1 /* 2 * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C 3 * 4 * Copyright (C) 2009-2011 Freescale Semiconductor. 5 * Author: Jack Lan <jack.lan@freescale.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the 9 * Free Software Foundation; either version 2 of the License, or (at your 10 * option) any later version. 11 */ 12 /* 13 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as 14 * recommened in .../Documentation/i2c/writing-clients section 15 * "Sending and receiving", using SMBus level communication is preferred. 16 */ 17 18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 19 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/interrupt.h> 23 #include <linux/i2c.h> 24 #include <linux/rtc.h> 25 #include <linux/bcd.h> 26 #include <linux/workqueue.h> 27 #include <linux/slab.h> 28 29 #define DS3232_REG_SECONDS 0x00 30 #define DS3232_REG_MINUTES 0x01 31 #define DS3232_REG_HOURS 0x02 32 #define DS3232_REG_AMPM 0x02 33 #define DS3232_REG_DAY 0x03 34 #define DS3232_REG_DATE 0x04 35 #define DS3232_REG_MONTH 0x05 36 #define DS3232_REG_CENTURY 0x05 37 #define DS3232_REG_YEAR 0x06 38 #define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */ 39 #define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */ 40 #define DS3232_REG_CR 0x0E /* Control register */ 41 # define DS3232_REG_CR_nEOSC 0x80 42 # define DS3232_REG_CR_INTCN 0x04 43 # define DS3232_REG_CR_A2IE 0x02 44 # define DS3232_REG_CR_A1IE 0x01 45 46 #define DS3232_REG_SR 0x0F /* control/status register */ 47 # define DS3232_REG_SR_OSF 0x80 48 # define DS3232_REG_SR_BSY 0x04 49 # define DS3232_REG_SR_A2F 0x02 50 # define DS3232_REG_SR_A1F 0x01 51 52 struct ds3232 { 53 struct i2c_client *client; 54 struct rtc_device *rtc; 55 struct work_struct work; 56 57 /* The mutex protects alarm operations, and prevents a race 58 * between the enable_irq() in the workqueue and the free_irq() 59 * in the remove function. 60 */ 61 struct mutex mutex; 62 bool suspended; 63 int exiting; 64 }; 65 66 static struct i2c_driver ds3232_driver; 67 68 static int ds3232_check_rtc_status(struct i2c_client *client) 69 { 70 int ret = 0; 71 int control, stat; 72 73 stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR); 74 if (stat < 0) 75 return stat; 76 77 if (stat & DS3232_REG_SR_OSF) 78 dev_warn(&client->dev, 79 "oscillator discontinuity flagged, " 80 "time unreliable\n"); 81 82 stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); 83 84 ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); 85 if (ret < 0) 86 return ret; 87 88 /* If the alarm is pending, clear it before requesting 89 * the interrupt, so an interrupt event isn't reported 90 * before everything is initialized. 91 */ 92 93 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); 94 if (control < 0) 95 return control; 96 97 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); 98 control |= DS3232_REG_CR_INTCN; 99 100 return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); 101 } 102 103 static int ds3232_read_time(struct device *dev, struct rtc_time *time) 104 { 105 struct i2c_client *client = to_i2c_client(dev); 106 int ret; 107 u8 buf[7]; 108 unsigned int year, month, day, hour, minute, second; 109 unsigned int week, twelve_hr, am_pm; 110 unsigned int century, add_century = 0; 111 112 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf); 113 114 if (ret < 0) 115 return ret; 116 if (ret < 7) 117 return -EIO; 118 119 second = buf[0]; 120 minute = buf[1]; 121 hour = buf[2]; 122 week = buf[3]; 123 day = buf[4]; 124 month = buf[5]; 