drivers/rtc/rtc-ds3232.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RTC client/driver for the Maxim/Dallas DS3232/DS3234 Real-Time Clock
   4  *
   5  * Copyright (C) 2009-2011 Freescale Semiconductor.
   6  * Author: Jack Lan <jack.lan@freescale.com>
   7  * Copyright (C) 2008 MIMOMax Wireless Ltd.
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/i2c.h>
  16 #include <linux/spi/spi.h>
  17 #include <linux/rtc.h>
  18 #include <linux/bcd.h>
  19 #include <linux/slab.h>
  20 #include <linux/regmap.h>
  21 #include <linux/hwmon.h>
  22
  23 #define DS3232_REG_SECONDS      0x00
  24 #define DS3232_REG_MINUTES      0x01
  25 #define DS3232_REG_HOURS        0x02
  26 #define DS3232_REG_AMPM         0x02
  27 #define DS3232_REG_DAY          0x03
  28 #define DS3232_REG_DATE         0x04
  29 #define DS3232_REG_MONTH        0x05
  30 #define DS3232_REG_CENTURY      0x05
  31 #define DS3232_REG_YEAR         0x06
  32 #define DS3232_REG_ALARM1       0x07       /* Alarm 1 BASE */
  33 #define DS3232_REG_ALARM2       0x0B       /* Alarm 2 BASE */
  34 #define DS3232_REG_CR           0x0E       /* Control register */
  35 #       define DS3232_REG_CR_nEOSC   0x80
  36 #       define DS3232_REG_CR_INTCN   0x04
  37 #       define DS3232_REG_CR_A2IE    0x02
  38 #       define DS3232_REG_CR_A1IE    0x01
  39
  40 #define DS3232_REG_SR           0x0F       /* control/status register */
  41 #       define DS3232_REG_SR_OSF     0x80
  42 #       define DS3232_REG_SR_BSY     0x04
  43 #       define DS3232_REG_SR_A2F     0x02
  44 #       define DS3232_REG_SR_A1F     0x01
  45
  46 #define DS3232_REG_TEMPERATURE  0x11
  47 #define DS3232_REG_SRAM_START   0x14
  48 #define DS3232_REG_SRAM_END     0xFF
  49
  50 #define DS3232_REG_SRAM_SIZE    236
  51
  52 struct ds3232 {
  53         struct device *dev;
  54         struct regmap *regmap;
  55         int irq;
  56         struct rtc_device *rtc;
  57
  58         bool suspended;
  59 };
  60
  61 static int ds3232_check_rtc_status(struct device *dev)
  62 {
  63         struct ds3232 *ds3232 = dev_get_drvdata(dev);
  64         int ret = 0;
  65         int control, stat;
  66
  67         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
  68         if (ret)
  69                 return ret;
  70
  71         if (stat & DS3232_REG_SR_OSF)
  72                 dev_warn(dev,
  73                                 "oscillator discontinuity flagged, "
  74                                 "time unreliable\n");
  75
  76         stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
  77
  78         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
  79         if (ret)
  80                 return ret;
  81
  82         /* If the alarm is pending, clear it before requesting
  83          * the interrupt, so an interrupt event isn't reported
  84          * before everything is initialized.
