linux/drivers/rtc/rtc-ds1307.c
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   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 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/init.h>
  15#include <linux/slab.h>
  16#include <linux/i2c.h>
  17#include <linux/string.h>
  18#include <linux/rtc.h>
  19#include <linux/bcd.h>
  20#include <linux/rtc/ds1307.h>
  21
  22/*
  23 * We can't determine type by probing, but if we expect pre-Linux code
  24 * to have set the chip up as a clock (turning on the oscillator and
  25 * setting the date and time), Linux can ignore the non-clock features.
  26 * That's a natural job for a factory or repair bench.
  27 */
  28enum ds_type {
  29        ds_1307,
  30        ds_1337,
  31        ds_1338,
  32        ds_1339,
  33        ds_1340,
  34        ds_1388,
  35        ds_3231,
  36        m41t00,
  37        mcp7941x,
  38        rx_8025,
  39        last_ds_type /* always last */
  40        /* rs5c372 too?  different address... */
  41};
  42
  43
  44/* RTC registers don't differ much, except for the century flag */
  45#define DS1307_REG_SECS         0x00    /* 00-59 */
  46#       define DS1307_BIT_CH            0x80
  47#       define DS1340_BIT_nEOSC         0x80
  48#       define MCP7941X_BIT_ST          0x80
  49#define DS1307_REG_MIN          0x01    /* 00-59 */
  50#define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  51#       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  52#       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  53#       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  54#       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  55#define DS1307_REG_WDAY         0x03    /* 01-07 */
  56#       define MCP7941X_BIT_VBATEN      0x08
  57#define DS1307_REG_MDAY         0x04    /* 01-31 */
  58#define DS1307_REG_MONTH        0x05    /* 01-12 */
  59#       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  60#define DS1307_REG_YEAR         0x06    /* 00-99 */
  61
  62/*
  63 * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  64 * start at 7, and they differ a LOT. Only control and status matter for
  65 * basic RTC date and time functionality; be careful using them.
  66 */
  67#define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  68#       define DS1307_BIT_OUT           0x80
  69#       define DS1338_BIT_OSF           0x20
  70#       define DS1307_BIT_SQWE          0x10
  71#       define DS1307_BIT_RS1           0x02
  72#       define DS1307_BIT_RS0           0x01
  73#define DS1337_REG_CONTROL      0x0e
  74#       define DS1337_BIT_nEOSC         0x80
  75#       define DS1339_BIT_BBSQI         0x20
  76#       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  77#       define DS1337_BIT_RS2           0x10
  78#       define DS1337_BIT_RS1           0x08
  79#       define DS1337_BIT_INTCN         0x04
  80#       define DS1337_BIT_A2IE          0x02
  81#       define DS1337_BIT_A1IE          0x01
  82#define DS1340_REG_CONTROL      0x07
  83#       define DS1340_BIT_OUT           0x80
  84#       define DS1340_BIT_FT            0x40
  85#       define DS1340_BIT_CALIB_SIGN    0x20
  86#       define DS1340_M_CALIBRATION     0x1f
  87#define DS1340_REG_FLAG         0x09
  88#       define DS1340_BIT_OSF           0x80
  89#define DS1337_REG_STATUS       0x0f
  90#       define DS1337_BIT_OSF           0x80
  91#       define DS1337_BIT_A2I           0x02
  92#       define DS1337_BIT_A1I           0x01
  93#define DS1339_REG_ALARM1_SECS  0x07
  94
  95#define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
  96
  97#define RX8025_REG_CTRL1        0x0e
  98#       define RX8025_BIT_2412          0x20
  99#define RX8025_REG_CTRL2        0x0f
 100#       define RX8025_BIT_PON           0x10
 101#       define RX8025_BIT_VDET          0x40
 102#       define RX8025_BIT_XST           0x20
 103
 104
 105struct ds1307 {
 106        u8                      offset; /* register's offset */
 107        u8                      regs[11];
 108        u16                     nvram_offset;
 109        struct bin_attribute    *nvram;
 110        enum ds_type            type;
 111        unsigned long           flags;
 112#define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 113#define HAS_ALARM       1               /* bit 1 == irq claimed */
 114        struct i2c_client       *client;
 115        struct rtc_device       *rtc;
 116        struct work_struct      work;
 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
 123struct chip_desc {
 124        unsigned                alarm:1;
 125        u16                     nvram_offset;
 126        u16                     nvram_size;
 127        u16                     trickle_charger_reg;
 128};
 129
