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/bcd.h>
  15 #include <linux/i2c.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/rtc/ds1307.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.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: %4ph, %3ph, %2ph\n", "alarm read",
 464                 &ds1307->regs[0], &ds1307->regs[4], &ds1307->regs[7]);
 465
 466         /*
 467          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 468          * and that all four fields are checked matches
 469          */
 470         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 471         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 472         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 473         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 474         t->time.tm_mon = -1;
 475         t->time.tm_year = -1;
 476         t->time.tm_wday = -1;
 477         t->time.tm_yday = -1;
 478         t->time.tm_isdst = -1;
 479
 480         /* ... and status */
 481         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 482         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 483
 484         dev_dbg(dev, "%s secs=%d, mins=%d, "
 485                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 486                 "alarm read", t->time.tm_sec, t->time.tm_min,
 487                 t->time.tm_hour, t->time.tm_mday,
 488                 t->enabled, t->pending);
 489
 490         return 0;
 491 }
 492
 493 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 494 {
 495         struct i2c_client       *client = to_i2c_client(dev);
 496         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 497         unsigned char           *buf = ds1307->regs;
 498         u8                      control, status;
 499         int                     ret;
 500
 501         if (!test_bit(HAS_ALARM, &ds1307->flags))
 502                 return -EINVAL;
 503
 504         dev_dbg(dev, "%s secs=%d, mins=%d, "
 505                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 506                 "alarm set", t->time.tm_sec, t->time.tm_min,
 507                 t->time.tm_hour, t->time.tm_mday,
 508                 t->enabled, t->pending);
 509
 510         /* read current status of both alarms and the chip */
 511         ret = ds1307->read_block_data(client,
 512                         DS1339_REG_ALARM1_SECS, 9, buf);
 513         if (ret != 9) {
 514                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 515                 return -EIO;
 516         }
 517         control = ds1307->regs[7];
 518         status = ds1307->regs[8];
 519
 520         dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
 521                 &ds1307->regs[0], &ds1307->regs[4], control, status);
 522
 523         /* set ALARM1, using 24 hour and day-of-month modes */
 524         buf[0] = bin2bcd(t->time.tm_sec);
 525         buf[1] = bin2bcd(t->time.tm_min);
 526         buf[2] = bin2bcd(t->time.tm_hour);
 527         buf[3] = bin2bcd(t->time.tm_mday);
 528
 529         /* set ALARM2 to non-garbage */
 530         buf[4] = 0;
 531         buf[5] = 0;
 532         buf[6] = 0;
 533
 534         /* optionally enable ALARM1 */
 535         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 536         if (t->enabled) {
 537                 dev_dbg(dev, "alarm IRQ armed\n");
 538                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 539         }
 540         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 541
 542         ret = ds1307->write_block_data(client,
 543                         DS1339_REG_ALARM1_SECS, 9, buf);
 544         if (ret < 0) {
 545                 dev_err(dev, "can't set alarm time\n");
 546                 return ret;
 547         }
 548
 549         return 0;
 550 }
 551
 552 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 553 {
 554         struct i2c_client       *client = to_i2c_client(dev);
 555         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 556         int                     ret;
 557
 558         if (!test_bit(HAS_ALARM, &ds1307->flags))
 559                 return -ENOTTY;
 560
 561         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 562         if (ret < 0)
 563                 return ret;
 564
 565         if (enabled)
 566                 ret |= DS1337_BIT_A1IE;
 567         else
 568                 ret &= ~DS1337_BIT_A1IE;
 569
 570         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 571         if (ret < 0)
 572                 return ret;
 573
 574         return 0;
 575 }
 576
 577 static const struct rtc_class_ops ds13xx_rtc_ops = {
 578         .read_time      = ds1307_get_time,
 579         .set_time       = ds1307_set_time,
 580         .read_alarm     = ds1337_read_alarm,
 581         .set_alarm      = ds1337_set_alarm,
 582         .alarm_irq_enable = ds1307_alarm_irq_enable,
 583 };
 584
 585 /*----------------------------------------------------------------------*/
 586
 587 /*
 588  * Alarm support for mcp794xx devices.
