drivers/rtc/rtc-x1205.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * An i2c driver for the Xicor/Intersil X1205 RTC
   4  * Copyright 2004 Karen Spearel
   5  * Copyright 2005 Alessandro Zummo
   6  *
   7  * please send all reports to:
   8  *      Karen Spearel <kas111 at gmail dot com>
   9  *      Alessandro Zummo <a.zummo@towertech.it>
  10  *
  11  * based on a lot of other RTC drivers.
  12  *
  13  * Information and datasheet:
  14  * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
  15  */
  16
  17 #include <linux/i2c.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc.h>
  20 #include <linux/delay.h>
  21 #include <linux/module.h>
  22 #include <linux/bitops.h>
  23
  24 /* offsets into CCR area */
  25
  26 #define CCR_SEC                 0
  27 #define CCR_MIN                 1
  28 #define CCR_HOUR                2
  29 #define CCR_MDAY                3
  30 #define CCR_MONTH               4
  31 #define CCR_YEAR                5
  32 #define CCR_WDAY                6
  33 #define CCR_Y2K                 7
  34
  35 #define X1205_REG_SR            0x3F    /* status register */
  36 #define X1205_REG_Y2K           0x37
  37 #define X1205_REG_DW            0x36
  38 #define X1205_REG_YR            0x35
  39 #define X1205_REG_MO            0x34
  40 #define X1205_REG_DT            0x33
  41 #define X1205_REG_HR            0x32
  42 #define X1205_REG_MN            0x31
  43 #define X1205_REG_SC            0x30
  44 #define X1205_REG_DTR           0x13
  45 #define X1205_REG_ATR           0x12
  46 #define X1205_REG_INT           0x11
  47 #define X1205_REG_0             0x10
  48 #define X1205_REG_Y2K1          0x0F
  49 #define X1205_REG_DWA1          0x0E
  50 #define X1205_REG_YRA1          0x0D
  51 #define X1205_REG_MOA1          0x0C
  52 #define X1205_REG_DTA1          0x0B
  53 #define X1205_REG_HRA1          0x0A
  54 #define X1205_REG_MNA1          0x09
  55 #define X1205_REG_SCA1          0x08
  56 #define X1205_REG_Y2K0          0x07
  57 #define X1205_REG_DWA0          0x06
  58 #define X1205_REG_YRA0          0x05
  59 #define X1205_REG_MOA0          0x04
  60 #define X1205_REG_DTA0          0x03
  61 #define X1205_REG_HRA0          0x02
  62 #define X1205_REG_MNA0          0x01
  63 #define X1205_REG_SCA0          0x00
  64
  65 #define X1205_CCR_BASE          0x30    /* Base address of CCR */
  66 #define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
  67
  68 #define X1205_SR_RTCF           0x01    /* Clock failure */
  69 #define X1205_SR_WEL            0x02    /* Write Enable Latch */
  70 #define X1205_SR_RWEL           0x04    /* Register Write Enable */
  71 #define X1205_SR_AL0            0x20    /* Alarm 0 match */
  72
  73 #define X1205_DTR_DTR0          0x01
  74 #define X1205_DTR_DTR1          0x02
  75 #define X1205_DTR_DTR2          0x04
  76
  77 #define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
  78
  79 #define X1205_INT_AL0E          0x20    /* Alarm 0 enable */
  80
  81 static struct i2c_driver x1205_driver;
  82
  83 /*
  84  * In the routines that deal directly with the x1205 hardware, we use
  85  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
  86  * Epoch is initialized as 2000. Time is set to UTC.
