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         mcp794xx,
  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 MCP794XX_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 MCP794XX_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         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 118                                u8 length, u8 *values);
 119         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 120                                 u8 length, const u8 *values);
 121 };
 122
 123 struct chip_desc {
 124         unsigned                alarm:1;
 125         u16                     nvram_offset;
 126         u16                     nvram_size;
 127         u16                     trickle_charger_reg;
 128         u8                      trickle_charger_setup;
 129         u8                      (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
 130 };
 131
 132 static u8 do_trickle_setup_ds1339(struct i2c_client *,
 133                                   uint32_t ohms, bool diode);
 134
 135 static struct chip_desc chips[last_ds_type] = {
 136         [ds_1307] = {
 137                 .nvram_offset   = 8,
 138                 .nvram_size     = 56,
 139         },
 140         [ds_1337] = {
 141                 .alarm          = 1,
 142         },
 143         [ds_1338] = {
 144                 .nvram_offset   = 8,
 145                 .nvram_size     = 56,
 146         },
 147         [ds_1339] = {
 148                 .alarm          = 1,
 149                 .trickle_charger_reg = 0x10,
 150                 .do_trickle_setup = &do_trickle_setup_ds1339,
 151         },
 152         [ds_1340] = {
 153                 .trickle_charger_reg = 0x08,
 154         },
 155         [ds_1388] = {
 156                 .trickle_charger_reg = 0x0a,
 157         },
 158         [ds_3231] = {
 159                 .alarm          = 1,
 160         },
 161         [mcp794xx] = {
 162                 .alarm          = 1,
 163                 /* this is battery backed SRAM */
 164                 .nvram_offset   = 0x20,
 165                 .nvram_size     = 0x40,
 166         },
 167 };
 168
 169 static const struct i2c_device_id ds1307_id[] = {
 170         { "ds1307", ds_1307 },
 171         { "ds1337", ds_1337 },
 172         { "ds1338", ds_1338 },
 173         { "ds1339", ds_1339 },
 174         { "ds1388", ds_1388 },
 175         { "ds1340", ds_1340 },
 176         { "ds3231", ds_3231 },
 177         { "m41t00", m41t00 },
 178         { "mcp7940x", mcp794xx },
 179         { "mcp7941x", mcp794xx },
 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 ds1337 and ds1339 both have two alarms, but we only use the first
 314  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 315  * signal; ds1339 chips have only one alarm signal.
 316  */
 317 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 318 {
 319         struct i2c_client       *client = dev_id;
 320         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 321         struct mutex            *lock = &ds1307->rtc->ops_lock;
 322         int                     stat, control;
 323
 324         mutex_lock(lock);
 325         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 326         if (stat < 0)
 327                 goto out;
 328
 329         if (stat & DS1337_BIT_A1I) {
 330                 stat &= ~DS1337_BIT_A1I;
 331                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 332
 333                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 334                 if (control < 0)
 335                         goto out;
 336
 337                 control &= ~DS1337_BIT_A1IE;
 338                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 339
 340                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 341         }
 342
 343 out:
 344         mutex_unlock(lock);
 345
 346         return IRQ_HANDLED;
 347 }
 348
 349 /*----------------------------------------------------------------------*/
 350
 351 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 352 {
 353         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 354         int             tmp;
 355
 356         /* read the RTC date and time registers all at once */
 357         tmp = ds1307->read_block_data(ds1307->client,
 358                 ds1307->offset, 7, ds1307->regs);
 359         if (tmp != 7) {
 360                 dev_err(dev, "%s error %d\n", "read", tmp);
 361                 return -EIO;
 362         }
 363
 364         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 365
 366         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 367         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 368         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 369         t->tm_hour = bcd2bin(tmp);
 370         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 371         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 372         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 373         t->tm_mon = bcd2bin(tmp) - 1;
 374
 375         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 376         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 377
 378         dev_dbg(dev, "%s secs=%d, mins=%d, "
 379                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 380                 "read", t->tm_sec, t->tm_min,
 381                 t->tm_hour, t->tm_mday,
 382                 t->tm_mon, t->tm_year, t->tm_wday);
 383
 384         /* initial clock setting can be undefined */
 385         return rtc_valid_tm(t);
 386 }
 387
 388 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 389 {
 390         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 391         int             result;
 392         int             tmp;
 393         u8              *buf = ds1307->regs;
 394
 395         dev_dbg(dev, "%s secs=%d, mins=%d, "
 396                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 397                 "write", t->tm_sec, t->tm_min,
 398                 t->tm_hour, t->tm_mday,
 399                 t->tm_mon, t->tm_year, t->tm_wday);
 400
 401         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 402         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 403         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 404         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 405         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 406         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 407
 408         /* assume 20YY not 19YY */
 409         tmp = t->tm_year - 100;
 410         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 411
 412         switch (ds1307->type) {
 413         case ds_1337:
 414         case ds_1339:
 415         case ds_3231:
 416                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 417                 break;
 418         case ds_1340:
 419                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 420                                 | DS1340_BIT_CENTURY;
 421                 break;
 422         case mcp794xx:
 423                 /*
 424                  * these bits were cleared when preparing the date/time
 425                  * values and need to be set again before writing the
 426                  * buffer out to the device.
