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  *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/i2c.h>
  18 #include <linux/string.h>
  19 #include <linux/rtc.h>
  20 #include <linux/bcd.h>
  21 #include <linux/rtc/ds1307.h>
  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
  96 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
  97
  98 #define RX8025_REG_CTRL1        0x0e
  99 #       define RX8025_BIT_2412          0x20
 100 #define RX8025_REG_CTRL2        0x0f
 101 #       define RX8025_BIT_PON           0x10
 102 #       define RX8025_BIT_VDET          0x40
 103 #       define RX8025_BIT_XST           0x20
 104
 105
 106 struct ds1307 {
 107         u8                      offset; /* register's offset */
 108         u8                      regs[11];
 109         u16                     nvram_offset;
 110         struct bin_attribute    *nvram;
 111         enum ds_type            type;
 112         unsigned long           flags;
 113 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 114 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 115         struct i2c_client       *client;
 116         struct rtc_device       *rtc;
 117         struct work_struct      work;
 118         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 119                                u8 length, u8 *values);
 120         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 121                                 u8 length, const u8 *values);
 122 };
 123
 124 struct chip_desc {
 125         unsigned                alarm:1;
 126         u16                     nvram_offset;
 127         u16                     nvram_size;
 128         u16                     trickle_charger_reg;
 129 };
 130
 131 static const struct chip_desc chips[last_ds_type] = {
 132         [ds_1307] = {
 133                 .nvram_offset   = 8,
 134                 .nvram_size     = 56,
 135         },
 136         [ds_1337] = {
 137                 .alarm          = 1,
 138         },
 139         [ds_1338] = {
 140                 .nvram_offset   = 8,
 141                 .nvram_size     = 56,
 142         },
 143         [ds_1339] = {
 144                 .alarm          = 1,
 145                 .trickle_charger_reg = 0x10,
 146         },
 147         [ds_1340] = {
 148                 .trickle_charger_reg = 0x08,
 149         },
 150         [ds_1388] = {
 151                 .trickle_charger_reg = 0x0a,
 152         },
 153         [ds_3231] = {
 154                 .alarm          = 1,
 155         },
 156         [mcp7941x] = {
 157                 .alarm          = 1,
 158                 /* this is battery backed SRAM */
 159                 .nvram_offset   = 0x20,
 160                 .nvram_size     = 0x40,
 161         },
 162 };
 163
 164 static const struct i2c_device_id ds1307_id[] = {
 165         { "ds1307", ds_1307 },
 166         { "ds1337", ds_1337 },
 167         { "ds1338", ds_1338 },
 168         { "ds1339", ds_1339 },
 169         { "ds1388", ds_1388 },
 170         { "ds1340", ds_1340 },
 171         { "ds3231", ds_3231 },
 172         { "m41t00", m41t00 },
 173         { "mcp7941x", mcp7941x },
 174         { "pt7c4338", ds_1307 },
 175         { "rx8025", rx_8025 },
 176         { }
 177 };
 178 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 179
 180 /*----------------------------------------------------------------------*/
 181
 182 #define BLOCK_DATA_MAX_TRIES 10
 183
 184 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 185                                        u8 command, u8 length, u8 *values)
 186 {
 187         s32 i, data;
 188
 189         for (i = 0; i < length; i++) {
 190                 data = i2c_smbus_read_byte_data(client, command + i);
 191                 if (data < 0)
 192                         return data;
 193                 values[i] = data;
 194         }
 195         return i;
 196 }
 197
 198 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 199                                   u8 length, u8 *values)
 200 {
 201         u8 oldvalues[255];
 202         s32 ret;
 203         int tries = 0;
 204
 205         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 206         ret = ds1307_read_block_data_once(client, command, length, values);
 207         if (ret < 0)
 208                 return ret;
 209         do {
 210                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 211                         dev_err(&client->dev,
 212                                 "ds1307_read_block_data failed\n");
 213                         return -EIO;
 214                 }
 215                 memcpy(oldvalues, values, length);
 216                 ret = ds1307_read_block_data_once(client, command, length,
 217                                                   values);
 218                 if (ret < 0)
 219                         return ret;
 220         } while (memcmp(oldvalues, values, length));
 221         return length;
 222 }
 223
 224 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 225                                    u8 length, const u8 *values)
 226 {
 227         u8 currvalues[255];
 228         int tries = 0;
 229
 230         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 231         do {
 232                 s32 i, ret;
 233
 234                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 235                         dev_err(&client->dev,
 236                                 "ds1307_write_block_data failed\n");
 237                         return -EIO;
 238                 }
 239                 for (i = 0; i < length; i++) {
 240                         ret = i2c_smbus_write_byte_data(client, command + i,
 241                                                         values[i]);
 242                         if (ret < 0)
 243                                 return ret;
 244                 }
 245                 ret = ds1307_read_block_data_once(client, command, length,
 246                                                   currvalues);
 247                 if (ret < 0)
 248                         return ret;
 249         } while (memcmp(currvalues, values, length));
 250         return length;
 251 }
 252
 253 /*----------------------------------------------------------------------*/
 254
 255 /* These RTC devices are not designed to be connected to a SMbus adapter.
