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/of_device.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/pm_wakeirq.h>
  21 #include <linux/rtc/ds1307.h>
  22 #include <linux/rtc.h>
  23 #include <linux/slab.h>
  24 #include <linux/string.h>
  25
  26 /*
  27  * We can't determine type by probing, but if we expect pre-Linux code
  28  * to have set the chip up as a clock (turning on the oscillator and
  29  * setting the date and time), Linux can ignore the non-clock features.
  30  * That's a natural job for a factory or repair bench.
  31  */
  32 enum ds_type {
  33         ds_1307,
  34         ds_1337,
  35         ds_1338,
  36         ds_1339,
  37         ds_1340,
  38         ds_1388,
  39         ds_3231,
  40         m41t00,
  41         mcp794xx,
  42         rx_8025,
  43         last_ds_type /* always last */
  44         /* rs5c372 too?  different address... */
  45 };
  46
  47
  48 /* RTC registers don't differ much, except for the century flag */
  49 #define DS1307_REG_SECS         0x00    /* 00-59 */
  50 #       define DS1307_BIT_CH            0x80
  51 #       define DS1340_BIT_nEOSC         0x80
  52 #       define MCP794XX_BIT_ST          0x80
  53 #define DS1307_REG_MIN          0x01    /* 00-59 */
  54 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  55 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  56 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  57 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  58 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  59 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  60 #       define MCP794XX_BIT_VBATEN      0x08
  61 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  62 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  63 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  64 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  65
  66 /*
  67  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  68  * start at 7, and they differ a LOT. Only control and status matter for
  69  * basic RTC date and time functionality; be careful using them.
  70  */
  71 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  72 #       define DS1307_BIT_OUT           0x80
  73 #       define DS1338_BIT_OSF           0x20
  74 #       define DS1307_BIT_SQWE          0x10
  75 #       define DS1307_BIT_RS1           0x02
  76 #       define DS1307_BIT_RS0           0x01
  77 #define DS1337_REG_CONTROL      0x0e
  78 #       define DS1337_BIT_nEOSC         0x80
  79 #       define DS1339_BIT_BBSQI         0x20
  80 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  81 #       define DS1337_BIT_RS2           0x10
  82 #       define DS1337_BIT_RS1           0x08
  83 #       define DS1337_BIT_INTCN         0x04
  84 #       define DS1337_BIT_A2IE          0x02
  85 #       define DS1337_BIT_A1IE          0x01
  86 #define DS1340_REG_CONTROL      0x07
  87 #       define DS1340_BIT_OUT           0x80
  88 #       define DS1340_BIT_FT            0x40
  89 #       define DS1340_BIT_CALIB_SIGN    0x20
  90 #       define DS1340_M_CALIBRATION     0x1f
  91 #define DS1340_REG_FLAG         0x09
  92 #       define DS1340_BIT_OSF           0x80
  93 #define DS1337_REG_STATUS       0x0f
  94 #       define DS1337_BIT_OSF           0x80
  95 #       define DS1337_BIT_A2I           0x02
  96 #       define DS1337_BIT_A1I           0x01
  97 #define DS1339_REG_ALARM1_SECS  0x07
  98
  99 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
 100
 101 #define RX8025_REG_CTRL1        0x0e
 102 #       define RX8025_BIT_2412          0x20
 103 #define RX8025_REG_CTRL2        0x0f
 104 #       define RX8025_BIT_PON           0x10
 105 #       define RX8025_BIT_VDET          0x40
 106 #       define RX8025_BIT_XST           0x20
 107
 108
 109 struct ds1307 {
 110         u8                      offset; /* register's offset */
 111         u8                      regs[11];
 112         u16                     nvram_offset;
 113         struct bin_attribute    *nvram;
 114         enum ds_type            type;
 115         unsigned long           flags;
 116 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 117 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 118         struct i2c_client       *client;
 119         struct rtc_device       *rtc;
 120         int                     wakeirq;
 121         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 122                                u8 length, u8 *values);
 123         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 124                                 u8 length, const u8 *values);
 125 };
 126
 127 struct chip_desc {
 128         unsigned                alarm:1;
 129         u16                     nvram_offset;
 130         u16                     nvram_size;
 131         u16                     trickle_charger_reg;
 132         u8                      trickle_charger_setup;
 133         u8                      (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
 134 };
 135
 136 static u8 do_trickle_setup_ds1339(struct i2c_client *,
 137                                   uint32_t ohms, bool diode);
 138
 139 static struct chip_desc chips[last_ds_type] = {
 140         [ds_1307] = {
 141                 .nvram_offset   = 8,
 142                 .nvram_size     = 56,
 143         },
 144         [ds_1337] = {
 145                 .alarm          = 1,
 146         },
 147         [ds_1338] = {
 148                 .nvram_offset   = 8,
 149                 .nvram_size     = 56,
 150         },
 151         [ds_1339] = {
 152                 .alarm          = 1,
 153                 .trickle_charger_reg = 0x10,
 154                 .do_trickle_setup = &do_trickle_setup_ds1339,
 155         },
 156         [ds_1340] = {
 157                 .trickle_charger_reg = 0x08,
 158         },
 159         [ds_1388] = {
 160                 .trickle_charger_reg = 0x0a,
 161         },
 162         [ds_3231] = {
 163                 .alarm          = 1,
 164         },
 165         [mcp794xx] = {
