git.oblomov.eu Git - linux-2.6/blob - drivers/rtc/rtc-ds1307.c

   1 /*
   2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
   3  *
   4  *  Copyright (C) 2005 James Chapman (ds1337 core)
   5  *  Copyright (C) 2006 David Brownell
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/slab.h>
  15 #include <linux/i2c.h>
  16 #include <linux/string.h>
  17 #include <linux/rtc.h>
  18 #include <linux/bcd.h>
  19
  20
  21
  22 /* We can't determine type by probing, but if we expect pre-Linux code
  23  * to have set the chip up as a clock (turning on the oscillator and
  24  * setting the date and time), Linux can ignore the non-clock features.
  25  * That's a natural job for a factory or repair bench.
  26  *
  27  * This is currently a simple no-alarms driver.  If your board has the
  28  * alarm irq wired up on a ds1337 or ds1339, and you want to use that,
  29  * then look at the rtc-rs5c372 driver for code to steal...
  30  */
  31 enum ds_type {
  32         ds_1307,
  33         ds_1337,
  34         ds_1338,
  35         ds_1339,
  36         ds_1340,
  37         m41t00,
  38         // rs5c372 too?  different address...
  39 };
  40
  41
  42 /* RTC registers don't differ much, except for the century flag */
  43 #define DS1307_REG_SECS         0x00    /* 00-59 */
  44 #       define DS1307_BIT_CH            0x80
  45 #       define DS1340_BIT_nEOSC         0x80
  46 #define DS1307_REG_MIN          0x01    /* 00-59 */
  47 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  48 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  49 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  50 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  51 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  52 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  53 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  54 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  55 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  56 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  57
  58 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  59  * start at 7, and they differ a LOT. Only control and status matter for
  60  * basic RTC date and time functionality; be careful using them.
  61  */
  62 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  63 #       define DS1307_BIT_OUT           0x80
  64 #       define DS1338_BIT_OSF           0x20
  65 #       define DS1307_BIT_SQWE          0x10
  66 #       define DS1307_BIT_RS1           0x02
  67 #       define DS1307_BIT_RS0           0x01
  68 #define DS1337_REG_CONTROL      0x0e
  69 #       define DS1337_BIT_nEOSC         0x80
  70 #       define DS1337_BIT_RS2           0x10
  71 #       define DS1337_BIT_RS1           0x08
  72 #       define DS1337_BIT_INTCN         0x04
  73 #       define DS1337_BIT_A2IE          0x02
  74 #       define DS1337_BIT_A1IE          0x01
  75 #define DS1340_REG_CONTROL      0x07
  76 #       define DS1340_BIT_OUT           0x80
  77 #       define DS1340_BIT_FT            0x40
  78 #       define DS1340_BIT_CALIB_SIGN    0x20
  79 #       define DS1340_M_CALIBRATION     0x1f
  80 #define DS1340_REG_FLAG         0x09
  81 #       define DS1340_BIT_OSF           0x80
  82 #define DS1337_REG_STATUS       0x0f
  83 #       define DS1337_BIT_OSF           0x80
  84 #       define DS1337_BIT_A2I           0x02
  85 #       define DS1337_BIT_A1I           0x01
  86 #define DS1339_REG_TRICKLE      0x10
  87
  88
  89
  90 struct ds1307 {
  91         u8                      reg_addr;
  92         bool                    has_nvram;
  93         u8                      regs[8];
  94         enum ds_type            type;
  95         struct i2c_msg          msg[2];
  96         struct i2c_client       *client;
  97         struct i2c_client       dev;
  98         struct rtc_device       *rtc;
  99 };
 100
 101 struct chip_desc {
 102         char                    name[9];
 103         unsigned                nvram56:1;
 104         unsigned                alarm:1;
 105         enum ds_type            type;
 106 };
 107
 108 static const struct chip_desc chips[] = { {
 109         .name           = "ds1307",
 110         .type           = ds_1307,
 111         .nvram56        = 1,
 112 }, {
 113         .name           = "ds1337",
 114         .type           = ds_1337,
 115         .alarm          = 1,
 116 }, {
 117         .name           = "ds1338",
 118         .type           = ds_1338,
 119         .nvram56        = 1,
 120 }, {
 121         .name           = "ds1339",
 122         .type           = ds_1339,
 123         .alarm          = 1,
 124 }, {
 125         .name           = "ds1340",
 126         .type           = ds_1340,
 127 }, {
 128         .name           = "m41t00",
 129         .type           = m41t00,
 130 }, };
 131
 132 static inline const struct chip_desc *find_chip(const char *s)
 133 {
 134         unsigned i;
 135
 136         for (i = 0; i < ARRAY_SIZE(chips); i++)
 137                 if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
 138                         return &chips[i];
 139         return NULL;
 140 }
 141
