Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 1 | /* |
| 2 | * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C |
| 3 | * |
| 4 | * Copyright (C) 2009-2010 Freescale Semiconductor. |
Lan Chunhe-B25806 | f46418c | 2010-10-27 15:33:12 -0700 | [diff] [blame] | 5 | * Author: Jack Lan <jack.lan@freescale.com> |
Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 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 | int exiting; |
| 61 | }; |
| 62 | |
| 63 | static struct i2c_driver ds3232_driver; |
| 64 | |
| 65 | static int ds3232_check_rtc_status(struct i2c_client *client) |
| 66 | { |
| 67 | int ret = 0; |
| 68 | int control, stat; |
| 69 | |
| 70 | stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR); |
| 71 | if (stat < 0) |
| 72 | return stat; |
| 73 | |
| 74 | if (stat & DS3232_REG_SR_OSF) |
| 75 | dev_warn(&client->dev, |
| 76 | "oscillator discontinuity flagged, " |
| 77 | "time unreliable\n"); |
| 78 | |
| 79 | stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); |
| 80 | |
| 81 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); |
| 82 | if (ret < 0) |
| 83 | return ret; |
| 84 | |
| 85 | /* If the alarm is pending, clear it before requesting |
| 86 | * the interrupt, so an interrupt event isn't reported |
| 87 | * before everything is initialized. |
| 88 | */ |
| 89 | |
| 90 | control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); |
| 91 | if (control < 0) |
| 92 | return control; |
| 93 | |
| 94 | control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); |
| 95 | control |= DS3232_REG_CR_INTCN; |
| 96 | |
| 97 | return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); |
| 98 | } |
| 99 | |
| 100 | static int ds3232_read_time(struct device *dev, struct rtc_time *time) |
| 101 | { |
| 102 | struct i2c_client *client = to_i2c_client(dev); |
| 103 | int ret; |
| 104 | u8 buf[7]; |
| 105 | unsigned int year, month, day, hour, minute, second; |
| 106 | unsigned int week, twelve_hr, am_pm; |
| 107 | unsigned int century, add_century = 0; |
| 108 | |
| 109 | ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf); |
| 110 | |
| 111 | if (ret < 0) |
| 112 | return ret; |
| 113 | if (ret < 7) |
| 114 | return -EIO; |
| 115 | |
| 116 | second = buf[0]; |
| 117 | minute = buf[1]; |
| 118 | hour = buf[2]; |
| 119 | week = buf[3]; |
| 120 | day = buf[4]; |
| 121 | month = buf[5]; |
| 122 | year = buf[6]; |
| 123 | |
| 124 | /* Extract additional information for AM/PM and century */ |
| 125 | |
| 126 | twelve_hr = hour & 0x40; |
| 127 | am_pm = hour & 0x20; |
| 128 | century = month & 0x80; |
| 129 | |
| 130 | /* Write to rtc_time structure */ |
| 131 | |
| 132 | time->tm_sec = bcd2bin(second); |
| 133 | time->tm_min = bcd2bin(minute); |
| 134 | if (twelve_hr) { |
| 135 | /* Convert to 24 hr */ |
| 136 | if (am_pm) |
| 137 | time->tm_hour = bcd2bin(hour & 0x1F) + 12; |
| 138 | else |
| 139 | time->tm_hour = bcd2bin(hour & 0x1F); |
| 140 | } else { |
| 141 | time->tm_hour = bcd2bin(hour); |
| 142 | } |
| 143 | |
| 144 | time->tm_wday = bcd2bin(week); |
| 145 | time->tm_mday = bcd2bin(day); |
| 146 | time->tm_mon = bcd2bin(month & 0x7F); |
| 147 | if (century) |
| 148 | add_century = 100; |
| 149 | |
| 150 | time->tm_year = bcd2bin(year) + add_century; |
| 151 | |
| 152 | return rtc_valid_tm(time); |
| 153 | } |
| 154 | |
| 155 | static int ds3232_set_time(struct device *dev, struct rtc_time *time) |
| 156 | { |
| 157 | struct i2c_client *client = to_i2c_client(dev); |
| 158 | u8 buf[7]; |
| 159 | |
| 160 | /* Extract time from rtc_time and load into ds3232*/ |
| 161 | |
| 162 | buf[0] = bin2bcd(time->tm_sec); |
| 163 | buf[1] = bin2bcd(time->tm_min); |
| 164 | buf[2] = bin2bcd(time->tm_hour); |
| 165 | buf[3] = bin2bcd(time->tm_wday); /* Day of the week */ |
