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                 /* this is battery backed SRAM */
 158                 .nvram_offset   = 0x20,
 159                 .nvram_size     = 0x40,
 160         },
 161 };
 162
 163 static const struct i2c_device_id ds1307_id[] = {
 164         { "ds1307", ds_1307 },
 165         { "ds1337", ds_1337 },
 166         { "ds1338", ds_1338 },
 167         { "ds1339", ds_1339 },
 168         { "ds1388", ds_1388 },
 169         { "ds1340", ds_1340 },
 170         { "ds3231", ds_3231 },
 171         { "m41t00", m41t00 },
 172         { "mcp7941x", mcp7941x },
 173         { "pt7c4338", ds_1307 },
 174         { "rx8025", rx_8025 },
 175         { }
 176 };
 177 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 178
 179 /*----------------------------------------------------------------------*/
 180
 181 #define BLOCK_DATA_MAX_TRIES 10
 182
 183 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 184                                        u8 command, u8 length, u8 *values)
 185 {
 186         s32 i, data;
 187
 188         for (i = 0; i < length; i++) {
 189                 data = i2c_smbus_read_byte_data(client, command + i);
 190                 if (data < 0)
 191                         return data;
 192                 values[i] = data;
 193         }
 194         return i;
 195 }
 196
 197 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 198                                   u8 length, u8 *values)
 199 {
 200         u8 oldvalues[255];
 201         s32 ret;
 202         int tries = 0;
 203
 204         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 205         ret = ds1307_read_block_data_once(client, command, length, values);
 206         if (ret < 0)
 207                 return ret;
 208         do {
 209                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 210                         dev_err(&client->dev,
 211                                 "ds1307_read_block_data failed\n");
 212                         return -EIO;
 213                 }
 214                 memcpy(oldvalues, values, length);
 215                 ret = ds1307_read_block_data_once(client, command, length,
 216                                                   values);
 217                 if (ret < 0)
 218                         return ret;
 219         } while (memcmp(oldvalues, values, length));
 220         return length;
 221 }
 222
 223 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 224                                    u8 length, const u8 *values)
 225 {
 226         u8 currvalues[255];
 227         int tries = 0;
 228
 229         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 230         do {
 231                 s32 i, ret;
 232
 233                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 234                         dev_err(&client->dev,
 235                                 "ds1307_write_block_data failed\n");
 236                         return -EIO;
 237                 }
 238                 for (i = 0; i < length; i++) {
 239                         ret = i2c_smbus_write_byte_data(client, command + i,
 240                                                         values[i]);
 241                         if (ret < 0)
 242                                 return ret;
 243                 }
 244                 ret = ds1307_read_block_data_once(client, command, length,
 245                                                   currvalues);
 246                 if (ret < 0)
 247                         return ret;
 248         } while (memcmp(currvalues, values, length));
 249         return length;
 250 }
 251
 252 /*----------------------------------------------------------------------*/
 253
 254 /* These RTC devices are not designed to be connected to a SMbus adapter.
 255    SMbus limits block operations length to 32 bytes, whereas it's not
 256    limited on I2C buses. As a result, accesses may exceed 32 bytes;
 257    in that case, split them into smaller blocks */
 258
 259 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
 260                                 u8 command, u8 length, const u8 *values)
 261 {
 262         u8 suboffset = 0;
 263
 264         if (length <= I2C_SMBUS_BLOCK_MAX)
 265                 return i2c_smbus_write_i2c_block_data(client,
 266                                         command, length, values);
 267
 268         while (suboffset < length) {
 269                 s32 retval = i2c_smbus_write_i2c_block_data(client,
 270                                 command + suboffset,
 271                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 272                                 values + suboffset);
 273                 if (retval < 0)
 274                         return retval;
 275
 276                 suboffset += I2C_SMBUS_BLOCK_MAX;
 277         }
 278         return length;
 279 }
 280
 281 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
 282                                 u8 command, u8 length, u8 *values)
 283 {
 284         u8 suboffset = 0;
 285
 286         if (length <= I2C_SMBUS_BLOCK_MAX)
 287                 return i2c_smbus_read_i2c_block_data(client,
 288                                         command, length, values);
 289
 290         while (suboffset < length) {
 291                 s32 retval = i2c_smbus_read_i2c_block_data(client,
 292                                 command + suboffset,
 293                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 294                                 values + suboffset);
 295                 if (retval < 0)
 296                         return retval;
 297
 298                 suboffset += I2C_SMBUS_BLOCK_MAX;
 299         }
 300         return length;
 301 }
 302
 303 /*----------------------------------------------------------------------*/
 304
 305 /*
 306  * The IRQ logic includes a "real" handler running in IRQ context just
 307  * long enough to schedule this workqueue entry.   We need a task context
 308  * to talk to the RTC, since I2C I/O calls require that; and disable the
 309  * IRQ until we clear its status on the chip, so that this handler can
 310  * work with any type of triggering (not just falling edge).