 589  */
 590
 591 #define MCP794XX_REG_CONTROL            0x07
 592 #       define MCP794XX_BIT_ALM0_EN     0x10
 593 #       define MCP794XX_BIT_ALM1_EN     0x20
 594 #define MCP794XX_REG_ALARM0_BASE        0x0a
 595 #define MCP794XX_REG_ALARM0_CTRL        0x0d
 596 #define MCP794XX_REG_ALARM1_BASE        0x11
 597 #define MCP794XX_REG_ALARM1_CTRL        0x14
 598 #       define MCP794XX_BIT_ALMX_IF     (1 << 3)
 599 #       define MCP794XX_BIT_ALMX_C0     (1 << 4)
 600 #       define MCP794XX_BIT_ALMX_C1     (1 << 5)
 601 #       define MCP794XX_BIT_ALMX_C2     (1 << 6)
 602 #       define MCP794XX_BIT_ALMX_POL    (1 << 7)
 603 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
 604                                          MCP794XX_BIT_ALMX_C1 | \
 605                                          MCP794XX_BIT_ALMX_C2)
 606
 607 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 608 {
 609         struct i2c_client       *client = dev_id;
 610         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 611         struct mutex            *lock = &ds1307->rtc->ops_lock;
 612         int reg, ret;
 613
 614         mutex_lock(lock);
 615
 616         /* Check and clear alarm 0 interrupt flag. */
 617         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
 618         if (reg < 0)
 619                 goto out;
 620         if (!(reg & MCP794XX_BIT_ALMX_IF))
 621                 goto out;
 622         reg &= ~MCP794XX_BIT_ALMX_IF;
 623         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
 624         if (ret < 0)
 625                 goto out;
 626
 627         /* Disable alarm 0. */
 628         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
 629         if (reg < 0)
 630                 goto out;
 631         reg &= ~MCP794XX_BIT_ALM0_EN;
 632         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
 633         if (ret < 0)
 634                 goto out;
 635
 636         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 637
 638 out:
 639         mutex_unlock(lock);
 640
 641         return IRQ_HANDLED;
 642 }
 643
 644 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 645 {
 646         struct i2c_client *client = to_i2c_client(dev);
 647         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 648         u8 *regs = ds1307->regs;
 649         int ret;
 650
 651         if (!test_bit(HAS_ALARM, &ds1307->flags))
 652                 return -EINVAL;
 653
 654         /* Read control and alarm 0 registers. */
 655         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 656         if (ret < 0)
 657                 return ret;
 658
 659         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 660
 661         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 662         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
 663         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
 664         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
 665         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
 666         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
 667         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
 668         t->time.tm_year = -1;
 669         t->time.tm_yday = -1;
 670         t->time.tm_isdst = -1;
 671
 672         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 673                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
 674                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 675                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 676                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
 677                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
 678                 (ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 679
 680         return 0;
 681 }
 682
 683 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 684 {
 685         struct i2c_client *client = to_i2c_client(dev);
 686         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 687         unsigned char *regs = ds1307->regs;
 688         int ret;
 689
 690         if (!test_bit(HAS_ALARM, &ds1307->flags))
 691                 return -EINVAL;
 692
 693         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 694                 "enabled=%d pending=%d\n", __func__,
 695                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 696                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 697                 t->enabled, t->pending);
 698
 699         /* Read control and alarm 0 registers. */
 700         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 701         if (ret < 0)
 702                 return ret;
 703
 704         /* Set alarm 0, using 24-hour and day-of-month modes. */
 705         regs[3] = bin2bcd(t->time.tm_sec);
 706         regs[4] = bin2bcd(t->time.tm_min);
 707         regs[5] = bin2bcd(t->time.tm_hour);
 708         regs[6] = bin2bcd(t->time.tm_wday + 1);
 709         regs[7] = bin2bcd(t->time.tm_mday);
 710         regs[8] = bin2bcd(t->time.tm_mon + 1);
 711
 712         /* Clear the alarm 0 interrupt flag. */
 713         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 714         /* Set alarm match: second, minute, hour, day, date, month. */
 715         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 716         /* Disable interrupt. We will not enable until completely programmed */
 717         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 718
 719         ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 720         if (ret < 0)