 166                 .alarm          = 1,
 167                 /* this is battery backed SRAM */
 168                 .nvram_offset   = 0x20,
 169                 .nvram_size     = 0x40,
 170         },
 171 };
 172
 173 static const struct i2c_device_id ds1307_id[] = {
 174         { "ds1307", ds_1307 },
 175         { "ds1337", ds_1337 },
 176         { "ds1338", ds_1338 },
 177         { "ds1339", ds_1339 },
 178         { "ds1388", ds_1388 },
 179         { "ds1340", ds_1340 },
 180         { "ds3231", ds_3231 },
 181         { "m41t00", m41t00 },
 182         { "mcp7940x", mcp794xx },
 183         { "mcp7941x", mcp794xx },
 184         { "pt7c4338", ds_1307 },
 185         { "rx8025", rx_8025 },
 186         { }
 187 };
 188 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 189
 190 /*----------------------------------------------------------------------*/
 191
 192 #define BLOCK_DATA_MAX_TRIES 10
 193
 194 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 195                                        u8 command, u8 length, u8 *values)
 196 {
 197         s32 i, data;
 198
 199         for (i = 0; i < length; i++) {
 200                 data = i2c_smbus_read_byte_data(client, command + i);
 201                 if (data < 0)
 202                         return data;
 203                 values[i] = data;
 204         }
 205         return i;
 206 }
 207
 208 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 209                                   u8 length, u8 *values)
 210 {
 211         u8 oldvalues[255];
 212         s32 ret;
 213         int tries = 0;
 214
 215         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 216         ret = ds1307_read_block_data_once(client, command, length, values);
 217         if (ret < 0)
 218                 return ret;
 219         do {
 220                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 221                         dev_err(&client->dev,
 222                                 "ds1307_read_block_data failed\n");
 223                         return -EIO;
 224                 }
 225                 memcpy(oldvalues, values, length);
 226                 ret = ds1307_read_block_data_once(client, command, length,
 227                                                   values);
 228                 if (ret < 0)
 229                         return ret;
 230         } while (memcmp(oldvalues, values, length));
 231         return length;
 232 }
 233
 234 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 235                                    u8 length, const u8 *values)
 236 {
 237         u8 currvalues[255];
 238         int tries = 0;
 239
 240         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 241         do {
 242                 s32 i, ret;
 243
 244                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 245                         dev_err(&client->dev,
 246                                 "ds1307_write_block_data failed\n");
 247                         return -EIO;
 248                 }
 249                 for (i = 0; i < length; i++) {
 250                         ret = i2c_smbus_write_byte_data(client, command + i,
 251                                                         values[i]);
 252                         if (ret < 0)
 253                                 return ret;
 254                 }
 255                 ret = ds1307_read_block_data_once(client, command, length,
 256                                                   currvalues);
 257                 if (ret < 0)
 258                         return ret;
 259         } while (memcmp(currvalues, values, length));
 260         return length;
 261 }
 262
 263 /*----------------------------------------------------------------------*/
 264
 265 /* These RTC devices are not designed to be connected to a SMbus adapter.
 266    SMbus limits block operations length to 32 bytes, whereas it's not
 267    limited on I2C buses. As a result, accesses may exceed 32 bytes;
 268    in that case, split them into smaller blocks */
 269
 270 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
 271                                 u8 command, u8 length, const u8 *values)
 272 {
 273         u8 suboffset = 0;
 274
 275         if (length <= I2C_SMBUS_BLOCK_MAX)
 276                 return i2c_smbus_write_i2c_block_data(client,
 277                                         command, length, values);
 278
 279         while (suboffset < length) {
 280                 s32 retval = i2c_smbus_write_i2c_block_data(client,
 281                                 command + suboffset,
 282                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 283                                 values + suboffset);
 284                 if (retval < 0)
 285                         return retval;
 286
 287                 suboffset += I2C_SMBUS_BLOCK_MAX;
 288         }
 289         return length;
 290 }
 291
 292 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
 293                                 u8 command, u8 length, u8 *values)
 294 {
 295         u8 suboffset = 0;
 296
 297         if (length <= I2C_SMBUS_BLOCK_MAX)
 298                 return i2c_smbus_read_i2c_block_data(client,
 299                                         command, length, values);
 300
 301         while (suboffset < length) {
 302                 s32 retval = i2c_smbus_read_i2c_block_data(client,
 303                                 command + suboffset,
 304                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
 305                                 values + suboffset);
 306                 if (retval < 0)
 307                         return retval;
 308
 309                 suboffset += I2C_SMBUS_BLOCK_MAX;
 310         }
 311         return length;
 312 }
 313
 314 /*----------------------------------------------------------------------*/
 315
 316 /*
 317  * The ds1337 and ds1339 both have two alarms, but we only use the first
 318  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 319  * signal; ds1339 chips have only one alarm signal.