  85          */
  86
  87         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
  88         if (ret)
  89                 return ret;
  90
  91         control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
  92         control |= DS3232_REG_CR_INTCN;
  93
  94         return regmap_write(ds3232->regmap, DS3232_REG_CR, control);
  95 }
  96
  97 static int ds3232_read_time(struct device *dev, struct rtc_time *time)
  98 {
  99         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 100         int ret;
 101         u8 buf[7];
 102         unsigned int year, month, day, hour, minute, second;
 103         unsigned int week, twelve_hr, am_pm;
 104         unsigned int century, add_century = 0;
 105
 106         ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_SECONDS, buf, 7);
 107         if (ret)
 108                 return ret;
 109
 110         second = buf[0];
 111         minute = buf[1];
 112         hour = buf[2];
 113         week = buf[3];
 114         day = buf[4];
 115         month = buf[5];
 116         year = buf[6];
 117
 118         /* Extract additional information for AM/PM and century */
 119
 120         twelve_hr = hour & 0x40;
 121         am_pm = hour & 0x20;
 122         century = month & 0x80;
 123
 124         /* Write to rtc_time structure */
 125
 126         time->tm_sec = bcd2bin(second);
 127         time->tm_min = bcd2bin(minute);
 128         if (twelve_hr) {
 129                 /* Convert to 24 hr */
 130                 if (am_pm)
 131                         time->tm_hour = bcd2bin(hour & 0x1F) + 12;
 132                 else
 133                         time->tm_hour = bcd2bin(hour & 0x1F);
 134         } else {
 135                 time->tm_hour = bcd2bin(hour);
 136         }
 137
 138         /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
 139         time->tm_wday = bcd2bin(week) - 1;
 140         time->tm_mday = bcd2bin(day);
 141         /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
 142         time->tm_mon = bcd2bin(month & 0x7F) - 1;
 143         if (century)
 144                 add_century = 100;
 145
 146         time->tm_year = bcd2bin(year) + add_century;
 147
 148         return 0;
 149 }
 150
 151 static int ds3232_set_time(struct device *dev, struct rtc_time *time)
 152 {
 153         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 154         u8 buf[7];
 155
 156         /* Extract time from rtc_time and load into ds3232*/
 157
 158         buf[0] = bin2bcd(time->tm_sec);
 159         buf[1] = bin2bcd(time->tm_min);
 160         buf[2] = bin2bcd(time->tm_hour);
 161         /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
 162         buf[3] = bin2bcd(time->tm_wday + 1);
 163         buf[4] = bin2bcd(time->tm_mday); /* Date */
 164         /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
 165         buf[5] = bin2bcd(time->tm_mon + 1);
 166         if (time->tm_year >= 100) {
 167                 buf[5] |= 0x80;
 168                 buf[6] = bin2bcd(time->tm_year - 100);
 169         } else {
 170                 buf[6] = bin2bcd(time->tm_year);
 171         }
 172
 173         return regmap_bulk_write(ds3232->regmap, DS3232_REG_SECONDS, buf, 7);
 174 }
 175
 176 /*
 177  * DS3232 has two alarm, we only use alarm1
 178  * According to linux specification, only support one-shot alarm
 179  * no periodic alarm mode
 180  */
 181 static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 182 {
 183         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 184         int control, stat;
 185         int ret;
 186         u8 buf[4];
 187
 188         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 189         if (ret)
 190                 goto out;
 191         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 192         if (ret)
 193                 goto out;
 194         ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_ALARM1, buf, 4);
 195         if (ret)
 196                 goto out;
 197
 198         alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
 199         alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
 200         alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
 201         alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
 202
 203         alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
 204         alarm->pending = !!(stat & DS3232_REG_SR_A1F);
 205
 206         ret = 0;
 207 out:
 208         return ret;
 209 }
 210
 211 /*
 212  * linux rtc-module does not support wday alarm
 213  * and only 24h time mode supported indeed
 214  */
 215 static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 216 {
 217         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 218         int control, stat;
 219         int ret;
 220         u8 buf[4];
 221
 222         if (ds3232->irq <= 0)
 223                 return -EINVAL;
 224
 225         buf[0] = bin2bcd(alarm->time.tm_sec);
 226         buf[1] = bin2bcd(alarm->time.tm_min);
 227         buf[2] = bin2bcd(alarm->time.tm_hour);
 228         buf[3] = bin2bcd(alarm->time.tm_mday);
 229
 230         /* clear alarm interrupt enable bit */
 231         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 232         if (ret)
 233                 goto out;
 234         control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
 235         ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 236         if (ret)
 237                 goto out;
 238
 239         /* clear any pending alarm flag */
 240         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 241         if (ret)
 242                 goto out;
 243         stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
 244         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
 245         if (ret)
 246                 goto out;
 247
 248         ret = regmap_bulk_write(ds3232->regmap, DS3232_REG_ALARM1, buf, 4);
 249         if (ret)
 250                 goto out;
 251
 252         if (alarm->enabled) {
 253                 control |= DS3232_REG_CR_A1IE;
 254                 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 255         }
 256 out:
 257         return ret;
 258 }
 259
 260 static int ds3232_update_alarm(struct device *dev, unsigned int enabled)
 261 {
 262         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 263         int control;
 264         int ret;
 265
 266         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 267         if (ret)
 268                 return ret;
 269
 270         if (enabled)
 271                 /* enable alarm1 interrupt */
 272                 control |= DS3232_REG_CR_A1IE;
 273         else
 274                 /* disable alarm1 interrupt */
 275                 control &= ~(DS3232_REG_CR_A1IE);
 276         ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 277
 278         return ret;
 279 }
 280
 281 /*
 282  * Temperature sensor support for ds3232/ds3234 devices.
