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 #include <linux/rtc/ds1307.h>
  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         mcp7941x,
  38         rx_8025,
  39         last_ds_type /* always last */
  40         /* rs5c372 too?  different address... */
  41 };
  42
  43
  44 /* RTC registers don't differ much, except for the century flag */
  45 #define DS1307_REG_SECS         0x00    /* 00-59 */
  46 #       define DS1307_BIT_CH            0x80
  47 #       define DS1340_BIT_nEOSC         0x80
  48 #       define MCP7941X_BIT_ST          0x80
  49 #define DS1307_REG_MIN          0x01    /* 00-59 */
  50 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  51 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  52 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  53 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  54 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  55 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  56 #       define MCP7941X_BIT_VBATEN      0x08
  57 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  58 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  59 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  60 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  61
  62 /*
  63  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  64  * start at 7, and they differ a LOT. Only control and status matter for
  65  * basic RTC date and time functionality; be careful using them.
  66  */
  67 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  68 #       define DS1307_BIT_OUT           0x80
  69 #       define DS1338_BIT_OSF           0x20
  70 #       define DS1307_BIT_SQWE          0x10
  71 #       define DS1307_BIT_RS1           0x02
  72 #       define DS1307_BIT_RS0           0x01
  73 #define DS1337_REG_CONTROL      0x0e
  74 #       define DS1337_BIT_nEOSC         0x80
  75 #       define DS1339_BIT_BBSQI         0x20
  76 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  77 #       define DS1337_BIT_RS2           0x10
  78 #       define DS1337_BIT_RS1           0x08
  79 #       define DS1337_BIT_INTCN         0x04
  80 #       define DS1337_BIT_A2IE          0x02
  81 #       define DS1337_BIT_A1IE          0x01
  82 #define DS1340_REG_CONTROL      0x07
  83 #       define DS1340_BIT_OUT           0x80
  84 #       define DS1340_BIT_FT            0x40
  85 #       define DS1340_BIT_CALIB_SIGN    0x20
  86 #       define DS1340_M_CALIBRATION     0x1f
  87 #define DS1340_REG_FLAG         0x09
  88 #       define DS1340_BIT_OSF           0x80
  89 #define DS1337_REG_STATUS       0x0f
  90 #       define DS1337_BIT_OSF           0x80
  91 #       define DS1337_BIT_A2I           0x02
  92 #       define DS1337_BIT_A1I           0x01
  93 #define DS1339_REG_ALARM1_SECS  0x07
  94
  95 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
  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         u16                     nvram_offset;
 109         struct bin_attribute    *nvram;
 110         enum ds_type            type;
 111         unsigned long           flags;
 112 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 113 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 114         struct i2c_client       *client;
 115         struct rtc_device       *rtc;
 116         struct work_struct      work;
 117         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 118                                u8 length, u8 *values);
 119         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 120                                 u8 length, const u8 *values);
 121 };
 122
 123 struct chip_desc {
 124         unsigned                alarm:1;
 125         u16                     nvram_offset;
 126         u16                     nvram_size;
 127         u16                     trickle_charger_reg;
 128 };
 129
 130 static const struct chip_desc chips[last_ds_type] = {
 131         [ds_1307] = {
 132                 .nvram_offset   = 8,
 133                 .nvram_size     = 56,
 134         },
 135         [ds_1337] = {
 136                 .alarm          = 1,
 137         },
 138         [ds_1338] = {
 139                 .nvram_offset   = 8,
 140                 .nvram_size     = 56,
 141         },
 142         [ds_1339] = {
 143                 .alarm          = 1,
 144                 .trickle_charger_reg = 0x10,
 145         },
 146         [ds_1340] = {
 147                 .trickle_charger_reg = 0x08,
 148         },
 149         [ds_1388] = {