 320  */
 321 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 322 {
 323         struct i2c_client       *client = dev_id;
 324         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 325         struct mutex            *lock = &ds1307->rtc->ops_lock;
 326         int                     stat, control;
 327
 328         mutex_lock(lock);
 329         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 330         if (stat < 0)
 331                 goto out;
 332
 333         if (stat & DS1337_BIT_A1I) {
 334                 stat &= ~DS1337_BIT_A1I;
 335                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 336
 337                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 338                 if (control < 0)
 339                         goto out;
 340
 341                 control &= ~DS1337_BIT_A1IE;
 342                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 343
 344                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 345         }
 346
 347 out:
 348         mutex_unlock(lock);
 349
 350         return IRQ_HANDLED;
 351 }
 352
 353 /*----------------------------------------------------------------------*/
 354
 355 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 356 {
 357         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 358         int             tmp;
 359
 360         /* read the RTC date and time registers all at once */
 361         tmp = ds1307->read_block_data(ds1307->client,
 362                 ds1307->offset, 7, ds1307->regs);
 363         if (tmp != 7) {
 364                 dev_err(dev, "%s error %d\n", "read", tmp);
 365                 return -EIO;
 366         }
 367
 368         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 369
 370         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 371         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 372         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 373         t->tm_hour = bcd2bin(tmp);
 374         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 375         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 376         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 377         t->tm_mon = bcd2bin(tmp) - 1;
 378
 379         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 380         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 381
 382         dev_dbg(dev, "%s secs=%d, mins=%d, "
 383                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 384                 "read", t->tm_sec, t->tm_min,
 385                 t->tm_hour, t->tm_mday,
 386                 t->tm_mon, t->tm_year, t->tm_wday);
 387
 388         /* initial clock setting can be undefined */
 389         return rtc_valid_tm(t);
 390 }
 391
 392 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 393 {
 394         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 395         int             result;
 396         int             tmp;
 397         u8              *buf = ds1307->regs;
 398
 399         dev_dbg(dev, "%s secs=%d, mins=%d, "
 400                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 401                 "write", t->tm_sec, t->tm_min,
 402                 t->tm_hour, t->tm_mday,
 403                 t->tm_mon, t->tm_year, t->tm_wday);
 404
 405         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 406         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 407         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 408         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 409         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 410         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 411
 412         /* assume 20YY not 19YY */
 413         tmp = t->tm_year - 100;
 414         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 415
 416         switch (ds1307->type) {
 417         case ds_1337:
 418         case ds_1339:
 419         case ds_3231:
 420                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 421                 break;
 422         case ds_1340:
 423                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 424                                 | DS1340_BIT_CENTURY;
 425                 break;
 426         case mcp794xx:
 427                 /*
 428                  * these bits were cleared when preparing the date/time
 429                  * values and need to be set again before writing the
 430                  * buffer out to the device.
 431                  */
 432                 buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
 433                 buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
 434                 break;
 435         default:
 436                 break;
 437         }
 438
 439         dev_dbg(dev, "%s: %7ph\n", "write", buf);
 440
 441         result = ds1307->write_block_data(ds1307->client,
 442                 ds1307->offset, 7, buf);
 443         if (result < 0) {
 444                 dev_err(dev, "%s error %d\n", "write", result);
 445                 return result;
 446         }
 447         return 0;
 448 }
 449
 450 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 451 {
 452         struct i2c_client       *client = to_i2c_client(dev);
 453         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 454         int                     ret;
 455
 456         if (!test_bit(HAS_ALARM, &ds1307->flags))
 457                 return -EINVAL;
 458
 459         /* read all ALARM1, ALARM2, and status registers at once */