 130static const struct chip_desc chips[last_ds_type] = {
 131        [ds_1307] = {
 132                .nvram_offset   = 8,
 133                .nvram_size     = 56,
 134        },
 135        [ds_1337] = {
 136                .alarm          = 1,
 137        },
 138        [ds_1338] = {
 139                .nvram_offset   = 8,
 140                .nvram_size     = 56,
 141        },
 142        [ds_1339] = {
 143                .alarm          = 1,
 144                .trickle_charger_reg = 0x10,
 145        },
 146        [ds_1340] = {
 147                .trickle_charger_reg = 0x08,
 148        },
 149        [ds_1388] = {
 150                .trickle_charger_reg = 0x0a,
 151        },
 152        [ds_3231] = {
 153                .alarm          = 1,
 154        },
 155        [mcp7941x] = {
 156                /* this is battery backed SRAM */
 157                .nvram_offset   = 0x20,
 158                .nvram_size     = 0x40,
 159        },
 160};
 161
 162static const struct i2c_device_id ds1307_id[] = {
 163        { "ds1307", ds_1307 },
 164        { "ds1337", ds_1337 },
 165        { "ds1338", ds_1338 },
 166        { "ds1339", ds_1339 },
 167        { "ds1388", ds_1388 },
 168        { "ds1340", ds_1340 },
 169        { "ds3231", ds_3231 },
 170        { "m41t00", m41t00 },
 171        { "mcp7941x", mcp7941x },
 172        { "pt7c4338", ds_1307 },
 173        { "rx8025", rx_8025 },
 174        { }
 175};
 176MODULE_DEVICE_TABLE(i2c, ds1307_id);
 177
 178/*----------------------------------------------------------------------*/
 179
 180#define BLOCK_DATA_MAX_TRIES 10
 181
 182static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 183                                       u8 command, u8 length, u8 *values)
 184{
 185        s32 i, data;
 186
 187        for (i = 0; i < length; i++) {
 188                data = i2c_smbus_read_byte_data(client, command + i);
 189                if (data < 0)
 190                        return data;
 191                values[i] = data;
 192        }
 193        return i;
 194}
 195
 196static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 197                                  u8 length, u8 *values)
 198{
 199        u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 200        s32 ret;
 201        int tries = 0;
 202
 203        dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 204        ret = ds1307_read_block_data_once(client, command, length, values);
 205        if (ret < 0)
 206                return ret;
 207        do {
 208                if (++tries > BLOCK_DATA_MAX_TRIES) {
 209                        dev_err(&client->dev,
 210                                "ds1307_read_block_data failed\n");
 211                        return -EIO;
 212                }
 213                memcpy(oldvalues, values, length);
 214                ret = ds1307_read_block_data_once(client, command, length,
 215                                                  values);
 216                if (ret < 0)
 217                        return ret;
 218        } while (memcmp(oldvalues, values, length));
 219        return length;
 220}
 221
 222static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 223                                   u8 length, const u8 *values)
 224{
 225        u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 226        int tries = 0;
 227
 228        dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 229        do {
 230                s32 i, ret;
 231
 232                if (++tries > BLOCK_DATA_MAX_TRIES) {
 233                        dev_err(&client->dev,
 234                                "ds1307_write_block_data failed\n");
 235                        return -EIO;
 236                }
 237                for (i = 0; i < length; i++) {
 238                        ret = i2c_smbus_write_byte_data(client, command + i,
 239                                                        values[i]);
 240                        if (ret < 0)
 241                                return ret;
 242                }
 243                ret = ds1307_read_block_data_once(client, command, length,
 244                                                  currvalues);
 245                if (ret < 0)
 246                        return ret;
 247        } while (memcmp(currvalues, values, length));
 248        return length;
 249}
 250
 251/*----------------------------------------------------------------------*/
 252
 253/*
 254 * The IRQ logic includes a "real" handler running in IRQ context just
 255 * long enough to schedule this workqueue entry.   We need a task context
 256 * to talk to the RTC, since I2C I/O calls require that; and disable the
 257 * IRQ until we clear its status on the chip, so that this handler can
 258 * work with any type of triggering (not just falling edge).