 256    SMbus limits block operations length to 32 bytes, whereas it's not
 257    limited on I2C buses. As a result, accesses may exceed 32 bytes;
 258    in that case, split them into smaller blocks */
 259
 260 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
 261                                 u8 command, u8 length, const u8 *values)
 262 {
 263         u8 suboffset = 0;
 264
 265         if (length <= I2C_SMBUS_BLOCK_MAX)
 266                 return i2c_smbus_write_i2c_block_data(client,
 267                                         command, length, values);
 268
 269         while (suboffset < length) {
 270                 s32 retval = i2c_smbus_write_i2c_block_data(client,
 271                                 command + suboffset,
 272                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 273                                 values + suboffset);
 274                 if (retval < 0)
 275                         return retval;
 276
 277                 suboffset += I2C_SMBUS_BLOCK_MAX;
 278         }
 279         return length;
 280 }
 281
 282 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
 283                                 u8 command, u8 length, u8 *values)
 284 {
 285         u8 suboffset = 0;
 286
 287         if (length <= I2C_SMBUS_BLOCK_MAX)
 288                 return i2c_smbus_read_i2c_block_data(client,
 289                                         command, length, values);
 290
 291         while (suboffset < length) {
 292                 s32 retval = i2c_smbus_read_i2c_block_data(client,
 293                                 command + suboffset,
 294                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 295                                 values + suboffset);
 296                 if (retval < 0)
 297                         return retval;
 298
 299                 suboffset += I2C_SMBUS_BLOCK_MAX;
 300         }
 301         return length;
 302 }
 303
 304 /*----------------------------------------------------------------------*/
 305
 306 /*
 307  * The IRQ logic includes a "real" handler running in IRQ context just
 308  * long enough to schedule this workqueue entry.   We need a task context
 309  * to talk to the RTC, since I2C I/O calls require that; and disable the
 310  * IRQ until we clear its status on the chip, so that this handler can
 311  * work with any type of triggering (not just falling edge).
 312  *
 313  * The ds1337 and ds1339 both have two alarms, but we only use the first
 314  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 315  * signal; ds1339 chips have only one alarm signal.
 316  */
 317 static void ds1307_work(struct work_struct *work)
 318 {
 319         struct ds1307           *ds1307;
 320         struct i2c_client       *client;
 321         struct mutex            *lock;
 322         int                     stat, control;
 323
 324         ds1307 = container_of(work, struct ds1307, work);
 325         client = ds1307->client;
 326         lock = &ds1307->rtc->ops_lock;
 327
 328         mutex_lock(lock);
 329         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 330         if (stat < 0)
 331                 goto out;
 332
 333         if (stat & DS1337_BIT_A1I) {
 334                 stat &= ~DS1337_BIT_A1I;
 335                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 336
 337                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 338                 if (control < 0)
 339                         goto out;
 340
 341                 control &= ~DS1337_BIT_A1IE;
 342                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 343
 344                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 345         }
 346
 347 out:
 348         if (test_bit(HAS_ALARM, &ds1307->flags))
 349                 enable_irq(client->irq);
 350         mutex_unlock(lock);
 351 }
 352
 353 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 354 {
 355         struct i2c_client       *client = dev_id;
 356         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 357
 358         disable_irq_nosync(irq);
 359         schedule_work(&ds1307->work);
 360         return IRQ_HANDLED;
 361 }
 362
 363 /*----------------------------------------------------------------------*/
 364
 365 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 366 {
 367         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 368         int             tmp;
 369
 370         /* read the RTC date and time registers all at once */
 371         tmp = ds1307->read_block_data(ds1307->client,
 372                 ds1307->offset, 7, ds1307->regs);
 373         if (tmp != 7) {
 374                 dev_err(dev, "%s error %d\n", "read", tmp);
 375                 return -EIO;
 376         }
 377
 378         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 379
 380         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 381         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 382         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 383         t->tm_hour = bcd2bin(tmp);
 384         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 385         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 386         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 387         t->tm_mon = bcd2bin(tmp) - 1;
