drivers/rtc/rtc-x1205.c

   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
  85 static 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  */
  92 static 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
 149 static 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
 176 static 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
 280 static 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
 294 static 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
 335 static 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
 378 struct x1205_limit
 379 {
 380         unsigned char reg, mask, min, max;
 381 };
 382
 383 static 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
 494 static 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
 529 static 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
 535 static 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
 541 static 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
 547 static 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
 560 static 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
 568 static 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 }
 579 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
 580
 581 static 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 }
 592 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
 593
 594 static 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
 609 static 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
 616 static 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
 660 exit_devreg:
 661         rtc_device_unregister(rtc);
 662
 663         return err;
 664 }
 665
 666 static 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
 675 static const struct i2c_device_id x1205_id[] = {
 676         { "x1205", 0 },
 677         { }
 678 };
 679 MODULE_DEVICE_TABLE(i2c, x1205_id);
 680
 681 static 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
 690 module_i2c_driver(x1205_driver);
 691
 692 MODULE_AUTHOR(
 693         "Karen Spearel <kas111 at gmail dot com>, "
 694         "Alessandro Zummo <a.zummo@towertech.it>");
 695 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
 696 MODULE_LICENSE("GPL");
 697 MODULE_VERSION(DRV_VERSION);