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->enabled = !!(control & DS3232_REG_CR_A1IE);
 201         alarm->pending = !!(stat & DS3232_REG_SR_A1F);
 202
 203         ret = 0;
 204 out:
 205         return ret;
 206 }
 207
 208 /*
 209  * linux rtc-module does not support wday alarm
 210  * and only 24h time mode supported indeed
 211  */
 212 static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 213 {
 214         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 215         int control, stat;
 216         int ret;
 217         u8 buf[4];
 218
 219         if (ds3232->irq <= 0)
 220                 return -EINVAL;
 221
 222         buf[0] = bin2bcd(alarm->time.tm_sec);
 223         buf[1] = bin2bcd(alarm->time.tm_min);
 224         buf[2] = bin2bcd(alarm->time.tm_hour);
 225         buf[3] = bin2bcd(alarm->time.tm_mday);
 226
 227         /* clear alarm interrupt enable bit */
 228         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 229         if (ret)
 230                 goto out;
 231         control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
 232         ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 233         if (ret)
 234                 goto out;
 235
 236         /* clear any pending alarm flag */
 237         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 238         if (ret)
 239                 goto out;
 240         stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
 241         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
 242         if (ret)
 243                 goto out;
 244
 245         ret = regmap_bulk_write(ds3232->regmap, DS3232_REG_ALARM1, buf, 4);
 246         if (ret)
 247                 goto out;
 248
 249         if (alarm->enabled) {
 250                 control |= DS3232_REG_CR_A1IE;
 251                 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 252         }
 253 out:
 254         return ret;
 255 }
 256
 257 static int ds3232_update_alarm(struct device *dev, unsigned int enabled)
 258 {
 259         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 260         int control;
 261         int ret;
 262
 263         ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 264         if (ret)
 265                 return ret;
 266
 267         if (enabled)
 268                 /* enable alarm1 interrupt */
 269                 control |= DS3232_REG_CR_A1IE;
 270         else
 271                 /* disable alarm1 interrupt */
 272                 control &= ~(DS3232_REG_CR_A1IE);
 273         ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
 274
 275         return ret;
 276 }
 277
 278 static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
 279 {
 280         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 281
 282         if (ds3232->irq <= 0)
 283                 return -EINVAL;
 284
 285         return ds3232_update_alarm(dev, enabled);
 286 }
 287
 288 static irqreturn_t ds3232_irq(int irq, void *dev_id)
 289 {
 290         struct device *dev = dev_id;
 291         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 292         struct mutex *lock = &ds3232->rtc->ops_lock;
 293         int ret;
 294         int stat, control;
 295
 296         mutex_lock(lock);
 297
 298         ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
 299         if (ret)
 300                 goto unlock;
 301
 302         if (stat & DS3232_REG_SR_A1F) {
 303                 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
 304                 if (ret) {
 305                         dev_warn(ds3232->dev,
 306                                  "Read Control Register error %d\n", ret);
 307                 } else {
 308                         /* disable alarm1 interrupt */
 309                         control &= ~(DS3232_REG_CR_A1IE);
 310                         ret = regmap_write(ds3232->regmap, DS3232_REG_CR,
 311                                            control);
 312                         if (ret) {
 313                                 dev_warn(ds3232->dev,
 314                                          "Write Control Register error %d\n",
 315                                          ret);
 316                                 goto unlock;
 317                         }
 318
 319                         /* clear the alarm pend flag */
 320                         stat &= ~DS3232_REG_SR_A1F;
 321                         ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