 283  * A user-initiated temperature conversion is not started by this function,
 284  * so the temperature is updated once every 64 seconds.
 285  */
 286 static int ds3232_hwmon_read_temp(struct device *dev, long int *mC)
 287 {
 288         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 289         u8 temp_buf[2];
 290         s16 temp;
 291         int ret;
 292
 293         ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_TEMPERATURE, temp_buf,
 294                                sizeof(temp_buf));
 295         if (ret < 0)
 296                 return ret;
 297
 298         /*
 299          * Temperature is represented as a 10-bit code with a resolution of
 300          * 0.25 degree celsius and encoded in two's complement format.
 301          */
 302         temp = (temp_buf[0] << 8) | temp_buf[1];
 303         temp >>= 6;
 304         *mC = temp * 250;
 305
 306         return 0;
 307 }
 308
 309 static umode_t ds3232_hwmon_is_visible(const void *data,
 310                                        enum hwmon_sensor_types type,
 311                                        u32 attr, int channel)
 312 {
 313         if (type != hwmon_temp)
 314                 return 0;
 315
 316         switch (attr) {
 317         case hwmon_temp_input:
 318                 return 0444;
 319         default:
 320                 return 0;
 321         }
 322 }
 323
 324 static int ds3232_hwmon_read(struct device *dev,
 325                              enum hwmon_sensor_types type,
 326                              u32 attr, int channel, long *temp)
 327 {
 328         int err;
 329
 330         switch (attr) {
 331         case hwmon_temp_input:
 332                 err = ds3232_hwmon_read_temp(dev, temp);
 333                 break;
 334         default:
 335                 err = -EOPNOTSUPP;
 336                 break;
 337         }
 338
 339         return err;
 340 }
 341
 342 static u32 ds3232_hwmon_chip_config[] = {
 343         HWMON_C_REGISTER_TZ,
 344         0
 345 };
 346
 347 static const struct hwmon_channel_info ds3232_hwmon_chip = {
 348         .type = hwmon_chip,
 349         .config = ds3232_hwmon_chip_config,
 350 };
 351
 352 static u32 ds3232_hwmon_temp_config[] = {
 353         HWMON_T_INPUT,
 354         0
 355 };
 356
 357 static const struct hwmon_channel_info ds3232_hwmon_temp = {
 358         .type = hwmon_temp,
 359         .config = ds3232_hwmon_temp_config,
 360 };
 361
 362 static const struct hwmon_channel_info *ds3232_hwmon_info[] = {
 363         &ds3232_hwmon_chip,
 364         &ds3232_hwmon_temp,
 365         NULL
 366 };
 367
 368 static const struct hwmon_ops ds3232_hwmon_hwmon_ops = {
 369         .is_visible = ds3232_hwmon_is_visible,
 370         .read = ds3232_hwmon_read,
 371 };
 372
 373 static const struct hwmon_chip_info ds3232_hwmon_chip_info = {
 374         .ops = &ds3232_hwmon_hwmon_ops,
 375         .info = ds3232_hwmon_info,
 376 };
 377
 378 static void ds3232_hwmon_register(struct device *dev, const char *name)
 379 {
 380         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 381         struct device *hwmon_dev;
 382
 383         if (!IS_ENABLED(CONFIG_RTC_DRV_DS3232_HWMON))
 384                 return;
 385
 386         hwmon_dev = devm_hwmon_device_register_with_info(dev, name, ds3232,
 387                                                         &ds3232_hwmon_chip_info,
 388                                                         NULL);
 389         if (IS_ERR(hwmon_dev)) {
 390                 dev_err(dev, "unable to register hwmon device %ld\n",
 391                         PTR_ERR(hwmon_dev));
 392         }
 393 }
 394
 395 static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
 396 {
 397         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 398
 399         if (ds3232->irq <= 0)
 400                 return -EINVAL;
 401
 402         return ds3232_update_alarm(dev, enabled);
 403 }
 404
 405 static irqreturn_t ds3232_irq(int irq, void *dev_id)
 406 {