 311  *
 312  * The ds1337 and ds1339 both have two alarms, but we only use the first
 313  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 314  * signal; ds1339 chips have only one alarm signal.
 315  */
 316 static void ds1307_work(struct work_struct *work)
 317 {
 318         struct ds1307           *ds1307;
 319         struct i2c_client       *client;
 320         struct mutex            *lock;
 321         int                     stat, control;
 322
 323         ds1307 = container_of(work, struct ds1307, work);
 324         client = ds1307->client;
 325         lock = &ds1307->rtc->ops_lock;
 326
 327         mutex_lock(lock);
 328         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 329         if (stat < 0)
 330                 goto out;
 331
 332         if (stat & DS1337_BIT_A1I) {
 333                 stat &= ~DS1337_BIT_A1I;
 334                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 335
 336                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 337                 if (control < 0)
 338                         goto out;
 339
 340                 control &= ~DS1337_BIT_A1IE;
 341                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 342
 343                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 344         }
 345
 346 out:
 347         if (test_bit(HAS_ALARM, &ds1307->flags))
 348                 enable_irq(client->irq);
 349         mutex_unlock(lock);
 350 }
 351
 352 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 353 {
 354         struct i2c_client       *client = dev_id;
 355         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 356
 357         disable_irq_nosync(irq);
 358         schedule_work(&ds1307->work);
 359         return IRQ_HANDLED;
 360 }
 361
 362 /*----------------------------------------------------------------------*/
 363
 364 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 365 {
 366         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 367         int             tmp;
 368
 369         /* read the RTC date and time registers all at once */
 370         tmp = ds1307->read_block_data(ds1307->client,
 371                 ds1307->offset, 7, ds1307->regs);
 372         if (tmp != 7) {
 373                 dev_err(dev, "%s error %d\n", "read", tmp);
 374                 return -EIO;
 375         }
 376
 377         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 378
 379         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 380         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 381         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 382         t->tm_hour = bcd2bin(tmp);
 383         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 384         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 385         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 386         t->tm_mon = bcd2bin(tmp) - 1;
 387
 388         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 389         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 390
 391         dev_dbg(dev, "%s secs=%d, mins=%d, "
 392                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 393                 "read", t->tm_sec, t->tm_min,
 394                 t->tm_hour, t->tm_mday,
 395                 t->tm_mon, t->tm_year, t->tm_wday);
 396
 397         /* initial clock setting can be undefined */
 398         return rtc_valid_tm(t);
 399 }
 400
 401 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 402 {
 403         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 404         int             result;
 405         int             tmp;
 406         u8              *buf = ds1307->regs;
 407
 408         dev_dbg(dev, "%s secs=%d, mins=%d, "
 409                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 410                 "write", t->tm_sec, t->tm_min,
 411                 t->tm_hour, t->tm_mday,
 412                 t->tm_mon, t->tm_year, t->tm_wday);
 413
 414         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 415         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 416         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 417         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 418         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 419         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 420
 421         /* assume 20YY not 19YY */
 422         tmp = t->tm_year - 100;
 423         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 424
 425         switch (ds1307->type) {
 426         case ds_1337:
 427         case ds_1339:
 428         case ds_3231:
 429                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 430                 break;
 431         case ds_1340:
 432                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 433                                 | DS1340_BIT_CENTURY;
 434                 break;
 435         case mcp7941x:
 436                 /*
 437                  * these bits were cleared when preparing the date/time
 438                  * values and need to be set again before writing the
 439                  * buffer out to the device.
