linux/drivers/rtc/rtc-x1205.c
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   1/*
   2 * An i2c driver for the Xicor/Intersil X1205 RTC
   3 * Copyright 2004 Karen Spearel
   4 * Copyright 2005 Alessandro Zummo
   5 *
   6 * please send all reports to:
   7 *      Karen Spearel <kas111 at gmail dot com>
   8 *      Alessandro Zummo <a.zummo@towertech.it>
   9 *
  10 * based on a lot of other RTC drivers.
  11 *
  12 * Information and datasheet:
  13 * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
  14 *
  15 * This program is free software; you can redistribute it and/or modify
  16 * it under the terms of the GNU General Public License version 2 as
  17 * published by the Free Software Foundation.
  18 */
  19
  20#include <linux/i2c.h>
  21#include <linux/bcd.h>
  22#include <linux/rtc.h>
  23#include <linux/delay.h>
  24#include <linux/module.h>
  25
  26#define DRV_VERSION "1.0.8"
  27
  28/* offsets into CCR area */
  29
  30#define CCR_SEC                 0
  31#define CCR_MIN                 1
  32#define CCR_HOUR                2
  33#define CCR_MDAY                3
  34#define CCR_MONTH               4
  35#define CCR_YEAR                5
  36#define CCR_WDAY                6
  37#define CCR_Y2K                 7
  38
  39#define X1205_REG_SR            0x3F    /* status register */
  40#define X1205_REG_Y2K           0x37
  41#define X1205_REG_DW            0x36
  42#define X1205_REG_YR            0x35
  43#define X1205_REG_MO            0x34
  44#define X1205_REG_DT            0x33
  45#define X1205_REG_HR            0x32
  46#define X1205_REG_MN            0x31
  47#define X1205_REG_SC            0x30
  48#define X1205_REG_DTR           0x13
  49#define X1205_REG_ATR           0x12
  50#define X1205_REG_INT           0x11
  51#define X1205_REG_0             0x10
  52#define X1205_REG_Y2K1          0x0F
  53#define X1205_REG_DWA1          0x0E
  54#define X1205_REG_YRA1          0x0D
  55#define X1205_REG_MOA1          0x0C
  56#define X1205_REG_DTA1          0x0B
  57#define X1205_REG_HRA1          0x0A
  58#define X1205_REG_MNA1          0x09
  59#define X1205_REG_SCA1          0x08
  60#define X1205_REG_Y2K0          0x07
  61#define X1205_REG_DWA0          0x06
  62#define X1205_REG_YRA0          0x05
  63#define X1205_REG_MOA0          0x04
  64#define X1205_REG_DTA0          0x03
  65#define X1205_REG_HRA0          0x02
  66#define X1205_REG_MNA0          0x01
  67#define X1205_REG_SCA0          0x00
  68
  69#define X1205_CCR_BASE          0x30    /* Base address of CCR */
  70#define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
  71
  72#define X1205_SR_RTCF           0x01    /* Clock failure */
  73#define X1205_SR_WEL            0x02    /* Write Enable Latch */
  74#define X1205_SR_RWEL           0x04    /* Register Write Enable */
  75#define X1205_SR_AL0            0x20    /* Alarm 0 match */
  76
  77#define X1205_DTR_DTR0          0x01
  78#define X1205_DTR_DTR1          0x02
  79#define X1205_DTR_DTR2          0x04
  80
  81#define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
  82
  83#define X1205_INT_AL0E          0x20    /* Alarm 0 enable */
  84
  85static struct i2c_driver x1205_driver;
  86
  87/*
  88 * In the routines that deal directly with the x1205 hardware, we use
  89 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
  90 * Epoch is initialized as 2000. Time is set to UTC.