 388
 389         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 390         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 391
 392         dev_dbg(dev, "%s secs=%d, mins=%d, "
 393                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 394                 "read", t->tm_sec, t->tm_min,
 395                 t->tm_hour, t->tm_mday,
 396                 t->tm_mon, t->tm_year, t->tm_wday);
 397
 398         /* initial clock setting can be undefined */
 399         return rtc_valid_tm(t);
 400 }
 401
 402 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 403 {
 404         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 405         int             result;
 406         int             tmp;
 407         u8              *buf = ds1307->regs;
 408
 409         dev_dbg(dev, "%s secs=%d, mins=%d, "
 410                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 411                 "write", t->tm_sec, t->tm_min,
 412                 t->tm_hour, t->tm_mday,
 413                 t->tm_mon, t->tm_year, t->tm_wday);
 414
 415         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 416         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 417         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 418         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 419         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 420         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 421
 422         /* assume 20YY not 19YY */
 423         tmp = t->tm_year - 100;
 424         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 425
 426         switch (ds1307->type) {
 427         case ds_1337:
 428         case ds_1339:
 429         case ds_3231:
 430                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 431                 break;
 432         case ds_1340:
 433                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 434                                 | DS1340_BIT_CENTURY;
 435                 break;
 436         case mcp7941x:
 437                 /*
 438                  * these bits were cleared when preparing the date/time
 439                  * values and need to be set again before writing the
 440                  * buffer out to the device.
 441                  */
 442                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 443                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 444                 break;
 445         default:
 446                 break;
 447         }
 448
 449         dev_dbg(dev, "%s: %7ph\n", "write", buf);
 450
 451         result = ds1307->write_block_data(ds1307->client,
 452                 ds1307->offset, 7, buf);
 453         if (result < 0) {
 454                 dev_err(dev, "%s error %d\n", "write", result);
 455                 return result;
 456         }
 457         return 0;
 458 }
 459
 460 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 461 {
 462         struct i2c_client       *client = to_i2c_client(dev);
 463         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 464         int                     ret;
 465
 466         if (!test_bit(HAS_ALARM, &ds1307->flags))
 467                 return -EINVAL;
 468
 469         /* read all ALARM1, ALARM2, and status registers at once */
 470         ret = ds1307->read_block_data(client,
 471                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 472         if (ret != 9) {
 473                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 474                 return -EIO;
 475         }
 476
 477         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 478                         "alarm read",
 479                         ds1307->regs[0], ds1307->regs[1],
 480                         ds1307->regs[2], ds1307->regs[3],
 481                         ds1307->regs[4], ds1307->regs[5],
 482                         ds1307->regs[6], ds1307->regs[7],
 483                         ds1307->regs[8]);
 484
 485         /*
 486          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 487          * and that all four fields are checked matches
 488          */
 489         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 490         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 491         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 492         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 493         t->time.tm_mon = -1;
 494         t->time.tm_year = -1;
 495         t->time.tm_wday = -1;
 496         t->time.tm_yday = -1;
 497         t->time.tm_isdst = -1;
 498
 499         /* ... and status */
 500         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 501         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 502
 503         dev_dbg(dev, "%s secs=%d, mins=%d, "
 504                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 505                 "alarm read", t->time.tm_sec, t->time.tm_min,
 506                 t->time.tm_hour, t->time.tm_mday,
 507                 t->enabled, t->pending);
 508
 509         return 0;
 510 }
 511
