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         u8                      trickle_charger_setup;
 130         u8                      (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
 131 };
 132
 133 static u8 do_trickle_setup_ds1339(struct i2c_client *,
 134                                   uint32_t ohms, bool diode);
 135
 136 static struct chip_desc chips[last_ds_type] = {
 137         [ds_1307] = {
 138                 .nvram_offset   = 8,
 139                 .nvram_size     = 56,
 140         },
 141         [ds_1337] = {
 142                 .alarm          = 1,
 143         },
 144         [ds_1338] = {
 145                 .nvram_offset   = 8,
 146                 .nvram_size     = 56,
 147         },
 148         [ds_1339] = {
 149                 .alarm          = 1,
 150                 .trickle_charger_reg = 0x10,
 151                 .do_trickle_setup = &do_trickle_setup_ds1339,
 152         },
 153         [ds_1340] = {
 154                 .trickle_charger_reg = 0x08,
 155         },
 156         [ds_1388] = {
 157                 .trickle_charger_reg = 0x0a,
 158         },
 159         [ds_3231] = {
 160                 .alarm          = 1,
 161         },
 162         [mcp7941x] = {
 163                 .alarm          = 1,
 164                 /* this is battery backed SRAM */
 165                 .nvram_offset   = 0x20,
 166                 .nvram_size     = 0x40,
 167         },
 168 };
 169
 170 static const struct i2c_device_id ds1307_id[] = {
 171         { "ds1307", ds_1307 },
 172         { "ds1337", ds_1337 },
 173         { "ds1338", ds_1338 },
 174         { "ds1339", ds_1339 },
 175         { "ds1388", ds_1388 },
 176         { "ds1340", ds_1340 },
 177         { "ds3231", ds_3231 },
 178         { "m41t00", m41t00 },
 179         { "mcp7941x", mcp7941x },
 180         { "pt7c4338", ds_1307 },
 181         { "rx8025", rx_8025 },
 182         { }
 183 };
 184 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 185
 186 /*----------------------------------------------------------------------*/
 187
 188 #define BLOCK_DATA_MAX_TRIES 10
 189
 190 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 191                                        u8 command, u8 length, u8 *values)
 192 {
 193         s32 i, data;
 194
 195         for (i = 0; i < length; i++) {
 196                 data = i2c_smbus_read_byte_data(client, command + i);
 197                 if (data < 0)
 198                         return data;
 199                 values[i] = data;
 200         }
 201         return i;
 202 }
 203
 204 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 205                                   u8 length, u8 *values)
 206 {
 207         u8 oldvalues[255];
 208         s32 ret;
 209         int tries = 0;
 210
 211         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 212         ret = ds1307_read_block_data_once(client, command, length, values);
 213         if (ret < 0)
 214                 return ret;
 215         do {
 216                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 217                         dev_err(&client->dev,
 218                                 "ds1307_read_block_data failed\n");
 219                         return -EIO;
 220                 }
 221                 memcpy(oldvalues, values, length);
 222                 ret = ds1307_read_block_data_once(client, command, length,
 223                                                   values);
 224                 if (ret < 0)
 225                         return ret;
 226         } while (memcmp(oldvalues, values, length));
 227         return length;
 228 }
 229
 230 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 231                                    u8 length, const u8 *values)
 232 {
 233         u8 currvalues[255];
 234         int tries = 0;
 235
 236         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 237         do {
 238                 s32 i, ret;
 239
 240                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 241                         dev_err(&client->dev,
 242                                 "ds1307_write_block_data failed\n");
 243                         return -EIO;
 244                 }
 245                 for (i = 0; i < length; i++) {
 246                         ret = i2c_smbus_write_byte_data(client, command + i,
 247                                                         values[i]);
 248                         if (ret < 0)
 249                                 return ret;
 250                 }
 251                 ret = ds1307_read_block_data_once(client, command, length,
 252                                                   currvalues);
 253                 if (ret < 0)
 254                         return ret;
 255         } while (memcmp(currvalues, values, length));
 256         return length;
 257 }
 258
 259 /*----------------------------------------------------------------------*/
 260
 261 /* These RTC devices are not designed to be connected to a SMbus adapter.