  91 */
  92static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
  93                                unsigned char reg_base)
  94{
  95        unsigned char dt_addr[2] = { 0, reg_base };
  96        unsigned char buf[8];
  97        int i;
  98
  99        struct i2c_msg msgs[] = {
 100                {/* setup read ptr */
 101                        .addr = client->addr,
 102                        .len = 2,
 103                        .buf = dt_addr
 104                },
 105                {/* read date */
 106                        .addr = client->addr,
 107                        .flags = I2C_M_RD,
 108                        .len = 8,
 109                        .buf = buf
 110                },
 111        };
 112
 113        /* read date registers */
 114        if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 115                dev_err(&client->dev, "%s: read error\n", __func__);
 116                return -EIO;
 117        }
 118
 119        dev_dbg(&client->dev,
 120                "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
 121                "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
 122                __func__,
 123                buf[0], buf[1], buf[2], buf[3],
 124                buf[4], buf[5], buf[6], buf[7]);
 125
 126        /* Mask out the enable bits if these are alarm registers */
 127        if (reg_base < X1205_CCR_BASE)
 128                for (i = 0; i <= 4; i++)
 129                        buf[i] &= 0x7F;
 130
 131        tm->tm_sec = bcd2bin(buf[CCR_SEC]);
 132        tm->tm_min = bcd2bin(buf[CCR_MIN]);
 133        tm->tm_hour = bcd2bin(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
 134        tm->tm_mday = bcd2bin(buf[CCR_MDAY]);
 135        tm->tm_mon = bcd2bin(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
 136        tm->tm_year = bcd2bin(buf[CCR_YEAR])
 137                        + (bcd2bin(buf[CCR_Y2K]) * 100) - 1900;
 138        tm->tm_wday = buf[CCR_WDAY];
 139
 140        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 141                "mday=%d, mon=%d, year=%d, wday=%d\n",
 142                __func__,
 143                tm->tm_sec, tm->tm_min, tm->tm_hour,
 144                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 145
 146        return 0;
 147}
 148
 149static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
 150{
 151        static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
 152
 153        struct i2c_msg msgs[] = {
 154                {     /* setup read ptr */
 155                        .addr = client->addr,
 156                        .len = 2,
 157                        .buf = sr_addr
 158                },
 159                {    /* read status */
 160                        .addr = client->addr,
 161                        .flags = I2C_M_RD,
 162                        .len = 1,
 163                        .buf = sr
 164                },
 165        };
 166
 167        /* read status register */
 168        if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 169                dev_err(&client->dev, "%s: read error\n", __func__);
 170                return -EIO;
 171        }
 172
 173        return 0;
 174}
 175
 176static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
 177                        u8 reg_base, unsigned char alm_enable)
 178{
 179        int i, xfer;
 180        unsigned char rdata[10] = { 0, reg_base };
 181        unsigned char *buf = rdata + 2;
 182
 183        static const unsigned char wel[3] = { 0, X1205_REG_SR,
 184                                                X1205_SR_WEL };
 185
 186        static const unsigned char rwel[3] = { 0, X1205_REG_SR,
 187                                                X1205_SR_WEL | X1205_SR_RWEL };
 188
 189        static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
 190
 191        dev_dbg(&client->dev,
 192                "%s: sec=%d min=%d hour=%d mday=%d mon=%d year=%d wday=%d\n",
 193                __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday,
 194                tm->tm_mon, tm->tm_year, tm->tm_wday);
 195
 196        buf[CCR_SEC] = bin2bcd(tm->tm_sec);
 197        buf[CCR_MIN] = bin2bcd(tm->tm_min);
 198
 199        /* set hour and 24hr bit */
 200        buf[CCR_HOUR] = bin2bcd(tm->tm_hour) | X1205_HR_MIL;
 201
 202        buf[CCR_MDAY] = bin2bcd(tm->tm_mday);
 203
 204        /* month, 1 - 12 */
 205        buf[CCR_MONTH] = bin2bcd(tm->tm_mon + 1);
 206
 207        /* year, since the rtc epoch*/
 208        buf[CCR_YEAR] = bin2bcd(tm->tm_year % 100);
 209        buf[CCR_WDAY] = tm->tm_wday & 0x07;
 210        buf[CCR_Y2K] = bin2bcd((tm->tm_year + 1900) / 100);
 211
 212        /* If writing alarm registers, set compare bits on registers 0-4 */
 213        if (reg_base < X1205_CCR_BASE)
 214                for (i = 0; i <= 4; i++)
 215                        buf[i] |= 0x80;
 216
 217        /* this sequence is required to unlock the chip */
 218        if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
 219                dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
 220                return -EIO;
 221        }
 222
 223        if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
 224                dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
 225                return -EIO;
 226        }
 227