  87  */
  88 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
  89                                 unsigned char reg_base)
  90 {
  91         unsigned char dt_addr[2] = { 0, reg_base };
  92         unsigned char buf[8];
  93         int i;
  94
  95         struct i2c_msg msgs[] = {
  96                 {/* setup read ptr */
  97                         .addr = client->addr,
  98                         .len = 2,
  99                         .buf = dt_addr
 100                 },
 101                 {/* read date */
 102                         .addr = client->addr,
 103                         .flags = I2C_M_RD,
 104                         .len = 8,
 105                         .buf = buf
 106                 },
 107         };
 108
 109         /* read date registers */
 110         if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 111                 dev_err(&client->dev, "%s: read error\n", __func__);
 112                 return -EIO;
 113         }
 114
 115         dev_dbg(&client->dev,
 116                 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
 117                 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
 118                 __func__,
 119                 buf[0], buf[1], buf[2], buf[3],
 120                 buf[4], buf[5], buf[6], buf[7]);
 121
 122         /* Mask out the enable bits if these are alarm registers */
 123         if (reg_base < X1205_CCR_BASE)
 124                 for (i = 0; i <= 4; i++)
 125                         buf[i] &= 0x7F;
 126
 127         tm->tm_sec = bcd2bin(buf[CCR_SEC]);
 128         tm->tm_min = bcd2bin(buf[CCR_MIN]);
 129         tm->tm_hour = bcd2bin(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
 130         tm->tm_mday = bcd2bin(buf[CCR_MDAY]);
 131         tm->tm_mon = bcd2bin(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
 132         tm->tm_year = bcd2bin(buf[CCR_YEAR])
 133                         + (bcd2bin(buf[CCR_Y2K]) * 100) - 1900;
 134         tm->tm_wday = buf[CCR_WDAY];
 135
 136         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 137                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 138                 __func__,
 139                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 140                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 141
 142         return 0;
 143 }
 144
 145 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
 146 {
 147         static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
 148
 149         struct i2c_msg msgs[] = {
 150                 {     /* setup read ptr */
 151                         .addr = client->addr,
 152                         .len = 2,
 153                         .buf = sr_addr
 154                 },
 155                 {    /* read status */
 156                         .addr = client->addr,
 157                         .flags = I2C_M_RD,
 158                         .len = 1,
 159                         .buf = sr
 160                 },
 161         };
 162
 163         /* read status register */
 164         if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 165                 dev_err(&client->dev, "%s: read error\n", __func__);
 166                 return -EIO;
 167         }
 168
 169         return 0;
 170 }
 171
 172 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
 173                         u8 reg_base, unsigned char alm_enable)
 174 {
 175         int i, xfer;
 176         unsigned char rdata[10] = { 0, reg_base };
 177         unsigned char *buf = rdata + 2;
 178
 179         static const unsigned char wel[3] = { 0, X1205_REG_SR,
 180                                                 X1205_SR_WEL };
 181
 182         static const unsigned char rwel[3] = { 0, X1205_REG_SR,
 183                                                 X1205_SR_WEL | X1205_SR_RWEL };
 184
 185         static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
 186
 187         dev_dbg(&client->dev,
 188                 "%s: sec=%d min=%d hour=%d mday=%d mon=%d year=%d wday=%d\n",
 189                 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday,
 190                 tm->tm_mon, tm->tm_year, tm->tm_wday);
 191
 192         buf[CCR_SEC] = bin2bcd(tm->tm_sec);
 193         buf[CCR_MIN] = bin2bcd(tm->tm_min);
 194
 195         /* set hour and 24hr bit */
 196         buf[CCR_HOUR] = bin2bcd(tm->tm_hour) | X1205_HR_MIL;
 197
 198         buf[CCR_MDAY] = bin2bcd(tm->tm_mday);
 199
 200         /* month, 1 - 12 */
 201         buf[CCR_MONTH] = bin2bcd(tm->tm_mon + 1);
 202
 203         /* year, since the rtc epoch*/
 204         buf[CCR_YEAR] = bin2bcd(tm->tm_year % 100);
 205         buf[CCR_WDAY] = tm->tm_wday & 0x07;
 206         buf[CCR_Y2K] = bin2bcd((tm->tm_year + 1900) / 100);
 207
 208         /* If writing alarm registers, set compare bits on registers 0-4 */
 209         if (reg_base < X1205_CCR_BASE)
 210                 for (i = 0; i <= 4; i++)
 211                         buf[i] |= 0x80;
 212
 213         /* this sequence is required to unlock the chip */
 214         xfer = i2c_master_send(client, wel, 3);
 215         if (xfer != 3) {
 216                 dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
 217                 return -EIO;
 218         }
 219
 220         xfer = i2c_master_send(client, rwel, 3);
 221         if (xfer != 3) {
 222                 dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
 223                 return -EIO;
 224         }
