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: %02x %02x %02x %02x %02x %02x %02x\n",
 326                        "read",
 327                        ds1307->regs[0], ds1307->regs[1],
 328                        ds1307->regs[2], ds1307->regs[3],
 329                        ds1307->regs[4], ds1307->regs[5],
 330                        ds1307->regs[6]);
 331
 332        t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 333        t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 334        tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 335        t->tm_hour = bcd2bin(tmp);
 336        t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 337        t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 338        tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 339        t->tm_mon = bcd2bin(tmp) - 1;
 340
 341        /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 342        t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 343
 344        dev_dbg(dev, "%s secs=%d, mins=%d, "
 345                "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 346                "read", t->tm_sec, t->tm_min,
 347                t->tm_hour, t->tm_mday,
 348                t->tm_mon, t->tm_year, t->tm_wday);
 349
 350        /* initial clock setting can be undefined */
 351        return rtc_valid_tm(t);
 352}
 353
 354static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 355{
 356        struct ds1307   *ds1307 = dev_get_drvdata(dev);
 357        int             result;
 358        int             tmp;
 359        u8              *buf = ds1307->regs;
 360
 361        dev_dbg(dev, "%s secs=%d, mins=%d, "
 362                "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 363                "write", t->tm_sec, t->tm_min,
 364                t->tm_hour, t->tm_mday,
 365                t->tm_mon, t->tm_year, t->tm_wday);
 366
 367        buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 368        buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 369        buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 370        buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 371        buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 372        buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 373
 374        /* assume 20YY not 19YY */
 375        tmp = t->tm_year - 100;
 376        buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 377
 378        switch (ds1307->type) {
 379        case ds_1337:
 380        case ds_1339:
 381        case ds_3231:
 382                buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 383                break;
 384        case ds_1340:
 385                buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 386                                | DS1340_BIT_CENTURY;
 387                break;
 388        case mcp7941x:
 389                /*
 390                 * these bits were cleared when preparing the date/time
 391                 * values and need to be set again before writing the
 392                 * buffer out to the device.
 393                 */
 394                buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 395                buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 396                break;
 397        default:
 398                break;
 399        }
 400
 401        dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 402                "write", buf[0], buf[1], buf[2], buf[3],
 403                buf[4], buf[5], buf[6]);
 404
 405        result = ds1307->write_block_data(ds1307->client,
 406                ds1307->offset, 7, buf);
 407        if (result < 0) {
 408                dev_err(dev, "%s error %d\n", "write", result);
 409                return result;
 410        }
 411        return 0;
 412}
 413
 414static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 415{
 416        struct i2c_client       *client = to_i2c_client(dev);
 417        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 418        int                     ret;
 419
 420        if (!test_bit(HAS_ALARM, &ds1307->flags))
 421                return -EINVAL;
 422
 423        /* read all ALARM1, ALARM2, and status registers at once */
 424        ret = ds1307->read_block_data(client,
 425                        DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 426        if (ret != 9) {
 427                dev_err(dev, "%s error %d\n", "alarm read", ret);
 428                return -EIO;
 429        }
 430
 431        dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 432                        "alarm read",
 433                        ds1307->regs[0], ds1307->regs[1],
 434                        ds1307->regs[2], ds1307->regs[3],
 435                        ds1307->regs[4], ds1307->regs[5],
 436                        ds1307->regs[6], ds1307->regs[7],
 437                        ds1307->regs[8]);
 438
 439        /*
 440         * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 441         * and that all four fields are checked matches
 442         */
 443        t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 444        t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 445        t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 446        t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 447        t->time.tm_mon = -1;
 448        t->time.tm_year = -1;
 449        t->time.tm_wday = -1;
 450        t->time.tm_yday = -1;
 451        t->time.tm_isdst = -1;
 452
 453        /* ... and status */
 454        t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 455        t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 456
 457        dev_dbg(dev, "%s secs=%d, mins=%d, "