 512 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 513 {
 514         struct i2c_client       *client = to_i2c_client(dev);
 515         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 516         unsigned char           *buf = ds1307->regs;
 517         u8                      control, status;
 518         int                     ret;
 519
 520         if (!test_bit(HAS_ALARM, &ds1307->flags))
 521                 return -EINVAL;
 522
 523         dev_dbg(dev, "%s secs=%d, mins=%d, "
 524                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 525                 "alarm set", t->time.tm_sec, t->time.tm_min,
 526                 t->time.tm_hour, t->time.tm_mday,
 527                 t->enabled, t->pending);
 528
 529         /* read current status of both alarms and the chip */
 530         ret = ds1307->read_block_data(client,
 531                         DS1339_REG_ALARM1_SECS, 9, buf);
 532         if (ret != 9) {
 533                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 534                 return -EIO;
 535         }
 536         control = ds1307->regs[7];
 537         status = ds1307->regs[8];
 538
 539         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 540                         "alarm set (old status)",
 541                         ds1307->regs[0], ds1307->regs[1],
 542                         ds1307->regs[2], ds1307->regs[3],
 543                         ds1307->regs[4], ds1307->regs[5],
 544                         ds1307->regs[6], control, status);
 545
 546         /* set ALARM1, using 24 hour and day-of-month modes */
 547         buf[0] = bin2bcd(t->time.tm_sec);
 548         buf[1] = bin2bcd(t->time.tm_min);
 549         buf[2] = bin2bcd(t->time.tm_hour);
 550         buf[3] = bin2bcd(t->time.tm_mday);
 551
 552         /* set ALARM2 to non-garbage */
 553         buf[4] = 0;
 554         buf[5] = 0;
 555         buf[6] = 0;
 556
 557         /* optionally enable ALARM1 */
 558         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 559         if (t->enabled) {
 560                 dev_dbg(dev, "alarm IRQ armed\n");
 561                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 562         }
 563         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 564
 565         ret = ds1307->write_block_data(client,
 566                         DS1339_REG_ALARM1_SECS, 9, buf);
 567         if (ret < 0) {
 568                 dev_err(dev, "can't set alarm time\n");
 569                 return ret;
 570         }
 571
 572         return 0;
 573 }
 574
 575 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 576 {
 577         struct i2c_client       *client = to_i2c_client(dev);
 578         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 579         int                     ret;
 580
 581         if (!test_bit(HAS_ALARM, &ds1307->flags))
 582                 return -ENOTTY;
 583
 584         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 585         if (ret < 0)
 586                 return ret;
 587
 588         if (enabled)
 589                 ret |= DS1337_BIT_A1IE;
 590         else
 591                 ret &= ~DS1337_BIT_A1IE;
 592
 593         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 594         if (ret < 0)
 595                 return ret;
 596
 597         return 0;
 598 }
 599
 600 static const struct rtc_class_ops ds13xx_rtc_ops = {
 601         .read_time      = ds1307_get_time,
 602         .set_time       = ds1307_set_time,
 603         .read_alarm     = ds1337_read_alarm,
 604         .set_alarm      = ds1337_set_alarm,
 605         .alarm_irq_enable = ds1307_alarm_irq_enable,
 606 };
 607
 608 /*----------------------------------------------------------------------*/
 609
 610 /*
 611  * Alarm support for mcp7941x devices.
 612  */
 613
 614 #define MCP7941X_REG_CONTROL            0x07
 615 #       define MCP7941X_BIT_ALM0_EN     0x10
 616 #       define MCP7941X_BIT_ALM1_EN     0x20
 617 #define MCP7941X_REG_ALARM0_BASE        0x0a
 618 #define MCP7941X_REG_ALARM0_CTRL        0x0d
 619 #define MCP7941X_REG_ALARM1_BASE        0x11
 620 #define MCP7941X_REG_ALARM1_CTRL        0x14
 621 #       define MCP7941X_BIT_ALMX_IF     (1 << 3)
 622 #       define MCP7941X_BIT_ALMX_C0     (1 << 4)
 623 #       define MCP7941X_BIT_ALMX_C1     (1 << 5)
 624 #       define MCP7941X_BIT_ALMX_C2     (1 << 6)
 625 #       define MCP7941X_BIT_ALMX_POL    (1 << 7)
 626 #       define MCP7941X_MSK_ALMX_MATCH  (MCP7941X_BIT_ALMX_C0 | \
 627                                          MCP7941X_BIT_ALMX_C1 | \
 628                                          MCP7941X_BIT_ALMX_C2)
 629
 630 static void mcp7941x_work(struct work_struct *work)
 631 {
 632         struct ds1307 *ds1307 = container_of(work, struct ds1307, work);
 633         struct i2c_client *client = ds1307->client;
 634         int reg, ret;
 635
 636         mutex_lock(&ds1307->rtc->ops_lock);
 637
 638         /* Check and clear alarm 0 interrupt flag. */
 639         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_ALARM0_CTRL);
 640         if (reg < 0)
 641                 goto out;
 642         if (!(reg & MCP7941X_BIT_ALMX_IF))
 643                 goto out;
 644         reg &= ~MCP7941X_BIT_ALMX_IF;
