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