 262    SMbus limits block operations length to 32 bytes, whereas it's not
 263    limited on I2C buses. As a result, accesses may exceed 32 bytes;
 264    in that case, split them into smaller blocks */
 265
 266 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
 267                                 u8 command, u8 length, const u8 *values)
 268 {
 269         u8 suboffset = 0;
 270
 271         if (length <= I2C_SMBUS_BLOCK_MAX)
 272                 return i2c_smbus_write_i2c_block_data(client,
 273                                         command, length, values);
 274
 275         while (suboffset < length) {
 276                 s32 retval = i2c_smbus_write_i2c_block_data(client,
 277                                 command + suboffset,
 278                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 279                                 values + suboffset);
 280                 if (retval < 0)
 281                         return retval;
 282
 283                 suboffset += I2C_SMBUS_BLOCK_MAX;
 284         }
 285         return length;
 286 }
 287
 288 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
 289                                 u8 command, u8 length, u8 *values)
 290 {
 291         u8 suboffset = 0;
 292
 293         if (length <= I2C_SMBUS_BLOCK_MAX)
 294                 return i2c_smbus_read_i2c_block_data(client,
 295                                         command, length, values);
 296
 297         while (suboffset < length) {
 298                 s32 retval = i2c_smbus_read_i2c_block_data(client,
 299                                 command + suboffset,
 300                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 301                                 values + suboffset);
 302                 if (retval < 0)
 303                         return retval;
 304
 305                 suboffset += I2C_SMBUS_BLOCK_MAX;
 306         }
 307         return length;
 308 }
 309
 310 /*----------------------------------------------------------------------*/
 311
 312 /*
 313  * The IRQ logic includes a "real" handler running in IRQ context just
 314  * long enough to schedule this workqueue entry.   We need a task context
 315  * to talk to the RTC, since I2C I/O calls require that; and disable the
 316  * IRQ until we clear its status on the chip, so that this handler can
 317  * work with any type of triggering (not just falling edge).
 318  *
 319  * The ds1337 and ds1339 both have two alarms, but we only use the first
 320  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 321  * signal; ds1339 chips have only one alarm signal.
 322  */
 323 static void ds1307_work(struct work_struct *work)
 324 {
 325         struct ds1307           *ds1307;
 326         struct i2c_client       *client;
 327         struct mutex            *lock;
 328         int                     stat, control;
 329
 330         ds1307 = container_of(work, struct ds1307, work);
 331         client = ds1307->client;
 332         lock = &ds1307->rtc->ops_lock;
 333
 334         mutex_lock(lock);
 335         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 336         if (stat < 0)
 337                 goto out;
 338
 339         if (stat & DS1337_BIT_A1I) {
 340                 stat &= ~DS1337_BIT_A1I;
 341                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 342
 343                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 344                 if (control < 0)
 345                         goto out;
 346
 347                 control &= ~DS1337_BIT_A1IE;
 348                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 349
 350                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 351         }
 352
 353 out:
 354         if (test_bit(HAS_ALARM, &ds1307->flags))
 355                 enable_irq(client->irq);
 356         mutex_unlock(lock);
 357 }
 358
 359 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 360 {
 361         struct i2c_client       *client = dev_id;
 362         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 363
 364         disable_irq_nosync(irq);
 365         schedule_work(&ds1307->work);
 366         return IRQ_HANDLED;
 367 }
 368
 369 /*----------------------------------------------------------------------*/
 370
 371 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 372 {
 373         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 374         int             tmp;
 375
 376         /* read the RTC date and time registers all at once */
 377         tmp = ds1307->read_block_data(ds1307->client,
 378                 ds1307->offset, 7, ds1307->regs);
 379         if (tmp != 7) {
 380                 dev_err(dev, "%s error %d\n", "read", tmp);
 381                 return -EIO;
 382         }
 383
 384         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 385
 386         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 387         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 388         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 389         t->tm_hour = bcd2bin(tmp);
 390         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 391         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 392         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 393         t->tm_mon = bcd2bin(tmp) - 1;
 394
 395         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 396         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 397
 398         dev_dbg(dev, "%s secs=%d, mins=%d, "
 399                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 400                 "read", t->tm_sec, t->tm_min,
 401                 t->tm_hour, t->tm_mday,
 402                 t->tm_mon, t->tm_year, t->tm_wday);
 403
 404         /* initial clock setting can be undefined */
 405         return rtc_valid_tm(t);
 406 }
 407
 408 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 409 {
 410         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 411         int             result;
 412         int             tmp;
 413         u8              *buf = ds1307->regs;
 414
 415         dev_dbg(dev, "%s secs=%d, mins=%d, "
 416                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 417                 "write", t->tm_sec, t->tm_min,
 418                 t->tm_hour, t->tm_mday,
 419                 t->tm_mon, t->tm_year, t->tm_wday);
 420
 421         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 422         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 423         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 424         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 425         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 426         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 427
 428         /* assume 20YY not 19YY */
 429         tmp = t->tm_year - 100;
 430         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 431
 432         switch (ds1307->type) {
 433         case ds_1337:
 434         case ds_1339:
 435         case ds_3231:
 436                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 437                 break;
 438         case ds_1340:
 439                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 440                                 | DS1340_BIT_CENTURY;
 441                 break;
 442         case mcp7941x:
 443                 /*
 444                  * these bits were cleared when preparing the date/time
 445                  * values and need to be set again before writing the
 446                  * buffer out to the device.