 645         ret = i2c_smbus_write_byte_data(client, MCP7941X_REG_ALARM0_CTRL, reg);
 646         if (ret < 0)
 647                 goto out;
 648
 649         /* Disable alarm 0. */
 650         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_CONTROL);
 651         if (reg < 0)
 652                 goto out;
 653         reg &= ~MCP7941X_BIT_ALM0_EN;
 654         ret = i2c_smbus_write_byte_data(client, MCP7941X_REG_CONTROL, reg);
 655         if (ret < 0)
 656                 goto out;
 657
 658         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 659
 660 out:
 661         if (test_bit(HAS_ALARM, &ds1307->flags))
 662                 enable_irq(client->irq);
 663         mutex_unlock(&ds1307->rtc->ops_lock);
 664 }
 665
 666 static int mcp7941x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 667 {
 668         struct i2c_client *client = to_i2c_client(dev);
 669         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 670         u8 *regs = ds1307->regs;
 671         int ret;
 672
 673         if (!test_bit(HAS_ALARM, &ds1307->flags))
 674                 return -EINVAL;
 675
 676         /* Read control and alarm 0 registers. */
 677         ret = ds1307->read_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
 678         if (ret < 0)
 679                 return ret;
 680
 681         t->enabled = !!(regs[0] & MCP7941X_BIT_ALM0_EN);
 682
 683         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 684         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
 685         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
 686         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
 687         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
 688         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
 689         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
 690         t->time.tm_year = -1;
 691         t->time.tm_yday = -1;
 692         t->time.tm_isdst = -1;
 693
 694         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 695                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
 696                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 697                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 698                 !!(ds1307->regs[6] & MCP7941X_BIT_ALMX_POL),
 699                 !!(ds1307->regs[6] & MCP7941X_BIT_ALMX_IF),
 700                 (ds1307->regs[6] & MCP7941X_MSK_ALMX_MATCH) >> 4);
 701
 702         return 0;
 703 }
 704
 705 static int mcp7941x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 706 {
 707         struct i2c_client *client = to_i2c_client(dev);
 708         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 709         unsigned char *regs = ds1307->regs;
 710         int ret;
 711
 712         if (!test_bit(HAS_ALARM, &ds1307->flags))
 713                 return -EINVAL;
 714
 715         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 716                 "enabled=%d pending=%d\n", __func__,
 717                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 718                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 719                 t->enabled, t->pending);
 720
 721         /* Read control and alarm 0 registers. */
 722         ret = ds1307->read_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
 723         if (ret < 0)
 724                 return ret;
 725
 726         /* Set alarm 0, using 24-hour and day-of-month modes. */
 727         regs[3] = bin2bcd(t->time.tm_sec);
 728         regs[4] = bin2bcd(t->time.tm_min);
 729         regs[5] = bin2bcd(t->time.tm_hour);
 730         regs[6] = bin2bcd(t->time.tm_wday) + 1;
 731         regs[7] = bin2bcd(t->time.tm_mday);
 732         regs[8] = bin2bcd(t->time.tm_mon) + 1;
 733
 734         /* Clear the alarm 0 interrupt flag. */
 735         regs[6] &= ~MCP7941X_BIT_ALMX_IF;
 736         /* Set alarm match: second, minute, hour, day, date, month. */
 737         regs[6] |= MCP7941X_MSK_ALMX_MATCH;
 738
 739         if (t->enabled)
 740                 regs[0] |= MCP7941X_BIT_ALM0_EN;
 741         else
 742                 regs[0] &= ~MCP7941X_BIT_ALM0_EN;
 743
 744         ret = ds1307->write_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
 745         if (ret < 0)
 746                 return ret;
 747
 748         return 0;
 749 }
 750
 751 static int mcp7941x_alarm_irq_enable(struct device *dev, unsigned int enabled)
 752 {
 753         struct i2c_client *client = to_i2c_client(dev);
 754         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 755         int reg;
 756
 757         if (!test_bit(HAS_ALARM, &ds1307->flags))
 758                 return -EINVAL;
 759
 760         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_CONTROL);
 761         if (reg < 0)
 762                 return reg;
 763
 764         if (enabled)
 765                 reg |= MCP7941X_BIT_ALM0_EN;
 766         else
 767                 reg &= ~MCP7941X_BIT_ALM0_EN;
 768
 769         return i2c_smbus_write_byte_data(client, MCP7941X_REG_CONTROL, reg);
 770 }
 771
 772 static const struct rtc_class_ops mcp7941x_rtc_ops = {
 773         .read_time      = ds1307_get_time,
 774         .set_time       = ds1307_set_time,