 427                  */
 428                 buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
 429                 buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
 430                 break;
 431         default:
 432                 break;
 433         }
 434
 435         dev_dbg(dev, "%s: %7ph\n", "write", buf);
 436
 437         result = ds1307->write_block_data(ds1307->client,
 438                 ds1307->offset, 7, buf);
 439         if (result < 0) {
 440                 dev_err(dev, "%s error %d\n", "write", result);
 441                 return result;
 442         }
 443         return 0;
 444 }
 445
 446 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 447 {
 448         struct i2c_client       *client = to_i2c_client(dev);
 449         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 450         int                     ret;
 451
 452         if (!test_bit(HAS_ALARM, &ds1307->flags))
 453                 return -EINVAL;
 454
 455         /* read all ALARM1, ALARM2, and status registers at once */
 456         ret = ds1307->read_block_data(client,
 457                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 458         if (ret != 9) {
 459                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 460                 return -EIO;
 461         }
 462
 463         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 464                         "alarm read",
 465                         ds1307->regs[0], ds1307->regs[1],
 466                         ds1307->regs[2], ds1307->regs[3],
 467                         ds1307->regs[4], ds1307->regs[5],
 468                         ds1307->regs[6], ds1307->regs[7],
 469                         ds1307->regs[8]);
 470
 471         /*
 472          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 473          * and that all four fields are checked matches
 474          */
 475         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 476         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 477         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 478         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 479         t->time.tm_mon = -1;
 480         t->time.tm_year = -1;
 481         t->time.tm_wday = -1;
 482         t->time.tm_yday = -1;
 483         t->time.tm_isdst = -1;
 484
 485         /* ... and status */
 486         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 487         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 488
 489         dev_dbg(dev, "%s secs=%d, mins=%d, "
 490                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 491                 "alarm read", t->time.tm_sec, t->time.tm_min,
 492                 t->time.tm_hour, t->time.tm_mday,
 493                 t->enabled, t->pending);
 494
 495         return 0;
 496 }
 497
 498 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 499 {
 500         struct i2c_client       *client = to_i2c_client(dev);
 501         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 502         unsigned char           *buf = ds1307->regs;
 503         u8                      control, status;
 504         int                     ret;
 505
 506         if (!test_bit(HAS_ALARM, &ds1307->flags))
 507                 return -EINVAL;
 508
 509         dev_dbg(dev, "%s secs=%d, mins=%d, "
 510                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 511                 "alarm set", t->time.tm_sec, t->time.tm_min,
 512                 t->time.tm_hour, t->time.tm_mday,
 513                 t->enabled, t->pending);
 514
 515         /* read current status of both alarms and the chip */
 516         ret = ds1307->read_block_data(client,
 517                         DS1339_REG_ALARM1_SECS, 9, buf);
 518         if (ret != 9) {
 519                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 520                 return -EIO;
 521         }
 522         control = ds1307->regs[7];
 523         status = ds1307->regs[8];
 524
 525         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 526                         "alarm set (old status)",
 527                         ds1307->regs[0], ds1307->regs[1],
 528                         ds1307->regs[2], ds1307->regs[3],
 529                         ds1307->regs[4], ds1307->regs[5],
 530                         ds1307->regs[6], control, status);
 531
 532         /* set ALARM1, using 24 hour and day-of-month modes */
 533         buf[0] = bin2bcd(t->time.tm_sec);
 534         buf[1] = bin2bcd(t->time.tm_min);
 535         buf[2] = bin2bcd(t->time.tm_hour);
 536         buf[3] = bin2bcd(t->time.tm_mday);
 537
 538         /* set ALARM2 to non-garbage */
 539         buf[4] = 0;
 540         buf[5] = 0;
 541         buf[6] = 0;
 542
 543         /* optionally enable ALARM1 */
 544         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 545         if (t->enabled) {
 546                 dev_dbg(dev, "alarm IRQ armed\n");
 547                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 548         }
 549         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 550
 551         ret = ds1307->write_block_data(client,