 142 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 143 {
 144         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 145         int             tmp;
 146
 147         /* read the RTC date and time registers all at once */
 148         ds1307->msg[1].flags = I2C_M_RD;
 149         ds1307->msg[1].len = 7;
 150
 151         tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
 152                         ds1307->msg, 2);
 153         if (tmp != 2) {
 154                 dev_err(dev, "%s error %d\n", "read", tmp);
 155                 return -EIO;
 156         }
 157
 158         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 159                         "read",
 160                         ds1307->regs[0], ds1307->regs[1],
 161                         ds1307->regs[2], ds1307->regs[3],
 162                         ds1307->regs[4], ds1307->regs[5],
 163                         ds1307->regs[6]);
 164
 165         t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 166         t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 167         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 168         t->tm_hour = BCD2BIN(tmp);
 169         t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 170         t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 171         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 172         t->tm_mon = BCD2BIN(tmp) - 1;
 173
 174         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 175         t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;
 176
 177         dev_dbg(dev, "%s secs=%d, mins=%d, "
 178                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 179                 "read", t->tm_sec, t->tm_min,
 180                 t->tm_hour, t->tm_mday,
 181                 t->tm_mon, t->tm_year, t->tm_wday);
 182
 183         /* initial clock setting can be undefined */
 184         return rtc_valid_tm(t);
 185 }
 186
 187 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 188 {
 189         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 190         int             result;
 191         int             tmp;
 192         u8              *buf = ds1307->regs;
 193
 194         dev_dbg(dev, "%s secs=%d, mins=%d, "
 195                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 196                 "write", t->tm_sec, t->tm_min,
 197                 t->tm_hour, t->tm_mday,
 198                 t->tm_mon, t->tm_year, t->tm_wday);
 199
 200         *buf++ = 0;             /* first register addr */
 201         buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
 202         buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
 203         buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
 204         buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
 205         buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
 206         buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);
 207
 208         /* assume 20YY not 19YY */
 209         tmp = t->tm_year - 100;
 210         buf[DS1307_REG_YEAR] = BIN2BCD(tmp);
 211
 212         switch (ds1307->type) {
 213         case ds_1337:
 214         case ds_1339:
 215                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 216                 break;
 217         case ds_1340:
 218                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 219                                 | DS1340_BIT_CENTURY;
 220                 break;
 221         default:
 222                 break;
 223         }
 224
 225         ds1307->msg[1].flags = 0;
 226         ds1307->msg[1].len = 8;
 227
 228         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 229                 "write", buf[0], buf[1], buf[2], buf[3],
 230                 buf[4], buf[5], buf[6]);
 231
 232         result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
 233                         &ds1307->msg[1], 1);
 234         if (result != 1) {
 235                 dev_err(dev, "%s error %d\n", "write", tmp);
 236                 return -EIO;
 237         }
 238         return 0;
 239 }
 240
 241 static const struct rtc_class_ops ds13xx_rtc_ops = {
 242         .read_time      = ds1307_get_time,
 243         .set_time       = ds1307_set_time,
 244 };
 245
 246 /*----------------------------------------------------------------------*/
 247
 248 #define NVRAM_SIZE      56
 249
 250 static ssize_t
 251 ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
 252                 char *buf, loff_t off, size_t count)
 253 {
 254         struct i2c_client       *client;
 255         struct ds1307           *ds1307;
 256         struct i2c_msg          msg[2];
 257         int                     result;
 258
 259         client = kobj_to_i2c_client(kobj);
 260         ds1307 = i2c_get_clientdata(client);
 261
 262         if (unlikely(off >= NVRAM_SIZE))
 263                 return 0;
 264         if ((off + count) > NVRAM_SIZE)
 265                 count = NVRAM_SIZE - off;
 266         if (unlikely(!count))
 267                 return count;
 268
 269         msg[0].addr = client->addr;
 270         msg[0].flags = 0;