 460         ret = ds1307->read_block_data(client,
 461                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 462         if (ret != 9) {
 463                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 464                 return -EIO;
 465         }
 466
 467         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 468                         "alarm read",
 469                         ds1307->regs[0], ds1307->regs[1],
 470                         ds1307->regs[2], ds1307->regs[3],
 471                         ds1307->regs[4], ds1307->regs[5],
 472                         ds1307->regs[6], ds1307->regs[7],
 473                         ds1307->regs[8]);
 474
 475         /*
 476          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 477          * and that all four fields are checked matches
 478          */
 479         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 480         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 481         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 482         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 483         t->time.tm_mon = -1;
 484         t->time.tm_year = -1;
 485         t->time.tm_wday = -1;
 486         t->time.tm_yday = -1;
 487         t->time.tm_isdst = -1;
 488
 489         /* ... and status */
 490         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 491         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 492
 493         dev_dbg(dev, "%s secs=%d, mins=%d, "
 494                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 495                 "alarm read", t->time.tm_sec, t->time.tm_min,
 496                 t->time.tm_hour, t->time.tm_mday,
 497                 t->enabled, t->pending);
 498
 499         return 0;
 500 }
 501
 502 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 503 {
 504         struct i2c_client       *client = to_i2c_client(dev);
 505         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 506         unsigned char           *buf = ds1307->regs;
 507         u8                      control, status;
 508         int                     ret;
 509
 510         if (!test_bit(HAS_ALARM, &ds1307->flags))
 511                 return -EINVAL;
 512
 513         dev_dbg(dev, "%s secs=%d, mins=%d, "
 514                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 515                 "alarm set", t->time.tm_sec, t->time.tm_min,
 516                 t->time.tm_hour, t->time.tm_mday,
 517                 t->enabled, t->pending);
 518
 519         /* read current status of both alarms and the chip */
 520         ret = ds1307->read_block_data(client,
 521                         DS1339_REG_ALARM1_SECS, 9, buf);
 522         if (ret != 9) {
 523                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 524                 return -EIO;
 525         }
 526         control = ds1307->regs[7];
 527         status = ds1307->regs[8];
 528
 529         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 530                         "alarm set (old status)",
 531                         ds1307->regs[0], ds1307->regs[1],
 532                         ds1307->regs[2], ds1307->regs[3],
 533                         ds1307->regs[4], ds1307->regs[5],
 534                         ds1307->regs[6], control, status);
 535
 536         /* set ALARM1, using 24 hour and day-of-month modes */
 537         buf[0] = bin2bcd(t->time.tm_sec);
 538         buf[1] = bin2bcd(t->time.tm_min);
 539         buf[2] = bin2bcd(t->time.tm_hour);
 540         buf[3] = bin2bcd(t->time.tm_mday);
 541
 542         /* set ALARM2 to non-garbage */
 543         buf[4] = 0;
 544         buf[5] = 0;
 545         buf[6] = 0;
 546
 547         /* optionally enable ALARM1 */
 548         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 549         if (t->enabled) {
 550                 dev_dbg(dev, "alarm IRQ armed\n");
 551                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 552         }
 553         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 554
 555         ret = ds1307->write_block_data(client,
 556                         DS1339_REG_ALARM1_SECS, 9, buf);
 557         if (ret < 0) {
 558                 dev_err(dev, "can't set alarm time\n");
 559                 return ret;
 560         }
 561
 562         return 0;
 563 }
 564
 565 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 566 {
 567         struct i2c_client       *client = to_i2c_client(dev);
 568         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 569         int                     ret;
 570
 571         if (!test_bit(HAS_ALARM, &ds1307->flags))
 572                 return -ENOTTY;
 573
 574         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 575         if (ret < 0)
 576                 return ret;
 577
 578         if (enabled)
 579                 ret |= DS1337_BIT_A1IE;
 580         else
 581                 ret &= ~DS1337_BIT_A1IE;
 582
 583         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 584         if (ret < 0)
 585                 return ret;
 586
 587         return 0;
 588 }
 589
 590 static const struct rtc_class_ops ds13xx_rtc_ops = {
 591         .read_time      = ds1307_get_time,
 592         .set_time       = ds1307_set_time,
 593         .read_alarm     = ds1337_read_alarm,
 594         .set_alarm      = ds1337_set_alarm,
 595         .alarm_irq_enable = ds1307_alarm_irq_enable,
 596 };
 597
 598 /*----------------------------------------------------------------------*/
 599
 600 /*
 601  * Alarm support for mcp794xx devices.
