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 <jack.lan@freescale.com> 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 if (ds3232->irq > 0) { 373 ret = devm_request_threaded_irq(dev, ds3232->irq, NULL, 374 ds3232_irq, 375 IRQF_SHARED | IRQF_ONESHOT, 376 name, dev); 377 if (ret) { 378 ds3232->irq = 0; 379 dev_err(dev, "unable to request IRQ\n"); 380 } else 381 device_init_wakeup(dev, 1); 382 } 383 ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops, 384 THIS_MODULE); 385 386 return PTR_ERR_OR_ZERO(ds3232->rtc); 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 }; 427 428 regmap = devm_regmap_init_i2c(client, &config); 429 if (IS_ERR(regmap)) { 430 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n", 431 __func__, PTR_ERR(regmap)); 432 return PTR_ERR(regmap); 433 } 434 435 return ds3232_probe(&client->dev, regmap, client->irq, client->name); 436 } 437 438 static const struct i2c_device_id ds3232_id[] = { 439 { "ds3232", 0 }, 440 { } 441 }; 442 MODULE_DEVICE_TABLE(i2c, ds3232_id); 443 444 static struct i2c_driver ds3232_driver = { 445 .driver = { 446 .name = "rtc-ds3232", 447 .pm = &ds3232_pm_ops, 448 }, 449 .probe = ds3232_i2c_probe, 450 .id_table = ds3232_id, 451 }; 452 453 static int ds3232_register_driver(void) 454 { 455 return i2c_add_driver(&ds3232_driver); 456 } 457 458 static void ds3232_unregister_driver(void) 459 { 460 i2c_del_driver(&ds3232_driver); 461 } 462 463 #else 464 465 static int ds3232_register_driver(void) 466 { 467 return 0; 468 } 469 470 static void ds3232_unregister_driver(void) 471 { 472 } 473 474 #endif 475 476 #if IS_ENABLED(CONFIG_SPI_MASTER) 477 478 static int ds3234_probe(struct spi_device *spi) 479 { 480 int res; 481 unsigned int tmp; 482 static const struct regmap_config config = { 483 .reg_bits = 8, 484 .val_bits = 8, 485 .write_flag_mask = 0x80, 486 }; 487 struct regmap *regmap; 488 489 regmap = devm_regmap_init_spi(spi, &config); 490 if (IS_ERR(regmap)) { 491 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n", 492 __func__, PTR_ERR(regmap)); 493 return PTR_ERR(regmap); 494 } 495 496 spi->mode = SPI_MODE_3; 497 spi->bits_per_word = 8; 498 spi_setup(spi); 499 500 res = regmap_read(regmap, DS3232_REG_SECONDS, &tmp); 501 if (res) 502 return res; 503 504 /* Control settings 505 * 506 * CONTROL_REG 507 * BIT 7 6 5 4 3 2 1 0 508 * EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE 509 * 510 * 0 0 0 1 1 1 0 0 511 * 512 * CONTROL_STAT_REG 513 * BIT 7 6 5 4 3 2 1 0 514 * OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F 515 * 516 * 1 0 0 0 1 0 0 0 517 */ 518 res = regmap_read(regmap, DS3232_REG_CR, &tmp); 519 if (res) 520 return res; 521 res = regmap_write(regmap, DS3232_REG_CR, tmp & 0x1c); 522 if (res) 523 return res; 524 525 res = regmap_read(regmap, DS3232_REG_SR, &tmp); 526 if (res) 527 return res; 528 res = regmap_write(regmap, DS3232_REG_SR, tmp & 0x88); 529 if (res) 530 return res; 531 532 /* Print our settings */ 533 res = regmap_read(regmap, DS3232_REG_CR, &tmp); 534 if (res) 535 return res; 536 dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp); 537 538 res = regmap_read(regmap, DS3232_REG_SR, &tmp); 539 if (res) 540 return res; 541 dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp); 542 543 return ds3232_probe(&spi->dev, regmap, spi->irq, "ds3234"); 544 } 545 546 static struct spi_driver ds3234_driver = { 547 .driver = { 548 .name = "ds3234", 549 }, 550 .probe = ds3234_probe, 551 }; 552 553 static int ds3234_register_driver(void) 554 { 555 return spi_register_driver(&ds3234_driver); 556 } 557 558 static void ds3234_unregister_driver(void) 559 { 560 spi_unregister_driver(&ds3234_driver); 561 } 562 563 #else 564 565 static int ds3234_register_driver(void) 566 { 567 return 0; 568 } 569 570 static void ds3234_unregister_driver(void) 571 { 572 } 573 574 #endif 575 576 static int __init ds323x_init(void) 577 { 578 int ret; 579 580 ret = ds3232_register_driver(); 581 if (ret) { 582 pr_err("Failed to register ds3232 driver: %d\n", ret); 583 return ret; 584 } 585 586 ret = ds3234_register_driver(); 587 if (ret) { 588 pr_err("Failed to register ds3234 driver: %d\n", ret); 589 ds3232_unregister_driver(); 590 } 591 592 return ret; 593 } 594 module_init(ds323x_init) 595 596 static void __exit ds323x_exit(void) 597 { 598 ds3234_unregister_driver(); 599 ds3232_unregister_driver(); 600 } 601 module_exit(ds323x_exit) 602 603 MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>"); 604 MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>"); 605 MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver"); 606 MODULE_LICENSE("GPL"); 607 MODULE_ALIAS("spi:ds3234"); 608