 150                 .trickle_charger_reg = 0x0a,
 151         },
 152         [ds_3231] = {
 153                 .alarm          = 1,
 154         },
 155         [mcp7941x] = {
 156                 /* this is battery backed SRAM */
 157                 .nvram_offset   = 0x20,
 158                 .nvram_size     = 0x40,
 159         },
 160 };
 161
 162 static const struct i2c_device_id ds1307_id[] = {
 163         { "ds1307", ds_1307 },
 164         { "ds1337", ds_1337 },
 165         { "ds1338", ds_1338 },
 166         { "ds1339", ds_1339 },
 167         { "ds1388", ds_1388 },
 168         { "ds1340", ds_1340 },
 169         { "ds3231", ds_3231 },
 170         { "m41t00", m41t00 },
 171         { "mcp7941x", mcp7941x },
 172         { "pt7c4338", ds_1307 },
 173         { "rx8025", rx_8025 },
 174         { }
 175 };
 176 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 177
 178 /*----------------------------------------------------------------------*/
 179
 180 #define BLOCK_DATA_MAX_TRIES 10
 181
 182 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 183                                        u8 command, u8 length, u8 *values)
 184 {
 185         s32 i, data;
 186
 187         for (i = 0; i < length; i++) {
 188                 data = i2c_smbus_read_byte_data(client, command + i);
 189                 if (data < 0)
 190                         return data;
 191                 values[i] = data;
 192         }
 193         return i;
 194 }
 195
 196 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 197                                   u8 length, u8 *values)
 198 {
 199         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 200         s32 ret;
 201         int tries = 0;
 202
 203         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 204         ret = ds1307_read_block_data_once(client, command, length, values);
 205         if (ret < 0)
 206                 return ret;
 207         do {
 208                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 209                         dev_err(&client->dev,
 210                                 "ds1307_read_block_data failed\n");
 211                         return -EIO;
 212                 }
 213                 memcpy(oldvalues, values, length);
 214                 ret = ds1307_read_block_data_once(client, command, length,
 215                                                   values);
 216                 if (ret < 0)
 217                         return ret;
 218         } while (memcmp(oldvalues, values, length));
 219         return length;
 220 }
 221
 222 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 223                                    u8 length, const u8 *values)
 224 {
 225         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 226         int tries = 0;
 227
 228         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 229         do {
 230                 s32 i, ret;
 231
 232                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 233                         dev_err(&client->dev,
 234                                 "ds1307_write_block_data failed\n");
 235                         return -EIO;
 236                 }
 237                 for (i = 0; i < length; i++) {
 238                         ret = i2c_smbus_write_byte_data(client, command + i,
 239                                                         values[i]);
 240                         if (ret < 0)
 241                                 return ret;
 242                 }
 243                 ret = ds1307_read_block_data_once(client, command, length,
 244                                                   currvalues);
 245                 if (ret < 0)
 246                         return ret;
 247         } while (memcmp(currvalues, values, length));
 248         return length;
 249 }
 250
 251 /*----------------------------------------------------------------------*/
 252
 253 /*
 254  * The IRQ logic includes a "real" handler running in IRQ context just
 255  * long enough to schedule this workqueue entry.   We need a task context
 256  * to talk to the RTC, since I2C I/O calls require that; and disable the
 257  * IRQ until we clear its status on the chip, so that this handler can
 258  * work with any type of triggering (not just falling edge).
 259  *
 260  * The ds1337 and ds1339 both have two alarms, but we only use the first
 261  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 262  * signal; ds1339 chips have only one alarm signal.