 602  */
 603
 604 #define MCP794XX_REG_CONTROL            0x07
 605 #       define MCP794XX_BIT_ALM0_EN     0x10
 606 #       define MCP794XX_BIT_ALM1_EN     0x20
 607 #define MCP794XX_REG_ALARM0_BASE        0x0a
 608 #define MCP794XX_REG_ALARM0_CTRL        0x0d
 609 #define MCP794XX_REG_ALARM1_BASE        0x11
 610 #define MCP794XX_REG_ALARM1_CTRL        0x14
 611 #       define MCP794XX_BIT_ALMX_IF     (1 << 3)
 612 #       define MCP794XX_BIT_ALMX_C0     (1 << 4)
 613 #       define MCP794XX_BIT_ALMX_C1     (1 << 5)
 614 #       define MCP794XX_BIT_ALMX_C2     (1 << 6)
 615 #       define MCP794XX_BIT_ALMX_POL    (1 << 7)
 616 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
 617                                          MCP794XX_BIT_ALMX_C1 | \
 618                                          MCP794XX_BIT_ALMX_C2)
 619
 620 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 621 {
 622         struct i2c_client       *client = dev_id;
 623         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 624         struct mutex            *lock = &ds1307->rtc->ops_lock;
 625         int reg, ret;
 626
 627         mutex_lock(lock);
 628
 629         /* Check and clear alarm 0 interrupt flag. */
 630         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
 631         if (reg < 0)
 632                 goto out;
 633         if (!(reg & MCP794XX_BIT_ALMX_IF))
 634                 goto out;
 635         reg &= ~MCP794XX_BIT_ALMX_IF;
 636         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
 637         if (ret < 0)
 638                 goto out;
 639
 640         /* Disable alarm 0. */
 641         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
 642         if (reg < 0)
 643                 goto out;
 644         reg &= ~MCP794XX_BIT_ALM0_EN;
 645         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
 646         if (ret < 0)
 647                 goto out;
 648
 649         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 650
 651 out:
 652         mutex_unlock(lock);
 653
 654         return IRQ_HANDLED;
 655 }
 656
 657 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 658 {
 659         struct i2c_client *client = to_i2c_client(dev);
 660         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 661         u8 *regs = ds1307->regs;
 662         int ret;
 663
 664         if (!test_bit(HAS_ALARM, &ds1307->flags))
 665                 return -EINVAL;
 666
 667         /* Read control and alarm 0 registers. */
 668         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 669         if (ret < 0)
 670                 return ret;
 671
 672         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 673
 674         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 675         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
 676         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
 677         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
 678         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
 679         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
 680         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
 681         t->time.tm_year = -1;
 682         t->time.tm_yday = -1;
 683         t->time.tm_isdst = -1;
 684
 685         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 686                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
 687                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 688                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 689                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
 690                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
 691                 (ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 692
 693         return 0;
 694 }
 695
 696 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 697 {
 698         struct i2c_client *client = to_i2c_client(dev);
 699         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 700         unsigned char *regs = ds1307->regs;
 701         int ret;
 702
 703         if (!test_bit(HAS_ALARM, &ds1307->flags))
 704                 return -EINVAL;
 705
 706         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 707                 "enabled=%d pending=%d\n", __func__,
 708                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 709                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 710                 t->enabled, t->pending);
 711
 712         /* Read control and alarm 0 registers. */
 713         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 714         if (ret < 0)
 715                 return ret;
 716
 717         /* Set alarm 0, using 24-hour and day-of-month modes. */
 718         regs[3] = bin2bcd(t->time.tm_sec);
 719         regs[4] = bin2bcd(t->time.tm_min);
 720         regs[5] = bin2bcd(t->time.tm_hour);
 721         regs[6] = bin2bcd(t->time.tm_wday) + 1;
 722         regs[7] = bin2bcd(t->time.tm_mday);
 723         regs[8] = bin2bcd(t->time.tm_mon) + 1;
 724
 725         /* Clear the alarm 0 interrupt flag. */
 726         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 727         /* Set alarm match: second, minute, hour, day, date, month. */
 728         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 729         /* Disable interrupt. We will not enable until completely programmed */
 730         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 731
 732         ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
 733         if (ret < 0)
 734                 return ret;
 735
 736         if (!t->enabled)
 737                 return 0;
 738         regs[0] |= MCP794XX_BIT_ALM0_EN;
 739         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
 740 }
 741
 742 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 743 {
 744         struct i2c_client *client = to_i2c_client(dev);
 745         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 746         int reg;
 747
 748         if (!test_bit(HAS_ALARM, &ds1307->flags))
 749                 return -EINVAL;
 750
 751         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
 752         if (reg < 0)
 753                 return reg;
 754
 755         if (enabled)
 756                 reg |= MCP794XX_BIT_ALM0_EN;
 757         else
 758                 reg &= ~MCP794XX_BIT_ALM0_EN;
 759
 760         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
 761 }
 762
 763 static const struct rtc_class_ops mcp794xx_rtc_ops = {
 764         .read_time      = ds1307_get_time,
 765         .set_time       = ds1307_set_time,
 766         .read_alarm     = mcp794xx_read_alarm,
 767         .set_alarm      = mcp794xx_set_alarm,
 768         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
 769 };
 770
 771 /*----------------------------------------------------------------------*/
 772
 773 static ssize_t
 774 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 775                 struct bin_attribute *attr,