 447                  */
 448                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 449                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 450                 break;
 451         default:
 452                 break;
 453         }
 454
 455         dev_dbg(dev, "%s: %7ph\n", "write", buf);
 456
 457         result = ds1307->write_block_data(ds1307->client,
 458                 ds1307->offset, 7, buf);
 459         if (result < 0) {
 460                 dev_err(dev, "%s error %d\n", "write", result);
 461                 return result;
 462         }
 463         return 0;
 464 }
 465
 466 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 467 {
 468         struct i2c_client       *client = to_i2c_client(dev);
 469         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 470         int                     ret;
 471
 472         if (!test_bit(HAS_ALARM, &ds1307->flags))
 473                 return -EINVAL;
 474
 475         /* read all ALARM1, ALARM2, and status registers at once */
 476         ret = ds1307->read_block_data(client,
 477                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 478         if (ret != 9) {
 479                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 480                 return -EIO;
 481         }
 482
 483         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 484                         "alarm read",
 485                         ds1307->regs[0], ds1307->regs[1],
 486                         ds1307->regs[2], ds1307->regs[3],
 487                         ds1307->regs[4], ds1307->regs[5],
 488                         ds1307->regs[6], ds1307->regs[7],
 489                         ds1307->regs[8]);
 490
 491         /*
 492          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 493          * and that all four fields are checked matches
 494          */
 495         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 496         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 497         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 498         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 499         t->time.tm_mon = -1;
 500         t->time.tm_year = -1;
 501         t->time.tm_wday = -1;
 502         t->time.tm_yday = -1;
 503         t->time.tm_isdst = -1;
 504
 505         /* ... and status */
 506         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 507         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 508
 509         dev_dbg(dev, "%s secs=%d, mins=%d, "
 510                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 511                 "alarm read", t->time.tm_sec, t->time.tm_min,
 512                 t->time.tm_hour, t->time.tm_mday,
 513                 t->enabled, t->pending);
 514
 515         return 0;
 516 }
 517
 518 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 519 {
 520         struct i2c_client       *client = to_i2c_client(dev);
 521         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 522         unsigned char           *buf = ds1307->regs;
 523         u8                      control, status;
 524         int                     ret;
 525
 526         if (!test_bit(HAS_ALARM, &ds1307->flags))
 527                 return -EINVAL;
 528
 529         dev_dbg(dev, "%s secs=%d, mins=%d, "
 530                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 531                 "alarm set", t->time.tm_sec, t->time.tm_min,
 532                 t->time.tm_hour, t->time.tm_mday,
 533                 t->enabled, t->pending);
 534
 535         /* read current status of both alarms and the chip */
 536         ret = ds1307->read_block_data(client,
 537                         DS1339_REG_ALARM1_SECS, 9, buf);
 538         if (ret != 9) {
 539                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 540                 return -EIO;
 541         }
 542         control = ds1307->regs[7];
 543         status = ds1307->regs[8];
 544
 545         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 546                         "alarm set (old status)",
 547                         ds1307->regs[0], ds1307->regs[1],
 548                         ds1307->regs[2], ds1307->regs[3],
 549                         ds1307->regs[4], ds1307->regs[5],
 550                         ds1307->regs[6], control, status);
 551
 552         /* set ALARM1, using 24 hour and day-of-month modes */
 553         buf[0] = bin2bcd(t->time.tm_sec);
 554         buf[1] = bin2bcd(t->time.tm_min);
 555         buf[2] = bin2bcd(t->time.tm_hour);
 556         buf[3] = bin2bcd(t->time.tm_mday);
 557
 558         /* set ALARM2 to non-garbage */
 559         buf[4] = 0;
 560         buf[5] = 0;
 561         buf[6] = 0;
 562
 563         /* optionally enable ALARM1 */
 564         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 565         if (t->enabled) {
 566                 dev_dbg(dev, "alarm IRQ armed\n");
 567                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 568         }
 569         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 570
 571         ret = ds1307->write_block_data(client,
 572                         DS1339_REG_ALARM1_SECS, 9, buf);
 573         if (ret < 0) {
 574                 dev_err(dev, "can't set alarm time\n");
 575                 return ret;
 576         }
 577
 578         return 0;
 579 }
 580
 581 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 582 {
 583         struct i2c_client       *client = to_i2c_client(dev);
 584         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 585         int                     ret;
 586
 587         if (!test_bit(HAS_ALARM, &ds1307->flags))
 588                 return -ENOTTY;
 589
 590         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 591         if (ret < 0)
 592                 return ret;
 593
 594         if (enabled)
 595                 ret |= DS1337_BIT_A1IE;
 596         else
 597                 ret &= ~DS1337_BIT_A1IE;
 598
 599         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 600         if (ret < 0)
 601                 return ret;
 602
 603         return 0;
 604 }
 605
 606 static const struct rtc_class_ops ds13xx_rtc_ops = {
 607         .read_time      = ds1307_get_time,
 608         .set_time       = ds1307_set_time,
 609         .read_alarm     = ds1337_read_alarm,
 610         .set_alarm      = ds1337_set_alarm,
 611         .alarm_irq_enable = ds1307_alarm_irq_enable,
 612 };
 613
 614 /*----------------------------------------------------------------------*/
 615
 616 /*
 617  * Alarm support for mcp7941x devices.