 552                         DS1339_REG_ALARM1_SECS, 9, buf);
 553         if (ret < 0) {
 554                 dev_err(dev, "can't set alarm time\n");
 555                 return ret;
 556         }
 557
 558         return 0;
 559 }
 560
 561 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 562 {
 563         struct i2c_client       *client = to_i2c_client(dev);
 564         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 565         int                     ret;
 566
 567         if (!test_bit(HAS_ALARM, &ds1307->flags))
 568                 return -ENOTTY;
 569
 570         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 571         if (ret < 0)
 572                 return ret;
 573
 574         if (enabled)
 575                 ret |= DS1337_BIT_A1IE;
 576         else
 577                 ret &= ~DS1337_BIT_A1IE;
 578
 579         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 580         if (ret < 0)
 581                 return ret;
 582
 583         return 0;
 584 }
 585
 586 static const struct rtc_class_ops ds13xx_rtc_ops = {
 587         .read_time      = ds1307_get_time,
 588         .set_time       = ds1307_set_time,
 589         .read_alarm     = ds1337_read_alarm,
 590         .set_alarm      = ds1337_set_alarm,
 591         .alarm_irq_enable = ds1307_alarm_irq_enable,
 592 };
 593
 594 /*----------------------------------------------------------------------*/
 595
 596 /*
 597  * Alarm support for mcp794xx devices.
 598  */
 599
 600 #define MCP794XX_REG_CONTROL            0x07
 601 #       define MCP794XX_BIT_ALM0_EN     0x10
 602 #       define MCP794XX_BIT_ALM1_EN     0x20
 603 #define MCP794XX_REG_ALARM0_BASE        0x0a
 604 #define MCP794XX_REG_ALARM0_CTRL        0x0d
 605 #define MCP794XX_REG_ALARM1_BASE        0x11
 606 #define MCP794XX_REG_ALARM1_CTRL        0x14
 607 #       define MCP794XX_BIT_ALMX_IF     (1 << 3)
 608 #       define MCP794XX_BIT_ALMX_C0     (1 << 4)
 609 #       define MCP794XX_BIT_ALMX_C1     (1 << 5)
 610 #       define MCP794XX_BIT_ALMX_C2     (1 << 6)
 611 #       define MCP794XX_BIT_ALMX_POL    (1 << 7)
 612 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
 613                                          MCP794XX_BIT_ALMX_C1 | \
 614                                          MCP794XX_BIT_ALMX_C2)
 615
 616 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 617 {
 618         struct i2c_client       *client = dev_id;
 619         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 620         struct mutex            *lock = &ds1307->rtc->ops_lock;
 621         int reg, ret;
 622
 623         mutex_lock(lock);
 624
 625         /* Check and clear alarm 0 interrupt flag. */
 626         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
 627         if (reg < 0)
 628                 goto out;
 629         if (!(reg & MCP794XX_BIT_ALMX_IF))
 630                 goto out;
 631         reg &= ~MCP794XX_BIT_ALMX_IF;
 632         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
 633         if (ret < 0)
 634                 goto out;
 635
 636         /* Disable alarm 0. */
 637         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
 638         if (reg < 0)
 639                 goto out;
 640         reg &= ~MCP794XX_BIT_ALM0_EN;
 641         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
 642         if (ret < 0)
 643                 goto out;
 644
 645         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 646
 647 out:
 648         mutex_unlock(lock);
 649
 650         return IRQ_HANDLED;
 651 }
 652
 653 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 654 {
 655         struct i2c_client *client = to_i2c_client(dev);
 656         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 657         u8 *regs = ds1307->regs;
 658         int ret;
 659
 660         if (!test_bit(HAS_ALARM, &ds1307->flags))
 661                 return -EINVAL;
 662
 663         /* Read control and alarm 0 registers. */
 664         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 665         if (ret < 0)
 666                 return ret;
 667
 668         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 669
 670         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 671         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
 672         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
 673         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
 674         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
 675         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
 676         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
 677         t->time.tm_year = -1;
 678         t->time.tm_yday = -1;
 679         t->time.tm_isdst = -1;
 680
 681         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 682                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
 683                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 684                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 685                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