 440                  */
 441                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 442                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 443                 break;
 444         default:
 445                 break;
 446         }
 447
 448         dev_dbg(dev, "%s: %7ph\n", "write", buf);
 449
 450         result = ds1307->write_block_data(ds1307->client,
 451                 ds1307->offset, 7, buf);
 452         if (result < 0) {
 453                 dev_err(dev, "%s error %d\n", "write", result);
 454                 return result;
 455         }
 456         return 0;
 457 }
 458
 459 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 460 {
 461         struct i2c_client       *client = to_i2c_client(dev);
 462         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 463         int                     ret;
 464
 465         if (!test_bit(HAS_ALARM, &ds1307->flags))
 466                 return -EINVAL;
 467
 468         /* read all ALARM1, ALARM2, and status registers at once */
 469         ret = ds1307->read_block_data(client,
 470                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 471         if (ret != 9) {
 472                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 473                 return -EIO;
 474         }
 475
 476         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 477                         "alarm read",
 478                         ds1307->regs[0], ds1307->regs[1],
 479                         ds1307->regs[2], ds1307->regs[3],
 480                         ds1307->regs[4], ds1307->regs[5],
 481                         ds1307->regs[6], ds1307->regs[7],
 482                         ds1307->regs[8]);
 483
 484         /*
 485          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 486          * and that all four fields are checked matches
 487          */
 488         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 489         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 490         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 491         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 492         t->time.tm_mon = -1;
 493         t->time.tm_year = -1;
 494         t->time.tm_wday = -1;
 495         t->time.tm_yday = -1;
 496         t->time.tm_isdst = -1;
 497
 498         /* ... and status */
 499         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 500         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 501
 502         dev_dbg(dev, "%s secs=%d, mins=%d, "
 503                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 504                 "alarm read", t->time.tm_sec, t->time.tm_min,
 505                 t->time.tm_hour, t->time.tm_mday,
 506                 t->enabled, t->pending);
 507
 508         return 0;
 509 }
 510
 511 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 512 {
 513         struct i2c_client       *client = to_i2c_client(dev);
 514         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 515         unsigned char           *buf = ds1307->regs;
 516         u8                      control, status;
 517         int                     ret;
 518
 519         if (!test_bit(HAS_ALARM, &ds1307->flags))
 520                 return -EINVAL;
 521
 522         dev_dbg(dev, "%s secs=%d, mins=%d, "
 523                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 524                 "alarm set", t->time.tm_sec, t->time.tm_min,
 525                 t->time.tm_hour, t->time.tm_mday,
 526                 t->enabled, t->pending);
 527
 528         /* read current status of both alarms and the chip */
 529         ret = ds1307->read_block_data(client,
 530                         DS1339_REG_ALARM1_SECS, 9, buf);
 531         if (ret != 9) {
 532                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 533                 return -EIO;
 534         }
 535         control = ds1307->regs[7];
 536         status = ds1307->regs[8];
 537
 538         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 539                         "alarm set (old status)",
 540                         ds1307->regs[0], ds1307->regs[1],
 541                         ds1307->regs[2], ds1307->regs[3],
 542                         ds1307->regs[4], ds1307->regs[5],
 543                         ds1307->regs[6], control, status);
 544
 545         /* set ALARM1, using 24 hour and day-of-month modes */
 546         buf[0] = bin2bcd(t->time.tm_sec);
 547         buf[1] = bin2bcd(t->time.tm_min);
 548         buf[2] = bin2bcd(t->time.tm_hour);
 549         buf[3] = bin2bcd(t->time.tm_mday);
 550
 551         /* set ALARM2 to non-garbage */
 552         buf[4] = 0;
 553         buf[5] = 0;
 554         buf[6] = 0;
 555
 556         /* optionally enable ALARM1 */
 557         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 558         if (t->enabled) {
 559                 dev_dbg(dev, "alarm IRQ armed\n");
 560                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 561         }
 562         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 563
 564         ret = ds1307->write_block_data(client,
 565                         DS1339_REG_ALARM1_SECS, 9, buf);
 566         if (ret < 0) {
 567                 dev_err(dev, "can't set alarm time\n");
 568                 return ret;
 569         }
 570
 571         return 0;
 572 }
 573
 574 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 575 {
 576         struct i2c_client       *client = to_i2c_client(dev);
 577         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 578         int                     ret;
 579
 580         if (!test_bit(HAS_ALARM, &ds1307->flags))
 581                 return -ENOTTY;
 582