 228        xfer = i2c_master_send(client, rdata, sizeof(rdata));
 229        if (xfer != sizeof(rdata)) {
 230                dev_err(&client->dev,
 231                        "%s: result=%d addr=%02x, data=%02x\n",
 232                        __func__,
 233                         xfer, rdata[1], rdata[2]);
 234                return -EIO;
 235        }
 236
 237        /* If we wrote to the nonvolatile region, wait 10msec for write cycle*/
 238        if (reg_base < X1205_CCR_BASE) {
 239                unsigned char al0e[3] = { 0, X1205_REG_INT, 0 };
 240
 241                msleep(10);
 242
 243                /* ...and set or clear the AL0E bit in the INT register */
 244
 245                /* Need to set RWEL again as the write has cleared it */
 246                xfer = i2c_master_send(client, rwel, 3);
 247                if (xfer != 3) {
 248                        dev_err(&client->dev,
 249                                "%s: aloe rwel - %d\n",
 250                                __func__,
 251                                xfer);
 252                        return -EIO;
 253                }
 254
 255                if (alm_enable)
 256                        al0e[2] = X1205_INT_AL0E;
 257
 258                xfer = i2c_master_send(client, al0e, 3);
 259                if (xfer != 3) {
 260                        dev_err(&client->dev,
 261                                "%s: al0e - %d\n",
 262                                __func__,
 263                                xfer);
 264                        return -EIO;
 265                }
 266
 267                /* and wait 10msec again for this write to complete */
 268                msleep(10);
 269        }
 270
 271        /* disable further writes */
 272        if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
 273                dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
 274                return -EIO;
 275        }
 276
 277        return 0;
 278}
 279
 280static int x1205_fix_osc(struct i2c_client *client)
 281{
 282        int err;
 283        struct rtc_time tm;
 284
 285        memset(&tm, 0, sizeof(tm));
 286
 287        err = x1205_set_datetime(client, &tm, X1205_CCR_BASE, 0);
 288        if (err < 0)
 289                dev_err(&client->dev, "unable to restart the oscillator\n");
 290
 291        return err;
 292}
 293
 294static int x1205_get_dtrim(struct i2c_client *client, int *trim)
 295{
 296        unsigned char dtr;
 297        static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
 298
 299        struct i2c_msg msgs[] = {
 300                {       /* setup read ptr */
 301                        .addr = client->addr,
 302                        .len = 2,
 303                        .buf = dtr_addr
 304                },
 305                {      /* read dtr */
 306                        .addr = client->addr,
 307                        .flags = I2C_M_RD,
 308                        .len = 1,
 309                        .buf = &dtr
 310                },
 311        };
 312
 313        /* read dtr register */
 314        if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 315                dev_err(&client->dev, "%s: read error\n", __func__);
 316                return -EIO;
 317        }
 318
 319        dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr);
 320
 321        *trim = 0;
 322
 323        if (dtr & X1205_DTR_DTR0)
 324                *trim += 20;
 325
 326        if (dtr & X1205_DTR_DTR1)
 327                *trim += 10;
 328
 329        if (dtr & X1205_DTR_DTR2)
 330                *trim = -*trim;
 331
 332        return 0;
 333}
 334
 335static int x1205_get_atrim(struct i2c_client *client, int *trim)
 336{
 337        s8 atr;
 338        static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
 339
 340        struct i2c_msg msgs[] = {
 341                {/* setup read ptr */
 342                        .addr = client->addr,
 343                        .len = 2,
 344                        .buf = atr_addr
 345                },
 346                {/* read atr */
 347                        .addr = client->addr,
 348                        .flags = I2C_M_RD,
 349                        .len = 1,
 350                        .buf = &atr
 351                },
 352        };
 353
 354        /* read atr register */
 355        if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 356                dev_err(&client->dev, "%s: read error\n", __func__);
 357                return -EIO;
 358        }
 359
 360        dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
 361
 362        /* atr is a two's complement value on 6 bits,
 363         * perform sign extension. The formula is
 364         * Catr = (atr * 0.25pF) + 11.00pF.
 365         */
 366        if (atr & 0x20)
 367                atr |= 0xC0;
 368
 369        dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
 370
 371        *trim = (atr * 250) + 11000;
 372
 373        dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim);
 374
 375        return 0;
 376}
 377
 378struct x1205_limit
 379{
 380        unsigned char reg, mask, min, max;
 381};
 382
 383static int x1205_validate_client(struct i2c_client *client)
 384{
 385        int i, xfer;
 386
 387        /* Probe array. We will read the register at the specified
 388         * address and check if the given bits are zero.