| 166 | buf[4] = bin2bcd(time->tm_mday); /* Date */ |
| 167 | buf[5] = bin2bcd(time->tm_mon); |
| 168 | if (time->tm_year >= 100) { |
| 169 | buf[5] |= 0x80; |
| 170 | buf[6] = bin2bcd(time->tm_year - 100); |
| 171 | } else { |
| 172 | buf[6] = bin2bcd(time->tm_year); |
| 173 | } |
| 174 | |
| 175 | return i2c_smbus_write_i2c_block_data(client, |
| 176 | DS3232_REG_SECONDS, 7, buf); |
| 177 | } |
| 178 | |
Lan Chunhe-B25806 | f46418c | 2010-10-27 15:33:12 -0700 | [diff] [blame] | 179 | /* |
| 180 | * DS3232 has two alarm, we only use alarm1 |
| 181 | * According to linux specification, only support one-shot alarm |
| 182 | * no periodic alarm mode |
| 183 | */ |
| 184 | static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
| 185 | { |
| 186 | struct i2c_client *client = to_i2c_client(dev); |
| 187 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 188 | int control, stat; |
| 189 | int ret; |
| 190 | u8 buf[4]; |
| 191 | |
| 192 | mutex_lock(&ds3232->mutex); |
| 193 | |
| 194 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR); |
| 195 | if (ret < 0) |
| 196 | goto out; |
| 197 | stat = ret; |
| 198 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR); |
| 199 | if (ret < 0) |
| 200 | goto out; |
| 201 | control = ret; |
| 202 | ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); |
| 203 | if (ret < 0) |
| 204 | goto out; |
| 205 | |
| 206 | alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F); |
| 207 | alarm->time.tm_min = bcd2bin(buf[1] & 0x7F); |
| 208 | alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F); |
| 209 | alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F); |
| 210 | |
| 211 | alarm->time.tm_mon = -1; |
| 212 | alarm->time.tm_year = -1; |
| 213 | alarm->time.tm_wday = -1; |
| 214 | alarm->time.tm_yday = -1; |
| 215 | alarm->time.tm_isdst = -1; |
| 216 | |
| 217 | alarm->enabled = !!(control & DS3232_REG_CR_A1IE); |
| 218 | alarm->pending = !!(stat & DS3232_REG_SR_A1F); |
| 219 | |
| 220 | ret = 0; |
| 221 | out: |
| 222 | mutex_unlock(&ds3232->mutex); |
| 223 | return ret; |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * linux rtc-module does not support wday alarm |
| 228 | * and only 24h time mode supported indeed |
| 229 | */ |
| 230 | static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
| 231 | { |
| 232 | struct i2c_client *client = to_i2c_client(dev); |
| 233 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 234 | int control, stat; |
| 235 | int ret; |
| 236 | u8 buf[4]; |
| 237 | |
| 238 | if (client->irq <= 0) |
| 239 | return -EINVAL; |
| 240 | |
| 241 | mutex_lock(&ds3232->mutex); |
| 242 | |
| 243 | buf[0] = bin2bcd(alarm->time.tm_sec); |
| 244 | buf[1] = bin2bcd(alarm->time.tm_min); |
| 245 | buf[2] = bin2bcd(alarm->time.tm_hour); |
| 246 | buf[3] = bin2bcd(alarm->time.tm_mday); |
| 247 | |
| 248 | /* clear alarm interrupt enable bit */ |
| 249 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR); |
| 250 | if (ret < 0) |
| 251 | goto out; |
| 252 | control = ret; |
| 253 | control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); |
| 254 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); |
| 255 | if (ret < 0) |
| 256 | goto out; |
| 257 | |
| 258 | /* clear any pending alarm flag */ |
| 259 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR); |
| 260 | if (ret < 0) |
| 261 | goto out; |
| 262 | stat = ret; |
| 263 | stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); |
| 264 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); |
| 265 | if (ret < 0) |
| 266 | goto out; |
| 267 | |
| 268 | ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); |
| 269 | |
| 270 | if (alarm->enabled) { |
| 271 | control |= DS3232_REG_CR_A1IE; |
| 272 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); |