 583         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 584         if (ret < 0)
 585                 return ret;
 586
 587         if (enabled)
 588                 ret |= DS1337_BIT_A1IE;
 589         else
 590                 ret &= ~DS1337_BIT_A1IE;
 591
 592         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 593         if (ret < 0)
 594                 return ret;
 595
 596         return 0;
 597 }
 598
 599 static const struct rtc_class_ops ds13xx_rtc_ops = {
 600         .read_time      = ds1307_get_time,
 601         .set_time       = ds1307_set_time,
 602         .read_alarm     = ds1337_read_alarm,
 603         .set_alarm      = ds1337_set_alarm,
 604         .alarm_irq_enable = ds1307_alarm_irq_enable,
 605 };
 606
 607 /*----------------------------------------------------------------------*/
 608
 609 static ssize_t
 610 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 611                 struct bin_attribute *attr,
 612                 char *buf, loff_t off, size_t count)
 613 {
 614         struct i2c_client       *client;
 615         struct ds1307           *ds1307;
 616         int                     result;
 617
 618         client = kobj_to_i2c_client(kobj);
 619         ds1307 = i2c_get_clientdata(client);
 620
 621         if (unlikely(off >= ds1307->nvram->size))
 622                 return 0;
 623         if ((off + count) > ds1307->nvram->size)
 624                 count = ds1307->nvram->size - off;
 625         if (unlikely(!count))
 626                 return count;
 627
 628         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 629                                                                 count, buf);
 630         if (result < 0)
 631                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 632         return result;
 633 }
 634
 635 static ssize_t
 636 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 637                 struct bin_attribute *attr,
 638                 char *buf, loff_t off, size_t count)
 639 {
 640         struct i2c_client       *client;
 641         struct ds1307           *ds1307;
 642         int                     result;
 643
 644         client = kobj_to_i2c_client(kobj);
 645         ds1307 = i2c_get_clientdata(client);
 646
 647         if (unlikely(off >= ds1307->nvram->size))
 648                 return -EFBIG;
 649         if ((off + count) > ds1307->nvram->size)
 650                 count = ds1307->nvram->size - off;
 651         if (unlikely(!count))
 652                 return count;
 653
 654         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 655                                                                 count, buf);
 656         if (result < 0) {
 657                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 658                 return result;
 659         }
 660         return count;
 661 }
 662
 663 /*----------------------------------------------------------------------*/
 664
 665 static int ds1307_probe(struct i2c_client *client,
 666                         const struct i2c_device_id *id)
 667 {
 668         struct ds1307           *ds1307;
 669         int                     err = -ENODEV;
 670         int                     tmp;
 671         const struct chip_desc  *chip = &chips[id->driver_data];
 672         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 673         int                     want_irq = false;
 674         unsigned char           *buf;
 675         struct ds1307_platform_data *pdata = client->dev.platform_data;
 676         static const int        bbsqi_bitpos[] = {
 677                 [ds_1337] = 0,
 678                 [ds_1339] = DS1339_BIT_BBSQI,
 679                 [ds_3231] = DS3231_BIT_BBSQW,
 680         };
 681
 682         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 683             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 684                 return -EIO;
 685
 686         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
 687         if (!ds1307)
 688                 return -ENOMEM;
 689
 690         i2c_set_clientdata(client, ds1307);
 691
 692         ds1307->client  = client;
 693         ds1307->type    = id->driver_data;
 694
 695         if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
 696                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 697                         DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
 698
 699         buf = ds1307->regs;
 700         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 701                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
 702                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
 703         } else {
 704                 ds1307->read_block_data = ds1307_read_block_data;
 705                 ds1307->write_block_data = ds1307_write_block_data;
 706         }
 707
 708         switch (ds1307->type) {
 709         case ds_1337:
 710         case ds_1339:
 711         case ds_3231:
 712                 /* get registers that the "rtc" read below won't read... */
 713                 tmp = ds1307->read_block_data(ds1307->client,
 714                                 DS1337_REG_CONTROL, 2, buf);
 715                 if (tmp != 2) {
 716                         dev_dbg(&client->dev, "read error %d\n", tmp);
 717                         err = -EIO;
 718                         goto exit;
 719                 }
 720
 721                 /* oscillator off?  turn it on, so clock can tick. */
 722                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 723                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 724
 725                 /*
 726                  * Using IRQ?  Disable the square wave and both alarms.