 263  */
 264 static void ds1307_work(struct work_struct *work)
 265 {
 266         struct ds1307           *ds1307;
 267         struct i2c_client       *client;
 268         struct mutex            *lock;
 269         int                     stat, control;
 270
 271         ds1307 = container_of(work, struct ds1307, work);
 272         client = ds1307->client;
 273         lock = &ds1307->rtc->ops_lock;
 274
 275         mutex_lock(lock);
 276         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 277         if (stat < 0)
 278                 goto out;
 279
 280         if (stat & DS1337_BIT_A1I) {
 281                 stat &= ~DS1337_BIT_A1I;
 282                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 283
 284                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 285                 if (control < 0)
 286                         goto out;
 287
 288                 control &= ~DS1337_BIT_A1IE;
 289                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 290
 291                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 292         }
 293
 294 out:
 295         if (test_bit(HAS_ALARM, &ds1307->flags))
 296                 enable_irq(client->irq);
 297         mutex_unlock(lock);
 298 }
 299
 300 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 301 {
 302         struct i2c_client       *client = dev_id;
 303         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 304
 305         disable_irq_nosync(irq);
 306         schedule_work(&ds1307->work);
 307         return IRQ_HANDLED;
 308 }
 309
 310 /*----------------------------------------------------------------------*/
 311
 312 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 313 {
 314         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 315         int             tmp;
 316
 317         /* read the RTC date and time registers all at once */
 318         tmp = ds1307->read_block_data(ds1307->client,
 319                 ds1307->offset, 7, ds1307->regs);
 320         if (tmp != 7) {
 321                 dev_err(dev, "%s error %d\n", "read", tmp);
 322                 return -EIO;
 323         }
 324
 325         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 326                         "read",
 327                         ds1307->regs[0], ds1307->regs[1],
 328                         ds1307->regs[2], ds1307->regs[3],
 329                         ds1307->regs[4], ds1307->regs[5],
 330                         ds1307->regs[6]);
 331
 332         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 333         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 334         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 335         t->tm_hour = bcd2bin(tmp);
 336         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 337         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 338         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 339         t->tm_mon = bcd2bin(tmp) - 1;
 340
 341         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 342         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 343
 344         dev_dbg(dev, "%s secs=%d, mins=%d, "
 345                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 346                 "read", t->tm_sec, t->tm_min,
 347                 t->tm_hour, t->tm_mday,
 348                 t->tm_mon, t->tm_year, t->tm_wday);
 349
 350         /* initial clock setting can be undefined */
 351         return rtc_valid_tm(t);
 352 }
 353
 354 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 355 {
 356         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 357         int             result;
 358         int             tmp;
 359         u8              *buf = ds1307->regs;
 360
 361         dev_dbg(dev, "%s secs=%d, mins=%d, "
 362                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 363                 "write", t->tm_sec, t->tm_min,
 364                 t->tm_hour, t->tm_mday,
 365                 t->tm_mon, t->tm_year, t->tm_wday);
 366
 367         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 368         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 369         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 370         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 371         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 372         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 373
 374         /* assume 20YY not 19YY */
 375         tmp = t->tm_year - 100;
 376         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 377
 378         switch (ds1307->type) {
 379         case ds_1337:
 380         case ds_1339:
 381         case ds_3231:
 382                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 383                 break;
 384         case ds_1340:
 385                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 386                                 | DS1340_BIT_CENTURY;
 387                 break;
 388         case mcp7941x:
 389                 /*
 390                  * these bits were cleared when preparing the date/time
 391                  * values and need to be set again before writing the
 392                  * buffer out to the device.
 393                  */
 394                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 395                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 396                 break;
 397         default:
 398                 break;
 399         }
 400
 401         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 402                 "write", buf[0], buf[1], buf[2], buf[3],
