drivers/rtc/rtc-ds3232.c

   1 /*
   2  * RTC client/driver for the Maxim/Dallas DS3232/DS3234 Real-Time Clock
   3  *
   4  * Copyright (C) 2009-2011 Freescale Semiconductor.
   5  * Author: Jack Lan <[email protected]>
   6  * Copyright (C) 2008 MIMOMax Wireless Ltd.
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/i2c.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/rtc.h>
  22 #include <linux/bcd.h>
  23 #include <linux/slab.h>
  24 #include <linux/regmap.h>
  25
  26 #define DS3232_REG_SECONDS      0x00
  27 #define DS3232_REG_MINUTES      0x01
  28 #define DS3232_REG_HOURS        0x02
  29 #define DS3232_REG_AMPM         0x02
  30 #define DS3232_REG_DAY          0x03
  31 #define DS3232_REG_DATE         0x04
  32 #define DS3232_REG_MONTH        0x05
  33 #define DS3232_REG_CENTURY      0x05
  34 #define DS3232_REG_YEAR         0x06
  35 #define DS3232_REG_ALARM1         0x07  /* Alarm 1 BASE */
  36 #define DS3232_REG_ALARM2         0x0B  /* Alarm 2 BASE */
  37 #define DS3232_REG_CR           0x0E    /* Control register */
  38 #       define DS3232_REG_CR_nEOSC        0x80
  39 #       define DS3232_REG_CR_INTCN        0x04
  40 #       define DS3232_REG_CR_A2IE        0x02
  41 #       define DS3232_REG_CR_A1IE        0x01
  42
  43 #define DS3232_REG_SR   0x0F    /* control/status register */
  44 #       define DS3232_REG_SR_OSF   0x80
  45 #       define DS3232_REG_SR_BSY   0x04
  46 #       define DS3232_REG_SR_A2F   0x02
  47 #       define DS3232_REG_SR_A1F   0x01
  48
  49 struct ds3232 {
  50         struct device *dev;
  51         struct regmap *regmap;
  52         int irq;
  53         struct rtc_device *rtc;
  54
  55         bool suspended;
  56 };
  57
  58 static int ds3232_check_rtc_status(struct device *dev)
  59 {
  60         struct ds3232 *ds3232 = dev_get_drvdata(dev);
  61         int ret = 0;
  62         int control, stat;
  63
  64         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
  65         if (ret)
  66                 return ret;
  67
  68         if (stat & DS3232_REG_SR_OSF)
  69                 dev_warn(dev,
  70                                 "oscillator discontinuity flagged, "
  71                                 "time unreliable\n");
  72
  73         stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
  74
  75         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
  76         if (ret)
  77                 return ret;
  78
  79         /* If the alarm is pending, clear it before requesting
  80          * the interrupt, so an interrupt event isn't reported
  81          * before everything is initialized.
  82          */
  83
  84         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
  85         if (ret)
  86                 return ret;
  87
  88         control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
  89         control |= DS3232_REG_CR_INTCN;
  90
  91         return regmap_write(ds3232->regmap, DS3232_REG_CR, control);
  92 }
  93
  94 static int ds3232_read_time(struct device *dev, struct rtc_time *time)
  95 {
  96         struct ds3232 *ds3232 = dev_get_drvdata(dev);
  97         int ret;
  98         u8 buf[7];
  99         unsigned int year, month, day, hour, minute, second;
 100         unsigned int week, twelve_hr, am_pm;
 101         unsigned int century, add_century = 0;
 102
 103         ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_SECONDS, buf, 7);
 104         if (ret)
 105                 return ret;
 106
 107         second = buf[0];
 108         minute = buf[1];
 109         hour = buf[2];
 110         week = buf[3];
 111         day = buf[4];
 112         month = buf[5];
 113         year = buf[6];
 114
 115         /* Extract additional information for AM/PM and century */
 116
 117         twelve_hr = hour & 0x40;
 118         am_pm = hour & 0x20;
 119         century = month & 0x80;
 120
 121         /* Write to rtc_time structure */
 122
 123         time->tm_sec = bcd2bin(second);
 124         time->tm_min = bcd2bin(minute);
 125         if (twelve_hr) {
 126                 /* Convert to 24 hr */
 127                 if (am_pm)
 128                         time->tm_hour = bcd2bin(hour & 0x1F) + 12;
 129                 else
 130                         time->tm_hour = bcd2bin(hour & 0x1F);
 131         } else {
 132                 time->tm_hour = bcd2bin(hour);
 133         }
 134
 135         /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
 136         time->tm_wday = bcd2bin(week) - 1;
 137         time->tm_mday = bcd2bin(day);
 138         /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
 139         time->tm_mon = bcd2bin(month & 0x7F) - 1;
 140         if (century)
 141                 add_century = 100;
 142
 143         time->tm_year = bcd2bin(year) + add_century;
 144
 145         return rtc_valid_tm(time);
 146 }
 147
 148 static int ds3232_set_time(struct device *dev, struct rtc_time *time)
 149 {
 150         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 151         u8 buf[7];
 152
 153         /* Extract time from rtc_time and load into ds3232*/