 618  */
 619
 620 #define MCP7941X_REG_CONTROL            0x07
 621 #       define MCP7941X_BIT_ALM0_EN     0x10
 622 #       define MCP7941X_BIT_ALM1_EN     0x20
 623 #define MCP7941X_REG_ALARM0_BASE        0x0a
 624 #define MCP7941X_REG_ALARM0_CTRL        0x0d
 625 #define MCP7941X_REG_ALARM1_BASE        0x11
 626 #define MCP7941X_REG_ALARM1_CTRL        0x14
 627 #       define MCP7941X_BIT_ALMX_IF     (1 << 3)
 628 #       define MCP7941X_BIT_ALMX_C0     (1 << 4)
 629 #       define MCP7941X_BIT_ALMX_C1     (1 << 5)
 630 #       define MCP7941X_BIT_ALMX_C2     (1 << 6)
 631 #       define MCP7941X_BIT_ALMX_POL    (1 << 7)
 632 #       define MCP7941X_MSK_ALMX_MATCH  (MCP7941X_BIT_ALMX_C0 | \
 633                                          MCP7941X_BIT_ALMX_C1 | \
 634                                          MCP7941X_BIT_ALMX_C2)
 635
 636 static void mcp7941x_work(struct work_struct *work)
 637 {
 638         struct ds1307 *ds1307 = container_of(work, struct ds1307, work);
 639         struct i2c_client *client = ds1307->client;
 640         int reg, ret;
 641
 642         mutex_lock(&ds1307->rtc->ops_lock);
 643
 644         /* Check and clear alarm 0 interrupt flag. */
 645         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_ALARM0_CTRL);
 646         if (reg < 0)
 647                 goto out;
 648         if (!(reg & MCP7941X_BIT_ALMX_IF))
 649                 goto out;
 650         reg &= ~MCP7941X_BIT_ALMX_IF;
 651         ret = i2c_smbus_write_byte_data(client, MCP7941X_REG_ALARM0_CTRL, reg);
 652         if (ret < 0)
 653                 goto out;
 654
 655         /* Disable alarm 0. */
 656         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_CONTROL);
 657         if (reg < 0)
 658                 goto out;
 659         reg &= ~MCP7941X_BIT_ALM0_EN;
 660         ret = i2c_smbus_write_byte_data(client, MCP7941X_REG_CONTROL, reg);
 661         if (ret < 0)
 662                 goto out;
 663
 664         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 665
 666 out:
 667         if (test_bit(HAS_ALARM, &ds1307->flags))
 668                 enable_irq(client->irq);
 669         mutex_unlock(&ds1307->rtc->ops_lock);
 670 }
 671
 672 static int mcp7941x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 673 {
 674         struct i2c_client *client = to_i2c_client(dev);
 675         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 676         u8 *regs = ds1307->regs;
 677         int ret;
 678
 679         if (!test_bit(HAS_ALARM, &ds1307->flags))
 680                 return -EINVAL;
 681
 682         /* Read control and alarm 0 registers. */
 683         ret = ds1307->read_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
 684         if (ret < 0)
 685                 return ret;
 686
 687         t->enabled = !!(regs[0] & MCP7941X_BIT_ALM0_EN);
 688
 689         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 690         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
 691         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
 692         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
 693         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
 694         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
 695         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
 696         t->time.tm_year = -1;
 697         t->time.tm_yday = -1;
 698         t->time.tm_isdst = -1;
 699
 700         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 701                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
 702                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 703                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 704                 !!(ds1307->regs[6] & MCP7941X_BIT_ALMX_POL),
 705                 !!(ds1307->regs[6] & MCP7941X_BIT_ALMX_IF),
 706                 (ds1307->regs[6] & MCP7941X_MSK_ALMX_MATCH) >> 4);
 707
 708         return 0;
 709 }
 710
 711 static int mcp7941x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 712 {
 713         struct i2c_client *client = to_i2c_client(dev);
 714         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 715         unsigned char *regs = ds1307->regs;
 716         int ret;
 717
 718         if (!test_bit(HAS_ALARM, &ds1307->flags))
 719                 return -EINVAL;
 720
 721         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 722                 "enabled=%d pending=%d\n", __func__,
 723                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 724                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 725                 t->enabled, t->pending);
 726