 389         */
 390        static const unsigned char probe_zero_pattern[] = {
 391                /* register, mask */
 392                X1205_REG_SR,   0x18,
 393                X1205_REG_DTR,  0xF8,
 394                X1205_REG_ATR,  0xC0,
 395                X1205_REG_INT,  0x18,
 396                X1205_REG_0,    0xFF,
 397        };
 398
 399        static const struct x1205_limit probe_limits_pattern[] = {
 400                /* register, mask, min, max */
 401                { X1205_REG_Y2K,        0xFF,   19,     20      },
 402                { X1205_REG_DW,         0xFF,   0,      6       },
 403                { X1205_REG_YR,         0xFF,   0,      99      },
 404                { X1205_REG_MO,         0xFF,   0,      12      },
 405                { X1205_REG_DT,         0xFF,   0,      31      },
 406                { X1205_REG_HR,         0x7F,   0,      23      },
 407                { X1205_REG_MN,         0xFF,   0,      59      },
 408                { X1205_REG_SC,         0xFF,   0,      59      },
 409                { X1205_REG_Y2K1,       0xFF,   19,     20      },
 410                { X1205_REG_Y2K0,       0xFF,   19,     20      },
 411        };
 412
 413        /* check that registers have bits a 0 where expected */
 414        for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
 415                unsigned char buf;
 416
 417                unsigned char addr[2] = { 0, probe_zero_pattern[i] };
 418
 419                struct i2c_msg msgs[2] = {
 420                        {
 421                                .addr = client->addr,
 422                                .len = 2,
 423                                .buf = addr
 424                        },
 425                        {
 426                                .addr = client->addr,
 427                                .flags = I2C_M_RD,
 428                                .len = 1,
 429                                .buf = &buf
 430                        },
 431                };
 432
 433                if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
 434                        dev_err(&client->dev,
 435                                "%s: could not read register %x\n",
 436                                __func__, probe_zero_pattern[i]);
 437
 438                        return -EIO;
 439                }
 440
 441                if ((buf & probe_zero_pattern[i+1]) != 0) {
 442                        dev_err(&client->dev,
 443                                "%s: register=%02x, zero pattern=%d, value=%x\n",
 444                                __func__, probe_zero_pattern[i], i, buf);
 445
 446                        return -ENODEV;
 447                }
 448        }
 449
 450        /* check limits (only registers with bcd values) */
 451        for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
 452                unsigned char reg, value;
 453
 454                unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
 455
 456                struct i2c_msg msgs[2] = {
 457                        {
 458                                .addr = client->addr,
 459                                .len = 2,
 460                                .buf = addr
 461                        },
 462                        {
 463                                .addr = client->addr,
 464                                .flags = I2C_M_RD,
 465                                .len = 1,
 466                                .buf = &reg
 467                        },
 468                };
 469
 470                if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
 471                        dev_err(&client->dev,
 472                                "%s: could not read register %x\n",
 473                                __func__, probe_limits_pattern[i].reg);
 474
 475                        return -EIO;
 476                }
 477
 478                value = bcd2bin(reg & probe_limits_pattern[i].mask);
 479
 480                if (value > probe_limits_pattern[i].max ||
 481                        value < probe_limits_pattern[i].min) {
 482                        dev_dbg(&client->dev,
 483                                "%s: register=%x, lim pattern=%d, value=%d\n",
 484                                __func__, probe_limits_pattern[i].reg,
 485                                i, value);
 486
 487                        return -ENODEV;
 488                }
 489        }
 490
 491        return 0;
 492}
 493
 494static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 495{
 496        int err;
 497        unsigned char intreg, status;
 498        static unsigned char int_addr[2] = { 0, X1205_REG_INT };
 499        struct i2c_client *client = to_i2c_client(dev);
 500        struct i2c_msg msgs[] = {
 501                { /* setup read ptr */
 502                        .addr = client->addr,
 503                        .len = 2,
 504                        .buf = int_addr
 505                },
 506                {/* read INT register */
 507
 508                        .addr = client->addr,
 509                        .flags = I2C_M_RD,
 510                        .len = 1,
 511                        .buf = &intreg
 512                },
 513        };
 514
 515        /* read interrupt register and status register */
 516        if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 517                dev_err(&client->dev, "%s: read error\n", __func__);
 518                return -EIO;
 519        }
 520        err = x1205_get_status(client, &status);
 521        if (err == 0) {
 522                alrm->pending = (status & X1205_SR_AL0) ? 1 : 0;