 775         .read_alarm     = mcp7941x_read_alarm,
 776         .set_alarm      = mcp7941x_set_alarm,
 777         .alarm_irq_enable = mcp7941x_alarm_irq_enable,
 778 };
 779
 780 /*----------------------------------------------------------------------*/
 781
 782 static ssize_t
 783 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 784                 struct bin_attribute *attr,
 785                 char *buf, loff_t off, size_t count)
 786 {
 787         struct i2c_client       *client;
 788         struct ds1307           *ds1307;
 789         int                     result;
 790
 791         client = kobj_to_i2c_client(kobj);
 792         ds1307 = i2c_get_clientdata(client);
 793
 794         if (unlikely(off >= ds1307->nvram->size))
 795                 return 0;
 796         if ((off + count) > ds1307->nvram->size)
 797                 count = ds1307->nvram->size - off;
 798         if (unlikely(!count))
 799                 return count;
 800
 801         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 802                                                                 count, buf);
 803         if (result < 0)
 804                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 805         return result;
 806 }
 807
 808 static ssize_t
 809 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 810                 struct bin_attribute *attr,
 811                 char *buf, loff_t off, size_t count)
 812 {
 813         struct i2c_client       *client;
 814         struct ds1307           *ds1307;
 815         int                     result;
 816
 817         client = kobj_to_i2c_client(kobj);
 818         ds1307 = i2c_get_clientdata(client);
 819
 820         if (unlikely(off >= ds1307->nvram->size))
 821                 return -EFBIG;
 822         if ((off + count) > ds1307->nvram->size)
 823                 count = ds1307->nvram->size - off;
 824         if (unlikely(!count))
 825                 return count;
 826
 827         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 828                                                                 count, buf);
 829         if (result < 0) {
 830                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 831                 return result;
 832         }
 833         return count;
 834 }
 835
 836 /*----------------------------------------------------------------------*/
 837
 838 static int ds1307_probe(struct i2c_client *client,
 839                         const struct i2c_device_id *id)
 840 {
 841         struct ds1307           *ds1307;
 842         int                     err = -ENODEV;
 843         int                     tmp;
 844         const struct chip_desc  *chip = &chips[id->driver_data];
 845         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 846         bool                    want_irq = false;
 847         unsigned char           *buf;
 848         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
 849         static const int        bbsqi_bitpos[] = {
 850                 [ds_1337] = 0,
 851                 [ds_1339] = DS1339_BIT_BBSQI,
 852                 [ds_3231] = DS3231_BIT_BBSQW,
 853         };
 854         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
 855
 856         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 857             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 858                 return -EIO;
 859
 860         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
 861         if (!ds1307)
 862                 return -ENOMEM;
 863
 864         i2c_set_clientdata(client, ds1307);
 865
 866         ds1307->client  = client;
 867         ds1307->type    = id->driver_data;
 868
 869         if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
 870                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 871                         DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
 872
 873         buf = ds1307->regs;
 874         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 875                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
 876                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
 877         } else {
 878                 ds1307->read_block_data = ds1307_read_block_data;
 879                 ds1307->write_block_data = ds1307_write_block_data;
 880         }
 881
 882         switch (ds1307->type) {
 883         case ds_1337:
 884         case ds_1339:
 885         case ds_3231:
 886                 /* get registers that the "rtc" read below won't read... */
 887                 tmp = ds1307->read_block_data(ds1307->client,
 888                                 DS1337_REG_CONTROL, 2, buf);
 889                 if (tmp != 2) {
 890                         dev_dbg(&client->dev, "read error %d\n", tmp);
 891                         err = -EIO;
 892                         goto exit;
 893                 }
 894
 895                 /* oscillator off?  turn it on, so clock can tick. */
 896                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 897                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 898
 899                 /*
 900                  * Using IRQ?  Disable the square wave and both alarms.