 403                 buf[4], buf[5], buf[6]);
 404
 405         result = ds1307->write_block_data(ds1307->client,
 406                 ds1307->offset, 7, buf);
 407         if (result < 0) {
 408                 dev_err(dev, "%s error %d\n", "write", result);
 409                 return result;
 410         }
 411         return 0;
 412 }
 413
 414 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 415 {
 416         struct i2c_client       *client = to_i2c_client(dev);
 417         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 418         int                     ret;
 419
 420         if (!test_bit(HAS_ALARM, &ds1307->flags))
 421                 return -EINVAL;
 422
 423         /* read all ALARM1, ALARM2, and status registers at once */
 424         ret = ds1307->read_block_data(client,
 425                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 426         if (ret != 9) {
 427                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 428                 return -EIO;
 429         }
 430
 431         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 432                         "alarm read",
 433                         ds1307->regs[0], ds1307->regs[1],
 434                         ds1307->regs[2], ds1307->regs[3],
 435                         ds1307->regs[4], ds1307->regs[5],
 436                         ds1307->regs[6], ds1307->regs[7],
 437                         ds1307->regs[8]);
 438
 439         /*
 440          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 441          * and that all four fields are checked matches
 442          */
 443         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 444         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 445         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 446         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 447         t->time.tm_mon = -1;
 448         t->time.tm_year = -1;
 449         t->time.tm_wday = -1;
 450         t->time.tm_yday = -1;
 451         t->time.tm_isdst = -1;
 452
 453         /* ... and status */
 454         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 455         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 456
 457         dev_dbg(dev, "%s secs=%d, mins=%d, "
 458                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 459                 "alarm read", t->time.tm_sec, t->time.tm_min,
 460                 t->time.tm_hour, t->time.tm_mday,
 461                 t->enabled, t->pending);
 462
 463         return 0;
 464 }
 465
 466 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 467 {
 468         struct i2c_client       *client = to_i2c_client(dev);
 469         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 470         unsigned char           *buf = ds1307->regs;
 471         u8                      control, status;
 472         int                     ret;
 473
 474         if (!test_bit(HAS_ALARM, &ds1307->flags))
 475                 return -EINVAL;
 476
 477         dev_dbg(dev, "%s secs=%d, mins=%d, "
 478                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 479                 "alarm set", t->time.tm_sec, t->time.tm_min,
 480                 t->time.tm_hour, t->time.tm_mday,
 481                 t->enabled, t->pending);
 482
 483         /* read current status of both alarms and the chip */
 484         ret = ds1307->read_block_data(client,
 485                         DS1339_REG_ALARM1_SECS, 9, buf);
 486         if (ret != 9) {
 487                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 488                 return -EIO;
 489         }
 490         control = ds1307->regs[7];
 491         status = ds1307->regs[8];
 492
 493         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 494                         "alarm set (old status)",
 495                         ds1307->regs[0], ds1307->regs[1],
 496                         ds1307->regs[2], ds1307->regs[3],
 497                         ds1307->regs[4], ds1307->regs[5],
 498                         ds1307->regs[6], control, status);
 499
 500         /* set ALARM1, using 24 hour and day-of-month modes */
 501         buf[0] = bin2bcd(t->time.tm_sec);
 502         buf[1] = bin2bcd(t->time.tm_min);
 503         buf[2] = bin2bcd(t->time.tm_hour);
 504         buf[3] = bin2bcd(t->time.tm_mday);
 505
 506         /* set ALARM2 to non-garbage */
 507         buf[4] = 0;
 508         buf[5] = 0;
 509         buf[6] = 0;
 510
 511         /* optionally enable ALARM1 */
 512         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 513         if (t->enabled) {
 514                 dev_dbg(dev, "alarm IRQ armed\n");
 515                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 516         }
 517         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 518
 519         ret = ds1307->write_block_data(client,
 520                         DS1339_REG_ALARM1_SECS, 9, buf);
 521         if (ret < 0) {
 522                 dev_err(dev, "can't set alarm time\n");
 523                 return ret;
 524         }
 525
 526         return 0;
 527 }
 528
 529 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 530 {
 531         struct i2c_client       *client = to_i2c_client(dev);
 532         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 533         int                     ret;
 534
 535         if (!test_bit(HAS_ALARM, &ds1307->flags))
 536                 return -ENOTTY;
 537
 538         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 539         if (ret < 0)
 540                 return ret;
 541