 271         msg[0].len = 1;
 272         msg[0].buf = buf;
 273
 274         buf[0] = 8 + off;
 275
 276         msg[1].addr = client->addr;
 277         msg[1].flags = I2C_M_RD;
 278         msg[1].len = count;
 279         msg[1].buf = buf;
 280
 281         result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
 282         if (result != 2) {
 283                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 284                 return -EIO;
 285         }
 286         return count;
 287 }
 288
 289 static ssize_t
 290 ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
 291                 char *buf, loff_t off, size_t count)
 292 {
 293         struct i2c_client       *client;
 294         u8                      buffer[NVRAM_SIZE + 1];
 295         int                     ret;
 296
 297         client = kobj_to_i2c_client(kobj);
 298
 299         if (unlikely(off >= NVRAM_SIZE))
 300                 return -EFBIG;
 301         if ((off + count) > NVRAM_SIZE)
 302                 count = NVRAM_SIZE - off;
 303         if (unlikely(!count))
 304                 return count;
 305
 306         buffer[0] = 8 + off;
 307         memcpy(buffer + 1, buf, count);
 308
 309         ret = i2c_master_send(client, buffer, count + 1);
 310         return (ret < 0) ? ret : (ret - 1);
 311 }
 312
 313 static struct bin_attribute nvram = {
 314         .attr = {
 315                 .name   = "nvram",
 316                 .mode   = S_IRUGO | S_IWUSR,
 317                 .owner  = THIS_MODULE,
 318         },
 319
 320         .read   = ds1307_nvram_read,
 321         .write  = ds1307_nvram_write,
 322         .size   = NVRAM_SIZE,
 323 };
 324
 325 /*----------------------------------------------------------------------*/
 326
 327 static struct i2c_driver ds1307_driver;
 328
 329 static int __devinit ds1307_probe(struct i2c_client *client)
 330 {
 331         struct ds1307           *ds1307;
 332         int                     err = -ENODEV;
 333         int                     tmp;
 334         const struct chip_desc  *chip;
 335         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 336
 337         chip = find_chip(client->name);
 338         if (!chip) {
 339                 dev_err(&client->dev, "unknown chip type '%s'\n",
 340                                 client->name);
 341                 return -ENODEV;
 342         }
 343
 344         if (!i2c_check_functionality(adapter,
 345                         I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 346                 return -EIO;
 347
 348         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
 349                 return -ENOMEM;
 350
 351         ds1307->client = client;
 352         i2c_set_clientdata(client, ds1307);
 353
 354         ds1307->msg[0].addr = client->addr;
 355         ds1307->msg[0].flags = 0;
 356         ds1307->msg[0].len = 1;
 357         ds1307->msg[0].buf = &ds1307->reg_addr;
 358
 359         ds1307->msg[1].addr = client->addr;
 360         ds1307->msg[1].flags = I2C_M_RD;
 361         ds1307->msg[1].len = sizeof(ds1307->regs);
 362         ds1307->msg[1].buf = ds1307->regs;
 363
 364         ds1307->type = chip->type;
 365
 366         switch (ds1307->type) {
 367         case ds_1337:
 368         case ds_1339:
 369                 ds1307->reg_addr = DS1337_REG_CONTROL;
 370                 ds1307->msg[1].len = 2;
 371
 372                 /* get registers that the "rtc" read below won't read... */
 373                 tmp = i2c_transfer(adapter, ds1307->msg, 2);
 374                 if (tmp != 2) {
 375                         pr_debug("read error %d\n", tmp);
 376                         err = -EIO;
 377                         goto exit_free;
 378                 }
 379
 380                 ds1307->reg_addr = 0;
 381                 ds1307->msg[1].len = sizeof(ds1307->regs);
 382
 383                 /* oscillator off?  turn it on, so clock can tick. */
 384                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 385                         i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 386                                 ds1307->regs[0] & ~DS1337_BIT_nEOSC);
 387
 388                 /* oscillator fault?  clear flag, and warn */
 389                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 390                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 391                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 392                         dev_warn(&client->dev, "SET TIME!\n");
 393                 }
 394                 break;
 395         default:
 396                 break;
 397         }
 398
 399 read_rtc:
 400         /* read RTC registers */
 401
 402         tmp = i2c_transfer(adapter, ds1307->msg, 2);
 403         if (tmp != 2) {
 404                 pr_debug("read error %d\n", tmp);
 405                 err = -EIO;
 406                 goto exit_free;
 407         }
 408
 409         /* minimal sanity checking; some chips (like DS1340) don't
 410          * specify the extra bits as must-be-zero, but there are
 411          * still a few values that are clearly out-of-range.