 727         /* Read control and alarm 0 registers. */
 728         ret = ds1307->read_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
 729         if (ret < 0)
 730                 return ret;
 731
 732         /* Set alarm 0, using 24-hour and day-of-month modes. */
 733         regs[3] = bin2bcd(t->time.tm_sec);
 734         regs[4] = bin2bcd(t->time.tm_min);
 735         regs[5] = bin2bcd(t->time.tm_hour);
 736         regs[6] = bin2bcd(t->time.tm_wday) + 1;
 737         regs[7] = bin2bcd(t->time.tm_mday);
 738         regs[8] = bin2bcd(t->time.tm_mon) + 1;
 739
 740         /* Clear the alarm 0 interrupt flag. */
 741         regs[6] &= ~MCP7941X_BIT_ALMX_IF;
 742         /* Set alarm match: second, minute, hour, day, date, month. */
 743         regs[6] |= MCP7941X_MSK_ALMX_MATCH;
 744
 745         if (t->enabled)
 746                 regs[0] |= MCP7941X_BIT_ALM0_EN;
 747         else
 748                 regs[0] &= ~MCP7941X_BIT_ALM0_EN;
 749
 750         ret = ds1307->write_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
 751         if (ret < 0)
 752                 return ret;
 753
 754         return 0;
 755 }
 756
 757 static int mcp7941x_alarm_irq_enable(struct device *dev, unsigned int enabled)
 758 {
 759         struct i2c_client *client = to_i2c_client(dev);
 760         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 761         int reg;
 762
 763         if (!test_bit(HAS_ALARM, &ds1307->flags))
 764                 return -EINVAL;
 765
 766         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_CONTROL);
 767         if (reg < 0)
 768                 return reg;
 769
 770         if (enabled)
 771                 reg |= MCP7941X_BIT_ALM0_EN;
 772         else
 773                 reg &= ~MCP7941X_BIT_ALM0_EN;
 774
 775         return i2c_smbus_write_byte_data(client, MCP7941X_REG_CONTROL, reg);
 776 }
 777
 778 static const struct rtc_class_ops mcp7941x_rtc_ops = {
 779         .read_time      = ds1307_get_time,
 780         .set_time       = ds1307_set_time,
 781         .read_alarm     = mcp7941x_read_alarm,
 782         .set_alarm      = mcp7941x_set_alarm,
 783         .alarm_irq_enable = mcp7941x_alarm_irq_enable,
 784 };
 785
 786 /*----------------------------------------------------------------------*/
 787
 788 static ssize_t
 789 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 790                 struct bin_attribute *attr,
 791                 char *buf, loff_t off, size_t count)
 792 {
 793         struct i2c_client       *client;
 794         struct ds1307           *ds1307;
 795         int                     result;
 796
 797         client = kobj_to_i2c_client(kobj);
 798         ds1307 = i2c_get_clientdata(client);
 799
 800         if (unlikely(off >= ds1307->nvram->size))
 801                 return 0;
 802         if ((off + count) > ds1307->nvram->size)
 803                 count = ds1307->nvram->size - off;
 804         if (unlikely(!count))
 805                 return count;
 806
 807         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 808                                                                 count, buf);
 809         if (result < 0)
 810                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 811         return result;
 812 }
 813
 814 static ssize_t
 815 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 816                 struct bin_attribute *attr,
 817                 char *buf, loff_t off, size_t count)
 818 {
 819         struct i2c_client       *client;
 820         struct ds1307           *ds1307;
 821         int                     result;
 822
 823         client = kobj_to_i2c_client(kobj);
 824         ds1307 = i2c_get_clientdata(client);
 825
 826         if (unlikely(off >= ds1307->nvram->size))
 827                 return -EFBIG;
 828         if ((off + count) > ds1307->nvram->size)
 829                 count = ds1307->nvram->size - off;
 830         if (unlikely(!count))
 831                 return count;
 832
 833         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 834                                                                 count, buf);
 835         if (result < 0) {
 836                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 837                 return result;
 838         }
 839         return count;
 840 }
 841
 842
 843 /*----------------------------------------------------------------------*/
 844
 845 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
 846                                   uint32_t ohms, bool diode)
 847 {
 848         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 849                 DS1307_TRICKLE_CHARGER_NO_DIODE;