 542         if (enabled)
 543                 ret |= DS1337_BIT_A1IE;
 544         else
 545                 ret &= ~DS1337_BIT_A1IE;
 546
 547         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 548         if (ret < 0)
 549                 return ret;
 550
 551         return 0;
 552 }
 553
 554 static const struct rtc_class_ops ds13xx_rtc_ops = {
 555         .read_time      = ds1307_get_time,
 556         .set_time       = ds1307_set_time,
 557         .read_alarm     = ds1337_read_alarm,
 558         .set_alarm      = ds1337_set_alarm,
 559         .alarm_irq_enable = ds1307_alarm_irq_enable,
 560 };
 561
 562 /*----------------------------------------------------------------------*/
 563
 564 static ssize_t
 565 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 566                 struct bin_attribute *attr,
 567                 char *buf, loff_t off, size_t count)
 568 {
 569         struct i2c_client       *client;
 570         struct ds1307           *ds1307;
 571         int                     result;
 572
 573         client = kobj_to_i2c_client(kobj);
 574         ds1307 = i2c_get_clientdata(client);
 575
 576         if (unlikely(off >= ds1307->nvram->size))
 577                 return 0;
 578         if ((off + count) > ds1307->nvram->size)
 579                 count = ds1307->nvram->size - off;
 580         if (unlikely(!count))
 581                 return count;
 582
 583         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 584                                                                 count, buf);
 585         if (result < 0)
 586                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 587         return result;
 588 }
 589
 590 static ssize_t
 591 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 592                 struct bin_attribute *attr,
 593                 char *buf, loff_t off, size_t count)
 594 {
 595         struct i2c_client       *client;
 596         struct ds1307           *ds1307;
 597         int                     result;
 598
 599         client = kobj_to_i2c_client(kobj);
 600         ds1307 = i2c_get_clientdata(client);
 601
 602         if (unlikely(off >= ds1307->nvram->size))
 603                 return -EFBIG;
 604         if ((off + count) > ds1307->nvram->size)
 605                 count = ds1307->nvram->size - off;
 606         if (unlikely(!count))
 607                 return count;
 608
 609         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 610                                                                 count, buf);
 611         if (result < 0) {
 612                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 613                 return result;
 614         }
 615         return count;
 616 }
 617
 618 /*----------------------------------------------------------------------*/
 619
 620 static int __devinit ds1307_probe(struct i2c_client *client,
 621                                   const struct i2c_device_id *id)
 622 {
 623         struct ds1307           *ds1307;
 624         int                     err = -ENODEV;
 625         int                     tmp;
 626         const struct chip_desc  *chip = &chips[id->driver_data];
 627         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 628         int                     want_irq = false;
 629         unsigned char           *buf;
 630         struct ds1307_platform_data *pdata = client->dev.platform_data;
 631         static const int        bbsqi_bitpos[] = {
 632                 [ds_1337] = 0,
 633                 [ds_1339] = DS1339_BIT_BBSQI,
 634                 [ds_3231] = DS3231_BIT_BBSQW,
 635         };
 636
 637         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 638             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 639                 return -EIO;
 640
 641         ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
 642         if (!ds1307)
 643                 return -ENOMEM;
 644
 645         i2c_set_clientdata(client, ds1307);
 646
 647         ds1307->client  = client;
 648         ds1307->type    = id->driver_data;
 649
 650         if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
 651                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 652                         DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
 653
 654         buf = ds1307->regs;
 655         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 656                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 657                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 658         } else {
 659                 ds1307->read_block_data = ds1307_read_block_data;
 660                 ds1307->write_block_data = ds1307_write_block_data;
 661         }
 662
 663         switch (ds1307->type) {
 664         case ds_1337:
 665         case ds_1339:
 666         case ds_3231:
 667                 /* get registers that the "rtc" read below won't read... */
 668                 tmp = ds1307->read_block_data(ds1307->client,
 669                                 DS1337_REG_CONTROL, 2, buf);
 670                 if (tmp != 2) {
 671                         pr_debug("read error %d\n", tmp);
 672                         err = -EIO;
 673                         goto exit_free;
 674                 }
 675
 676                 /* oscillator off?  turn it on, so clock can tick. */
 677                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 678                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 679
 680                 /*
 681                  * Using IRQ?  Disable the square wave and both alarms.