| 273 | } |
| 274 | out: |
| 275 | mutex_unlock(&ds3232->mutex); |
| 276 | return ret; |
| 277 | } |
| 278 | |
| 279 | static void ds3232_update_alarm(struct i2c_client *client) |
| 280 | { |
| 281 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 282 | int control; |
| 283 | int ret; |
| 284 | u8 buf[4]; |
| 285 | |
| 286 | mutex_lock(&ds3232->mutex); |
| 287 | |
| 288 | ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); |
| 289 | if (ret < 0) |
| 290 | goto unlock; |
| 291 | |
| 292 | buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? |
| 293 | 0x80 : buf[0]; |
| 294 | buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? |
| 295 | 0x80 : buf[1]; |
| 296 | buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? |
| 297 | 0x80 : buf[2]; |
| 298 | buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? |
| 299 | 0x80 : buf[3]; |
| 300 | |
| 301 | ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); |
| 302 | if (ret < 0) |
| 303 | goto unlock; |
| 304 | |
| 305 | control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); |
| 306 | if (control < 0) |
| 307 | goto unlock; |
| 308 | |
| 309 | if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF)) |
| 310 | /* enable alarm1 interrupt */ |
| 311 | control |= DS3232_REG_CR_A1IE; |
| 312 | else |
| 313 | /* disable alarm1 interrupt */ |
| 314 | control &= ~(DS3232_REG_CR_A1IE); |
| 315 | i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); |
| 316 | |
| 317 | unlock: |
| 318 | mutex_unlock(&ds3232->mutex); |
| 319 | } |
| 320 | |
| 321 | static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled) |
| 322 | { |
| 323 | struct i2c_client *client = to_i2c_client(dev); |
| 324 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 325 | |
| 326 | if (client->irq <= 0) |
| 327 | return -EINVAL; |
| 328 | |
| 329 | if (enabled) |
| 330 | ds3232->rtc->irq_data |= RTC_AF; |
| 331 | else |
| 332 | ds3232->rtc->irq_data &= ~RTC_AF; |
| 333 | |
| 334 | ds3232_update_alarm(client); |
| 335 | return 0; |
| 336 | } |
| 337 | |
| 338 | static int ds3232_update_irq_enable(struct device *dev, unsigned int enabled) |
| 339 | { |
| 340 | struct i2c_client *client = to_i2c_client(dev); |
| 341 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 342 | |
| 343 | if (client->irq <= 0) |
| 344 | return -EINVAL; |
| 345 | |
| 346 | if (enabled) |
| 347 | ds3232->rtc->irq_data |= RTC_UF; |
| 348 | else |
| 349 | ds3232->rtc->irq_data &= ~RTC_UF; |
| 350 | |
| 351 | ds3232_update_alarm(client); |
| 352 | return 0; |
| 353 | } |
| 354 | |
Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 355 | static irqreturn_t ds3232_irq(int irq, void *dev_id) |
| 356 | { |
| 357 | struct i2c_client *client = dev_id; |
| 358 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 359 | |
| 360 | disable_irq_nosync(irq); |
| 361 | schedule_work(&ds3232->work); |
| 362 | return IRQ_HANDLED; |
| 363 | } |
| 364 | |
| 365 | static void ds3232_work(struct work_struct *work) |
| 366 | { |
| 367 | struct ds3232 *ds3232 = container_of(work, struct ds3232, work); |
| 368 | struct i2c_client *client = ds3232->client; |
| 369 | int stat, control; |
| 370 | |
| 371 | mutex_lock(&ds3232->mutex); |
| 372 | |
| 373 | stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR); |
| 374 | if (stat < 0) |
| 375 | goto unlock; |
| 376 | |
| 377 | if (stat & DS3232_REG_SR_A1F) { |
| 378 | control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); |
| 379 | if (control < 0) |
| 380 | goto out; |
| 381 | /* disable alarm1 interrupt */ |
| 382 | control &= ~(DS3232_REG_CR_A1IE); |
| 383 | i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); |
| 384 | |
| 385 | /* clear the alarm pend flag */ |
| 386 | stat &= ~DS3232_REG_SR_A1F; |