 776                 char *buf, loff_t off, size_t count)
 777 {
 778         struct i2c_client       *client;
 779         struct ds1307           *ds1307;
 780         int                     result;
 781
 782         client = kobj_to_i2c_client(kobj);
 783         ds1307 = i2c_get_clientdata(client);
 784
 785         if (unlikely(off >= ds1307->nvram->size))
 786                 return 0;
 787         if ((off + count) > ds1307->nvram->size)
 788                 count = ds1307->nvram->size - off;
 789         if (unlikely(!count))
 790                 return count;
 791
 792         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 793                                                                 count, buf);
 794         if (result < 0)
 795                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 796         return result;
 797 }
 798
 799 static ssize_t
 800 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 801                 struct bin_attribute *attr,
 802                 char *buf, loff_t off, size_t count)
 803 {
 804         struct i2c_client       *client;
 805         struct ds1307           *ds1307;
 806         int                     result;
 807
 808         client = kobj_to_i2c_client(kobj);
 809         ds1307 = i2c_get_clientdata(client);
 810
 811         if (unlikely(off >= ds1307->nvram->size))
 812                 return -EFBIG;
 813         if ((off + count) > ds1307->nvram->size)
 814                 count = ds1307->nvram->size - off;
 815         if (unlikely(!count))
 816                 return count;
 817
 818         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 819                                                                 count, buf);
 820         if (result < 0) {
 821                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 822                 return result;
 823         }
 824         return count;
 825 }
 826
 827
 828 /*----------------------------------------------------------------------*/
 829
 830 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
 831                                   uint32_t ohms, bool diode)
 832 {
 833         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 834                 DS1307_TRICKLE_CHARGER_NO_DIODE;
 835
 836         switch (ohms) {
 837         case 250:
 838                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 839                 break;
 840         case 2000:
 841                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 842                 break;
 843         case 4000:
 844                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 845                 break;
 846         default:
 847                 dev_warn(&client->dev,
 848                          "Unsupported ohm value %u in dt\n", ohms);
 849                 return 0;
 850         }
 851         return setup;
 852 }
 853
 854 static void ds1307_trickle_of_init(struct i2c_client *client,
 855                                    struct chip_desc *chip)
 856 {
 857         uint32_t ohms = 0;
 858         bool diode = true;
 859
 860         if (!chip->do_trickle_setup)
 861                 goto out;
 862         if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
 863                 goto out;
 864         if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
 865                 diode = false;
 866         chip->trickle_charger_setup = chip->do_trickle_setup(client,
 867                                                              ohms, diode);
 868 out:
 869         return;
 870 }
 871
 872 static int ds1307_probe(struct i2c_client *client,
 873                         const struct i2c_device_id *id)
 874 {
 875         struct ds1307           *ds1307;
 876         int                     err = -ENODEV;
 877         int                     tmp;
 878         struct chip_desc        *chip = &chips[id->driver_data];
 879         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 880         bool                    want_irq = false;
 881         unsigned char           *buf;
 882         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
 883         irq_handler_t   irq_handler = ds1307_irq;
 884
 885         static const int        bbsqi_bitpos[] = {
 886                 [ds_1337] = 0,
 887                 [ds_1339] = DS1339_BIT_BBSQI,
 888                 [ds_3231] = DS3231_BIT_BBSQW,
 889         };
 890         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
 891
 892         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 893             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 894                 return -EIO;
 895
 896         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
 897         if (!ds1307)
 898                 return -ENOMEM;
 899
 900         i2c_set_clientdata(client, ds1307);
 901
 902         ds1307->client  = client;
 903         ds1307->type    = id->driver_data;
 904
 905         if (!pdata && client->dev.of_node)
 906                 ds1307_trickle_of_init(client, chip);
 907         else if (pdata && pdata->trickle_charger_setup)
 908                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
 909
 910         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
 911                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
 912                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
 913                     chip->trickle_charger_reg);
 914                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 915                     DS13XX_TRICKLE_CHARGER_MAGIC |
 916                     chip->trickle_charger_setup);
 917         }
 918
 919         buf = ds1307->regs;
 920         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 921                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
 922                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
 923         } else {
 924                 ds1307->read_block_data = ds1307_read_block_data;
 925                 ds1307->write_block_data = ds1307_write_block_data;
 926         }
 927
 928         switch (ds1307->type) {
 929         case ds_1337:
 930         case ds_1339:
 931         case ds_3231:
 932                 /* get registers that the "rtc" read below won't read... */
 933                 tmp = ds1307->read_block_data(ds1307->client,
 934                                 DS1337_REG_CONTROL, 2, buf);
 935                 if (tmp != 2) {
 936                         dev_dbg(&client->dev, "read error %d\n", tmp);
 937                         err = -EIO;
 938                         goto exit;
 939                 }
 940
 941                 /* oscillator off?  turn it on, so clock can tick. */
 942                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 943                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 944
 945                 /*
 946                  * Using IRQ?  Disable the square wave and both alarms.