 407         struct device *dev = dev_id;
 408         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 409         int ret;
 410         int stat, control;
 411
 412         rtc_lock(ds3232->rtc);
 413
 414         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 415         if (ret)
 416                 goto unlock;
 417
 418         if (stat & DS3232_REG_SR_A1F) {
 419                 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 420                 if (ret) {
 421                         dev_warn(ds3232->dev,
 422                                  "Read Control Register error %d\n", ret);
 423                 } else {
 424                         /* disable alarm1 interrupt */
 425                         control &= ~(DS3232_REG_CR_A1IE);
 426                         ret = regmap_write(ds3232->regmap, DS3232_REG_CR,
 427                                            control);
 428                         if (ret) {
 429                                 dev_warn(ds3232->dev,
 430                                          "Write Control Register error %d\n",
 431                                          ret);
 432                                 goto unlock;
 433                         }
 434
 435                         /* clear the alarm pend flag */
 436                         stat &= ~DS3232_REG_SR_A1F;
 437                         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
 438                         if (ret) {
 439                                 dev_warn(ds3232->dev,
 440                                          "Write Status Register error %d\n",
 441                                          ret);
 442                                 goto unlock;
 443                         }
 444
 445                         rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
 446                 }
 447         }
 448
 449 unlock:
 450         rtc_unlock(ds3232->rtc);
 451
 452         return IRQ_HANDLED;
 453 }
 454
 455 static const struct rtc_class_ops ds3232_rtc_ops = {
 456         .read_time = ds3232_read_time,
 457         .set_time = ds3232_set_time,
 458         .read_alarm = ds3232_read_alarm,
 459         .set_alarm = ds3232_set_alarm,
 460         .alarm_irq_enable = ds3232_alarm_irq_enable,
 461 };
 462
 463 static int ds3232_nvmem_read(void *priv, unsigned int offset, void *val,
 464                              size_t bytes)
 465 {
 466         struct regmap *ds3232_regmap = (struct regmap *)priv;
 467
 468         return regmap_bulk_read(ds3232_regmap, DS3232_REG_SRAM_START + offset,
 469                                 val, bytes);
 470 }
 471
 472 static int ds3232_nvmem_write(void *priv, unsigned int offset, void *val,
 473                               size_t bytes)
 474 {
 475         struct regmap *ds3232_regmap = (struct regmap *)priv;
 476
 477         return regmap_bulk_write(ds3232_regmap, DS3232_REG_SRAM_START + offset,
 478                                  val, bytes);
 479 }
 480
 481 static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
 482                         const char *name)
 483 {
 484         struct ds3232 *ds3232;
 485         int ret;
 486         struct nvmem_config nvmem_cfg = {
 487                 .name = "ds3232_sram",
 488                 .stride = 1,
 489                 .size = DS3232_REG_SRAM_SIZE,
 490                 .word_size = 1,
 491                 .reg_read = ds3232_nvmem_read,
 492                 .reg_write = ds3232_nvmem_write,
 493                 .priv = regmap,
 494                 .type = NVMEM_TYPE_BATTERY_BACKED
 495         };
 496
 497         ds3232 = devm_kzalloc(dev, sizeof(*ds3232), GFP_KERNEL);
 498         if (!ds3232)
 499                 return -ENOMEM;
 500
 501         ds3232->regmap = regmap;
 502         ds3232->irq = irq;
 503         ds3232->dev = dev;
 504         dev_set_drvdata(dev, ds3232);
 505
 506         ret = ds3232_check_rtc_status(dev);
 507         if (ret)
 508                 return ret;
 509