 412          */
 413         tmp = ds1307->regs[DS1307_REG_SECS];
 414         switch (ds1307->type) {
 415         case ds_1307:
 416         case m41t00:
 417                 /* clock halted?  turn it on, so clock can tick. */
 418                 if (tmp & DS1307_BIT_CH) {
 419                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 420                         dev_warn(&client->dev, "SET TIME!\n");
 421                         goto read_rtc;
 422                 }
 423                 break;
 424         case ds_1338:
 425                 /* clock halted?  turn it on, so clock can tick. */
 426                 if (tmp & DS1307_BIT_CH)
 427                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 428
 429                 /* oscillator fault?  clear flag, and warn */
 430                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 431                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 432                                         ds1307->regs[DS1307_REG_CONTROL]
 433                                         & ~DS1338_BIT_OSF);
 434                         dev_warn(&client->dev, "SET TIME!\n");
 435                         goto read_rtc;
 436                 }
 437                 break;
 438         case ds_1340:
 439                 /* clock halted?  turn it on, so clock can tick. */
 440                 if (tmp & DS1340_BIT_nEOSC)
 441                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 442
 443                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 444                 if (tmp < 0) {
 445                         pr_debug("read error %d\n", tmp);
 446                         err = -EIO;
 447                         goto exit_free;
 448                 }
 449
 450                 /* oscillator fault?  clear flag, and warn */
 451                 if (tmp & DS1340_BIT_OSF) {
 452                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 453                         dev_warn(&client->dev, "SET TIME!\n");
 454                 }
 455                 break;
 456         case ds_1337:
 457         case ds_1339:
 458                 break;
 459         }
 460
 461         tmp = ds1307->regs[DS1307_REG_SECS];
 462         tmp = BCD2BIN(tmp & 0x7f);
 463         if (tmp > 60)
 464                 goto exit_bad;
 465         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 466         if (tmp > 60)
 467                 goto exit_bad;
 468
 469         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 470         if (tmp == 0 || tmp > 31)
 471                 goto exit_bad;
 472
 473         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
 474         if (tmp == 0 || tmp > 12)
 475                 goto exit_bad;
 476
 477         tmp = ds1307->regs[DS1307_REG_HOUR];
 478         switch (ds1307->type) {
 479         case ds_1340:
 480         case m41t00:
 481                 /* NOTE: ignores century bits; fix before deploying
 482                  * systems that will run through year 2100.
 483                  */
 484                 break;
 485         default:
 486                 if (!(tmp & DS1307_BIT_12HR))
 487                         break;
 488
 489                 /* Be sure we're in 24 hour mode.  Multi-master systems
 490                  * take note...
 491                  */
 492                 tmp = BCD2BIN(tmp & 0x1f);
 493                 if (tmp == 12)
 494                         tmp = 0;
 495                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 496                         tmp += 12;
 497                 i2c_smbus_write_byte_data(client,
 498                                 DS1307_REG_HOUR,
 499                                 BIN2BCD(tmp));
 500         }
 501
 502         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 503                                 &ds13xx_rtc_ops, THIS_MODULE);
 504         if (IS_ERR(ds1307->rtc)) {
 505                 err = PTR_ERR(ds1307->rtc);
 506                 dev_err(&client->dev,
 507                         "unable to register the class device\n");
 508                 goto exit_free;
 509         }
 510
 511         if (chip->nvram56) {
 512                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
 513                 if (err == 0) {
 514                         ds1307->has_nvram = true;
 515                         dev_info(&client->dev, "56 bytes nvram\n");
 516                 }
 517         }
 518
 519         return 0;
 520
 521 exit_bad:
 522         dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 523                         "bogus register",
 524                         ds1307->regs[0], ds1307->regs[1],
 525                         ds1307->regs[2], ds1307->regs[3],
 526                         ds1307->regs[4], ds1307->regs[5],
 527                         ds1307->regs[6]);
 528
 529 exit_free:
 530         kfree(ds1307);
 531         return err;
 532 }
 533
 534 static int __devexit ds1307_remove(struct i2c_client *client)
 535 {
 536         struct ds1307   *ds1307 = i2c_get_clientdata(client);
 537
 538         if (ds1307->has_nvram)
 539                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
 540
 541         rtc_device_unregister(ds1307->rtc);
 542         kfree(ds1307);
 543         return 0;
 544 }
 545
 546 static struct i2c_driver ds1307_driver = {
 547         .driver = {
 548                 .name   = "rtc-ds1307",
 549                 .owner  = THIS_MODULE,
 550         },
 551         .probe          = ds1307_probe,
 552         .remove         = __devexit_p(ds1307_remove),
 553 };
 554
 555 static int __init ds1307_init(void)
 556 {
 557         return i2c_add_driver(&ds1307_driver);
 558 }
 559 module_init(ds1307_init);
 560
 561 static void __exit ds1307_exit(void)
 562 {
 563         i2c_del_driver(&ds1307_driver);
 564 }
 565 module_exit(ds1307_exit);
 566
 567 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 568 MODULE_LICENSE("GPL");