 850
 851         switch (ohms) {
 852         case 250:
 853                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 854                 break;
 855         case 2000:
 856                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 857                 break;
 858         case 4000:
 859                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 860                 break;
 861         default:
 862                 dev_warn(&client->dev,
 863                          "Unsupported ohm value %u in dt\n", ohms);
 864                 return 0;
 865         }
 866         return setup;
 867 }
 868
 869 static void ds1307_trickle_of_init(struct i2c_client *client,
 870                                    struct chip_desc *chip)
 871 {
 872         uint32_t ohms = 0;
 873         bool diode = true;
 874
 875         if (!chip->do_trickle_setup)
 876                 goto out;
 877         if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
 878                 goto out;
 879         if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
 880                 diode = false;
 881         chip->trickle_charger_setup = chip->do_trickle_setup(client,
 882                                                              ohms, diode);
 883 out:
 884         return;
 885 }
 886
 887 static int ds1307_probe(struct i2c_client *client,
 888                         const struct i2c_device_id *id)
 889 {
 890         struct ds1307           *ds1307;
 891         int                     err = -ENODEV;
 892         int                     tmp;
 893         struct chip_desc        *chip = &chips[id->driver_data];
 894         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 895         bool                    want_irq = false;
 896         unsigned char           *buf;
 897         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
 898         static const int        bbsqi_bitpos[] = {
 899                 [ds_1337] = 0,
 900                 [ds_1339] = DS1339_BIT_BBSQI,
 901                 [ds_3231] = DS3231_BIT_BBSQW,
 902         };
 903         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
 904
 905         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 906             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 907                 return -EIO;
 908
 909         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
 910         if (!ds1307)
 911                 return -ENOMEM;
 912
 913         i2c_set_clientdata(client, ds1307);
 914
 915         ds1307->client  = client;
 916         ds1307->type    = id->driver_data;
 917
 918         if (!pdata && client->dev.of_node)
 919                 ds1307_trickle_of_init(client, chip);
 920         else if (pdata && pdata->trickle_charger_setup)
 921                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
 922
 923         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
 924                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
 925                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
 926                     chip->trickle_charger_reg);
 927                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 928                     DS13XX_TRICKLE_CHARGER_MAGIC |
 929                     chip->trickle_charger_setup);
 930         }
 931
 932         buf = ds1307->regs;
 933         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 934                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
 935                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
 936         } else {
 937                 ds1307->read_block_data = ds1307_read_block_data;
 938                 ds1307->write_block_data = ds1307_write_block_data;
 939         }
 940
 941         switch (ds1307->type) {
 942         case ds_1337:
 943         case ds_1339:
 944         case ds_3231:
 945                 /* get registers that the "rtc" read below won't read... */
 946                 tmp = ds1307->read_block_data(ds1307->client,
 947                                 DS1337_REG_CONTROL, 2, buf);
 948                 if (tmp != 2) {
 949                         dev_dbg(&client->dev, "read error %d\n", tmp);
 950                         err = -EIO;
 951                         goto exit;
 952                 }
 953
 954                 /* oscillator off?  turn it on, so clock can tick. */
 955                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 956                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 957
 958                 /*
 959                  * Using IRQ?  Disable the square wave and both alarms.