 225
 226         xfer = i2c_master_send(client, rdata, sizeof(rdata));
 227         if (xfer != sizeof(rdata)) {
 228                 dev_err(&client->dev,
 229                         "%s: result=%d addr=%02x, data=%02x\n",
 230                         __func__,
 231                          xfer, rdata[1], rdata[2]);
 232                 return -EIO;
 233         }
 234
 235         /* If we wrote to the nonvolatile region, wait 10msec for write cycle*/
 236         if (reg_base < X1205_CCR_BASE) {
 237                 unsigned char al0e[3] = { 0, X1205_REG_INT, 0 };
 238
 239                 msleep(10);
 240
 241                 /* ...and set or clear the AL0E bit in the INT register */
 242
 243                 /* Need to set RWEL again as the write has cleared it */
 244                 xfer = i2c_master_send(client, rwel, 3);
 245                 if (xfer != 3) {
 246                         dev_err(&client->dev,
 247                                 "%s: aloe rwel - %d\n",
 248                                 __func__,
 249                                 xfer);
 250                         return -EIO;
 251                 }
 252
 253                 if (alm_enable)
 254                         al0e[2] = X1205_INT_AL0E;
 255
 256                 xfer = i2c_master_send(client, al0e, 3);
 257                 if (xfer != 3) {
 258                         dev_err(&client->dev,
 259                                 "%s: al0e - %d\n",
 260                                 __func__,
 261                                 xfer);
 262                         return -EIO;
 263                 }
 264
 265                 /* and wait 10msec again for this write to complete */
 266                 msleep(10);
 267         }
 268
 269         /* disable further writes */
 270         xfer = i2c_master_send(client, diswe, 3);
 271         if (xfer != 3) {
 272                 dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
 273                 return -EIO;
 274         }
 275
 276         return 0;
 277 }
 278
 279 static int x1205_fix_osc(struct i2c_client *client)
 280 {
 281         int err;
 282         struct rtc_time tm;
 283
 284         memset(&tm, 0, sizeof(tm));
 285
 286         err = x1205_set_datetime(client, &tm, X1205_CCR_BASE, 0);
 287         if (err < 0)
 288                 dev_err(&client->dev, "unable to restart the oscillator\n");
 289
 290         return err;
 291 }
 292
 293 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
 294 {
 295         unsigned char dtr;
 296         static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
 297
 298         struct i2c_msg msgs[] = {
 299                 {       /* setup read ptr */
 300                         .addr = client->addr,
 301                         .len = 2,
 302                         .buf = dtr_addr
 303                 },
 304                 {      /* read dtr */
 305                         .addr = client->addr,
 306                         .flags = I2C_M_RD,
 307                         .len = 1,
 308                         .buf = &dtr
 309                 },
 310         };
 311
 312         /* read dtr register */
 313         if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 314                 dev_err(&client->dev, "%s: read error\n", __func__);
 315                 return -EIO;
 316         }
 317
 318         dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr);
 319
 320         *trim = 0;
 321
 322         if (dtr & X1205_DTR_DTR0)
 323                 *trim += 20;
 324
 325         if (dtr & X1205_DTR_DTR1)
 326                 *trim += 10;
 327
 328         if (dtr & X1205_DTR_DTR2)
 329                 *trim = -*trim;
 330
 331         return 0;
 332 }
 333
 334 static int x1205_get_atrim(struct i2c_client *client, int *trim)
 335 {
 336         s8 atr;
 337         static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
 338
 339         struct i2c_msg msgs[] = {
 340                 {/* setup read ptr */
 341                         .addr = client->addr,
 342                         .len = 2,
 343                         .buf = atr_addr
 344                 },
 345                 {/* read atr */
 346                         .addr = client->addr,
 347                         .flags = I2C_M_RD,
 348                         .len = 1,
 349                         .buf = &atr
 350                 },
 351         };
 352
 353         /* read atr register */
 354         if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 355                 dev_err(&client->dev, "%s: read error\n", __func__);
 356                 return -EIO;
 357         }
 358
 359         dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
 360
 361         /* atr is a two's complement value on 6 bits,
 362          * perform sign extension. The formula is
 363          * Catr = (atr * 0.25pF) + 11.00pF.
 364          */
 365         atr = sign_extend32(atr, 5);
 366
 367         dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
 368
 369         *trim = (atr * 250) + 11000;
 370
 371         dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim);
 372
 373         return 0;
 374 }
 375
 376 struct x1205_limit {
 377         unsigned char reg, mask, min, max;
 378 };
 379
 380 static int x1205_validate_client(struct i2c_client *client)
 381 {
 382         int i, xfer;
 383
 384         /* Probe array. We will read the register at the specified
 385          * address and check if the given bits are zero.