 721                 return ret;
 722
 723         if (!t->enabled)
 724                 return 0;
 725         regs[0] |= MCP794XX_BIT_ALM0_EN;
 726         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
 727 }
 728
 729 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 730 {
 731         struct i2c_client *client = to_i2c_client(dev);
 732         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 733         int reg;
 734
 735         if (!test_bit(HAS_ALARM, &ds1307->flags))
 736                 return -EINVAL;
 737
 738         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
 739         if (reg < 0)
 740                 return reg;
 741
 742         if (enabled)
 743                 reg |= MCP794XX_BIT_ALM0_EN;
 744         else
 745                 reg &= ~MCP794XX_BIT_ALM0_EN;
 746
 747         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
 748 }
 749
 750 static const struct rtc_class_ops mcp794xx_rtc_ops = {
 751         .read_time      = ds1307_get_time,
 752         .set_time       = ds1307_set_time,
 753         .read_alarm     = mcp794xx_read_alarm,
 754         .set_alarm      = mcp794xx_set_alarm,
 755         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
 756 };
 757
 758 /*----------------------------------------------------------------------*/
 759
 760 static ssize_t
 761 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 762                 struct bin_attribute *attr,
 763                 char *buf, loff_t off, size_t count)
 764 {
 765         struct i2c_client       *client;
 766         struct ds1307           *ds1307;
 767         int                     result;
 768
 769         client = kobj_to_i2c_client(kobj);
 770         ds1307 = i2c_get_clientdata(client);
 771
 772         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 773                                                                 count, buf);
 774         if (result < 0)
 775                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 776         return result;
 777 }
 778
 779 static ssize_t
 780 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 781                 struct bin_attribute *attr,
 782                 char *buf, loff_t off, size_t count)
 783 {
 784         struct i2c_client       *client;
 785         struct ds1307           *ds1307;
 786         int                     result;
 787
 788         client = kobj_to_i2c_client(kobj);
 789         ds1307 = i2c_get_clientdata(client);
 790
 791         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 792                                                                 count, buf);
 793         if (result < 0) {
 794                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 795                 return result;
 796         }
 797         return count;
 798 }
 799
 800
 801 /*----------------------------------------------------------------------*/
 802
 803 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
 804                                   uint32_t ohms, bool diode)
 805 {
 806         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 807                 DS1307_TRICKLE_CHARGER_NO_DIODE;
 808
 809         switch (ohms) {
 810         case 250:
 811                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 812                 break;
 813         case 2000:
 814                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 815                 break;
 816         case 4000:
 817                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 818                 break;
 819         default:
 820                 dev_warn(&client->dev,
 821                          "Unsupported ohm value %u in dt\n", ohms);
 822                 return 0;
 823         }
 824         return setup;
 825 }
 826
 827 static void ds1307_trickle_of_init(struct i2c_client *client,
 828                                    struct chip_desc *chip)
 829 {
 830         uint32_t ohms = 0;
 831         bool diode = true;
 832
 833         if (!chip->do_trickle_setup)
 834                 goto out;
 835         if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
 836                 goto out;
 837         if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
 838                 diode = false;
 839         chip->trickle_charger_setup = chip->do_trickle_setup(client,
 840                                                              ohms, diode);
 841 out:
 842         return;
 843 }
 844
 845 static int ds1307_probe(struct i2c_client *client,
 846                         const struct i2c_device_id *id)
 847 {
 848         struct ds1307           *ds1307;
 849         int                     err = -ENODEV;
 850         int                     tmp;
 851         struct chip_desc        *chip = &chips[id->driver_data];
 852         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 853         bool                    want_irq = false;
 854         unsigned char           *buf;
 855         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
 856         irq_handler_t   irq_handler = ds1307_irq;
 857
 858         static const int        bbsqi_bitpos[] = {
 859                 [ds_1337] = 0,
 860                 [ds_1339] = DS1339_BIT_BBSQI,
 861                 [ds_3231] = DS3231_BIT_BBSQW,
 862         };
 863         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
 864
 865         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 866             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 867                 return -EIO;
 868