 686                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
 687                 (ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 688
 689         return 0;
 690 }
 691
 692 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 693 {
 694         struct i2c_client *client = to_i2c_client(dev);
 695         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 696         unsigned char *regs = ds1307->regs;
 697         int ret;
 698
 699         if (!test_bit(HAS_ALARM, &ds1307->flags))
 700                 return -EINVAL;
 701
 702         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 703                 "enabled=%d pending=%d\n", __func__,
 704                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 705                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 706                 t->enabled, t->pending);
 707
 708         /* Read control and alarm 0 registers. */
 709         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 710         if (ret < 0)
 711                 return ret;
 712
 713         /* Set alarm 0, using 24-hour and day-of-month modes. */
 714         regs[3] = bin2bcd(t->time.tm_sec);
 715         regs[4] = bin2bcd(t->time.tm_min);
 716         regs[5] = bin2bcd(t->time.tm_hour);
 717         regs[6] = bin2bcd(t->time.tm_wday) + 1;
 718         regs[7] = bin2bcd(t->time.tm_mday);
 719         regs[8] = bin2bcd(t->time.tm_mon) + 1;
 720
 721         /* Clear the alarm 0 interrupt flag. */
 722         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 723         /* Set alarm match: second, minute, hour, day, date, month. */
 724         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 725         /* Disable interrupt. We will not enable until completely programmed */
 726         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 727
 728         ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 729         if (ret < 0)
 730                 return ret;
 731
 732         if (!t->enabled)
 733                 return 0;
 734         regs[0] |= MCP794XX_BIT_ALM0_EN;
 735         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
 736 }
 737
 738 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 739 {
 740         struct i2c_client *client = to_i2c_client(dev);
 741         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 742         int reg;
 743
 744         if (!test_bit(HAS_ALARM, &ds1307->flags))
 745                 return -EINVAL;
 746
 747         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
 748         if (reg < 0)
 749                 return reg;
 750
 751         if (enabled)
 752                 reg |= MCP794XX_BIT_ALM0_EN;
 753         else
 754                 reg &= ~MCP794XX_BIT_ALM0_EN;
 755
 756         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
 757 }
 758
 759 static const struct rtc_class_ops mcp794xx_rtc_ops = {
 760         .read_time      = ds1307_get_time,
 761         .set_time       = ds1307_set_time,
 762         .read_alarm     = mcp794xx_read_alarm,
 763         .set_alarm      = mcp794xx_set_alarm,
 764         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
 765 };
 766
 767 /*----------------------------------------------------------------------*/
 768
 769 static ssize_t
 770 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 771                 struct bin_attribute *attr,
 772                 char *buf, loff_t off, size_t count)
 773 {
 774         struct i2c_client       *client;
 775         struct ds1307           *ds1307;
 776         int                     result;
 777
 778         client = kobj_to_i2c_client(kobj);
 779         ds1307 = i2c_get_clientdata(client);
 780
 781         if (unlikely(off >= ds1307->nvram->size))
 782                 return 0;
 783         if ((off + count) > ds1307->nvram->size)
 784                 count = ds1307->nvram->size - off;
 785         if (unlikely(!count))
 786                 return count;
 787
 788         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 789                                                                 count, buf);
 790         if (result < 0)
 791                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 792         return result;
 793 }
 794
 795 static ssize_t
 796 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 797                 struct bin_attribute *attr,
 798                 char *buf, loff_t off, size_t count)
 799 {
 800         struct i2c_client       *client;
 801         struct ds1307           *ds1307;
 802         int                     result;
 803
 804         client = kobj_to_i2c_client(kobj);
 805         ds1307 = i2c_get_clientdata(client);
 806
 807         if (unlikely(off >= ds1307->nvram->size))
 808                 return -EFBIG;
 809         if ((off + count) > ds1307->nvram->size)
 810                 count = ds1307->nvram->size - off;
 811         if (unlikely(!count))
 812                 return count;
 813
 814         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 815                                                                 count, buf);
 816         if (result < 0) {