 947                  * For some variants, be sure alarms can trigger when we're
 948                  * running on Vbackup (BBSQI/BBSQW)
 949                  */
 950                 if (ds1307->client->irq > 0 && chip->alarm) {
 951                         ds1307->regs[0] |= DS1337_BIT_INTCN
 952                                         | bbsqi_bitpos[ds1307->type];
 953                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 954
 955                         want_irq = true;
 956                 }
 957
 958                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 959                                                         ds1307->regs[0]);
 960
 961                 /* oscillator fault?  clear flag, and warn */
 962                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 963                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 964                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 965                         dev_warn(&client->dev, "SET TIME!\n");
 966                 }
 967                 break;
 968
 969         case rx_8025:
 970                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 971                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 972                 if (tmp != 2) {
 973                         dev_dbg(&client->dev, "read error %d\n", tmp);
 974                         err = -EIO;
 975                         goto exit;
 976                 }
 977
 978                 /* oscillator off?  turn it on, so clock can tick. */
 979                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 980                         ds1307->regs[1] |= RX8025_BIT_XST;
 981                         i2c_smbus_write_byte_data(client,
 982                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 983                                                   ds1307->regs[1]);
 984                         dev_warn(&client->dev,
 985                                  "oscillator stop detected - SET TIME!\n");
 986                 }
 987
 988                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 989                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 990                         i2c_smbus_write_byte_data(client,
 991                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 992                                                   ds1307->regs[1]);
 993                         dev_warn(&client->dev, "power-on detected\n");
 994                 }
 995
 996                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 997                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 998                         i2c_smbus_write_byte_data(client,
 999                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1000                                                   ds1307->regs[1]);
1001                         dev_warn(&client->dev, "voltage drop detected\n");
1002                 }
1003
1004                 /* make sure we are running in 24hour mode */
1005                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1006                         u8 hour;
1007
1008                         /* switch to 24 hour mode */
1009                         i2c_smbus_write_byte_data(client,
1010                                                   RX8025_REG_CTRL1 << 4 | 0x08,
1011                                                   ds1307->regs[0] |
1012                                                   RX8025_BIT_2412);
1013
1014                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1015                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1016                         if (tmp != 2) {
1017                                 dev_dbg(&client->dev, "read error %d\n", tmp);
1018                                 err = -EIO;
1019                                 goto exit;
1020                         }
1021
1022                         /* correct hour */
1023                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1024                         if (hour == 12)
1025                                 hour = 0;
1026                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1027                                 hour += 12;
1028
1029                         i2c_smbus_write_byte_data(client,
1030                                                   DS1307_REG_HOUR << 4 | 0x08,
1031                                                   hour);
1032                 }
1033                 break;
1034         case ds_1388:
1035                 ds1307->offset = 1; /* Seconds starts at 1 */
1036                 break;
1037         case mcp794xx:
1038                 rtc_ops = &mcp794xx_rtc_ops;
1039                 if (ds1307->client->irq > 0 && chip->alarm) {
1040                         irq_handler = mcp794xx_irq;
1041                         want_irq = true;
1042                 }
1043                 break;
1044         default:
1045                 break;
1046         }
1047
1048 read_rtc:
1049         /* read RTC registers */
1050         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1051         if (tmp != 8) {
1052                 dev_dbg(&client->dev, "read error %d\n", tmp);
1053                 err = -EIO;
1054                 goto exit;
1055         }
1056
1057         /*
1058          * minimal sanity checking; some chips (like DS1340) don't
1059          * specify the extra bits as must-be-zero, but there are
1060          * still a few values that are clearly out-of-range.
1061          */
1062         tmp = ds1307->regs[DS1307_REG_SECS];
1063         switch (ds1307->type) {
1064         case ds_1307:
1065         case m41t00:
1066                 /* clock halted?  turn it on, so clock can tick. */
1067                 if (tmp & DS1307_BIT_CH) {
1068                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1069                         dev_warn(&client->dev, "SET TIME!\n");
1070                         goto read_rtc;
1071                 }
1072                 break;
1073         case ds_1338:
1074                 /* clock halted?  turn it on, so clock can tick. */
1075                 if (tmp & DS1307_BIT_CH)
1076                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1077
1078                 /* oscillator fault?  clear flag, and warn */
1079                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1080                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1081                                         ds1307->regs[DS1307_REG_CONTROL]
1082                                         & ~DS1338_BIT_OSF);
1083                         dev_warn(&client->dev, "SET TIME!\n");
1084                         goto read_rtc;
1085                 }
1086                 break;
1087         case ds_1340:
1088                 /* clock halted?  turn it on, so clock can tick. */
1089                 if (tmp & DS1340_BIT_nEOSC)
1090                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1091
1092                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1093                 if (tmp < 0) {
1094                         dev_dbg(&client->dev, "read error %d\n", tmp);
1095                         err = -EIO;
1096                         goto exit;
1097                 }
1098
1099                 /* oscillator fault?  clear flag, and warn */
1100                 if (tmp & DS1340_BIT_OSF) {
1101                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1102                         dev_warn(&client->dev, "SET TIME!\n");
1103                 }
1104                 break;
1105         case mcp794xx:
1106                 /* make sure that the backup battery is enabled */
1107                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1108                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1109                                         ds1307->regs[DS1307_REG_WDAY]
1110                                         | MCP794XX_BIT_VBATEN);
1111                 }
1112
1113                 /* clock halted?  turn it on, so clock can tick. */
1114                 if (!(tmp & MCP794XX_BIT_ST)) {
1115                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1116                                         MCP794XX_BIT_ST);
1117                         dev_warn(&client->dev, "SET TIME!\n");
1118                         goto read_rtc;
1119                 }
1120
1121                 break;
1122         default:
1123                 break;
1124         }
1125
1126         tmp = ds1307->regs[DS1307_REG_HOUR];
1127         switch (ds1307->type) {
1128         case ds_1340:
1129         case m41t00:
1130                 /*
1131                  * NOTE: ignores century bits; fix before deploying
1132                  * systems that will run through year 2100.