 259 *
 260 * The ds1337 and ds1339 both have two alarms, but we only use the first
 261 * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 262 * signal; ds1339 chips have only one alarm signal.
 263 */
 264static void ds1307_work(struct work_struct *work)
 265{
 266        struct ds1307           *ds1307;
 267        struct i2c_client       *client;
 268        struct mutex            *lock;
 269        int                     stat, control;
 270
 271        ds1307 = container_of(work, struct ds1307, work);
 272        client = ds1307->client;
 273        lock = &ds1307->rtc->ops_lock;
 274
 275        mutex_lock(lock);
 276        stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 277        if (stat < 0)
 278                goto out;
 279
 280        if (stat & DS1337_BIT_A1I) {
 281                stat &= ~DS1337_BIT_A1I;
 282                i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 283
 284                control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 285                if (control < 0)
 286                        goto out;
 287
 288                control &= ~DS1337_BIT_A1IE;
 289                i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 290
 291                rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 292        }
 293
 294out:
 295        if (test_bit(HAS_ALARM, &ds1307->flags))
 296                enable_irq(client->irq);
 297        mutex_unlock(lock);
 298}
 299
 300static irqreturn_t ds1307_irq(int irq, void *dev_id)
 301{
 302        struct i2c_client       *client = dev_id;
 303        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 304
 305        disable_irq_nosync(irq);
 306        schedule_work(&ds1307->work);
 307        return IRQ_HANDLED;
 308}
 309
 310/*----------------------------------------------------------------------*/
 311
 312static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 313{
 314        struct ds1307   *ds1307 = dev_get_drvdata(dev);
 315        int             tmp;
 316
 317        /* read the RTC date and time registers all at once */
 318        tmp = ds1307->read_block_data(ds1307->client,
 319                ds1307->offset, 7, ds1307->regs);
 320        if (tmp != 7) {
 321                dev_err(dev, "%s error %d\n", "read", tmp);
 322                return -EIO;
 323        }
 324
 325        dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 326
 327        t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 328        t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 329        tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 330        t->tm_hour = bcd2bin(tmp);
 331        t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 332        t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 333        tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 334        t->tm_mon = bcd2bin(tmp) - 1;
 335
 336        /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 337        t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 338
 339        dev_dbg(dev, "%s secs=%d, mins=%d, "
 340                "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 341                "read", t->tm_sec, t->tm_min,
 342                t->tm_hour, t->tm_mday,
 343                t->tm_mon, t->tm_year, t->tm_wday);
 344
 345        /* initial clock setting can be undefined */
 346        return rtc_valid_tm(t);
 347}
 348
 349static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 350{
 351        struct ds1307   *ds1307 = dev_get_drvdata(dev);
 352        int             result;
 353        int             tmp;
 354        u8              *buf = ds1307->regs;
 355
 356        dev_dbg(dev, "%s secs=%d, mins=%d, "
 357                "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 358                "write", t->tm_sec, t->tm_min,
 359                t->tm_hour, t->tm_mday,
 360                t->tm_mon, t->tm_year, t->tm_wday);
 361
 362        buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 363        buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 364        buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 365        buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 366        buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 367        buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 368
 369        /* assume 20YY not 19YY */
 370        tmp = t->tm_year - 100;
 371        buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 372
 373        switch (ds1307->type) {
 374        case ds_1337:
 375        case ds_1339:
 376        case ds_3231:
 377                buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 378                break;
 379        case ds_1340:
 380                buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 381                                | DS1340_BIT_CENTURY;
 382                break;
 383        case mcp7941x:
 384                /*
 385                 * these bits were cleared when preparing the date/time
 386                 * values and need to be set again before writing the
 387                 * buffer out to the device.