 817                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 818                 return result;
 819         }
 820         return count;
 821 }
 822
 823
 824 /*----------------------------------------------------------------------*/
 825
 826 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
 827                                   uint32_t ohms, bool diode)
 828 {
 829         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 830                 DS1307_TRICKLE_CHARGER_NO_DIODE;
 831
 832         switch (ohms) {
 833         case 250:
 834                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 835                 break;
 836         case 2000:
 837                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 838                 break;
 839         case 4000:
 840                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 841                 break;
 842         default:
 843                 dev_warn(&client->dev,
 844                          "Unsupported ohm value %u in dt\n", ohms);
 845                 return 0;
 846         }
 847         return setup;
 848 }
 849
 850 static void ds1307_trickle_of_init(struct i2c_client *client,
 851                                    struct chip_desc *chip)
 852 {
 853         uint32_t ohms = 0;
 854         bool diode = true;
 855
 856         if (!chip->do_trickle_setup)
 857                 goto out;
 858         if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
 859                 goto out;
 860         if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
 861                 diode = false;
 862         chip->trickle_charger_setup = chip->do_trickle_setup(client,
 863                                                              ohms, diode);
 864 out:
 865         return;
 866 }
 867
 868 static int ds1307_probe(struct i2c_client *client,
 869                         const struct i2c_device_id *id)
 870 {
 871         struct ds1307           *ds1307;
 872         int                     err = -ENODEV;
 873         int                     tmp;
 874         struct chip_desc        *chip = &chips[id->driver_data];
 875         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 876         bool                    want_irq = false;
 877         unsigned char           *buf;
 878         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
 879         irq_handler_t   irq_handler = ds1307_irq;
 880
 881         static const int        bbsqi_bitpos[] = {
 882                 [ds_1337] = 0,
 883                 [ds_1339] = DS1339_BIT_BBSQI,
 884                 [ds_3231] = DS3231_BIT_BBSQW,
 885         };
 886         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
 887
 888         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 889             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 890                 return -EIO;
 891
 892         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
 893         if (!ds1307)
 894                 return -ENOMEM;
 895
 896         i2c_set_clientdata(client, ds1307);
 897
 898         ds1307->client  = client;
 899         ds1307->type    = id->driver_data;
 900
 901         if (!pdata && client->dev.of_node)
 902                 ds1307_trickle_of_init(client, chip);
 903         else if (pdata && pdata->trickle_charger_setup)
 904                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
 905
 906         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
 907                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
 908                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
 909                     chip->trickle_charger_reg);
 910                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 911                     DS13XX_TRICKLE_CHARGER_MAGIC |
 912                     chip->trickle_charger_setup);
 913         }
 914
 915         buf = ds1307->regs;
 916         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 917                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
 918                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
 919         } else {
 920                 ds1307->read_block_data = ds1307_read_block_data;
 921                 ds1307->write_block_data = ds1307_write_block_data;
 922         }
 923
 924         switch (ds1307->type) {
 925         case ds_1337:
 926         case ds_1339:
 927         case ds_3231:
 928                 /* get registers that the "rtc" read below won't read... */
 929                 tmp = ds1307->read_block_data(ds1307->client,
 930                                 DS1337_REG_CONTROL, 2, buf);
 931                 if (tmp != 2) {
 932                         dev_dbg(&client->dev, "read error %d\n", tmp);
 933                         err = -EIO;
 934                         goto exit;
 935                 }
 936
 937                 /* oscillator off?  turn it on, so clock can tick. */
 938                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 939                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 940
 941                 /*
 942                  * Using IRQ?  Disable the square wave and both alarms.