125 year = buf[6]; 126 127 /* Extract additional information for AM/PM and century */ 128 129 twelve_hr = hour & 0x40; 130 am_pm = hour & 0x20; 131 century = month & 0x80; 132 133 /* Write to rtc_time structure */ 134 135 time->tm_sec = bcd2bin(second); 136 time->tm_min = bcd2bin(minute); 137 if (twelve_hr) { 138 /* Convert to 24 hr */ 139 if (am_pm) 140 time->tm_hour = bcd2bin(hour & 0x1F) + 12; 141 else 142 time->tm_hour = bcd2bin(hour & 0x1F); 143 } else { 144 time->tm_hour = bcd2bin(hour); 145 } 146 147 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */ 148 time->tm_wday = bcd2bin(week) - 1; 149 time->tm_mday = bcd2bin(day); 150 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */ 151 time->tm_mon = bcd2bin(month & 0x7F) - 1; 152 if (century) 153 add_century = 100; 154 155 time->tm_year = bcd2bin(year) + add_century; 156 157 return rtc_valid_tm(time); 158 } 159 160 static int ds3232_set_time(struct device *dev, struct rtc_time *time) 161 { 162 struct i2c_client *client = to_i2c_client(dev); 163 u8 buf[7]; 164 165 /* Extract time from rtc_time and load into ds3232*/ 166 167 buf[0] = bin2bcd(time->tm_sec); 168 buf[1] = bin2bcd(time->tm_min); 169 buf[2] = bin2bcd(time->tm_hour); 170 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */ 171 buf[3] = bin2bcd(time->tm_wday + 1); 172 buf[4] = bin2bcd(time->tm_mday); /* Date */ 173 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */ 174 buf[5] = bin2bcd(time->tm_mon + 1); 175 if (time->tm_year >= 100) { 176 buf[5] |= 0x80; 177 buf[6] = bin2bcd(time->tm_year - 100); 178 } else { 179 buf[6] = bin2bcd(time->tm_year); 180 } 181 182 return i2c_smbus_write_i2c_block_data(client, 183 DS3232_REG_SECONDS, 7, buf); 184 } 185 186 /* 187 * DS3232 has two alarm, we only use alarm1 188 * According to linux specification, only support one-shot alarm 189 * no periodic alarm mode 190 */ 191 static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) 192 { 193 struct i2c_client *client = to_i2c_client(dev); 194 struct ds3232 *ds3232 = i2c_get_clientdata(client); 195 int control, stat; 196 int ret; 197 u8 buf[4]; 198 199 mutex_lock(&ds3232->mutex); 200 201 ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR); 202 if (ret < 0) 203 goto out; 204 stat = ret; 205 ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR); 206 if (ret < 0) 207 goto out; 208 control = ret; 209 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); 210 if (ret < 0) 211 goto out; 212 213 alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F); 214 alarm->time.tm_min = bcd2bin(buf[1] & 0x7F); 215 alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F); 216 alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F); 217 218 alarm->time.tm_mon = -1; 219 alarm->time.tm_year = -1; 220 alarm->time.tm_wday = -1; 221 alarm->time.tm_yday = -1; 222 alarm->time.tm_isdst = -1; 223 224 alarm->enabled = !!(control & DS3232_REG_CR_A1IE); 225 alarm->pending = !!(stat & DS3232_REG_SR_A1F); 226 227 ret = 0; 228 out: 229 mutex_unlock(&ds3232->mutex); 230 return ret; 231 } 232 233 /* 234 * linux rtc-module does not support wday alarm 235 * and only 24h time mode supported indeed 236 */ 237 static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) 238 { 239 struct i2c_client *client = to_i2c_client(dev); 240 struct ds3232 *ds3232 = i2c_get_clientdata(client); 241 int control, stat; 242 int ret; 243 u8 buf[4]; 244 245 if (client->irq <= 0) 246 return -EINVAL; 247 248 mutex_lock(&ds3232->mutex); 249 250 buf[0] = bin2bcd(alarm->time.tm_sec); 251 