 869         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
 870         if (!ds1307)
 871                 return -ENOMEM;
 872
 873         i2c_set_clientdata(client, ds1307);
 874
 875         ds1307->client  = client;
 876         ds1307->type    = id->driver_data;
 877
 878         if (!pdata && client->dev.of_node)
 879                 ds1307_trickle_of_init(client, chip);
 880         else if (pdata && pdata->trickle_charger_setup)
 881                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
 882
 883         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
 884                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
 885                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
 886                     chip->trickle_charger_reg);
 887                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 888                     DS13XX_TRICKLE_CHARGER_MAGIC |
 889                     chip->trickle_charger_setup);
 890         }
 891
 892         buf = ds1307->regs;
 893         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 894                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
 895                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
 896         } else {
 897                 ds1307->read_block_data = ds1307_read_block_data;
 898                 ds1307->write_block_data = ds1307_write_block_data;
 899         }
 900
 901         switch (ds1307->type) {
 902         case ds_1337:
 903         case ds_1339:
 904         case ds_3231:
 905                 /* get registers that the "rtc" read below won't read... */
 906                 tmp = ds1307->read_block_data(ds1307->client,
 907                                 DS1337_REG_CONTROL, 2, buf);
 908                 if (tmp != 2) {
 909                         dev_dbg(&client->dev, "read error %d\n", tmp);
 910                         err = -EIO;
 911                         goto exit;
 912                 }
 913
 914                 /* oscillator off?  turn it on, so clock can tick. */
 915                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 916                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 917
 918                 /*
 919                  * Using IRQ?  Disable the square wave and both alarms.
 920                  * For some variants, be sure alarms can trigger when we're
 921                  * running on Vbackup (BBSQI/BBSQW)
 922                  */
 923                 if (ds1307->client->irq > 0 && chip->alarm) {
 924                         ds1307->regs[0] |= DS1337_BIT_INTCN
 925                                         | bbsqi_bitpos[ds1307->type];
 926                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 927
 928                         want_irq = true;
 929                 }
 930
 931                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 932                                                         ds1307->regs[0]);
 933
 934                 /* oscillator fault?  clear flag, and warn */
 935                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 936                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 937                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 938                         dev_warn(&client->dev, "SET TIME!\n");
 939                 }
 940                 break;
 941
 942         case rx_8025:
 943                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 944                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 945                 if (tmp != 2) {
 946                         dev_dbg(&client->dev, "read error %d\n", tmp);
 947                         err = -EIO;
 948                         goto exit;
 949                 }
 950
 951                 /* oscillator off?  turn it on, so clock can tick. */
 952                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 953                         ds1307->regs[1] |= RX8025_BIT_XST;
 954                         i2c_smbus_write_byte_data(client,
 955                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 956                                                   ds1307->regs[1]);
 957                         dev_warn(&client->dev,
 958                                  "oscillator stop detected - SET TIME!\n");
 959                 }
 960
 961                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 962                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 963                         i2c_smbus_write_byte_data(client,
 964                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 965                                                   ds1307->regs[1]);
 966                         dev_warn(&client->dev, "power-on detected\n");
 967                 }
 968
 969                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 970                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 971                         i2c_smbus_write_byte_data(client,
 972                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 973                                                   ds1307->regs[1]);
 974                         dev_warn(&client->dev, "voltage drop detected\n");
 975                 }
 976
 977                 /* make sure we are running in 24hour mode */
 978                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 979                         u8 hour;
 980
 981                         /* switch to 24 hour mode */
 982                         i2c_smbus_write_byte_data(client,