 458                "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 459                "alarm read", t->time.tm_sec, t->time.tm_min,
 460                t->time.tm_hour, t->time.tm_mday,
 461                t->enabled, t->pending);
 462
 463        return 0;
 464}
 465
 466static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 467{
 468        struct i2c_client       *client = to_i2c_client(dev);
 469        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 470        unsigned char           *buf = ds1307->regs;
 471        u8                      control, status;
 472        int                     ret;
 473
 474        if (!test_bit(HAS_ALARM, &ds1307->flags))
 475                return -EINVAL;
 476
 477        dev_dbg(dev, "%s secs=%d, mins=%d, "
 478                "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 479                "alarm set", t->time.tm_sec, t->time.tm_min,
 480                t->time.tm_hour, t->time.tm_mday,
 481                t->enabled, t->pending);
 482
 483        /* read current status of both alarms and the chip */
 484        ret = ds1307->read_block_data(client,
 485                        DS1339_REG_ALARM1_SECS, 9, buf);
 486        if (ret != 9) {
 487                dev_err(dev, "%s error %d\n", "alarm write", ret);
 488                return -EIO;
 489        }
 490        control = ds1307->regs[7];
 491        status = ds1307->regs[8];
 492
 493        dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 494                        "alarm set (old status)",
 495                        ds1307->regs[0], ds1307->regs[1],
 496                        ds1307->regs[2], ds1307->regs[3],
 497                        ds1307->regs[4], ds1307->regs[5],
 498                        ds1307->regs[6], control, status);
 499
 500        /* set ALARM1, using 24 hour and day-of-month modes */
 501        buf[0] = bin2bcd(t->time.tm_sec);
 502        buf[1] = bin2bcd(t->time.tm_min);
 503        buf[2] = bin2bcd(t->time.tm_hour);
 504        buf[3] = bin2bcd(t->time.tm_mday);
 505
 506        /* set ALARM2 to non-garbage */
 507        buf[4] = 0;
 508        buf[5] = 0;
 509        buf[6] = 0;
 510
 511        /* optionally enable ALARM1 */
 512        buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 513        if (t->enabled) {
 514                dev_dbg(dev, "alarm IRQ armed\n");
 515                buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 516        }
 517        buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 518
 519        ret = ds1307->write_block_data(client,
 520                        DS1339_REG_ALARM1_SECS, 9, buf);
 521        if (ret < 0) {
 522                dev_err(dev, "can't set alarm time\n");
 523                return ret;
 524        }
 525
 526        return 0;
 527}
 528
 529static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 530{
 531        struct i2c_client       *client = to_i2c_client(dev);
 532        struct ds1307           *ds1307 = i2c_get_clientdata(client);
 533        int                     ret;
 534
 535        if (!test_bit(HAS_ALARM, &ds1307->flags))
 536                return -ENOTTY;
 537
 538        ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 539        if (ret < 0)
 540                return ret;
 541
 542        if (enabled)
 543                ret |= DS1337_BIT_A1IE;
 544        else
 545                ret &= ~DS1337_BIT_A1IE;
 546
 547        ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 548        if (ret < 0)
 549                return ret;
 550
 551        return 0;
 552}
 553
 554static const struct rtc_class_ops ds13xx_rtc_ops = {
 555        .read_time      = ds1307_get_time,
 556        .set_time       = ds1307_set_time,
 557        .read_alarm     = ds1337_read_alarm,
 558        .set_alarm      = ds1337_set_alarm,
 559        .alarm_irq_enable = ds1307_alarm_irq_enable,
 560};
 561
 562/*----------------------------------------------------------------------*/
 563
 564static ssize_t
 565ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 566                struct bin_attribute *attr,
 567                char *buf, loff_t off, size_t count)
 568{
 569        struct i2c_client       *client;
 570        struct ds1307           *ds1307;
 571        int                     result;
 572
 573        client = kobj_to_i2c_client(kobj);
 574        ds1307 = i2c_get_clientdata(client);
 575
 576        if (unlikely(off >= ds1307->nvram->size))
 577                return 0;
 578        if ((off + count) > ds1307->nvram->size)
 579                count = ds1307->nvram->size - off;
 580        if (unlikely(!count))
 581                return count;
 582
 583        result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 584                                                                count, buf);
 585        if (result < 0)
 586                dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 587        return result;
 588}
 589
 590static ssize_t
 591ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 592                struct bin_attribute *attr,
 593                char *buf, loff_t off, size_t count)
 594{
 595        struct i2c_client       *client;
 596        struct ds1307           *ds1307;
 597        int                     result;
 598
 599        client = kobj_to_i2c_client(kobj);
 600        ds1307 = i2c_get_clientdata(client);
 601
 602        if (unlikely(off >= ds1307->nvram->size))
 603                return -EFBIG;
 604        if ((off + count) > ds1307->nvram->size)
 605                count = ds1307->nvram->size - off;
 606        if (unlikely(!count))
 607                return count;
 608
 609        result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 610                                                                count, buf);