 388                 */
 389                buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 390                buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 391                break;
 392        default:
 393                break;
 394        }
 395
 396        dev_dbg(dev, "%s: %7ph\n", "write", buf);
 397
 398        result = ds1307->write_block_data(ds1307->client,
 399                ds1307->offset, 7, buf);
 400        if (result < 0) {
 401                dev_err(dev, "%s error %d\n", "write", result);
 402                return result;
 403        }
 404        return 0;
 405}
 406
 407static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 408{
 409        struct i2c_client       *client = to_i2c_client(dev);
 410        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 411        int                     ret;
 412
 413        if (!test_bit(HAS_ALARM, &ds1307->flags))
 414                return -EINVAL;
 415
 416        /* read all ALARM1, ALARM2, and status registers at once */
 417        ret = ds1307->read_block_data(client,
 418                        DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 419        if (ret != 9) {
 420                dev_err(dev, "%s error %d\n", "alarm read", ret);
 421                return -EIO;
 422        }
 423
 424        dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 425                        "alarm read",
 426                        ds1307->regs[0], ds1307->regs[1],
 427                        ds1307->regs[2], ds1307->regs[3],
 428                        ds1307->regs[4], ds1307->regs[5],
 429                        ds1307->regs[6], ds1307->regs[7],
 430                        ds1307->regs[8]);
 431
 432        /*
 433         * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 434         * and that all four fields are checked matches
 435         */
 436        t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 437        t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 438        t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 439        t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 440        t->time.tm_mon = -1;
 441        t->time.tm_year = -1;
 442        t->time.tm_wday = -1;
 443        t->time.tm_yday = -1;
 444        t->time.tm_isdst = -1;
 445
 446        /* ... and status */
 447        t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 448        t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 449
 450        dev_dbg(dev, "%s secs=%d, mins=%d, "
 451                "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 452                "alarm read", t->time.tm_sec, t->time.tm_min,
 453                t->time.tm_hour, t->time.tm_mday,
 454                t->enabled, t->pending);
 455
 456        return 0;
 457}
 458
 459static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 460{
 461        struct i2c_client       *client = to_i2c_client(dev);
 462        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 463        unsigned char           *buf = ds1307->regs;
 464        u8                      control, status;
 465        int                     ret;
 466
 467        if (!test_bit(HAS_ALARM, &ds1307->flags))
 468                return -EINVAL;
 469
 470        dev_dbg(dev, "%s secs=%d, mins=%d, "
 471                "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 472                "alarm set", t->time.tm_sec, t->time.tm_min,
 473                t->time.tm_hour, t->time.tm_mday,
 474                t->enabled, t->pending);
 475
 476        /* read current status of both alarms and the chip */
 477        ret = ds1307->read_block_data(client,
 478                        DS1339_REG_ALARM1_SECS, 9, buf);
 479        if (ret != 9) {
 480                dev_err(dev, "%s error %d\n", "alarm write", ret);
 481                return -EIO;
 482        }
 483        control = ds1307->regs[7];
 484        status = ds1307->regs[8];
 485
 486        dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 487                        "alarm set (old status)",
 488                        ds1307->regs[0], ds1307->regs[1],
 489                        ds1307->regs[2], ds1307->regs[3],
 490                        ds1307->regs[4], ds1307->regs[5],
 491                        ds1307->regs[6], control, status);
 492
 493        /* set ALARM1, using 24 hour and day-of-month modes */
 494        buf[0] = bin2bcd(t->time.tm_sec);
 495        buf[1] = bin2bcd(t->time.tm_min);
 496        buf[2] = bin2bcd(t->time.tm_hour);
 497        buf[3] = bin2bcd(t->time.tm_mday);
 498
 499        /* set ALARM2 to non-garbage */
 500        buf[4] = 0;
 501        buf[5] = 0;
 502        buf[6] = 0;
 503
 504        /* optionally enable ALARM1 */
 505        buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 506        if (t->enabled) {
 507                dev_dbg(dev, "alarm IRQ armed\n");
 508                buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 509        }