 727                  * For some variants, be sure alarms can trigger when we're
 728                  * running on Vbackup (BBSQI/BBSQW)
 729                  */
 730                 if (ds1307->client->irq > 0 && chip->alarm) {
 731                         INIT_WORK(&ds1307->work, ds1307_work);
 732
 733                         ds1307->regs[0] |= DS1337_BIT_INTCN
 734                                         | bbsqi_bitpos[ds1307->type];
 735                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 736
 737                         want_irq = true;
 738                 }
 739
 740                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 741                                                         ds1307->regs[0]);
 742
 743                 /* oscillator fault?  clear flag, and warn */
 744                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 745                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 746                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 747                         dev_warn(&client->dev, "SET TIME!\n");
 748                 }
 749                 break;
 750
 751         case rx_8025:
 752                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 753                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 754                 if (tmp != 2) {
 755                         dev_dbg(&client->dev, "read error %d\n", tmp);
 756                         err = -EIO;
 757                         goto exit;
 758                 }
 759
 760                 /* oscillator off?  turn it on, so clock can tick. */
 761                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 762                         ds1307->regs[1] |= RX8025_BIT_XST;
 763                         i2c_smbus_write_byte_data(client,
 764                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 765                                                   ds1307->regs[1]);
 766                         dev_warn(&client->dev,
 767                                  "oscillator stop detected - SET TIME!\n");
 768                 }
 769
 770                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 771                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 772                         i2c_smbus_write_byte_data(client,
 773                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 774                                                   ds1307->regs[1]);
 775                         dev_warn(&client->dev, "power-on detected\n");
 776                 }
 777
 778                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 779                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 780                         i2c_smbus_write_byte_data(client,
 781                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 782                                                   ds1307->regs[1]);
 783                         dev_warn(&client->dev, "voltage drop detected\n");
 784                 }
 785
 786                 /* make sure we are running in 24hour mode */
 787                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 788                         u8 hour;
 789
 790                         /* switch to 24 hour mode */
 791                         i2c_smbus_write_byte_data(client,
 792                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 793                                                   ds1307->regs[0] |
 794                                                   RX8025_BIT_2412);
 795
 796                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 797                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 798                         if (tmp != 2) {
 799                                 dev_dbg(&client->dev, "read error %d\n", tmp);
 800                                 err = -EIO;
 801                                 goto exit;
 802                         }
 803
 804                         /* correct hour */
 805                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 806                         if (hour == 12)
 807                                 hour = 0;
 808                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 809                                 hour += 12;
 810
 811                         i2c_smbus_write_byte_data(client,
 812                                                   DS1307_REG_HOUR << 4 | 0x08,
 813                                                   hour);
 814                 }
 815                 break;
 816         case ds_1388:
 817                 ds1307->offset = 1; /* Seconds starts at 1 */
 818                 break;
 819         default:
 820                 break;
 821         }
 822
 823 read_rtc:
 824         /* read RTC registers */
 825         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 826         if (tmp != 8) {
 827                 dev_dbg(&client->dev, "read error %d\n", tmp);
 828                 err = -EIO;
 829                 goto exit;
 830         }
 831
 832         /*
 833          * minimal sanity checking; some chips (like DS1340) don't
 834          * specify the extra bits as must-be-zero, but there are
 835          * still a few values that are clearly out-of-range.
 836          */
 837         tmp = ds1307->regs[DS1307_REG_SECS];
 838         switch (ds1307->type) {
 839         case ds_1307:
 840         case m41t00:
 841                 /* clock halted?  turn it on, so clock can tick. */
 842                 if (tmp & DS1307_BIT_CH) {
 843                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 844                         dev_warn(&client->dev, "SET TIME!\n");
 845                         goto read_rtc;
 846                 }
 847                 break;
 848         case ds_1338:
 849                 /* clock halted?  turn it on, so clock can tick. */
 850                 if (tmp & DS1307_BIT_CH)
 851                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 852
 853                 /* oscillator fault?  clear flag, and warn */
 854                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 855                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 856                                         ds1307->regs[DS1307_REG_CONTROL]
 857                                         & ~DS1338_BIT_OSF);
 858                         dev_warn(&client->dev, "SET TIME!\n");
 859                         goto read_rtc;
 860                 }
 861                 break;
 862         case ds_1340:
 863                 /* clock halted?  turn it on, so clock can tick. */
 864                 if (tmp & DS1340_BIT_nEOSC)
 865                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 866
 867                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 868                 if (tmp < 0) {
 869                         dev_dbg(&client->dev, "read error %d\n", tmp);
 870                         err = -EIO;
 871                         goto exit;
 872                 }
 873
 874                 /* oscillator fault?  clear flag, and warn */
 875                 if (tmp & DS1340_BIT_OSF) {
 876                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 877                         dev_warn(&client->dev, "SET TIME!\n");
 878                 }
 879                 break;
 880         case mcp7941x:
 881                 /* make sure that the backup battery is enabled */
 882                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 883                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 884                                         ds1307->regs[DS1307_REG_WDAY]
 885                                         | MCP7941X_BIT_VBATEN);
 886                 }
 887
 888                 /* clock halted?  turn it on, so clock can tick. */
 889                 if (!(tmp & MCP7941X_BIT_ST)) {
 890                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 891                                         MCP7941X_BIT_ST);
 892                         dev_warn(&client->dev, "SET TIME!\n");
 893                         goto read_rtc;
 894                 }
 895
 896                 break;
 897         default:
 898                 break;
 899         }
 900
 901         tmp = ds1307->regs[DS1307_REG_HOUR];
 902         switch (ds1307->type) {
 903         case ds_1340:
 904         case m41t00:
 905                 /*
 906                  * NOTE: ignores century bits; fix before deploying
 907                  * systems that will run through year 2100.