 611        if (result < 0) {
 612                dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 613                return result;
 614        }
 615        return count;
 616}
 617
 618/*----------------------------------------------------------------------*/
 619
 620static int ds1307_probe(struct i2c_client *client,
 621                        const struct i2c_device_id *id)
 622{
 623        struct ds1307           *ds1307;
 624        int                     err = -ENODEV;
 625        int                     tmp;
 626        const struct chip_desc  *chip = &chips[id->driver_data];
 627        struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 628        int                     want_irq = false;
 629        unsigned char           *buf;
 630        struct ds1307_platform_data *pdata = client->dev.platform_data;
 631        static const int        bbsqi_bitpos[] = {
 632                [ds_1337] = 0,
 633                [ds_1339] = DS1339_BIT_BBSQI,
 634                [ds_3231] = DS3231_BIT_BBSQW,
 635        };
 636
 637        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 638            && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 639                return -EIO;
 640
 641        ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
 642        if (!ds1307)
 643                return -ENOMEM;
 644
 645        i2c_set_clientdata(client, ds1307);
 646
 647        ds1307->client  = client;
 648        ds1307->type    = id->driver_data;
 649
 650        if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
 651                i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 652                        DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
 653
 654        buf = ds1307->regs;
 655        if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 656                ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 657                ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 658        } else {
 659                ds1307->read_block_data = ds1307_read_block_data;
 660                ds1307->write_block_data = ds1307_write_block_data;
 661        }
 662
 663        switch (ds1307->type) {
 664        case ds_1337:
 665        case ds_1339:
 666        case ds_3231:
 667                /* get registers that the "rtc" read below won't read... */
 668                tmp = ds1307->read_block_data(ds1307->client,
 669                                DS1337_REG_CONTROL, 2, buf);
 670                if (tmp != 2) {
 671                        pr_debug("read error %d\n", tmp);
 672                        err = -EIO;
 673                        goto exit_free;
 674                }
 675
 676                /* oscillator off?  turn it on, so clock can tick. */
 677                if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 678                        ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 679
 680                /*
 681                 * Using IRQ?  Disable the square wave and both alarms.
 682                 * For some variants, be sure alarms can trigger when we're
 683                 * running on Vbackup (BBSQI/BBSQW)
 684                 */
 685                if (ds1307->client->irq > 0 && chip->alarm) {
 686                        INIT_WORK(&ds1307->work, ds1307_work);
 687
 688                        ds1307->regs[0] |= DS1337_BIT_INTCN
 689                                        | bbsqi_bitpos[ds1307->type];
 690                        ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 691
 692                        want_irq = true;
 693                }
 694
 695                i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 696                                                        ds1307->regs[0]);
 697
 698                /* oscillator fault?  clear flag, and warn */
 699                if (ds1307->regs[1] & DS1337_BIT_OSF) {
 700                        i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 701                                ds1307->regs[1] & ~DS1337_BIT_OSF);
 702                        dev_warn(&client->dev, "SET TIME!\n");
 703                }
 704                break;
 705
 706        case rx_8025:
 707                tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 708                                RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 709                if (tmp != 2) {
 710                        pr_debug("read error %d\n", tmp);
 711                        err = -EIO;
 712                        goto exit_free;
 713                }
 714
 715                /* oscillator off?  turn it on, so clock can tick. */
 716                if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 717                        ds1307->regs[1] |= RX8025_BIT_XST;
 718                        i2c_smbus_write_byte_data(client,
 719                                                  RX8025_REG_CTRL2 << 4 | 0x08,
 720                                                  ds1307->regs[1]);
 721                        dev_warn(&client->dev,
 722                                 "oscillator stop detected - SET TIME!\n");
 723                }
 724
 725                if (ds1307->regs[1] & RX8025_BIT_PON) {
 726                        ds1307->regs[1] &= ~RX8025_BIT_PON;
 727                        i2c_smbus_write_byte_data(client,
 728                                                  RX8025_REG_CTRL2 << 4 | 0x08,
 729                                                  ds1307->regs[1]);
 730                        dev_warn(&client->dev, "power-on detected\n");
 731                }
 732
 733                if (ds1307->regs[1] & RX8025_BIT_VDET) {
 734                        ds1307->regs[1] &= ~RX8025_BIT_VDET;
 735                        i2c_smbus_write_byte_data(client,