 901                  * For some variants, be sure alarms can trigger when we're
 902                  * running on Vbackup (BBSQI/BBSQW)
 903                  */
 904                 if (ds1307->client->irq > 0 && chip->alarm) {
 905                         INIT_WORK(&ds1307->work, ds1307_work);
 906
 907                         ds1307->regs[0] |= DS1337_BIT_INTCN
 908                                         | bbsqi_bitpos[ds1307->type];
 909                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 910
 911                         want_irq = true;
 912                 }
 913
 914                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 915                                                         ds1307->regs[0]);
 916
 917                 /* oscillator fault?  clear flag, and warn */
 918                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 919                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 920                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 921                         dev_warn(&client->dev, "SET TIME!\n");
 922                 }
 923                 break;
 924
 925         case rx_8025:
 926                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 927                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 928                 if (tmp != 2) {
 929                         dev_dbg(&client->dev, "read error %d\n", tmp);
 930                         err = -EIO;
 931                         goto exit;
 932                 }
 933
 934                 /* oscillator off?  turn it on, so clock can tick. */
 935                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 936                         ds1307->regs[1] |= RX8025_BIT_XST;
 937                         i2c_smbus_write_byte_data(client,
 938                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 939                                                   ds1307->regs[1]);
 940                         dev_warn(&client->dev,
 941                                  "oscillator stop detected - SET TIME!\n");
 942                 }
 943
 944                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 945                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 946                         i2c_smbus_write_byte_data(client,
 947                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 948                                                   ds1307->regs[1]);
 949                         dev_warn(&client->dev, "power-on detected\n");
 950                 }
 951
 952                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 953                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 954                         i2c_smbus_write_byte_data(client,
 955                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 956                                                   ds1307->regs[1]);
 957                         dev_warn(&client->dev, "voltage drop detected\n");
 958                 }
 959
 960                 /* make sure we are running in 24hour mode */
 961                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 962                         u8 hour;
 963
 964                         /* switch to 24 hour mode */
 965                         i2c_smbus_write_byte_data(client,
 966                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 967                                                   ds1307->regs[0] |
 968                                                   RX8025_BIT_2412);
 969
 970                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 971                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 972                         if (tmp != 2) {
 973                                 dev_dbg(&client->dev, "read error %d\n", tmp);
 974                                 err = -EIO;
 975                                 goto exit;
 976                         }
 977
 978                         /* correct hour */
 979                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 980                         if (hour == 12)
 981                                 hour = 0;
 982                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 983                                 hour += 12;
 984
 985                         i2c_smbus_write_byte_data(client,
 986                                                   DS1307_REG_HOUR << 4 | 0x08,
 987                                                   hour);
 988                 }
 989                 break;
 990         case ds_1388:
 991                 ds1307->offset = 1; /* Seconds starts at 1 */
 992                 break;
 993         case mcp7941x:
 994                 rtc_ops = &mcp7941x_rtc_ops;
 995                 if (ds1307->client->irq > 0 && chip->alarm) {
 996                         INIT_WORK(&ds1307->work, mcp7941x_work);
 997                         want_irq = true;
 998                 }
 999                 break;
1000         default:
1001                 break;
1002         }
1003
1004 read_rtc:
1005         /* read RTC registers */
1006         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1007         if (tmp != 8) {
1008                 dev_dbg(&client->dev, "read error %d\n", tmp);
1009                 err = -EIO;
1010                 goto exit;
1011         }
1012
1013         /*
1014          * minimal sanity checking; some chips (like DS1340) don't
1015          * specify the extra bits as must-be-zero, but there are
1016          * still a few values that are clearly out-of-range.
1017          */
1018         tmp = ds1307->regs[DS1307_REG_SECS];
1019         switch (ds1307->type) {
1020         case ds_1307:
1021         case m41t00:
1022                 /* clock halted?  turn it on, so clock can tick. */
1023                 if (tmp & DS1307_BIT_CH) {
1024                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1025                         dev_warn(&client->dev, "SET TIME!\n");
1026                         goto read_rtc;
1027                 }
1028                 break;
1029         case ds_1338:
1030                 /* clock halted?  turn it on, so clock can tick. */
1031                 if (tmp & DS1307_BIT_CH)
1032                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1033
1034                 /* oscillator fault?  clear flag, and warn */
1035                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1036                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1037                                         ds1307->regs[DS1307_REG_CONTROL]
1038                                         & ~DS1338_BIT_OSF);
1039                         dev_warn(&client->dev, "SET TIME!\n");
1040                         goto read_rtc;
1041                 }
1042                 break;
1043         case ds_1340:
1044                 /* clock halted?  turn it on, so clock can tick. */
1045                 if (tmp & DS1340_BIT_nEOSC)
1046                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1047
1048                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1049                 if (tmp < 0) {
1050                         dev_dbg(&client->dev, "read error %d\n", tmp);
1051                         err = -EIO;
1052                         goto exit;
1053                 }
1054
1055                 /* oscillator fault?  clear flag, and warn */
1056                 if (tmp & DS1340_BIT_OSF) {
1057                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1058                         dev_warn(&client->dev, "SET TIME!\n");
1059                 }
1060                 break;
1061         case mcp7941x:
1062                 /* make sure that the backup battery is enabled */
1063                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
1064                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1065                                         ds1307->regs[DS1307_REG_WDAY]
1066                                         | MCP7941X_BIT_VBATEN);
1067                 }
1068
1069                 /* clock halted?  turn it on, so clock can tick. */
1070                 if (!(tmp & MCP7941X_BIT_ST)) {
1071                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1072                                         MCP7941X_BIT_ST);
1073                         dev_warn(&client->dev, "SET TIME!\n");
1074                         goto read_rtc;
1075                 }
1076
1077                 break;
1078         default:
1079                 break;
1080         }
1081
1082         tmp = ds1307->regs[DS1307_REG_HOUR];
1083         switch (ds1307->type) {
1084         case ds_1340:
1085         case m41t00:
1086                 /*
1087                  * NOTE: ignores century bits; fix before deploying
1088                  * systems that will run through year 2100.