 523                alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0;
 524                err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE);
 525        }
 526        return err;
 527}
 528
 529static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 530{
 531        return x1205_set_datetime(to_i2c_client(dev),
 532                &alrm->time, X1205_ALM0_BASE, alrm->enabled);
 533}
 534
 535static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
 536{
 537        return x1205_get_datetime(to_i2c_client(dev),
 538                tm, X1205_CCR_BASE);
 539}
 540
 541static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
 542{
 543        return x1205_set_datetime(to_i2c_client(dev),
 544                tm, X1205_CCR_BASE, 0);
 545}
 546
 547static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
 548{
 549        int err, dtrim, atrim;
 550
 551        if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
 552                seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
 553
 554        if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
 555                seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
 556                        atrim / 1000, atrim % 1000);
 557        return 0;
 558}
 559
 560static const struct rtc_class_ops x1205_rtc_ops = {
 561        .proc           = x1205_rtc_proc,
 562        .read_time      = x1205_rtc_read_time,
 563        .set_time       = x1205_rtc_set_time,
 564        .read_alarm     = x1205_rtc_read_alarm,
 565        .set_alarm      = x1205_rtc_set_alarm,
 566};
 567
 568static ssize_t x1205_sysfs_show_atrim(struct device *dev,
 569                                struct device_attribute *attr, char *buf)
 570{
 571        int err, atrim;
 572
 573        err = x1205_get_atrim(to_i2c_client(dev), &atrim);
 574        if (err)
 575                return err;
 576
 577        return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
 578}
 579static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
 580
 581static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
 582                                struct device_attribute *attr, char *buf)
 583{
 584        int err, dtrim;
 585
 586        err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
 587        if (err)
 588                return err;
 589
 590        return sprintf(buf, "%d ppm\n", dtrim);
 591}
 592static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
 593
 594static int x1205_sysfs_register(struct device *dev)
 595{
 596        int err;
 597
 598        err = device_create_file(dev, &dev_attr_atrim);
 599        if (err)
 600                return err;
 601
 602        err = device_create_file(dev, &dev_attr_dtrim);
 603        if (err)
 604                device_remove_file(dev, &dev_attr_atrim);
 605
 606        return err;
 607}
 608
 609static void x1205_sysfs_unregister(struct device *dev)
 610{
 611        device_remove_file(dev, &dev_attr_atrim);
 612        device_remove_file(dev, &dev_attr_dtrim);
 613}
 614
 615
 616static int x1205_probe(struct i2c_client *client,
 617                        const struct i2c_device_id *id)
 618{
 619        int err = 0;
 620        unsigned char sr;
 621        struct rtc_device *rtc;
 622
 623        dev_dbg(&client->dev, "%s\n", __func__);
 624
 625        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 626                return -ENODEV;
 627
 628        if (x1205_validate_client(client) < 0)
 629                return -ENODEV;
 630
 631        dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 632
 633        rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
 634                                &x1205_rtc_ops, THIS_MODULE);
 635
 636        if (IS_ERR(rtc))
 637                return PTR_ERR(rtc);
 638
 639        i2c_set_clientdata(client, rtc);
 640
 641        /* Check for power failures and eventually enable the osc */
 642        if ((err = x1205_get_status(client, &sr)) == 0) {
 643                if (sr & X1205_SR_RTCF) {
 644                        dev_err(&client->dev,
 645                                "power failure detected, "
 646                                "please set the clock\n");
 647                        udelay(50);
 648                        x1205_fix_osc(client);
 649                }
 650        }
 651        else
 652                dev_err(&client->dev, "couldn't read status\n");
 653
 654        err = x1205_sysfs_register(&client->dev);
 655        if (err)
 656                goto exit_devreg;
 657
 658        return 0;
 659
 660exit_devreg:
 661        rtc_device_unregister(rtc);
 662
 663        return err;
 664}
 665
 666static int x1205_remove(struct i2c_client *client)
 667{
 668        struct rtc_device *rtc = i2c_get_clientdata(client);
 669
 670        rtc_device_unregister(rtc);
 671        x1205_sysfs_unregister(&client->dev);
 672        return 0;
 673}
 674
 675static const struct i2c_device_id x1205_id[] = {
 676        { "x1205", 0 },
 677        { }
 678};
 679MODULE_DEVICE_TABLE(i2c, x1205_id);
 680
 681static struct i2c_driver x1205_driver = {
 682        .driver         = {
 683                .name   = "rtc-x1205",
 684        },
 685        .probe          = x1205_probe,
 686        .remove         = x1205_remove,
 687        .id_table       = x1205_id,
 688};
 689
 690module_i2c_driver(x1205_driver);
 691
 692MODULE_AUTHOR(
 693        "Karen Spearel <kas111 at gmail dot com>, "
 694        "Alessandro Zummo <a.zummo@towertech.it>");
 695MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
 696MODULE_LICENSE("GPL");
 697MODULE_VERSION(DRV_VERSION);
 698
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