| 387 | i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); |
| 388 | |
| 389 | rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF); |
| 390 | } |
| 391 | |
| 392 | out: |
| 393 | if (!ds3232->exiting) |
| 394 | enable_irq(client->irq); |
| 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, |
Lan Chunhe-B25806 | f46418c | 2010-10-27 15:33:12 -0700 | [diff] [blame] | 402 | .read_alarm = ds3232_read_alarm, |
| 403 | .set_alarm = ds3232_set_alarm, |
| 404 | .alarm_irq_enable = ds3232_alarm_irq_enable, |
| 405 | .update_irq_enable = ds3232_update_irq_enable, |
Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 406 | }; |
| 407 | |
| 408 | static int __devinit ds3232_probe(struct i2c_client *client, |
| 409 | const struct i2c_device_id *id) |
| 410 | { |
| 411 | struct ds3232 *ds3232; |
| 412 | int ret; |
| 413 | |
| 414 | ds3232 = kzalloc(sizeof(struct ds3232), GFP_KERNEL); |
| 415 | if (!ds3232) |
| 416 | return -ENOMEM; |
| 417 | |
| 418 | ds3232->client = client; |
| 419 | i2c_set_clientdata(client, ds3232); |
| 420 | |
| 421 | INIT_WORK(&ds3232->work, ds3232_work); |
| 422 | mutex_init(&ds3232->mutex); |
| 423 | |
| 424 | ret = ds3232_check_rtc_status(client); |
| 425 | if (ret) |
| 426 | goto out_free; |
| 427 | |
| 428 | ds3232->rtc = rtc_device_register(client->name, &client->dev, |
| 429 | &ds3232_rtc_ops, THIS_MODULE); |
| 430 | if (IS_ERR(ds3232->rtc)) { |
| 431 | ret = PTR_ERR(ds3232->rtc); |
| 432 | dev_err(&client->dev, "unable to register the class device\n"); |
| 433 | goto out_irq; |
| 434 | } |
| 435 | |
| 436 | if (client->irq >= 0) { |
| 437 | ret = request_irq(client->irq, ds3232_irq, 0, |
| 438 | "ds3232", client); |
| 439 | if (ret) { |
| 440 | dev_err(&client->dev, "unable to request IRQ\n"); |
| 441 | goto out_free; |
| 442 | } |
| 443 | } |
| 444 | |
| 445 | return 0; |
| 446 | |
| 447 | out_irq: |
| 448 | if (client->irq >= 0) |
| 449 | free_irq(client->irq, client); |
| 450 | |
| 451 | out_free: |
Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 452 | kfree(ds3232); |
| 453 | return ret; |
| 454 | } |
| 455 | |
| 456 | static int __devexit ds3232_remove(struct i2c_client *client) |
| 457 | { |
| 458 | struct ds3232 *ds3232 = i2c_get_clientdata(client); |
| 459 | |
| 460 | if (client->irq >= 0) { |
| 461 | mutex_lock(&ds3232->mutex); |
| 462 | ds3232->exiting = 1; |
| 463 | mutex_unlock(&ds3232->mutex); |
| 464 | |
| 465 | free_irq(client->irq, client); |
Tejun Heo | 9db8995 | 2010-12-24 16:00:17 +0100 | [diff] [blame^] | 466 | cancel_work_sync(&ds3232->work); |
Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 467 | } |
| 468 | |
| 469 | rtc_device_unregister(ds3232->rtc); |
Roy Zang | c03675f | 2010-08-10 18:02:20 -0700 | [diff] [blame] | 470 | kfree(ds3232); |
| 471 | return 0; |
| 472 | } |
| 473 | |
| 474 | static const struct i2c_device_id ds3232_id[] = { |
| 475 | { "ds3232", 0 }, |
| 476 | { } |
| 477 | }; |
| 478 | MODULE_DEVICE_TABLE(i2c, ds3232_id); |
| 479 | |
| 480 | static struct i2c_driver ds3232_driver = { |
| 481 | .driver = { |
| 482 | .name = "rtc-ds3232", |
| 483 | .owner = THIS_MODULE, |
| 484 | }, |
| 485 | .probe = ds3232_probe, |
| 486 | .remove = __devexit_p(ds3232_remove), |
| 487 | .id_table = ds3232_id, |
| 488 | }; |
| 489 | |
| 490 | static int __init ds3232_init(void) |
| 491 | { |
| 492 | return i2c_add_driver(&ds3232_driver); |
| 493 | } |
| 494 | |
| 495 | static void __exit ds3232_exit(void) |
| 496 | { |
| 497 | i2c_del_driver(&ds3232_driver); |
| 498 | } |
| 499 | |
| 500 | module_init(ds3232_init); |
| 501 | module_exit(ds3232_exit); |
| 502 | |
| 503 | MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>"); |
| 504 | MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver"); |
| 505 | MODULE_LICENSE("GPL"); |