buf[1] = bin2bcd(alarm->time.tm_min); 252 buf[2] = bin2bcd(alarm->time.tm_hour); 253 buf[3] = bin2bcd(alarm->time.tm_mday); 254 255 /* clear alarm interrupt enable bit */ 256 ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR); 257 if (ret < 0) 258 goto out; 259 control = ret; 260 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); 261 ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); 262 if (ret < 0) 263 goto out; 264 265 /* clear any pending alarm flag */ 266 ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR); 267 if (ret < 0) 268 goto out; 269 stat = ret; 270 stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); 271 ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); 272 if (ret < 0) 273 goto out; 274 275 ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); 276 277 if (alarm->enabled) { 278 control |= DS3232_REG_CR_A1IE; 279 ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); 280 } 281 out: 282 mutex_unlock(&ds3232->mutex); 283 return ret; 284 } 285 286 static void ds3232_update_alarm(struct i2c_client *client) 287 { 288 struct ds3232 *ds3232 = i2c_get_clientdata(client); 289 int control; 290 int ret; 291 u8 buf[4]; 292 293 mutex_lock(&ds3232->mutex); 294 295 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); 296 if (ret < 0) 297 goto unlock; 298 299 buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? 300 0x80 : buf[0]; 301 buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? 302 0x80 : buf[1]; 303 buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? 304 0x80 : buf[2]; 305 buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? 306 0x80 : buf[3]; 307 308 ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); 309 if (ret < 0) 310 goto unlock; 311 312 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); 313 if (control < 0) 314 goto unlock; 315 316 if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF)) 317 /* enable alarm1 interrupt */ 318 control |= DS3232_REG_CR_A1IE; 319 else 320 /* disable alarm1 interrupt */ 321 control &= ~(DS3232_REG_CR_A1IE); 322 i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); 323 324 unlock: 325 mutex_unlock(&ds3232->mutex); 326 } 327 328 static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled) 329 { 330 struct i2c_client *client = to_i2c_client(dev); 331 struct ds3232 *ds3232 = i2c_get_clientdata(client); 332 333 if (client->irq <= 0) 334 return -EINVAL; 335 336 if (enabled) 337 ds3232->rtc->irq_data |= RTC_AF; 338 else 339 ds3232->rtc->irq_data &= ~RTC_AF; 340 341 ds3232_update_alarm(client); 342 return 0; 343 } 344 345 static irqreturn_t ds3232_irq(int irq, void *dev_id) 346 { 347 struct i2c_client *client = dev_id; 348 struct ds3232 *ds3232 = i2c_get_clientdata(client); 349 350 disable_irq_nosync(irq); 351 352 /* 353 * If rtc as a wakeup source, can't schedule the work 354 * at system resume flow, because at this time the i2c bus 355 * has not been resumed. 356 */ 357 if (!ds3232->suspended) 358 schedule_work(&ds3232->work); 359 360 return IRQ_HANDLED; 361 } 362 363 static void ds3232_work(struct work_struct *work) 364 { 365 struct ds3232 *ds3232 = container_of(work, struct ds3232, work); 366 struct i2c_client *client = ds3232->client; 367 int stat, control; 368 369 mutex_lock(&ds3232->mutex); 370 371 stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR); 372 if (stat < 0) 373 goto unlock; 374 375 if (stat & DS3232_REG_SR_A1F) { 376 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); 377 if (control < 0) { 378 pr_warn("Read Control Register error - Disable