 983                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 984                                                   ds1307->regs[0] |
 985                                                   RX8025_BIT_2412);
 986
 987                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 988                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 989                         if (tmp != 2) {
 990                                 dev_dbg(&client->dev, "read error %d\n", tmp);
 991                                 err = -EIO;
 992                                 goto exit;
 993                         }
 994
 995                         /* correct hour */
 996                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 997                         if (hour == 12)
 998                                 hour = 0;
 999                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1000                                 hour += 12;
1001
1002                         i2c_smbus_write_byte_data(client,
1003                                                   DS1307_REG_HOUR << 4 | 0x08,
1004                                                   hour);
1005                 }
1006                 break;
1007         case ds_1388:
1008                 ds1307->offset = 1; /* Seconds starts at 1 */
1009                 break;
1010         case mcp794xx:
1011                 rtc_ops = &mcp794xx_rtc_ops;
1012                 if (ds1307->client->irq > 0 && chip->alarm) {
1013                         irq_handler = mcp794xx_irq;
1014                         want_irq = true;
1015                 }
1016                 break;
1017         default:
1018                 break;
1019         }
1020
1021 read_rtc:
1022         /* read RTC registers */
1023         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1024         if (tmp != 8) {
1025                 dev_dbg(&client->dev, "read error %d\n", tmp);
1026                 err = -EIO;
1027                 goto exit;
1028         }
1029
1030         /*
1031          * minimal sanity checking; some chips (like DS1340) don't
1032          * specify the extra bits as must-be-zero, but there are
1033          * still a few values that are clearly out-of-range.
1034          */
1035         tmp = ds1307->regs[DS1307_REG_SECS];
1036         switch (ds1307->type) {
1037         case ds_1307:
1038         case m41t00:
1039                 /* clock halted?  turn it on, so clock can tick. */
1040                 if (tmp & DS1307_BIT_CH) {
1041                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1042                         dev_warn(&client->dev, "SET TIME!\n");
1043                         goto read_rtc;
1044                 }
1045                 break;
1046         case ds_1338:
1047                 /* clock halted?  turn it on, so clock can tick. */
1048                 if (tmp & DS1307_BIT_CH)
1049                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1050
1051                 /* oscillator fault?  clear flag, and warn */
1052                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1053                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1054                                         ds1307->regs[DS1307_REG_CONTROL]
1055                                         & ~DS1338_BIT_OSF);
1056                         dev_warn(&client->dev, "SET TIME!\n");
1057                         goto read_rtc;
1058                 }
1059                 break;
1060         case ds_1340:
1061                 /* clock halted?  turn it on, so clock can tick. */
1062                 if (tmp & DS1340_BIT_nEOSC)
1063                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1064
1065                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1066                 if (tmp < 0) {
1067                         dev_dbg(&client->dev, "read error %d\n", tmp);
1068                         err = -EIO;
1069                         goto exit;
1070                 }
1071
1072                 /* oscillator fault?  clear flag, and warn */
1073                 if (tmp & DS1340_BIT_OSF) {
1074                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1075                         dev_warn(&client->dev, "SET TIME!\n");
1076                 }
1077                 break;
1078         case mcp794xx:
1079                 /* make sure that the backup battery is enabled */
1080                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1081                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1082                                         ds1307->regs[DS1307_REG_WDAY]
1083                                         | MCP794XX_BIT_VBATEN);
1084                 }
1085
1086                 /* clock halted?  turn it on, so clock can tick. */
1087                 if (!(tmp & MCP794XX_BIT_ST)) {
1088                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1089                                         MCP794XX_BIT_ST);
1090                         dev_warn(&client->dev, "SET TIME!\n");
1091                         goto read_rtc;
1092                 }
1093
1094                 break;
1095         default:
1096                 break;
1097         }
1098
1099         tmp = ds1307->regs[DS1307_REG_HOUR];
1100         switch (ds1307->type) {
1101         case ds_1340:
1102         case m41t00:
1103                 /*
1104                  * NOTE: ignores century bits; fix before deploying
1105                  * systems that will run through year 2100.