 510         if (ds3232->irq > 0)
 511                 device_init_wakeup(dev, 1);
 512
 513         ds3232_hwmon_register(dev, name);
 514
 515         ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops,
 516                                                 THIS_MODULE);
 517         if (IS_ERR(ds3232->rtc))
 518                 return PTR_ERR(ds3232->rtc);
 519
 520         ret = devm_rtc_nvmem_register(ds3232->rtc, &nvmem_cfg);
 521         if(ret)
 522                 return ret;
 523
 524         if (ds3232->irq > 0) {
 525                 ret = devm_request_threaded_irq(dev, ds3232->irq, NULL,
 526                                                 ds3232_irq,
 527                                                 IRQF_SHARED | IRQF_ONESHOT,
 528                                                 name, dev);
 529                 if (ret) {
 530                         device_set_wakeup_capable(dev, 0);
 531                         ds3232->irq = 0;
 532                         dev_err(dev, "unable to request IRQ\n");
 533                 }
 534         }
 535
 536         return 0;
 537 }
 538
 539 #ifdef CONFIG_PM_SLEEP
 540 static int ds3232_suspend(struct device *dev)
 541 {
 542         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 543
 544         if (device_may_wakeup(dev)) {
 545                 if (enable_irq_wake(ds3232->irq))
 546                         dev_warn_once(dev, "Cannot set wakeup source\n");
 547         }
 548
 549         return 0;
 550 }
 551
 552 static int ds3232_resume(struct device *dev)
 553 {
 554         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 555
 556         if (device_may_wakeup(dev))
 557                 disable_irq_wake(ds3232->irq);
 558
 559         return 0;
 560 }
 561 #endif
 562
 563 static const struct dev_pm_ops ds3232_pm_ops = {
 564         SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
 565 };
 566
 567 #if IS_ENABLED(CONFIG_I2C)
 568
 569 static int ds3232_i2c_probe(struct i2c_client *client,
 570                             const struct i2c_device_id *id)
 571 {
 572         struct regmap *regmap;
 573         static const struct regmap_config config = {
 574                 .reg_bits = 8,
 575                 .val_bits = 8,
 576                 .max_register = DS3232_REG_SRAM_END,
 577         };
 578
 579         regmap = devm_regmap_init_i2c(client, &config);
 580         if (IS_ERR(regmap)) {
 581                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 582                         __func__, PTR_ERR(regmap));
 583                 return PTR_ERR(regmap);
 584         }
 585
 586         return ds3232_probe(&client->dev, regmap, client->irq, client->name);
 587 }
 588
 589 static const struct i2c_device_id ds3232_id[] = {
 590         { "ds3232", 0 },
 591         { }
 592 };
 593 MODULE_DEVICE_TABLE(i2c, ds3232_id);
 594
 595 static const  __maybe_unused struct of_device_id ds3232_of_match[] = {
 596         { .compatible = "dallas,ds3232" },
 597         { }
 598 };
 599 MODULE_DEVICE_TABLE(of, ds3232_of_match);
 600
 601 static struct i2c_driver ds3232_driver = {
 602         .driver = {
 603                 .name = "rtc-ds3232",
 604                 .of_match_table = of_match_ptr(ds3232_of_match),
 605                 .pm     = &ds3232_pm_ops,
 606         },
 607         .probe = ds3232_i2c_probe,
 608         .id_table = ds3232_id,
 609 };
 610
 611 static int ds3232_register_driver(void)
 612 {
 613         return i2c_add_driver(&ds3232_driver);
 614 }
 615
 616 static void ds3232_unregister_driver(void)
 617 {
 618         i2c_del_driver(&ds3232_driver);
 619 }
 620
 621 #else
 622
 623 static int ds3232_register_driver(void)
 624 {
 625         return 0;
 626 }
 627
 628 static void ds3232_unregister_driver(void)
 629 {
 630 }
 631
 632 #endif
 633
 634 #if IS_ENABLED(CONFIG_SPI_MASTER)
 635
 636 static int ds3234_probe(struct spi_device *spi)
 637 {
 638         int res;
 639         unsigned int tmp;
 640         static const struct regmap_config config = {