 943                  * For some variants, be sure alarms can trigger when we're
 944                  * running on Vbackup (BBSQI/BBSQW)
 945                  */
 946                 if (ds1307->client->irq > 0 && chip->alarm) {
 947                         ds1307->regs[0] |= DS1337_BIT_INTCN
 948                                         | bbsqi_bitpos[ds1307->type];
 949                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 950
 951                         want_irq = true;
 952                 }
 953
 954                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 955                                                         ds1307->regs[0]);
 956
 957                 /* oscillator fault?  clear flag, and warn */
 958                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 959                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 960                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 961                         dev_warn(&client->dev, "SET TIME!\n");
 962                 }
 963                 break;
 964
 965         case rx_8025:
 966                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 967                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 968                 if (tmp != 2) {
 969                         dev_dbg(&client->dev, "read error %d\n", tmp);
 970                         err = -EIO;
 971                         goto exit;
 972                 }
 973
 974                 /* oscillator off?  turn it on, so clock can tick. */
 975                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 976                         ds1307->regs[1] |= RX8025_BIT_XST;
 977                         i2c_smbus_write_byte_data(client,
 978                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 979                                                   ds1307->regs[1]);
 980                         dev_warn(&client->dev,
 981                                  "oscillator stop detected - SET TIME!\n");
 982                 }
 983
 984                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 985                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 986                         i2c_smbus_write_byte_data(client,
 987                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 988                                                   ds1307->regs[1]);
 989                         dev_warn(&client->dev, "power-on detected\n");
 990                 }
 991
 992                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 993                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 994                         i2c_smbus_write_byte_data(client,
 995                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 996                                                   ds1307->regs[1]);
 997                         dev_warn(&client->dev, "voltage drop detected\n");
 998                 }
 999
1000                 /* make sure we are running in 24hour mode */
1001                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1002                         u8 hour;
1003
1004                         /* switch to 24 hour mode */
1005                         i2c_smbus_write_byte_data(client,
1006                                                   RX8025_REG_CTRL1 << 4 | 0x08,
1007                                                   ds1307->regs[0] |
1008                                                   RX8025_BIT_2412);
1009
1010                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1011                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1012                         if (tmp != 2) {
1013                                 dev_dbg(&client->dev, "read error %d\n", tmp);
1014                                 err = -EIO;
1015                                 goto exit;
1016                         }
1017
1018                         /* correct hour */
1019                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1020                         if (hour == 12)
1021                                 hour = 0;
1022                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1023                                 hour += 12;
1024
1025                         i2c_smbus_write_byte_data(client,
1026                                                   DS1307_REG_HOUR << 4 | 0x08,
1027                                                   hour);
1028                 }
1029                 break;
1030         case ds_1388:
1031                 ds1307->offset = 1; /* Seconds starts at 1 */
1032                 break;
1033         case mcp794xx:
1034                 rtc_ops = &mcp794xx_rtc_ops;
1035                 if (ds1307->client->irq > 0 && chip->alarm) {
1036                         irq_handler = mcp794xx_irq;
1037                         want_irq = true;
1038                 }
1039                 break;
1040         default:
1041                 break;
1042         }
1043
1044 read_rtc:
1045         /* read RTC registers */
1046         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1047         if (tmp != 8) {
1048                 dev_dbg(&client->dev, "read error %d\n", tmp);
1049                 err = -EIO;
1050                 goto exit;
1051         }
1052
1053         /*
1054          * minimal sanity checking; some chips (like DS1340) don't
1055          * specify the extra bits as must-be-zero, but there are
1056          * still a few values that are clearly out-of-range.
1057          */
1058         tmp = ds1307->regs[DS1307_REG_SECS];
1059         switch (ds1307->type) {
1060         case ds_1307:
1061         case m41t00:
1062                 /* clock halted?  turn it on, so clock can tick. */
1063                 if (tmp & DS1307_BIT_CH) {
1064                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1065                         dev_warn(&client->dev, "SET TIME!\n");
1066                         goto read_rtc;
1067                 }
1068                 break;
1069         case ds_1338:
1070                 /* clock halted?  turn it on, so clock can tick. */
1071                 if (tmp & DS1307_BIT_CH)
1072                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1073
1074                 /* oscillator fault?  clear flag, and warn */
1075                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1076                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1077                                         ds1307->regs[DS1307_REG_CONTROL]
1078                                         & ~DS1338_BIT_OSF);
1079                         dev_warn(&client->dev, "SET TIME!\n");
1080                         goto read_rtc;
1081                 }
1082                 break;
1083         case ds_1340:
1084                 /* clock halted?  turn it on, so clock can tick. */
1085                 if (tmp & DS1340_BIT_nEOSC)
1086                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1087
1088                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1089                 if (tmp < 0) {
1090                         dev_dbg(&client->dev, "read error %d\n", tmp);
1091                         err = -EIO;
1092                         goto exit;
1093                 }
1094
1095                 /* oscillator fault?  clear flag, and warn */
1096                 if (tmp & DS1340_BIT_OSF) {
1097                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1098                         dev_warn(&client->dev, "SET TIME!\n");
1099                 }
1100                 break;
1101         case mcp794xx:
1102                 /* make sure that the backup battery is enabled */
1103                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1104                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1105                                         ds1307->regs[DS1307_REG_WDAY]
1106                                         | MCP794XX_BIT_VBATEN);
1107                 }
1108
1109                 /* clock halted?  turn it on, so clock can tick. */
1110                 if (!(tmp & MCP794XX_BIT_ST)) {
1111                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1112                                         MCP794XX_BIT_ST);
1113                         dev_warn(&client->dev, "SET TIME!\n");
1114                         goto read_rtc;
1115                 }
1116
1117                 break;
1118         default:
1119                 break;
1120         }
1121
1122         tmp = ds1307->regs[DS1307_REG_HOUR];
1123         switch (ds1307->type) {
1124         case ds_1340:
1125         case m41t00:
1126                 /*
1127                  * NOTE: ignores century bits; fix before deploying
1128                  * systems that will run through year 2100.