 154
 155         buf[0] = bin2bcd(time->tm_sec);
 156         buf[1] = bin2bcd(time->tm_min);
 157         buf[2] = bin2bcd(time->tm_hour);
 158         /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
 159         buf[3] = bin2bcd(time->tm_wday + 1);
 160         buf[4] = bin2bcd(time->tm_mday); /* Date */
 161         /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
 162         buf[5] = bin2bcd(time->tm_mon + 1);
 163         if (time->tm_year >= 100) {
 164                 buf[5] |= 0x80;
 165                 buf[6] = bin2bcd(time->tm_year - 100);
 166         } else {
 167                 buf[6] = bin2bcd(time->tm_year);
 168         }
 169
 170         return regmap_bulk_write(ds3232->regmap, DS3232_REG_SECONDS, buf, 7);
 171 }
 172
 173 /*
 174  * DS3232 has two alarm, we only use alarm1
 175  * According to linux specification, only support one-shot alarm
 176  * no periodic alarm mode
 177  */
 178 static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 179 {
 180         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 181         int control, stat;
 182         int ret;
 183         u8 buf[4];
 184
 185         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 186         if (ret)
 187                 goto out;
 188         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 189         if (ret)
 190                 goto out;
 191         ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_ALARM1, buf, 4);
 192         if (ret)
 193                 goto out;
 194
 195         alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
 196         alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
 197         alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
 198         alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
 199
 200         alarm->time.tm_mon = -1;
 201         alarm->time.tm_year = -1;
 202         alarm->time.tm_wday = -1;
 203         alarm->time.tm_yday = -1;
 204         alarm->time.tm_isdst = -1;
 205
 206         alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
 207         alarm->pending = !!(stat & DS3232_REG_SR_A1F);
 208
 209         ret = 0;
 210 out:
 211         return ret;
 212 }
 213
 214 /*
 215  * linux rtc-module does not support wday alarm
 216  * and only 24h time mode supported indeed
 217  */
 218 static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 219 {
 220         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 221         int control, stat;
 222         int ret;
 223         u8 buf[4];
 224
 225         if (ds3232->irq <= 0)
 226                 return -EINVAL;
 227
 228         buf[0] = bin2bcd(alarm->time.tm_sec);
 229         buf[1] = bin2bcd(alarm->time.tm_min);
 230         buf[2] = bin2bcd(alarm->time.tm_hour);
 231         buf[3] = bin2bcd(alarm->time.tm_mday);
 232
 233         /* clear alarm interrupt enable bit */
 234         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 235         if (ret)
 236                 goto out;
 237         control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
 238         ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 239         if (ret)
 240                 goto out;
 241
 242         /* clear any pending alarm flag */
 243         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 244         if (ret)
 245                 goto out;
 246         stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
 247         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
 248         if (ret)
 249                 goto out;
 250
 251         ret = regmap_bulk_write(ds3232->regmap, DS3232_REG_ALARM1, buf, 4);
 252         if (ret)
 253                 goto out;
 254
 255         if (alarm->enabled) {
 256                 control |= DS3232_REG_CR_A1IE;
 257                 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 258         }
 259 out:
 260         return ret;
 261 }
 262
 263 static int ds3232_update_alarm(struct device *dev, unsigned int enabled)
 264 {
 265         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 266         int control;
 267         int ret;
 268
 269         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 270         if (ret)
 271                 return ret;
 272
 273         if (enabled)
 274                 /* enable alarm1 interrupt */
 275                 control |= DS3232_REG_CR_A1IE;
 276         else
 277                 /* disable alarm1 interrupt */
 278                 control &= ~(DS3232_REG_CR_A1IE);
 279         ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 280
 281         return ret;
 282 }
 283
 284 static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
 285 {
 286         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 287
 288         if (ds3232->irq <= 0)
 289                 return -EINVAL;
 290
 291         return ds3232_update_alarm(dev, enabled);
 292 }
 293
 294 static irqreturn_t ds3232_irq(int irq, void *dev_id)
 295 {
 296         struct device *dev = dev_id;