 510        buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 511
 512        ret = ds1307->write_block_data(client,
 513                        DS1339_REG_ALARM1_SECS, 9, buf);
 514        if (ret < 0) {
 515                dev_err(dev, "can't set alarm time\n");
 516                return ret;
 517        }
 518
 519        return 0;
 520}
 521
 522static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 523{
 524        struct i2c_client       *client = to_i2c_client(dev);
 525        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 526        int                     ret;
 527
 528        if (!test_bit(HAS_ALARM, &ds1307->flags))
 529                return -ENOTTY;
 530
 531        ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 532        if (ret < 0)
 533                return ret;
 534
 535        if (enabled)
 536                ret |= DS1337_BIT_A1IE;
 537        else
 538                ret &= ~DS1337_BIT_A1IE;
 539
 540        ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 541        if (ret < 0)
 542                return ret;
 543
 544        return 0;
 545}
 546
 547static const struct rtc_class_ops ds13xx_rtc_ops = {
 548        .read_time      = ds1307_get_time,
 549        .set_time       = ds1307_set_time,
 550        .read_alarm     = ds1337_read_alarm,
 551        .set_alarm      = ds1337_set_alarm,
 552        .alarm_irq_enable = ds1307_alarm_irq_enable,
 553};
 554
 555/*----------------------------------------------------------------------*/
 556
 557static ssize_t
 558ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 559                struct bin_attribute *attr,
 560                char *buf, loff_t off, size_t count)
 561{
 562        struct i2c_client       *client;
 563        struct ds1307           *ds1307;
 564        int                     result;
 565
 566        client = kobj_to_i2c_client(kobj);
 567        ds1307 = i2c_get_clientdata(client);
 568
 569        if (unlikely(off >= ds1307->nvram->size))
 570                return 0;
 571        if ((off + count) > ds1307->nvram->size)
 572                count = ds1307->nvram->size - off;
 573        if (unlikely(!count))
 574                return count;
 575
 576        result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 577                                                                count, buf);
 578        if (result < 0)
 579                dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 580        return result;
 581}
 582
 583static ssize_t
 584ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 585                struct bin_attribute *attr,
 586                char *buf, loff_t off, size_t count)
 587{
 588        struct i2c_client       *client;
 589        struct ds1307           *ds1307;
 590        int                     result;
 591
 592        client = kobj_to_i2c_client(kobj);
 593        ds1307 = i2c_get_clientdata(client);
 594
 595        if (unlikely(off >= ds1307->nvram->size))
 596                return -EFBIG;
 597        if ((off + count) > ds1307->nvram->size)
 598                count = ds1307->nvram->size - off;
 599        if (unlikely(!count))
 600                return count;
 601
 602        result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 603                                                                count, buf);
 604        if (result < 0) {
 605                dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 606                return result;
 607        }
 608        return count;
 609}
 610
 611/*----------------------------------------------------------------------*/
 612
 613static int ds1307_probe(struct i2c_client *client,
 614                        const struct i2c_device_id *id)
 615{
 616        struct ds1307           *ds1307;
 617        int                     err = -ENODEV;
 618        int                     tmp;
 619        const struct chip_desc  *chip = &chips[id->driver_data];
 620        struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 621        int                     want_irq = false;
 622        unsigned char           *buf;
 623        struct ds1307_platform_data *pdata = client->dev.platform_data;
 624        static const int        bbsqi_bitpos[] = {
 625                [ds_1337] = 0,
 626                [ds_1339] = DS1339_BIT_BBSQI,
 627                [ds_3231] = DS3231_BIT_BBSQW,
 628        };
 629
 630        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 631            && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 632                return -EIO;
 633
 634        ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
 635        if (!ds1307)
 636                return -ENOMEM;
 637
 638        i2c_set_clientdata(client, ds1307);
 639
 640        ds1307->client  = client;
 641        ds1307->type    = id->driver_data;
 642
 643        if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
