbus_write_byte_data(client,
 717                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 718                                                   ds1307->regs[1]);
 719                         dev_warn(&client->dev, "power-on detected\n");
 720                 }
 721
 722                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 723                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 724                         i2c_smbus_write_byte_data(client,
 725                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 726                                                   ds1307->regs[1]);
 727                         dev_warn(&client->dev, "voltage drop detected\n");
 728                 }
 729
 730                 /* make sure we are running in 24hour mode */
 731                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 732                         u8 hour;
 733
 734                         /* switch to 24 hour mode */
 735                         i2c_smbus_write_byte_data(client,
 736                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 737                                                   ds1307->regs[0] |
 738                                                   RX8025_BIT_2412);
 739
 740                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 741                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 742                         if (tmp != 2) {
 743                                 pr_debug("read error %d\n", tmp);
 744                                 err = -EIO;
 745                                 goto exit_free;
 746                         }
 747
 748                         /* correct hour */
 749                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 750                         if (hour == 12)
 751                                 hour = 0;
 752                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 753                                 hour += 12;
 754
 755                         i2c_smbus_write_byte_data(client,
 756                                                   DS1307_REG_HOUR << 4 | 0x08,
 757                                                   hour);
 758                 }
 759                 break;
 760         case ds_1388:
 761                 ds1307->offset = 1; /* Seconds starts at 1 */
 762                 break;
 763         default:
 764                 break;
 765         }
 766
 767 read_rtc:
 768         /* read RTC registers */
 769         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 770         if (tmp != 8) {
 771                 pr_debug("read error %d\n", tmp);
 772                 err = -EIO;
 773                 goto exit_free;
 774         }
 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 mcp7941x:
 825                 /* make sure that the backup battery is enabled */
 826                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 827                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 828                                         ds1307->regs[DS1307_REG_WDAY]
 829                                         | MCP7941X_BIT_VBATEN);
 830                 }
 831
 832                 /* clock halted?  turn it on, so clock can tick. */
 833                 if (!(tmp & MCP7941X_BIT_ST)) {
 834                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 835                                         MCP7941X_BIT_ST);
 836                         dev_warn(&client->dev, "SET TIME!\n");
 837                         goto read_rtc;
 838                 }
 839
 840                 break;
 841         default:
 842                 break;
 843         }
 844
 845         tmp = ds1307->regs[DS1307_REG_HOUR];
 846         switch (ds1307->type) {
 847         case ds_1340:
 848         case m41t00:
 849                 /*
 850                  * NOTE: ignores century bits; fix before deploying
 851                  * systems that will run through year 2100.
 852                  */
 853                 break;
 854         case rx_8025:
 855                 break;
 856         default:
 857                 if (!(tmp & DS1307_BIT_12HR))
 858                         break;
 859
 860                 /*
 861                  * Be sure we're in 24 hour mode.  Multi-master systems
 862                  * take note...
 863                  */
 864                 tmp = bcd2bin(tmp & 0x1f);
 865                 if (tmp == 12)
 866                         tmp = 0;
 867                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 868                         tmp += 12;
 869                 i2c_smbus_write_byte_data(client,
 870                                 ds1307->offset + DS1307_REG_HOUR,
 871                                 bin2bcd(tmp));
 872         }
 873
 874         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 875                                 &ds13xx_rtc_ops, THIS_MODULE);
 876         if (IS_ERR(ds1307->rtc)) {
 877                 err = PTR_ERR(ds1307->rtc);
 878                 dev_err(&client->dev,
 879                         "unable to register the class device\n");
 880                 goto exit_free;
 881         }
 882
 883         if (want_irq) {
 884                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 885                           ds1307->rtc->name, client);
 886                 if (err) {
 887                         dev_err(&client->dev,
 888                                 "unable to request IRQ!\n");
 889                         goto exit_irq;
 890                 }
 891
 892                 device_set_wakeup_capable(&client->dev, 1);
 893                 set_bit(HAS_ALARM, &ds1307->flags);
 894                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 895         }
 896
 897         if (chip->nvram56) {
 898                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
 899                 if (err == 0) {
 900                         set_bit(HAS_NVRAM, &ds1307->flags);
 901                         dev_info(&client->dev, "56 bytes nvram\n");
 902                 }
 903         }
 904
 905         return 0;
 906
 907 exit_irq:
 908         rtc_device_unregister(ds1307->rtc);
 909 exit_free:
 910         kfree(ds1307);
 911         return err;
 912 }
 913
 914 static int __devexit ds1307_remove(struct i2c_client *client)
 915 {
 916         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 917
 918         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 919                 free_irq(client->irq, client);
 920                 cancel_work_sync(&ds1307->work);
 921         }
 922
 923         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
 924                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
 925
 926         rtc_device_unregister(ds1307->rtc);
 927         kfree(ds1307);
 928         return 0;
 929 }
 930
 931 static struct i2c_driver ds1307_driver = {
 932         .driver = {
 933                 .name   = "rtc-ds1307",
 934                 .owner  = THIS_MODULE,
 935         },
 936         .probe          = ds1307_probe,
 937         .remove         = __devexit_p(ds1307_remove),
 938         .id_table       = ds1307_id,
 939 };
 940
 941 module_i2c_driver(ds1307_driver);
 942
 943 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 944 MODULE_LICENSE("GPL");