1133                  */
1134                 break;
1135         case rx_8025:
1136                 break;
1137         default:
1138                 if (!(tmp & DS1307_BIT_12HR))
1139                         break;
1140
1141                 /*
1142                  * Be sure we're in 24 hour mode.  Multi-master systems
1143                  * take note...
1144                  */
1145                 tmp = bcd2bin(tmp & 0x1f);
1146                 if (tmp == 12)
1147                         tmp = 0;
1148                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1149                         tmp += 12;
1150                 i2c_smbus_write_byte_data(client,
1151                                 ds1307->offset + DS1307_REG_HOUR,
1152                                 bin2bcd(tmp));
1153         }
1154
1155         device_set_wakeup_capable(&client->dev, want_irq);
1156         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1157                                 rtc_ops, THIS_MODULE);
1158         if (IS_ERR(ds1307->rtc)) {
1159                 return PTR_ERR(ds1307->rtc);
1160         }
1161
1162         if (want_irq) {
1163                 struct device_node *node = client->dev.of_node;
1164
1165                 err = devm_request_threaded_irq(&client->dev,
1166                                                 client->irq, NULL, irq_handler,
1167                                                 IRQF_SHARED | IRQF_ONESHOT,
1168                                                 ds1307->rtc->name, client);
1169                 if (err) {
1170                         client->irq = 0;
1171                         dev_err(&client->dev, "unable to request IRQ!\n");
1172                         goto no_irq;
1173                 }
1174
1175                 set_bit(HAS_ALARM, &ds1307->flags);
1176                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1177
1178                 /* Currently supported by OF code only! */
1179                 if (!node)
1180                         goto no_irq;
1181
1182                 err = of_irq_get(node, 1);
1183                 if (err <= 0) {
1184                         if (err == -EPROBE_DEFER)
1185                                 goto exit;
1186                         goto no_irq;
1187                 }
1188                 ds1307->wakeirq = err;
1189
1190                 err = dev_pm_set_dedicated_wake_irq(&client->dev,
1191                                                     ds1307->wakeirq);
1192                 if (err) {
1193                         dev_err(&client->dev, "unable to setup wakeIRQ %d!\n",
1194                                 err);
1195                         goto exit;
1196                 }
1197         }
1198
1199 no_irq:
1200         if (chip->nvram_size) {
1201
1202                 ds1307->nvram = devm_kzalloc(&client->dev,
1203                                         sizeof(struct bin_attribute),
1204                                         GFP_KERNEL);
1205                 if (!ds1307->nvram) {
1206                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1207                 } else {
1208
1209                         ds1307->nvram->attr.name = "nvram";
1210                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1211
1212                         sysfs_bin_attr_init(ds1307->nvram);
1213
1214                         ds1307->nvram->read = ds1307_nvram_read;
1215                         ds1307->nvram->write = ds1307_nvram_write;
1216                         ds1307->nvram->size = chip->nvram_size;
1217                         ds1307->nvram_offset = chip->nvram_offset;
1218
1219                         err = sysfs_create_bin_file(&client->dev.kobj,
1220                                                     ds1307->nvram);
1221                         if (err) {
1222                                 dev_err(&client->dev,
1223                                         "unable to create sysfs file: %s\n",
1224                                         ds1307->nvram->attr.name);
1225                         } else {
1226                                 set_bit(HAS_NVRAM, &ds1307->flags);
1227                                 dev_info(&client->dev, "%zu bytes nvram\n",
1228                                          ds1307->nvram->size);
1229                         }
1230                 }
1231         }
1232
1233         return 0;
1234
1235 exit:
1236         return err;
1237 }
1238
1239 static int ds1307_remove(struct i2c_client *client)
1240 {
1241         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1242
1243         if (ds1307->wakeirq)
1244                 dev_pm_clear_wake_irq(&client->dev);
1245
1246         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1247                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1248
1249         return 0;
1250 }
1251
1252 static struct i2c_driver ds1307_driver = {
1253         .driver = {
1254                 .name   = "rtc-ds1307",
1255                 .owner  = THIS_MODULE,
1256         },
1257         .probe          = ds1307_probe,
1258         .remove         = ds1307_remove,
1259         .id_table       = ds1307_id,
1260 };
1261
1262 module_i2c_driver(ds1307_driver);
1263
1264 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1265 MODULE_LICENSE("GPL");