 644                i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 645                        DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
 646
 647        buf = ds1307->regs;
 648        if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 649                ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 650                ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 651        } else {
 652                ds1307->read_block_data = ds1307_read_block_data;
 653                ds1307->write_block_data = ds1307_write_block_data;
 654        }
 655
 656        switch (ds1307->type) {
 657        case ds_1337:
 658        case ds_1339:
 659        case ds_3231:
 660                /* get registers that the "rtc" read below won't read... */
 661                tmp = ds1307->read_block_data(ds1307->client,
 662                                DS1337_REG_CONTROL, 2, buf);
 663                if (tmp != 2) {
 664                        pr_debug("read error %d\n", tmp);
 665                        err = -EIO;
 666                        goto exit_free;
 667                }
 668
 669                /* oscillator off?  turn it on, so clock can tick. */
 670                if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 671                        ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 672
 673                /*
 674                 * Using IRQ?  Disable the square wave and both alarms.
 675                 * For some variants, be sure alarms can trigger when we're
 676                 * running on Vbackup (BBSQI/BBSQW)
 677                 */
 678                if (ds1307->client->irq > 0 && chip->alarm) {
 679                        INIT_WORK(&ds1307->work, ds1307_work);
 680
 681                        ds1307->regs[0] |= DS1337_BIT_INTCN
 682                                        | bbsqi_bitpos[ds1307->type];
 683                        ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 684
 685                        want_irq = true;
 686                }
 687
 688                i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 689                                                        ds1307->regs[0]);
 690
 691                /* oscillator fault?  clear flag, and warn */
 692                if (ds1307->regs[1] & DS1337_BIT_OSF) {
 693                        i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 694                                ds1307->regs[1] & ~DS1337_BIT_OSF);
 695                        dev_warn(&client->dev, "SET TIME!\n");
 696                }
 697                break;
 698
 699        case rx_8025:
 700                tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 701                                RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 702                if (tmp != 2) {
 703                        pr_debug("read error %d\n", tmp);
 704                        err = -EIO;
 705                        goto exit_free;
 706                }
 707
 708                /* oscillator off?  turn it on, so clock can tick. */
 709                if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 710                        ds1307->regs[1] |= RX8025_BIT_XST;
 711                        i2c_smbus_write_byte_data(client,
 712                                                  RX8025_REG_CTRL2 << 4 | 0x08,
 713                                                  ds1307->regs[1]);
 714                        dev_warn(&client->dev,
 715                                 "oscillator stop detected - SET TIME!\n");
 716                }
 717
 718                if (ds1307->regs[1] & RX8025_BIT_PON) {
 719                        ds1307->regs[1] &= ~RX8025_BIT_PON;
 720                        i2c_smbus_write_byte_data(client,
 721                                                  RX8025_REG_CTRL2 << 4 | 0x08,
 722                                                  ds1307->regs[1]);
 723                        dev_warn(&client->dev, "power-on detected\n");
 724                }
 725
 726                if (ds1307->regs[1] & RX8025_BIT_VDET) {
 727                        ds1307->regs[1] &= ~RX8025_BIT_VDET;
 728                        i2c_smbus_write_byte_data(client,
 729                                                  RX8025_REG_CTRL2 << 4 | 0x08,
 730                                                  ds1307->regs[1]);
 731                        dev_warn(&client->dev, "voltage drop detected\n");
 732                }
 733
 734                /* make sure we are running in 24hour mode */
 735                if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 736                        u8 hour;
 737
 738                        /* switch to 24 hour mode */
 739                        i2c_smbus_write_byte_data(client,
 740                                                  RX8025_REG_CTRL1 << 4 | 0x08,
 741                                                  ds1307->regs[0] |
 742                                                  RX8025_BIT_2412);
 743