 736                                                  RX8025_REG_CTRL2 << 4 | 0x08,
 737                                                  ds1307->regs[1]);
 738                        dev_warn(&client->dev, "voltage drop detected\n");
 739                }
 740
 741                /* make sure we are running in 24hour mode */
 742                if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 743                        u8 hour;
 744
 745                        /* switch to 24 hour mode */
 746                        i2c_smbus_write_byte_data(client,
 747                                                  RX8025_REG_CTRL1 << 4 | 0x08,
 748                                                  ds1307->regs[0] |
 749                                                  RX8025_BIT_2412);
 750
 751                        tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 752                                        RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 753                        if (tmp != 2) {
 754                                pr_debug("read error %d\n", tmp);
 755                                err = -EIO;
 756                                goto exit_free;
 757                        }
 758
 759                        /* correct hour */
 760                        hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 761                        if (hour == 12)
 762                                hour = 0;
 763                        if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 764                                hour += 12;
 765
 766                        i2c_smbus_write_byte_data(client,
 767                                                  DS1307_REG_HOUR << 4 | 0x08,
 768                                                  hour);
 769                }
 770                break;
 771        case ds_1388:
 772                ds1307->offset = 1; /* Seconds starts at 1 */
 773                break;
 774        default:
 775                break;
 776        }
 777
 778read_rtc:
 779        /* read RTC registers */
 780        tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 781        if (tmp != 8) {
 782                pr_debug("read error %d\n", tmp);
 783                err = -EIO;
 784                goto exit_free;
 785        }
 786
 787        /*
 788         * minimal sanity checking; some chips (like DS1340) don't
 789         * specify the extra bits as must-be-zero, but there are
 790         * still a few values that are clearly out-of-range.
 791         */
 792        tmp = ds1307->regs[DS1307_REG_SECS];
 793        switch (ds1307->type) {
 794        case ds_1307:
 795        case m41t00:
 796                /* clock halted?  turn it on, so clock can tick. */
 797                if (tmp & DS1307_BIT_CH) {
 798                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 799                        dev_warn(&client->dev, "SET TIME!\n");
 800                        goto read_rtc;
 801                }
 802                break;
 803        case ds_1338:
 804                /* clock halted?  turn it on, so clock can tick. */
 805                if (tmp & DS1307_BIT_CH)
 806                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 807
 808                /* oscillator fault?  clear flag, and warn */
 809                if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 810                        i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 811                                        ds1307->regs[DS1307_REG_CONTROL]
 812                                        & ~DS1338_BIT_OSF);
 813                        dev_warn(&client->dev, "SET TIME!\n");
 814                        goto read_rtc;
 815                }
 816                break;
 817        case ds_1340:
 818                /* clock halted?  turn it on, so clock can tick. */
 819                if (tmp & DS1340_BIT_nEOSC)
 820                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 821
 822                tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 823                if (tmp < 0) {
 824                        pr_debug("read error %d\n", tmp);
 825                        err = -EIO;
 826                        goto exit_free;
 827                }
 828
 829                /* oscillator fault?  clear flag, and warn */
 830                if (tmp & DS1340_BIT_OSF) {
 831                        i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 832                        dev_warn(&client->dev, "SET TIME!\n");
 833                }
 834                break;
 835        case mcp7941x:
 836                /* make sure that the backup battery is enabled */
 837                if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 838                        i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 839                                        ds1307->regs[DS1307_REG_WDAY]
 840                                        | MCP7941X_BIT_VBATEN);
 841                }
 842
 843                /* clock halted?  turn it on, so clock can tick. */
 844                if (!(tmp & MCP7941X_BIT_ST)) {
 845                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 846                                        MCP7941X_BIT_ST);
 847                        dev_warn(&client->dev, "SET TIME!\n");
 848                        goto read_rtc;
 849                }
 850
 851                break;
 852        default:
 853                break;
 854        }
 855
 856        tmp = ds1307->regs[DS1307_REG_HOUR];
 857        switch (ds1307->type) {
 858        case ds_1340:
 859        case m41t00:
 860                /*
 861                 * NOTE: ignores century bits; fix before deploying
 862                 * systems that will run through year 2100.