 682                  * For some variants, be sure alarms can trigger when we're
 683                  * running on Vbackup (BBSQI/BBSQW)
 684                  */
 685                 if (ds1307->client->irq > 0 && chip->alarm) {
 686                         INIT_WORK(&ds1307->work, ds1307_work);
 687
 688                         ds1307->regs[0] |= DS1337_BIT_INTCN
 689                                         | bbsqi_bitpos[ds1307->type];
 690                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 691
 692                         want_irq = true;
 693                 }
 694
 695                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 696                                                         ds1307->regs[0]);
 697
 698                 /* oscillator fault?  clear flag, and warn */
 699                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 700                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 701                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 702                         dev_warn(&client->dev, "SET TIME!\n");
 703                 }
 704                 break;
 705
 706         case rx_8025:
 707                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 708                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 709                 if (tmp != 2) {
 710                         pr_debug("read error %d\n", tmp);
 711                         err = -EIO;
 712                         goto exit_free;
 713                 }
 714
 715                 /* oscillator off?  turn it on, so clock can tick. */
 716                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 717                         ds1307->regs[1] |= RX8025_BIT_XST;
 718                         i2c_smbus_write_byte_data(client,
 719                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 720                                                   ds1307->regs[1]);
 721                         dev_warn(&client->dev,
 722                                  "oscillator stop detected - SET TIME!\n");
 723                 }
 724
 725                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 726                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 727                         i2c_smbus_write_byte_data(client,
 728                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 729                                                   ds1307->regs[1]);
 730                         dev_warn(&client->dev, "power-on detected\n");
 731                 }
 732
 733                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 734                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 735                         i2c_smbus_write_byte_data(client,
 736                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 737                                                   ds1307->regs[1]);
 738                         dev_warn(&client->dev, "voltage drop detected\n");
 739                 }
 740
 741                 /* make sure we are running in 24hour mode */
 742                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 743                         u8 hour;
 744
 745                         /* switch to 24 hour mode */
 746                         i2c_smbus_write_byte_data(client,
 747                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 748                                                   ds1307->regs[0] |
 749                                                   RX8025_BIT_2412);
 750
 751                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 752                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 753                         if (tmp != 2) {
 754                                 pr_debug("read error %d\n", tmp);
 755                                 err = -EIO;
 756                                 goto exit_free;
 757                         }
 758
 759                         /* correct hour */
 760                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 761                         if (hour == 12)
 762                                 hour = 0;
 763                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 764                                 hour += 12;
 765
 766                         i2c_smbus_write_byte_data(client,
 767                                                   DS1307_REG_HOUR << 4 | 0x08,
 768                                                   hour);
 769                 }
 770                 break;
 771         case ds_1388:
 772                 ds1307->offset = 1; /* Seconds starts at 1 */
 773                 break;
 774         default:
 775                 break;
 776         }
 777
 778 read_rtc:
 779         /* read RTC registers */
 780         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 781         if (tmp != 8) {
 782                 pr_debug("read error %d\n", tmp);
 783                 err = -EIO;
 784                 goto exit_free;
 785         }
 786
 787         /*
 788          * minimal sanity checking; some chips (like DS1340) don't
 789          * specify the extra bits as must-be-zero, but there are
 790          * still a few values that are clearly out-of-range.
 791          */
 792         tmp = ds1307->regs[DS1307_REG_SECS];
 793         switch (ds1307->type) {
 794         case ds_1307:
 795         case m41t00:
 796                 /* clock halted?  turn it on, so clock can tick. */
 797                 if (tmp & DS1307_BIT_CH) {
 798                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 799                         dev_warn(&client->dev, "SET TIME!\n");
 800                         goto read_rtc;
 801                 }
 802                 break;
 803         case ds_1338:
 804                 /* clock halted?  turn it on, so clock can tick. */
 805                 if (tmp & DS1307_BIT_CH)
 806                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 807
 808                 /* oscillator fault?  clear flag, and warn */
 809                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 810                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 811                                         ds1307->regs[DS1307_REG_CONTROL]
 812                                         & ~DS1338_BIT_OSF);
 813                         dev_warn(&client->dev, "SET TIME!\n");
 814                         goto read_rtc;
 815                 }
 816                 break;
 817         case ds_1340:
 818                 /* clock halted?  turn it on, so clock can tick. */
 819                 if (tmp & DS1340_BIT_nEOSC)
 820                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 821
 822                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 823                 if (tmp < 0) {
 824                         pr_debug("read error %d\n", tmp);
 825                         err = -EIO;
 826                         goto exit_free;
 827                 }
 828
 829                 /* oscillator fault?  clear flag, and warn */
 830                 if (tmp & DS1340_BIT_OSF) {
 831                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 832                         dev_warn(&client->dev, "SET TIME!\n");
 833                 }
 834                 break;
 835         case mcp7941x:
 836                 /* make sure that the backup battery is enabled */
 837                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 838                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 839                                         ds1307->regs[DS1307_REG_WDAY]
 840                                         | MCP7941X_BIT_VBATEN);
 841                 }
 842
 843                 /* clock halted?  turn it on, so clock can tick. */
 844                 if (!(tmp & MCP7941X_BIT_ST)) {
 845                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 846                                         MCP7941X_BIT_ST);
 847                         dev_warn(&client->dev, "SET TIME!\n");
 848                         goto read_rtc;
 849                 }
 850
 851                 break;
 852         default:
 853                 break;
 854         }
 855
 856         tmp = ds1307->regs[DS1307_REG_HOUR];
 857         switch (ds1307->type) {
 858         case ds_1340:
 859         case m41t00:
 860                 /*
 861                  * NOTE: ignores century bits; fix before deploying
 862                  * systems that will run through year 2100.