 744                        tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 745                                        RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 746                        if (tmp != 2) {
 747                                pr_debug("read error %d\n", tmp);
 748                                err = -EIO;
 749                                goto exit_free;
 750                        }
 751
 752                        /* correct hour */
 753                        hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 754                        if (hour == 12)
 755                                hour = 0;
 756                        if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 757                                hour += 12;
 758
 759                        i2c_smbus_write_byte_data(client,
 760                                                  DS1307_REG_HOUR << 4 | 0x08,
 761                                                  hour);
 762                }
 763                break;
 764        case ds_1388:
 765                ds1307->offset = 1; /* Seconds starts at 1 */
 766                break;
 767        default:
 768                break;
 769        }
 770
 771read_rtc:
 772        /* read RTC registers */
 773        tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 774        if (tmp != 8) {
 775                pr_debug("read error %d\n", tmp);
 776                err = -EIO;
 777                goto exit_free;
 778        }
 779
 780        /*
 781         * minimal sanity checking; some chips (like DS1340) don't
 782         * specify the extra bits as must-be-zero, but there are
 783         * still a few values that are clearly out-of-range.
 784         */
 785        tmp = ds1307->regs[DS1307_REG_SECS];
 786        switch (ds1307->type) {
 787        case ds_1307:
 788        case m41t00:
 789                /* clock halted?  turn it on, so clock can tick. */
 790                if (tmp & DS1307_BIT_CH) {
 791                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 792                        dev_warn(&client->dev, "SET TIME!\n");
 793                        goto read_rtc;
 794                }
 795                break;
 796        case ds_1338:
 797                /* clock halted?  turn it on, so clock can tick. */
 798                if (tmp & DS1307_BIT_CH)
 799                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 800
 801                /* oscillator fault?  clear flag, and warn */
 802                if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 803                        i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 804                                        ds1307->regs[DS1307_REG_CONTROL]
 805                                        & ~DS1338_BIT_OSF);
 806                        dev_warn(&client->dev, "SET TIME!\n");
 807                        goto read_rtc;
 808                }
 809                break;
 810        case ds_1340:
 811                /* clock halted?  turn it on, so clock can tick. */
 812                if (tmp & DS1340_BIT_nEOSC)
 813                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 814
 815                tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 816                if (tmp < 0) {
 817                        pr_debug("read error %d\n", tmp);
 818                        err = -EIO;
 819                        goto exit_free;
 820                }
 821
 822                /* oscillator fault?  clear flag, and warn */
 823                if (tmp & DS1340_BIT_OSF) {
 824                        i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 825                        dev_warn(&client->dev, "SET TIME!\n");
 826                }
 827                break;
 828        case mcp7941x:
 829                /* make sure that the backup battery is enabled */
 830                if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 831                        i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 832                                        ds1307->regs[DS1307_REG_WDAY]
 833                                        | MCP7941X_BIT_VBATEN);
 834                }
 835
 836                /* clock halted?  turn it on, so clock can tick. */
 837                if (!(tmp & MCP7941X_BIT_ST)) {
 838                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 839                                        MCP7941X_BIT_ST);
 840                        dev_warn(&client->dev, "SET TIME!\n");
 841                        goto read_rtc;
 842                }
 843
 844                break;
 845        default:
 846                break;
 847        }
 848
 849        tmp = ds1307->regs[DS1307_REG_HOUR];
 850        switch (ds1307->type) {
 851        case ds_1340:
 852        case m41t00:
 853                /*
 854                 * NOTE: ignores century bits; fix before deploying
 855                 * systems that will run through year 2100.