 960                  * For some variants, be sure alarms can trigger when we're
 961                  * running on Vbackup (BBSQI/BBSQW)
 962                  */
 963                 if (ds1307->client->irq > 0 && chip->alarm) {
 964                         INIT_WORK(&ds1307->work, ds1307_work);
 965
 966                         ds1307->regs[0] |= DS1337_BIT_INTCN
 967                                         | bbsqi_bitpos[ds1307->type];
 968                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 969
 970                         want_irq = true;
 971                 }
 972
 973                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 974                                                         ds1307->regs[0]);
 975
 976                 /* oscillator fault?  clear flag, and warn */
 977                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 978                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 979                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 980                         dev_warn(&client->dev, "SET TIME!\n");
 981                 }
 982                 break;
 983
 984         case rx_8025:
 985                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 986                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 987                 if (tmp != 2) {
 988                         dev_dbg(&client->dev, "read error %d\n", tmp);
 989                         err = -EIO;
 990                         goto exit;
 991                 }
 992
 993                 /* oscillator off?  turn it on, so clock can tick. */
 994                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 995                         ds1307->regs[1] |= RX8025_BIT_XST;
 996                         i2c_smbus_write_byte_data(client,
 997                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 998                                                   ds1307->regs[1]);
 999                         dev_warn(&client->dev,
1000                                  "oscillator stop detected - SET TIME!\n");
1001                 }
1002
1003                 if (ds1307->regs[1] & RX8025_BIT_PON) {
1004                         ds1307->regs[1] &= ~RX8025_BIT_PON;
1005                         i2c_smbus_write_byte_data(client,
1006                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1007                                                   ds1307->regs[1]);
1008                         dev_warn(&client->dev, "power-on detected\n");
1009                 }
1010
1011                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
1012                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
1013                         i2c_smbus_write_byte_data(client,
1014                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1015                                                   ds1307->regs[1]);
1016                         dev_warn(&client->dev, "voltage drop detected\n");
1017                 }
1018
1019                 /* make sure we are running in 24hour mode */
1020                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1021                         u8 hour;
1022
1023                         /* switch to 24 hour mode */
1024                         i2c_smbus_write_byte_data(client,
1025                                                   RX8025_REG_CTRL1 << 4 | 0x08,
1026                                                   ds1307->regs[0] |
1027                                                   RX8025_BIT_2412);
1028
1029                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1030                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1031                         if (tmp != 2) {
1032                                 dev_dbg(&client->dev, "read error %d\n", tmp);
1033                                 err = -EIO;
1034                                 goto exit;
1035                         }
1036
1037                         /* correct hour */
1038                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1039                         if (hour == 12)
1040                                 hour = 0;
1041                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1042                                 hour += 12;
1043
1044                         i2c_smbus_write_byte_data(client,
1045                                                   DS1307_REG_HOUR << 4 | 0x08,
1046                                                   hour);
1047                 }
1048                 break;
1049         case ds_1388:
1050                 ds1307->offset = 1; /* Seconds starts at 1 */
1051                 break;
1052         case mcp7941x:
1053                 rtc_ops = &mcp7941x_rtc_ops;
1054                 if (ds1307->client->irq > 0 && chip->alarm) {
1055                         INIT_WORK(&ds1307->work, mcp7941x_work);
1056                         want_irq = true;
1057                 }
1058                 break;
1059         default:
1060                 break;
1061         }
1062
1063 read_rtc:
1064         /* read RTC registers */
1065         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1066         if (tmp != 8) {
1067                 dev_dbg(&client->dev, "read error %d\n", tmp);
1068                 err = -EIO;
1069                 goto exit;
1070         }
1071
1072         /*
1073          * minimal sanity checking; some chips (like DS1340) don't
1074          * specify the extra bits as must-be-zero, but there are
1075          * still a few values that are clearly out-of-range.
1076          */
1077         tmp = ds1307->regs[DS1307_REG_SECS];
1078         switch (ds1307->type) {
1079         case ds_1307:
1080         case m41t00:
1081                 /* clock halted?  turn it on, so clock can tick. */
1082                 if (tmp & DS1307_BIT_CH) {
1083                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1084                         dev_warn(&client->dev, "SET TIME!\n");
1085                         goto read_rtc;
1086                 }
1087                 break;
1088         case ds_1338:
1089                 /* clock halted?  turn it on, so clock can tick. */
1090                 if (tmp & DS1307_BIT_CH)
1091                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1092
1093                 /* oscillator fault?  clear flag, and warn */
1094                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1095                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1096                                         ds1307->regs[DS1307_REG_CONTROL]
1097                                         & ~DS1338_BIT_OSF);
1098                         dev_warn(&client->dev, "SET TIME!\n");
1099                         goto read_rtc;
1100                 }
1101                 break;
1102         case ds_1340:
1103                 /* clock halted?  turn it on, so clock can tick. */
1104                 if (tmp & DS1340_BIT_nEOSC)
1105                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1106
1107                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1108                 if (tmp < 0) {
1109                         dev_dbg(&client->dev, "read error %d\n", tmp);
1110                         err = -EIO;
1111                         goto exit;
1112                 }
1113
1114                 /* oscillator fault?  clear flag, and warn */
1115                 if (tmp & DS1340_BIT_OSF) {
1116                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1117                         dev_warn(&client->dev, "SET TIME!\n");
1118                 }
1119                 break;
1120         case mcp7941x:
1121                 /* make sure that the backup battery is enabled */
1122                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
1123                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1124                                         ds1307->regs[DS1307_REG_WDAY]
1125                                         | MCP7941X_BIT_VBATEN);
1126                 }
1127
1128                 /* clock halted?  turn it on, so clock can tick. */
1129                 if (!(tmp & MCP7941X_BIT_ST)) {
1130                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1131                                         MCP7941X_BIT_ST);
1132                         dev_warn(&client->dev, "SET TIME!\n");
1133                         goto read_rtc;
1134                 }
1135
1136                 break;
1137         default:
1138                 break;
1139         }
1140
1141         tmp = ds1307->regs[DS1307_REG_HOUR];
1142         switch (ds1307->type) {
1143         case ds_1340:
1144         case m41t00:
1145                 /*
1146                  * NOTE: ignores century bits; fix before deploying
1147                  * systems that will run through year 2100.