 386          */
 387         static const unsigned char probe_zero_pattern[] = {
 388                 /* register, mask */
 389                 X1205_REG_SR,   0x18,
 390                 X1205_REG_DTR,  0xF8,
 391                 X1205_REG_ATR,  0xC0,
 392                 X1205_REG_INT,  0x18,
 393                 X1205_REG_0,    0xFF,
 394         };
 395
 396         static const struct x1205_limit probe_limits_pattern[] = {
 397                 /* register, mask, min, max */
 398                 { X1205_REG_Y2K,        0xFF,   19,     20      },
 399                 { X1205_REG_DW,         0xFF,   0,      6       },
 400                 { X1205_REG_YR,         0xFF,   0,      99      },
 401                 { X1205_REG_MO,         0xFF,   0,      12      },
 402                 { X1205_REG_DT,         0xFF,   0,      31      },
 403                 { X1205_REG_HR,         0x7F,   0,      23      },
 404                 { X1205_REG_MN,         0xFF,   0,      59      },
 405                 { X1205_REG_SC,         0xFF,   0,      59      },
 406                 { X1205_REG_Y2K1,       0xFF,   19,     20      },
 407                 { X1205_REG_Y2K0,       0xFF,   19,     20      },
 408         };
 409
 410         /* check that registers have bits a 0 where expected */
 411         for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
 412                 unsigned char buf;
 413
 414                 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
 415
 416                 struct i2c_msg msgs[2] = {
 417                         {
 418                                 .addr = client->addr,
 419                                 .len = 2,
 420                                 .buf = addr
 421                         },
 422                         {
 423                                 .addr = client->addr,
 424                                 .flags = I2C_M_RD,
 425                                 .len = 1,
 426                                 .buf = &buf
 427                         },
 428                 };
 429
 430                 xfer = i2c_transfer(client->adapter, msgs, 2);
 431                 if (xfer != 2) {
 432                         dev_err(&client->dev,
 433                                 "%s: could not read register %x\n",
 434                                 __func__, probe_zero_pattern[i]);
 435
 436                         return -EIO;
 437                 }
 438
 439                 if ((buf & probe_zero_pattern[i+1]) != 0) {
 440                         dev_err(&client->dev,
 441                                 "%s: register=%02x, zero pattern=%d, value=%x\n",
 442                                 __func__, probe_zero_pattern[i], i, buf);
 443
 444                         return -ENODEV;
 445                 }
 446         }
 447
 448         /* check limits (only registers with bcd values) */
 449         for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
 450                 unsigned char reg, value;
 451
 452                 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
 453
 454                 struct i2c_msg msgs[2] = {
 455                         {
 456                                 .addr = client->addr,
 457                                 .len = 2,
 458                                 .buf = addr
 459                         },
 460                         {
 461                                 .addr = client->addr,
 462                                 .flags = I2C_M_RD,
 463                                 .len = 1,
 464                                 .buf = &reg
 465                         },
 466                 };
 467
 468                 xfer = i2c_transfer(client->adapter, msgs, 2);
 469                 if (xfer != 2) {
 470                         dev_err(&client->dev,
 471                                 "%s: could not read register %x\n",
 472                                 __func__, probe_limits_pattern[i].reg);
 473
 474                         return -EIO;
 475                 }
 476
 477                 value = bcd2bin(reg & probe_limits_pattern[i].mask);
 478
 479                 if (value > probe_limits_pattern[i].max ||
 480                         value < probe_limits_pattern[i].min) {
 481                         dev_dbg(&client->dev,
 482                                 "%s: register=%x, lim pattern=%d, value=%d\n",
 483                                 __func__, probe_limits_pattern[i].reg,
 484                                 i, value);
 485
 486                         return -ENODEV;
 487                 }
 488         }
 489
 490         return 0;
 491 }
 492
 493 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 494 {
 495         int err;
 496         unsigned char intreg, status;
 497         static unsigned char int_addr[2] = { 0, X1205_REG_INT };
 498         struct i2c_client *client = to_i2c_client(dev);
 499         struct i2c_msg msgs[] = {
 500                 { /* setup read ptr */
 501                         .addr = client->addr,
 502                         .len = 2,
 503                         .buf = int_addr
 504                 },
 505                 {/* read INT register */
 506
 507                         .addr = client->addr,
 508                         .flags = I2C_M_RD,
 509                         .len = 1,
 510                         .buf = &intreg
 511                 },
 512         };
 513
 514         /* read interrupt register and status register */
 515         if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
 516                 dev_err(&client->dev, "%s: read error\n", __func__);
