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