 863                 */
 864                break;
 865        case rx_8025:
 866                break;
 867        default:
 868                if (!(tmp & DS1307_BIT_12HR))
 869                        break;
 870
 871                /*
 872                 * Be sure we're in 24 hour mode.  Multi-master systems
 873                 * take note...
 874                 */
 875                tmp = bcd2bin(tmp & 0x1f);
 876                if (tmp == 12)
 877                        tmp = 0;
 878                if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 879                        tmp += 12;
 880                i2c_smbus_write_byte_data(client,
 881                                ds1307->offset + DS1307_REG_HOUR,
 882                                bin2bcd(tmp));
 883        }
 884
 885        ds1307->rtc = rtc_device_register(client->name, &client->dev,
 886                                &ds13xx_rtc_ops, THIS_MODULE);
 887        if (IS_ERR(ds1307->rtc)) {
 888                err = PTR_ERR(ds1307->rtc);
 889                dev_err(&client->dev,
 890                        "unable to register the class device\n");
 891                goto exit_free;
 892        }
 893
 894        if (want_irq) {
 895                err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 896                          ds1307->rtc->name, client);
 897                if (err) {
 898                        dev_err(&client->dev,
 899                                "unable to request IRQ!\n");
 900                        goto exit_irq;
 901                }
 902
 903                device_set_wakeup_capable(&client->dev, 1);
 904                set_bit(HAS_ALARM, &ds1307->flags);
 905                dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 906        }
 907
 908        if (chip->nvram_size) {
 909                ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
 910                                                        GFP_KERNEL);
 911                if (!ds1307->nvram) {
 912                        err = -ENOMEM;
 913                        goto exit_nvram;
 914                }
 915                ds1307->nvram->attr.name = "nvram";
 916                ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
 917                sysfs_bin_attr_init(ds1307->nvram);
 918                ds1307->nvram->read = ds1307_nvram_read,
 919                ds1307->nvram->write = ds1307_nvram_write,
 920                ds1307->nvram->size = chip->nvram_size;
 921                ds1307->nvram_offset = chip->nvram_offset;
 922                err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
 923                if (err) {
 924                        kfree(ds1307->nvram);
 925                        goto exit_nvram;
 926                }
 927                set_bit(HAS_NVRAM, &ds1307->flags);
 928                dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
 929        }
 930
 931        return 0;
 932
 933exit_nvram:
 934exit_irq:
 935        rtc_device_unregister(ds1307->rtc);
 936exit_free:
 937        kfree(ds1307);
 938        return err;
 939}
 940
 941static int ds1307_remove(struct i2c_client *client)
 942{
 943        struct ds1307 *ds1307 = i2c_get_clientdata(client);
 944
 945        if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 946                free_irq(client->irq, client);
 947                cancel_work_sync(&ds1307->work);
 948        }
 949
 950        if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
 951                sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
 952                kfree(ds1307->nvram);
 953        }
 954
 955        rtc_device_unregister(ds1307->rtc);
 956        kfree(ds1307);
 957        return 0;
 958}
 959
 960static struct i2c_driver ds1307_driver = {
 961        .driver = {
 962                .name   = "rtc-ds1307",
 963                .owner  = THIS_MODULE,
 964        },
 965        .probe          = ds1307_probe,
 966        .remove         = ds1307_remove,
 967        .id_table       = ds1307_id,
 968};
 969
 970module_i2c_driver(ds1307_driver);
 971
 972MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 973MODULE_LICENSE("GPL");
 974
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