 297         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 298         struct mutex *lock = &ds3232->rtc->ops_lock;
 299         int ret;
 300         int stat, control;
 301
 302         mutex_lock(lock);
 303
 304         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 305         if (ret)
 306                 goto unlock;
 307
 308         if (stat & DS3232_REG_SR_A1F) {
 309                 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 310                 if (ret) {
 311                         dev_warn(ds3232->dev,
 312                                  "Read Control Register error %d\n", ret);
 313                 } else {
 314                         /* disable alarm1 interrupt */
 315                         control &= ~(DS3232_REG_CR_A1IE);
 316                         ret = regmap_write(ds3232->regmap, DS3232_REG_CR,
 317                                            control);
 318                         if (ret) {
 319                                 dev_warn(ds3232->dev,
 320                                          "Write Control Register error %d\n",
 321                                          ret);
 322                                 goto unlock;
 323                         }
 324
 325                         /* clear the alarm pend flag */
 326                         stat &= ~DS3232_REG_SR_A1F;
 327                         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
 328                         if (ret) {
 329                                 dev_warn(ds3232->dev,
 330                                          "Write Status Register error %d\n",
 331                                          ret);
 332                                 goto unlock;
 333                         }
 334
 335                         rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
 336                 }
 337         }
 338
 339 unlock:
 340         mutex_unlock(lock);
 341
 342         return IRQ_HANDLED;
 343 }
 344
 345 static const struct rtc_class_ops ds3232_rtc_ops = {
 346         .read_time = ds3232_read_time,
 347         .set_time = ds3232_set_time,
 348         .read_alarm = ds3232_read_alarm,
 349         .set_alarm = ds3232_set_alarm,
 350         .alarm_irq_enable = ds3232_alarm_irq_enable,
 351 };
 352
 353 static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
 354                         const char *name)
 355 {
 356         struct ds3232 *ds3232;
 357         int ret;
 358
 359         ds3232 = devm_kzalloc(dev, sizeof(*ds3232), GFP_KERNEL);
 360         if (!ds3232)
 361                 return -ENOMEM;
 362
 363         ds3232->regmap = regmap;
 364         ds3232->irq = irq;
 365         ds3232->dev = dev;
 366         dev_set_drvdata(dev, ds3232);
 367
 368         ret = ds3232_check_rtc_status(dev);
 369         if (ret)
 370                 return ret;
 371
 372         ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops,
 373                                                 THIS_MODULE);
 374         if (IS_ERR(ds3232->rtc))
 375                 return PTR_ERR(ds3232->rtc);
 376
 377         if (ds3232->irq > 0) {
 378                 ret = devm_request_threaded_irq(dev, ds3232->irq, NULL,
 379                                                 ds3232_irq,
 380                                                 IRQF_SHARED | IRQF_ONESHOT,
 381                                                 name, dev);
 382                 if (ret) {
 383                         ds3232->irq = 0;
 384                         dev_err(dev, "unable to request IRQ\n");
 385                 } else
 386                         device_init_wakeup(dev, 1);
 387         }
 388
 389         return 0;
 390 }
 391
 392 #ifdef CONFIG_PM_SLEEP
 393 static int ds3232_suspend(struct device *dev)
 394 {
 395         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 396
 397         if (device_may_wakeup(dev)) {
 398                 if (enable_irq_wake(ds3232->irq))
 399                         dev_warn_once(dev, "Cannot set wakeup source\n");
 400         }
 401
 402         return 0;
 403 }
 404
 405 static int ds3232_resume(struct device *dev)
 406 {
 407         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 408
 409         if (device_may_wakeup(dev))
 410                 disable_irq_wake(ds3232->irq);
 411
 412         return 0;
 413 }
 414 #endif
 415
 416 static const struct dev_pm_ops ds3232_pm_ops = {
 417         SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
 418 };
 419
 420 #if IS_ENABLED(CONFIG_I2C)
 421
 422 static int ds3232_i2c_probe(struct i2c_client *client,
 423                             const struct i2c_device_id *id)
 424 {
 425         struct regmap *regmap;
 426         static const struct regmap_config config = {
 427                 .reg_bits = 8,
 428                 .val_bits = 8,
 429         };
 430
 431         regmap = devm_regmap_init_i2c(client, &config);
 432         if (IS_ERR(regmap)) {
 433                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 434                         __func__, PTR_ERR(regmap));
 435                 return PTR_ERR(regmap);