 641                 .reg_bits = 8,
 642                 .val_bits = 8,
 643                 .max_register = DS3232_REG_SRAM_END,
 644                 .write_flag_mask = 0x80,
 645         };
 646         struct regmap *regmap;
 647
 648         regmap = devm_regmap_init_spi(spi, &config);
 649         if (IS_ERR(regmap)) {
 650                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 651                         __func__, PTR_ERR(regmap));
 652                 return PTR_ERR(regmap);
 653         }
 654
 655         spi->mode = SPI_MODE_3;
 656         spi->bits_per_word = 8;
 657         spi_setup(spi);
 658
 659         res = regmap_read(regmap, DS3232_REG_SECONDS, &tmp);
 660         if (res)
 661                 return res;
 662
 663         /* Control settings
 664          *
 665          * CONTROL_REG
 666          * BIT 7        6       5       4       3       2       1       0
 667          *     EOSC     BBSQW   CONV    RS2     RS1     INTCN   A2IE    A1IE
 668          *
 669          *     0        0       0       1       1       1       0       0
 670          *
 671          * CONTROL_STAT_REG
 672          * BIT 7        6       5       4       3       2       1       0
 673          *     OSF      BB32kHz CRATE1  CRATE0  EN32kHz BSY     A2F     A1F
 674          *
 675          *     1        0       0       0       1       0       0       0
 676          */
 677         res = regmap_read(regmap, DS3232_REG_CR, &tmp);
 678         if (res)
 679                 return res;
 680         res = regmap_write(regmap, DS3232_REG_CR, tmp & 0x1c);
 681         if (res)
 682                 return res;
 683
 684         res = regmap_read(regmap, DS3232_REG_SR, &tmp);
 685         if (res)
 686                 return res;
 687         res = regmap_write(regmap, DS3232_REG_SR, tmp & 0x88);
 688         if (res)
 689                 return res;
 690
 691         /* Print our settings */
 692         res = regmap_read(regmap, DS3232_REG_CR, &tmp);
 693         if (res)
 694                 return res;
 695         dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
 696
 697         res = regmap_read(regmap, DS3232_REG_SR, &tmp);
 698         if (res)
 699                 return res;
 700         dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
 701
 702         return ds3232_probe(&spi->dev, regmap, spi->irq, "ds3234");
 703 }
 704
 705 static struct spi_driver ds3234_driver = {
 706         .driver = {
 707                 .name    = "ds3234",
 708         },
 709         .probe   = ds3234_probe,
 710 };
 711
 712 static int ds3234_register_driver(void)
 713 {
 714         return spi_register_driver(&ds3234_driver);
 715 }
 716
 717 static void ds3234_unregister_driver(void)
 718 {
 719         spi_unregister_driver(&ds3234_driver);
 720 }
 721
 722 #else
 723
 724 static int ds3234_register_driver(void)
 725 {
 726         return 0;
 727 }
 728
 729 static void ds3234_unregister_driver(void)
 730 {
 731 }
 732
 733 #endif
 734
 735 static int __init ds323x_init(void)
 736 {
 737         int ret;
 738
 739         ret = ds3232_register_driver();
 740         if (ret) {
 741                 pr_err("Failed to register ds3232 driver: %d\n", ret);
 742                 return ret;
 743         }
 744
 745         ret = ds3234_register_driver();
 746         if (ret) {
 747                 pr_err("Failed to register ds3234 driver: %d\n", ret);
 748                 ds3232_unregister_driver();
 749         }
 750
 751         return ret;
 752 }
 753 module_init(ds323x_init)
 754
 755 static void __exit ds323x_exit(void)
 756 {
 757         ds3234_unregister_driver();
 758         ds3232_unregister_driver();
 759 }
 760 module_exit(ds323x_exit)
 761
 762 MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>");
 763 MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
 764 MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver");
 765 MODULE_LICENSE("GPL");
 766 MODULE_ALIAS("spi:ds3234");