 517                 return -EIO;
 518         }
 519         err = x1205_get_status(client, &status);
 520         if (err == 0) {
 521                 alrm->pending = (status & X1205_SR_AL0) ? 1 : 0;
 522                 alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0;
 523                 err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE);
 524         }
 525         return err;
 526 }
 527
 528 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 529 {
 530         return x1205_set_datetime(to_i2c_client(dev),
 531                 &alrm->time, X1205_ALM0_BASE, alrm->enabled);
 532 }
 533
 534 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
 535 {
 536         return x1205_get_datetime(to_i2c_client(dev),
 537                 tm, X1205_CCR_BASE);
 538 }
 539
 540 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
 541 {
 542         return x1205_set_datetime(to_i2c_client(dev),
 543                 tm, X1205_CCR_BASE, 0);
 544 }
 545
 546 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
 547 {
 548         int err, dtrim, atrim;
 549
 550         err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
 551         if (!err)
 552                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
 553
 554         err = x1205_get_atrim(to_i2c_client(dev), &atrim);
 555         if (!err)
 556                 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
 557                         atrim / 1000, atrim % 1000);
 558         return 0;
 559 }
 560
 561 static const struct rtc_class_ops x1205_rtc_ops = {
 562         .proc           = x1205_rtc_proc,
 563         .read_time      = x1205_rtc_read_time,
 564         .set_time       = x1205_rtc_set_time,
 565         .read_alarm     = x1205_rtc_read_alarm,
 566         .set_alarm      = x1205_rtc_set_alarm,
 567 };
 568
 569 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
 570                                 struct device_attribute *attr, char *buf)
 571 {
 572         int err, atrim;
 573
 574         err = x1205_get_atrim(to_i2c_client(dev), &atrim);
 575         if (err)
 576                 return err;
 577
 578         return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
 579 }
 580 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
 581
 582 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
 583                                 struct device_attribute *attr, char *buf)
 584 {
 585         int err, dtrim;
 586
 587         err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
 588         if (err)
 589                 return err;
 590
 591         return sprintf(buf, "%d ppm\n", dtrim);
 592 }
 593 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
 594
 595 static int x1205_sysfs_register(struct device *dev)
 596 {
 597         int err;
 598
 599         err = device_create_file(dev, &dev_attr_atrim);
 600         if (err)
 601                 return err;
 602
 603         err = device_create_file(dev, &dev_attr_dtrim);
 604         if (err)
 605                 device_remove_file(dev, &dev_attr_atrim);
 606
 607         return err;
 608 }
 609
 610 static void x1205_sysfs_unregister(struct device *dev)
 611 {
 612         device_remove_file(dev, &dev_attr_atrim);
 613         device_remove_file(dev, &dev_attr_dtrim);
 614 }
 615
 616
 617 static int x1205_probe(struct i2c_client *client)
 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         rtc = devm_rtc_device_register(&client->dev, x1205_driver.driver.name,
 632                                         &x1205_rtc_ops, THIS_MODULE);
 633
 634         if (IS_ERR(rtc))
 635                 return PTR_ERR(rtc);
 636
 637         i2c_set_clientdata(client, rtc);
 638
 639         /* Check for power failures and eventually enable the osc */
 640         err = x1205_get_status(client, &sr);
 641         if (!err) {
 642                 if (sr & X1205_SR_RTCF) {
 643                         dev_err(&client->dev,
 644                                 "power failure detected, "
 645                                 "please set the clock\n");
 646                         udelay(50);
 647                         x1205_fix_osc(client);
 648                 }
 649         } else {
 650                 dev_err(&client->dev, "couldn't read status\n");
 651         }
 652
 653         err = x1205_sysfs_register(&client->dev);
 654         if (err)
 655                 dev_err(&client->dev, "Unable to create sysfs entries\n");
 656
 657         return 0;
 658 }
 659
 660 static void x1205_remove(struct i2c_client *client)
 661 {
 662         x1205_sysfs_unregister(&client->dev);
 663 }
 664
 665 static const struct i2c_device_id x1205_id[] = {
 666         { "x1205", 0 },
 667         { }
 668 };
 669 MODULE_DEVICE_TABLE(i2c, x1205_id);
 670
 671 static const struct of_device_id x1205_dt_ids[] = {
 672         { .compatible = "xircom,x1205", },
 673         {},
 674 };
 675 MODULE_DEVICE_TABLE(of, x1205_dt_ids);
 676
 677 static struct i2c_driver x1205_driver = {
 678         .driver         = {
 679                 .name   = "rtc-x1205",
 680                 .of_match_table = x1205_dt_ids,
 681         },
 682         .probe          = x1205_probe,
 683         .remove         = x1205_remove,
 684         .id_table       = x1205_id,
 685 };
 686
 687 module_i2c_driver(x1205_driver);
 688
 689 MODULE_AUTHOR(
 690         "Karen Spearel <kas111 at gmail dot com>, "
 691         "Alessandro Zummo <a.zummo@towertech.it>");
 692 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
 693 MODULE_LICENSE("GPL");