IRQ%d\n", 379 client->irq); 380 } else { 381 /* disable alarm1 interrupt */ 382 control &= ~(DS3232_REG_CR_A1IE); 383 i2c_smbus_write_byte_data(client, DS3232_REG_CR, 384 control); 385 386 /* clear the alarm pend flag */ 387 stat &= ~DS3232_REG_SR_A1F; 388 i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); 389 390 rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF); 391 392 if (!ds3232->exiting) 393 enable_irq(client->irq); 394 } 395 } 396 397 unlock: 398 mutex_unlock(&ds3232->mutex); 399 } 400 401 static const struct rtc_class_ops ds3232_rtc_ops = { 402 .read_time = ds3232_read_time, 403 .set_time = ds3232_set_time, 404 .read_alarm = ds3232_read_alarm, 405 .set_alarm = ds3232_set_alarm, 406 .alarm_irq_enable = ds3232_alarm_irq_enable, 407 }; 408 409 static int ds3232_probe(struct i2c_client *client, 410 const struct i2c_device_id *id) 411 { 412 struct ds3232 *ds3232; 413 int ret; 414 415 ds3232 = devm_kzalloc(&client->dev, sizeof(struct ds3232), GFP_KERNEL); 416 if (!ds3232) 417 return -ENOMEM; 418 419 ds3232->client = client; 420 i2c_set_clientdata(client, ds3232); 421 422 INIT_WORK(&ds3232->work, ds3232_work); 423 mutex_init(&ds3232->mutex); 424 425 ret = ds3232_check_rtc_status(client); 426 if (ret) 427 return ret; 428 429 if (client->irq > 0) { 430 ret = devm_request_irq(&client->dev, client->irq, ds3232_irq, 431 IRQF_SHARED, "ds3232", client); 432 if (ret) { 433 dev_err(&client->dev, "unable to request IRQ\n"); 434 } 435 device_init_wakeup(&client->dev, 1); 436 } 437 ds3232->rtc = devm_rtc_device_register(&client->dev, client->name, 438 &ds3232_rtc_ops, THIS_MODULE); 439 return PTR_ERR_OR_ZERO(ds3232->rtc); 440 } 441 442 static int ds3232_remove(struct i2c_client *client) 443 { 444 struct ds3232 *ds3232 = i2c_get_clientdata(client); 445 446 if (client->irq > 0) { 447 mutex_lock(&ds3232->mutex); 448 ds3232->exiting = 1; 449 mutex_unlock(&ds3232->mutex); 450 451 devm_free_irq(&client->dev, client->irq, client); 452 cancel_work_sync(&ds3232->work); 453 } 454 455 return 0; 456 } 457 458 #ifdef CONFIG_PM_SLEEP 459 static int ds3232_suspend(struct device *dev) 460 { 461 struct ds3232 *ds3232 = dev_get_drvdata(dev); 462 struct i2c_client *client = to_i2c_client(dev); 463 464 if (device_can_wakeup(dev)) { 465 ds3232->suspended = true; 466 if (irq_set_irq_wake(client->irq, 1)) { 467 dev_warn_once(dev, "Cannot set wakeup source\n"); 468 ds3232->suspended = false; 469 } 470 } 471 472 return 0; 473 } 474 475 static int ds3232_resume(struct device *dev) 476 { 477 struct ds3232 *ds3232 = dev_get_drvdata(dev); 478 struct i2c_client *client = to_i2c_client(dev); 479 480 if (ds3232->suspended) { 481 ds3232->suspended = false; 482 483 /* Clear the hardware alarm pend flag */ 484 schedule_work(&ds3232->work); 485 486 irq_set_irq_wake(client->irq, 0); 487 } 488 489 return 0; 490 } 491 #endif 492 493 static const struct dev_pm_ops ds3232_pm_ops = { 494 SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume) 495 }; 496 497 static const struct i2c_device_id ds3232_id[] = { 498 { "ds3232", 0 }, 499 { } 500 }; 501 MODULE_DEVICE_TABLE(i2c, ds3232_id); 502 503 static struct i2c_driver ds3232_driver = { 504 .driver = { 505 .name = "rtc-ds3232", 506 .pm = &ds3232_pm_ops, 507 }, 508 .probe = ds3232_probe, 509 .remove = ds3232_remove, 510 .id_table = ds3232_id, 511 }; 512 513 module_i2c_driver(ds3232_driver); 514 515 MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>"); 516 MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver"); 517 MODULE_LICENSE("GPL"); 518