1148                  */
1149                 break;
1150         case rx_8025:
1151                 break;
1152         default:
1153                 if (!(tmp & DS1307_BIT_12HR))
1154                         break;
1155
1156                 /*
1157                  * Be sure we're in 24 hour mode.  Multi-master systems
1158                  * take note...
1159                  */
1160                 tmp = bcd2bin(tmp & 0x1f);
1161                 if (tmp == 12)
1162                         tmp = 0;
1163                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1164                         tmp += 12;
1165                 i2c_smbus_write_byte_data(client,
1166                                 ds1307->offset + DS1307_REG_HOUR,
1167                                 bin2bcd(tmp));
1168         }
1169
1170         device_set_wakeup_capable(&client->dev, want_irq);
1171         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1172                                 rtc_ops, THIS_MODULE);
1173         if (IS_ERR(ds1307->rtc)) {
1174                 return PTR_ERR(ds1307->rtc);
1175         }
1176
1177         if (want_irq) {
1178                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
1179                           ds1307->rtc->name, client);
1180                 if (err) {
1181                         client->irq = 0;
1182                         dev_err(&client->dev, "unable to request IRQ!\n");
1183                 } else {
1184
1185                         set_bit(HAS_ALARM, &ds1307->flags);
1186                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1187                 }
1188         }
1189
1190         if (chip->nvram_size) {
1191
1192                 ds1307->nvram = devm_kzalloc(&client->dev,
1193                                         sizeof(struct bin_attribute),
1194                                         GFP_KERNEL);
1195                 if (!ds1307->nvram) {
1196                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1197                 } else {
1198
1199                         ds1307->nvram->attr.name = "nvram";
1200                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1201
1202                         sysfs_bin_attr_init(ds1307->nvram);
1203
1204                         ds1307->nvram->read = ds1307_nvram_read;
1205                         ds1307->nvram->write = ds1307_nvram_write;
1206                         ds1307->nvram->size = chip->nvram_size;
1207                         ds1307->nvram_offset = chip->nvram_offset;
1208
1209                         err = sysfs_create_bin_file(&client->dev.kobj,
1210                                                     ds1307->nvram);
1211                         if (err) {
1212                                 dev_err(&client->dev,
1213                                         "unable to create sysfs file: %s\n",
1214                                         ds1307->nvram->attr.name);
1215                         } else {
1216                                 set_bit(HAS_NVRAM, &ds1307->flags);
1217                                 dev_info(&client->dev, "%zu bytes nvram\n",
1218                                          ds1307->nvram->size);
1219                         }
1220                 }
1221         }
1222
1223         return 0;
1224
1225 exit:
1226         return err;
1227 }
1228
1229 static int ds1307_remove(struct i2c_client *client)
1230 {
1231         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1232
1233         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
1234                 free_irq(client->irq, client);
1235                 cancel_work_sync(&ds1307->work);
1236         }
1237
1238         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1239                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1240
1241         return 0;
1242 }
1243
1244 static struct i2c_driver ds1307_driver = {
1245         .driver = {
1246                 .name   = "rtc-ds1307",
1247                 .owner  = THIS_MODULE,
1248         },
1249         .probe          = ds1307_probe,
1250         .remove         = ds1307_remove,
1251         .id_table       = ds1307_id,
1252 };
1253
1254 module_i2c_driver(ds1307_driver);
1255
1256 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1257 MODULE_LICENSE("GPL");