1089                  */
1090                 break;
1091         case rx_8025:
1092                 break;
1093         default:
1094                 if (!(tmp & DS1307_BIT_12HR))
1095                         break;
1096
1097                 /*
1098                  * Be sure we're in 24 hour mode.  Multi-master systems
1099                  * take note...
1100                  */
1101                 tmp = bcd2bin(tmp & 0x1f);
1102                 if (tmp == 12)
1103                         tmp = 0;
1104                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1105                         tmp += 12;
1106                 i2c_smbus_write_byte_data(client,
1107                                 ds1307->offset + DS1307_REG_HOUR,
1108                                 bin2bcd(tmp));
1109         }
1110
1111         device_set_wakeup_capable(&client->dev, want_irq);
1112         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1113                                 rtc_ops, THIS_MODULE);
1114         if (IS_ERR(ds1307->rtc)) {
1115                 return PTR_ERR(ds1307->rtc);
1116         }
1117
1118         if (want_irq) {
1119                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
1120                           ds1307->rtc->name, client);
1121                 if (err) {
1122                         client->irq = 0;
1123                         dev_err(&client->dev, "unable to request IRQ!\n");
1124                 } else {
1125
1126                         set_bit(HAS_ALARM, &ds1307->flags);
1127                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1128                 }
1129         }
1130
1131         if (chip->nvram_size) {
1132
1133                 ds1307->nvram = devm_kzalloc(&client->dev,
1134                                         sizeof(struct bin_attribute),
1135                                         GFP_KERNEL);
1136                 if (!ds1307->nvram) {
1137                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1138                 } else {
1139
1140                         ds1307->nvram->attr.name = "nvram";
1141                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1142
1143                         sysfs_bin_attr_init(ds1307->nvram);
1144
1145                         ds1307->nvram->read = ds1307_nvram_read;
1146                         ds1307->nvram->write = ds1307_nvram_write;
1147                         ds1307->nvram->size = chip->nvram_size;
1148                         ds1307->nvram_offset = chip->nvram_offset;
1149
1150                         err = sysfs_create_bin_file(&client->dev.kobj,
1151                                                     ds1307->nvram);
1152                         if (err) {
1153                                 dev_err(&client->dev,
1154                                         "unable to create sysfs file: %s\n",
1155                                         ds1307->nvram->attr.name);
1156                         } else {
1157                                 set_bit(HAS_NVRAM, &ds1307->flags);
1158                                 dev_info(&client->dev, "%zu bytes nvram\n",
1159                                          ds1307->nvram->size);
1160                         }
1161                 }
1162         }
1163
1164         return 0;
1165
1166 exit:
1167         return err;
1168 }
1169
1170 static int ds1307_remove(struct i2c_client *client)
1171 {
1172         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1173
1174         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
1175                 free_irq(client->irq, client);
1176                 cancel_work_sync(&ds1307->work);
1177         }
1178
1179         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1180                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1181
1182         return 0;
1183 }
1184
1185 static struct i2c_driver ds1307_driver = {
1186         .driver = {
1187                 .name   = "rtc-ds1307",
1188                 .owner  = THIS_MODULE,
1189         },
1190         .probe          = ds1307_probe,
1191         .remove         = ds1307_remove,
1192         .id_table       = ds1307_id,
1193 };
1194
1195 module_i2c_driver(ds1307_driver);
1196
1197 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1198 MODULE_LICENSE("GPL");