 322                         if (ret) {
 323                                 dev_warn(ds3232->dev,
 324                                          "Write Status Register error %d\n",
 325                                          ret);
 326                                 goto unlock;
 327                         }
 328
 329                         rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
 330                 }
 331         }
 332
 333 unlock:
 334         mutex_unlock(lock);
 335
 336         return IRQ_HANDLED;
 337 }
 338
 339 static const struct rtc_class_ops ds3232_rtc_ops = {
 340         .read_time = ds3232_read_time,
 341         .set_time = ds3232_set_time,
 342         .read_alarm = ds3232_read_alarm,
 343         .set_alarm = ds3232_set_alarm,
 344         .alarm_irq_enable = ds3232_alarm_irq_enable,
 345 };
 346
 347 static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
 348                         const char *name)
 349 {
 350         struct ds3232 *ds3232;
 351         int ret;
 352
 353         ds3232 = devm_kzalloc(dev, sizeof(*ds3232), GFP_KERNEL);
 354         if (!ds3232)
 355                 return -ENOMEM;
 356
 357         ds3232->regmap = regmap;
 358         ds3232->irq = irq;
 359         ds3232->dev = dev;
 360         dev_set_drvdata(dev, ds3232);
 361
 362         ret = ds3232_check_rtc_status(dev);
 363         if (ret)
 364                 return ret;
 365
 366         if (ds3232->irq > 0)
 367                 device_init_wakeup(dev, 1);
 368
 369         ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops,
 370                                                 THIS_MODULE);
 371         if (IS_ERR(ds3232->rtc))
 372                 return PTR_ERR(ds3232->rtc);
 373
 374         if (ds3232->irq > 0) {
 375                 ret = devm_request_threaded_irq(dev, ds3232->irq, NULL,
 376                                                 ds3232_irq,
 377                                                 IRQF_SHARED | IRQF_ONESHOT,
 378                                                 name, dev);
 379                 if (ret) {
 380                         device_set_wakeup_capable(dev, 0);
 381                         ds3232->irq = 0;
 382                         dev_err(dev, "unable to request IRQ\n");
 383                 }
 384         }
 385
 386         return 0;
 387 }
 388
 389 #ifdef CONFIG_PM_SLEEP
 390 static int ds3232_suspend(struct device *dev)
 391 {
 392         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 393
 394         if (device_may_wakeup(dev)) {
 395                 if (enable_irq_wake(ds3232->irq))
 396                         dev_warn_once(dev, "Cannot set wakeup source\n");
 397         }
 398
 399         return 0;
 400 }
 401
 402 static int ds3232_resume(struct device *dev)
 403 {
 404         struct ds3232 *ds3232 = dev_get_drvdata(dev);
 405
 406         if (device_may_wakeup(dev))
 407                 disable_irq_wake(ds3232->irq);
 408
 409         return 0;
 410 }
 411 #endif
 412
 413 static const struct dev_pm_ops ds3232_pm_ops = {
 414         SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
 415 };
 416
 417 #if IS_ENABLED(CONFIG_I2C)
 418
 419 static int ds3232_i2c_probe(struct i2c_client *client,
 420                             const struct i2c_device_id *id)
 421 {
 422         struct regmap *regmap;
 423         static const struct regmap_config config = {
 424                 .reg_bits = 8,
 425                 .val_bits = 8,
 426                 .max_register = 0x13,
 427         };
 428
 429         regmap = devm_regmap_init_i2c(client, &config);
 430         if (IS_ERR(regmap)) {
 431                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 432                         __func__, PTR_ERR(regmap));
 433                 return PTR_ERR(regmap);
 434         }
 435
 436         return ds3232_probe(&client->dev, regmap, client->irq, client->name);
 437 }
 438
 439 static const struct i2c_device_id ds3232_id[] = {
 440         { "ds3232", 0 },
 441         { }
 442 };
 443 MODULE_DEVICE_TABLE(i2c, ds3232_id);
 444
 445 static struct i2c_driver ds3232_driver = {
 446         .driver = {
 447                 .name = "rtc-ds3232",
 448                 .pm     = &ds3232_pm_ops,
 449         },
 450         .probe = ds3232_i2c_probe,
 451         .id_table = ds3232_id,
 452 };
 453
 454 static int ds3232_register_driver(void)
 455 {
 456         return i2c_add_driver(&ds3232_driver);
 457 }
 458