 436         }
 437
 438         return ds3232_probe(&client->dev, regmap, client->irq, client->name);
 439 }
 440
 441 static const struct i2c_device_id ds3232_id[] = {
 442         { "ds3232", 0 },
 443         { }
 444 };
 445 MODULE_DEVICE_TABLE(i2c, ds3232_id);
 446
 447 static struct i2c_driver ds3232_driver = {
 448         .driver = {
 449                 .name = "rtc-ds3232",
 450                 .pm     = &ds3232_pm_ops,
 451         },
 452         .probe = ds3232_i2c_probe,
 453         .id_table = ds3232_id,
 454 };
 455
 456 static int ds3232_register_driver(void)
 457 {
 458         return i2c_add_driver(&ds3232_driver);
 459 }
 460
 461 static void ds3232_unregister_driver(void)
 462 {
 463         i2c_del_driver(&ds3232_driver);
 464 }
 465
 466 #else
 467
 468 static int ds3232_register_driver(void)
 469 {
 470         return 0;
 471 }
 472
 473 static void ds3232_unregister_driver(void)
 474 {
 475 }
 476
 477 #endif
 478
 479 #if IS_ENABLED(CONFIG_SPI_MASTER)
 480
 481 static int ds3234_probe(struct spi_device *spi)
 482 {
 483         int res;
 484         unsigned int tmp;
 485         static const struct regmap_config config = {
 486                 .reg_bits = 8,
 487                 .val_bits = 8,
 488                 .write_flag_mask = 0x80,
 489         };
 490         struct regmap *regmap;
 491
 492         regmap = devm_regmap_init_spi(spi, &config);
 493         if (IS_ERR(regmap)) {
 494                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 495                         __func__, PTR_ERR(regmap));
 496                 return PTR_ERR(regmap);
 497         }
 498
 499         spi->mode = SPI_MODE_3;
 500         spi->bits_per_word = 8;
 501         spi_setup(spi);
 502
 503         res = regmap_read(regmap, DS3232_REG_SECONDS, &tmp);
 504         if (res)
 505                 return res;
 506
 507         /* Control settings
 508          *
 509          * CONTROL_REG
 510          * BIT 7        6       5       4       3       2       1       0
 511          *     EOSC     BBSQW   CONV    RS2     RS1     INTCN   A2IE    A1IE
 512          *
 513          *     0        0       0       1       1       1       0       0
 514          *
 515          * CONTROL_STAT_REG
 516          * BIT 7        6       5       4       3       2       1       0
 517          *     OSF      BB32kHz CRATE1  CRATE0  EN32kHz BSY     A2F     A1F
 518          *
 519          *     1        0       0       0       1       0       0       0
 520          */
 521         res = regmap_read(regmap, DS3232_REG_CR, &tmp);
 522         if (res)
 523                 return res;
 524         res = regmap_write(regmap, DS3232_REG_CR, tmp & 0x1c);
 525         if (res)
 526                 return res;
 527
 528         res = regmap_read(regmap, DS3232_REG_SR, &tmp);
 529         if (res)
 530                 return res;
 531         res = regmap_write(regmap, DS3232_REG_SR, tmp & 0x88);
 532         if (res)
 533                 return res;
 534
 535         /* Print our settings */
 536         res = regmap_read(regmap, DS3232_REG_CR, &tmp);
 537         if (res)
 538                 return res;
 539         dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
 540
 541         res = regmap_read(regmap, DS3232_REG_SR, &tmp);
 542         if (res)
 543                 return res;
 544         dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
 545
 546         return ds3232_probe(&spi->dev, regmap, spi->irq, "ds3234");
 547 }
 548
 549 static struct spi_driver ds3234_driver = {
 550         .driver = {
 551                 .name    = "ds3234",
 552         },
 553         .probe   = ds3234_probe,
 554 };
 555
 556 static int ds3234_register_driver(void)
 557 {
 558         return spi_register_driver(&ds3234_driver);
 559 }
 560
 561 static void ds3234_unregister_driver(void)
 562 {
 563         spi_unregister_driver(&ds3234_driver);
 564 }
 565
 566 #else
 567
 568 static int ds3234_register_driver(void)
 569 {
 570         return 0;
 571 }
 572
 573 static void ds3234_unregister_driver(void)
 574 {
 575 }
 576
 577 #endif
 578
 579 static int __init ds323x_init(void)
 580 {
 581         int ret;
 582
 583         ret = ds3232_register_driver();
 584         if (ret) {
 585                 pr_err("Failed to register ds3232 driver: %d\n", ret);
 586                 return ret;
 587         }
 588
 589         ret = ds3234_register_driver();
 590         if (ret) {
 591                 pr_err("Failed to register ds3234 driver: %d\n", ret);
 592                 ds3232_unregister_driver();
 593         }
 594
 595         return ret;
 596 }
 597 module_init(ds323x_init)
 598
 599 static void __exit ds323x_exit(void)
 600 {
 601         ds3234_unregister_driver();
 602         ds3232_unregister_driver();
 603 }
 604 module_exit(ds323x_exit)
 605
 606 MODULE_AUTHOR("Srikanth Srinivasan <[email protected]>");
 607 MODULE_AUTHOR("Dennis Aberilla <[email protected]>");
 608 MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver");
 609 MODULE_LICENSE("GPL");
 610 MODULE_ALIAS("spi:ds3234");