 908                  */
 909                 break;
 910         case rx_8025:
 911                 break;
 912         default:
 913                 if (!(tmp & DS1307_BIT_12HR))
 914                         break;
 915
 916                 /*
 917                  * Be sure we're in 24 hour mode.  Multi-master systems
 918                  * take note...
 919                  */
 920                 tmp = bcd2bin(tmp & 0x1f);
 921                 if (tmp == 12)
 922                         tmp = 0;
 923                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 924                         tmp += 12;
 925                 i2c_smbus_write_byte_data(client,
 926                                 ds1307->offset + DS1307_REG_HOUR,
 927                                 bin2bcd(tmp));
 928         }
 929
 930         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
 931                                 &ds13xx_rtc_ops, THIS_MODULE);
 932         if (IS_ERR(ds1307->rtc)) {
 933                 err = PTR_ERR(ds1307->rtc);
 934                 dev_err(&client->dev,
 935                         "unable to register the class device\n");
 936                 goto exit;
 937         }
 938
 939         if (want_irq) {
 940                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 941                           ds1307->rtc->name, client);
 942                 if (err) {
 943                         dev_err(&client->dev,
 944                                 "unable to request IRQ!\n");
 945                         goto exit;
 946                 }
 947
 948                 device_set_wakeup_capable(&client->dev, 1);
 949                 set_bit(HAS_ALARM, &ds1307->flags);
 950                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 951         }
 952
 953         if (chip->nvram_size) {
 954                 ds1307->nvram = devm_kzalloc(&client->dev,
 955                                         sizeof(struct bin_attribute),
 956                                         GFP_KERNEL);
 957                 if (!ds1307->nvram) {
 958                         err = -ENOMEM;
 959                         goto exit;
 960                 }
 961                 ds1307->nvram->attr.name = "nvram";
 962                 ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
 963                 sysfs_bin_attr_init(ds1307->nvram);
 964                 ds1307->nvram->read = ds1307_nvram_read;
 965                 ds1307->nvram->write = ds1307_nvram_write;
 966                 ds1307->nvram->size = chip->nvram_size;
 967                 ds1307->nvram_offset = chip->nvram_offset;
 968                 err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
 969                 if (err)
 970                         goto exit;
 971                 set_bit(HAS_NVRAM, &ds1307->flags);
 972                 dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
 973         }
 974
 975         return 0;
 976
 977 exit:
 978         return err;
 979 }
 980
 981 static int ds1307_remove(struct i2c_client *client)
 982 {
 983         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 984
 985         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 986                 free_irq(client->irq, client);
 987                 cancel_work_sync(&ds1307->work);
 988         }
 989
 990         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
 991                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
 992
 993         return 0;
 994 }
 995
 996 static struct i2c_driver ds1307_driver = {
 997         .driver = {
 998                 .name   = "rtc-ds1307",
 999                 .owner  = THIS_MODULE,
1000         },
1001         .probe          = ds1307_probe,
1002         .remove         = ds1307_remove,
1003         .id_table       = ds1307_id,
1004 };
1005
1006 module_i2c_driver(ds1307_driver);
1007
1008 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1009 MODULE_LICENSE("GPL");