 459 static void ds3232_unregister_driver(void)
 460 {
 461         i2c_del_driver(&ds3232_driver);
 462 }
 463
 464 #else
 465
 466 static int ds3232_register_driver(void)
 467 {
 468         return 0;
 469 }
 470
 471 static void ds3232_unregister_driver(void)
 472 {
 473 }
 474
 475 #endif
 476
 477 #if IS_ENABLED(CONFIG_SPI_MASTER)
 478
 479 static int ds3234_probe(struct spi_device *spi)
 480 {
 481         int res;
 482         unsigned int tmp;
 483         static const struct regmap_config config = {
 484                 .reg_bits = 8,
 485                 .val_bits = 8,
 486                 .max_register = 0x13,
 487                 .write_flag_mask = 0x80,
 488         };
 489         struct regmap *regmap;
 490
 491         regmap = devm_regmap_init_spi(spi, &config);
 492         if (IS_ERR(regmap)) {
 493                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 494                         __func__, PTR_ERR(regmap));
 495                 return PTR_ERR(regmap);
 496         }
 497
 498         spi->mode = SPI_MODE_3;
 499         spi->bits_per_word = 8;
 500         spi_setup(spi);
 501
 502         res = regmap_read(regmap, DS3232_REG_SECONDS, &tmp);
 503         if (res)
 504                 return res;
 505
 506         /* Control settings
 507          *
 508          * CONTROL_REG
 509          * BIT 7        6       5       4       3       2       1       0
 510          *     EOSC     BBSQW   CONV    RS2     RS1     INTCN   A2IE    A1IE
 511          *
 512          *     0        0       0       1       1       1       0       0
 513          *
 514          * CONTROL_STAT_REG
 515          * BIT 7        6       5       4       3       2       1       0
 516          *     OSF      BB32kHz CRATE1  CRATE0  EN32kHz BSY     A2F     A1F
 517          *
 518          *     1        0       0       0       1       0       0       0
 519          */
 520         res = regmap_read(regmap, DS3232_REG_CR, &tmp);
 521         if (res)
 522                 return res;
 523         res = regmap_write(regmap, DS3232_REG_CR, tmp & 0x1c);
 524         if (res)
 525                 return res;
 526
 527         res = regmap_read(regmap, DS3232_REG_SR, &tmp);
 528         if (res)
 529                 return res;
 530         res = regmap_write(regmap, DS3232_REG_SR, tmp & 0x88);
 531         if (res)
 532                 return res;
 533
 534         /* Print our settings */
 535         res = regmap_read(regmap, DS3232_REG_CR, &tmp);
 536         if (res)
 537                 return res;
 538         dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
 539
 540         res = regmap_read(regmap, DS3232_REG_SR, &tmp);
 541         if (res)
 542                 return res;
 543         dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
 544
 545         return ds3232_probe(&spi->dev, regmap, spi->irq, "ds3234");
 546 }
 547
 548 static struct spi_driver ds3234_driver = {
 549         .driver = {
 550                 .name    = "ds3234",
 551         },
 552         .probe   = ds3234_probe,
 553 };
 554
 555 static int ds3234_register_driver(void)
 556 {
 557         return spi_register_driver(&ds3234_driver);
 558 }
 559
 560 static void ds3234_unregister_driver(void)
 561 {
 562         spi_unregister_driver(&ds3234_driver);
 563 }
 564
 565 #else
 566
 567 static int ds3234_register_driver(void)
 568 {
 569         return 0;
 570 }
 571
 572 static void ds3234_unregister_driver(void)
 573 {
 574 }
 575
 576 #endif
 577
 578 static int __init ds323x_init(void)
 579 {
 580         int ret;
 581
 582         ret = ds3232_register_driver();
 583         if (ret) {
 584                 pr_err("Failed to register ds3232 driver: %d\n", ret);
 585                 return ret;
 586         }
 587
 588         ret = ds3234_register_driver();
 589         if (ret) {
 590                 pr_err("Failed to register ds3234 driver: %d\n", ret);
 591                 ds3232_unregister_driver();
 592         }
 593
 594         return ret;
 595 }
 596 module_init(ds323x_init)
 597
 598 static void __exit ds323x_exit(void)
 599 {
 600         ds3234_unregister_driver();
 601         ds3232_unregister_driver();
 602 }
 603 module_exit(ds323x_exit)
 604
 605 MODULE_AUTHOR("Srikanth Srinivasan <[email protected]>");
 606 MODULE_AUTHOR("Dennis Aberilla <[email protected]>");
 607 MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver");
 608 MODULE_LICENSE("GPL");
 609 MODULE_ALIAS("spi:ds3234");