1129                  */
1130                 break;
1131         case rx_8025:
1132                 break;
1133         default:
1134                 if (!(tmp & DS1307_BIT_12HR))
1135                         break;
1136
1137                 /*
1138                  * Be sure we're in 24 hour mode.  Multi-master systems
1139                  * take note...
1140                  */
1141                 tmp = bcd2bin(tmp & 0x1f);
1142                 if (tmp == 12)
1143                         tmp = 0;
1144                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1145                         tmp += 12;
1146                 i2c_smbus_write_byte_data(client,
1147                                 ds1307->offset + DS1307_REG_HOUR,
1148                                 bin2bcd(tmp));
1149         }
1150
1151         device_set_wakeup_capable(&client->dev, want_irq);
1152         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1153                                 rtc_ops, THIS_MODULE);
1154         if (IS_ERR(ds1307->rtc)) {
1155                 return PTR_ERR(ds1307->rtc);
1156         }
1157
1158         if (want_irq) {
1159                 err = request_threaded_irq(client->irq, NULL, irq_handler,
1160                                            IRQF_SHARED | IRQF_ONESHOT,
1161                                            ds1307->rtc->name, client);
1162                 if (err) {
1163                         client->irq = 0;
1164                         dev_err(&client->dev, "unable to request IRQ!\n");
1165                 } else {
1166
1167                         set_bit(HAS_ALARM, &ds1307->flags);
1168                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1169                 }
1170         }
1171
1172         if (chip->nvram_size) {
1173
1174                 ds1307->nvram = devm_kzalloc(&client->dev,
1175                                         sizeof(struct bin_attribute),
1176                                         GFP_KERNEL);
1177                 if (!ds1307->nvram) {
1178                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1179                 } else {
1180
1181                         ds1307->nvram->attr.name = "nvram";
1182                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1183
1184                         sysfs_bin_attr_init(ds1307->nvram);
1185
1186                         ds1307->nvram->read = ds1307_nvram_read;
1187                         ds1307->nvram->write = ds1307_nvram_write;
1188                         ds1307->nvram->size = chip->nvram_size;
1189                         ds1307->nvram_offset = chip->nvram_offset;
1190
1191                         err = sysfs_create_bin_file(&client->dev.kobj,
1192                                                     ds1307->nvram);
1193                         if (err) {
1194                                 dev_err(&client->dev,
1195                                         "unable to create sysfs file: %s\n",
1196                                         ds1307->nvram->attr.name);
1197                         } else {
1198                                 set_bit(HAS_NVRAM, &ds1307->flags);
1199                                 dev_info(&client->dev, "%zu bytes nvram\n",
1200                                          ds1307->nvram->size);
1201                         }
1202                 }
1203         }
1204
1205         return 0;
1206
1207 exit:
1208         return err;
1209 }
1210
1211 static int ds1307_remove(struct i2c_client *client)
1212 {
1213         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1214
1215         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags))
1216                 free_irq(client->irq, client);
1217
1218         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1219                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1220
1221         return 0;
1222 }
1223
1224 static struct i2c_driver ds1307_driver = {
1225         .driver = {
1226                 .name   = "rtc-ds1307",
1227                 .owner  = THIS_MODULE,
1228         },
1229         .probe          = ds1307_probe,
1230         .remove         = ds1307_remove,
1231         .id_table       = ds1307_id,
1232 };
1233
1234 module_i2c_driver(ds1307_driver);
1235
1236 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1237 MODULE_LICENSE("GPL");