1106                  */
1107                 break;
1108         case rx_8025:
1109                 break;
1110         default:
1111                 if (!(tmp & DS1307_BIT_12HR))
1112                         break;
1113
1114                 /*
1115                  * Be sure we're in 24 hour mode.  Multi-master systems
1116                  * take note...
1117                  */
1118                 tmp = bcd2bin(tmp & 0x1f);
1119                 if (tmp == 12)
1120                         tmp = 0;
1121                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1122                         tmp += 12;
1123                 i2c_smbus_write_byte_data(client,
1124                                 ds1307->offset + DS1307_REG_HOUR,
1125                                 bin2bcd(tmp));
1126         }
1127
1128         if (want_irq) {
1129                 device_set_wakeup_capable(&client->dev, true);
1130                 set_bit(HAS_ALARM, &ds1307->flags);
1131         }
1132         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1133                                 rtc_ops, THIS_MODULE);
1134         if (IS_ERR(ds1307->rtc)) {
1135                 return PTR_ERR(ds1307->rtc);
1136         }
1137
1138         if (want_irq) {
1139                 err = devm_request_threaded_irq(&client->dev,
1140                                                 client->irq, NULL, irq_handler,
1141                                                 IRQF_SHARED | IRQF_ONESHOT,
1142                                                 ds1307->rtc->name, client);
1143                 if (err) {
1144                         client->irq = 0;
1145                         device_set_wakeup_capable(&client->dev, false);
1146                         clear_bit(HAS_ALARM, &ds1307->flags);
1147                         dev_err(&client->dev, "unable to request IRQ!\n");
1148                 } else
1149                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1150         }
1151
1152         if (chip->nvram_size) {
1153
1154                 ds1307->nvram = devm_kzalloc(&client->dev,
1155                                         sizeof(struct bin_attribute),
1156                                         GFP_KERNEL);
1157                 if (!ds1307->nvram) {
1158                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1159                 } else {
1160
1161                         ds1307->nvram->attr.name = "nvram";
1162                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1163
1164                         sysfs_bin_attr_init(ds1307->nvram);
1165
1166                         ds1307->nvram->read = ds1307_nvram_read;
1167                         ds1307->nvram->write = ds1307_nvram_write;
1168                         ds1307->nvram->size = chip->nvram_size;
1169                         ds1307->nvram_offset = chip->nvram_offset;
1170
1171                         err = sysfs_create_bin_file(&client->dev.kobj,
1172                                                     ds1307->nvram);
1173                         if (err) {
1174                                 dev_err(&client->dev,
1175                                         "unable to create sysfs file: %s\n",
1176                                         ds1307->nvram->attr.name);
1177                         } else {
1178                                 set_bit(HAS_NVRAM, &ds1307->flags);
1179                                 dev_info(&client->dev, "%zu bytes nvram\n",
1180                                          ds1307->nvram->size);
1181                         }
1182                 }
1183         }
1184
1185         return 0;
1186
1187 exit:
1188         return err;
1189 }
1190
1191 static int ds1307_remove(struct i2c_client *client)
1192 {
1193         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1194
1195         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1196                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1197
1198         return 0;
1199 }
1200
1201 static struct i2c_driver ds1307_driver = {
1202         .driver = {
1203                 .name   = "rtc-ds1307",
1204         },
1205         .probe          = ds1307_probe,
1206         .remove         = ds1307_remove,
1207         .id_table       = ds1307_id,
1208 };
1209
1210 module_i2c_driver(ds1307_driver);
1211
1212 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1213 MODULE_LICENSE("GPL");