 856                 */
 857                break;
 858        case rx_8025:
 859                break;
 860        default:
 861                if (!(tmp & DS1307_BIT_12HR))
 862                        break;
 863
 864                /*
 865                 * Be sure we're in 24 hour mode.  Multi-master systems
 866                 * take note...
 867                 */
 868                tmp = bcd2bin(tmp & 0x1f);
 869                if (tmp == 12)
 870                        tmp = 0;
 871                if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 872                        tmp += 12;
 873                i2c_smbus_write_byte_data(client,
 874                                ds1307->offset + DS1307_REG_HOUR,
 875                                bin2bcd(tmp));
 876        }
 877
 878        ds1307->rtc = rtc_device_register(client->name, &client->dev,
 879                                &ds13xx_rtc_ops, THIS_MODULE);
 880        if (IS_ERR(ds1307->rtc)) {
 881                err = PTR_ERR(ds1307->rtc);
 882                dev_err(&client->dev,
 883                        "unable to register the class device\n");
 884                goto exit_free;
 885        }
 886
 887        if (want_irq) {
 888                err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 889                          ds1307->rtc->name, client);
 890                if (err) {
 891                        dev_err(&client->dev,
 892                                "unable to request IRQ!\n");
 893                        goto exit_irq;
 894                }
 895
 896                device_set_wakeup_capable(&client->dev, 1);
 897                set_bit(HAS_ALARM, &ds1307->flags);
 898                dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 899        }
 900
 901        if (chip->nvram_size) {
 902                ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
 903                                                        GFP_KERNEL);
 904                if (!ds1307->nvram) {
 905                        err = -ENOMEM;
 906                        goto exit_nvram;
 907                }
 908                ds1307->nvram->attr.name = "nvram";
 909                ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
 910                sysfs_bin_attr_init(ds1307->nvram);
 911                ds1307->nvram->read = ds1307_nvram_read,
 912                ds1307->nvram->write = ds1307_nvram_write,
 913                ds1307->nvram->size = chip->nvram_size;
 914                ds1307->nvram_offset = chip->nvram_offset;
 915                err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
 916                if (err) {
 917                        kfree(ds1307->nvram);
 918                        goto exit_nvram;
 919                }
 920                set_bit(HAS_NVRAM, &ds1307->flags);
 921                dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
 922        }
 923
 924        return 0;
 925
 926exit_nvram:
 927exit_irq:
 928        rtc_device_unregister(ds1307->rtc);
 929exit_free:
 930        kfree(ds1307);
 931        return err;
 932}
 933
 934static int ds1307_remove(struct i2c_client *client)
 935{
 936        struct ds1307 *ds1307 = i2c_get_clientdata(client);
 937
 938        if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 939                free_irq(client->irq, client);
 940                cancel_work_sync(&ds1307->work);
 941        }
 942
 943        if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
 944                sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
 945                kfree(ds1307->nvram);
 946        }
 947
 948        rtc_device_unregister(ds1307->rtc);
 949        kfree(ds1307);
 950        return 0;
 951}
 952
 953static struct i2c_driver ds1307_driver = {
 954        .driver = {
 955                .name   = "rtc-ds1307",
 956                .owner  = THIS_MODULE,
 957        },
 958        .probe          = ds1307_probe,
 959        .remove         = ds1307_remove,
 960        .id_table       = ds1307_id,
 961};
 962
 963module_i2c_driver(ds1307_driver);
 964
 965MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 966MODULE_LICENSE("GPL");
 967
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