 863                  */
 864                 break;
 865         case rx_8025:
 866                 break;
 867         default:
 868                 if (!(tmp & DS1307_BIT_12HR))
 869                         break;
 870
 871                 /*
 872                  * Be sure we're in 24 hour mode.  Multi-master systems
 873                  * take note...
 874                  */
 875                 tmp = bcd2bin(tmp & 0x1f);
 876                 if (tmp == 12)
 877                         tmp = 0;
 878                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 879                         tmp += 12;
 880                 i2c_smbus_write_byte_data(client,
 881                                 ds1307->offset + DS1307_REG_HOUR,
 882                                 bin2bcd(tmp));
 883         }
 884
 885         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 886                                 &ds13xx_rtc_ops, THIS_MODULE);
 887         if (IS_ERR(ds1307->rtc)) {
 888                 err = PTR_ERR(ds1307->rtc);
 889                 dev_err(&client->dev,
 890                         "unable to register the class device\n");
 891                 goto exit_free;
 892         }
 893
 894         if (want_irq) {
 895                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 896                           ds1307->rtc->name, client);
 897                 if (err) {
 898                         dev_err(&client->dev,
 899                                 "unable to request IRQ!\n");
 900                         goto exit_irq;
 901                 }
 902
 903                 device_set_wakeup_capable(&client->dev, 1);
 904                 set_bit(HAS_ALARM, &ds1307->flags);
 905                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 906         }
 907
 908         if (chip->nvram_size) {
 909                 ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
 910                                                         GFP_KERNEL);
 911                 if (!ds1307->nvram) {
 912                         err = -ENOMEM;
 913                         goto exit_nvram;
 914                 }
 915                 ds1307->nvram->attr.name = "nvram";
 916                 ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
 917                 sysfs_bin_attr_init(ds1307->nvram);
 918                 ds1307->nvram->read = ds1307_nvram_read,
 919                 ds1307->nvram->write = ds1307_nvram_write,
 920                 ds1307->nvram->size = chip->nvram_size;
 921                 ds1307->nvram_offset = chip->nvram_offset;
 922                 err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
 923                 if (err) {
 924                         kfree(ds1307->nvram);
 925                         goto exit_nvram;
 926                 }
 927                 set_bit(HAS_NVRAM, &ds1307->flags);
 928                 dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
 929         }
 930
 931         return 0;
 932
 933 exit_nvram:
 934 exit_irq:
 935         rtc_device_unregister(ds1307->rtc);
 936 exit_free:
 937         kfree(ds1307);
 938         return err;
 939 }
 940
 941 static int __devexit ds1307_remove(struct i2c_client *client)
 942 {
 943         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 944
 945         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 946                 free_irq(client->irq, client);
 947                 cancel_work_sync(&ds1307->work);
 948         }
 949
 950         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
 951                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
 952                 kfree(ds1307->nvram);
 953         }
 954
 955         rtc_device_unregister(ds1307->rtc);
 956         kfree(ds1307);
 957         return 0;
 958 }
 959
 960 static struct i2c_driver ds1307_driver = {
 961         .driver = {
 962                 .name   = "rtc-ds1307",
 963                 .owner  = THIS_MODULE,
 964         },
 965         .probe          = ds1307_probe,
 966         .remove         = __devexit_p(ds1307_remove),
 967         .id_table       = ds1307_id,
 968 };
 969
 970 module_i2c_driver(ds1307_driver);
 971
 972 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 973 MODULE_LICENSE("GPL");