| 1 | |
| 2 | * RTC subsystem, interface functions
|
| 3 | *
|
| 4 | * Copyright (C) 2005 Tower Technologies
|
| 5 | * Author: Alessandro Zummo <[email protected]>
|
| 6 | *
|
| 7 | * based on arch/arm/common/rtctime.c
|
| 8 | *
|
| 9 | * This program is free software; you can redistribute it and/or modify
|
| 10 | * it under the terms of the GNU General Public License version 2 as
|
| 11 | * published by the Free Software Foundation.
|
| 12 |
|
| 13 |
|
| 14 | #include <linux/rtc.h>
|
| 15 | #include <linux/sched.h>
|
| 16 | #include <linux/module.h>
|
| 17 | #include <linux/log2.h>
|
| 18 | #include <linux/workqueue.h>
|
| 19 |
|
| 20 | #define CREATE_TRACE_POINTS
|
| 21 | #include <trace/events/rtc.h>
|
| 22 |
|
| 23 | static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
|
| 24 | static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
|
| 25 |
|
| 26 | static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
|
| 27 | {
|
| 28 | time64_t secs;
|
| 29 |
|
| 30 | if (!rtc->offset_secs)
|
| 31 | return;
|
| 32 |
|
| 33 | secs = rtc_tm_to_time64(tm);
|
| 34 |
|
| 35 | |
| 36 | * Since the reading time values from RTC device are always in the RTC
|
| 37 | * original valid range, but we need to skip the overlapped region
|
| 38 | * between expanded range and original range, which is no need to add
|
| 39 | * the offset.
|
| 40 |
|
| 41 | if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
|
| 42 | (rtc->start_secs < rtc->range_min &&
|
| 43 | secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
|
| 44 | return;
|
| 45 |
|
| 46 | rtc_time64_to_tm(secs + rtc->offset_secs, tm);
|
| 47 | }
|
| 48 |
|
| 49 | static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
|
| 50 | {
|
| 51 | time64_t secs;
|
| 52 |
|
| 53 | if (!rtc->offset_secs)
|
| 54 | return;
|
| 55 |
|
| 56 | secs = rtc_tm_to_time64(tm);
|
| 57 |
|
| 58 | |
| 59 | * If the setting time values are in the valid range of RTC hardware
|
| 60 | * device, then no need to subtract the offset when setting time to RTC
|
| 61 | * device. Otherwise we need to subtract the offset to make the time
|
| 62 | * values are valid for RTC hardware device.
|
| 63 |
|
| 64 | if (secs >= rtc->range_min && secs <= rtc->range_max)
|
| 65 | return;
|
| 66 |
|
| 67 | rtc_time64_to_tm(secs - rtc->offset_secs, tm);
|
| 68 | }
|
| 69 |
|
| 70 | static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
|
| 71 | {
|
| 72 | if (rtc->range_min != rtc->range_max) {
|
| 73 | time64_t time = rtc_tm_to_time64(tm);
|
| 74 | time64_t range_min = rtc->set_start_time ? rtc->start_secs :
|
| 75 | rtc->range_min;
|
| 76 | time64_t range_max = rtc->set_start_time ?
|
| 77 | (rtc->start_secs + rtc->range_max - rtc->range_min) :
|
| 78 | rtc->range_max;
|
| 79 |
|
| 80 | if (time < range_min || time > range_max)
|
| 81 | return -ERANGE;
|
| 82 | }
|
| 83 |
|
| 84 | return 0;
|
| 85 | }
|
| 86 |
|
| 87 | static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
|
| 88 | {
|
| 89 | int err;
|
| 90 | if (!rtc->ops)
|
| 91 | err = -ENODEV;
|
| 92 | else if (!rtc->ops->read_time)
|
| 93 | err = -EINVAL;
|
| 94 | else {
|
| 95 | memset(tm, 0, sizeof(struct rtc_time));
|
| 96 | err = rtc->ops->read_time(rtc->dev.parent, tm);
|
| 97 | if (err < 0) {
|
| 98 | dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
|
| 99 | err);
|
| 100 | return err;
|
| 101 | }
|
| 102 |
|
| 103 | rtc_add_offset(rtc, tm);
|
| 104 |
|
| 105 | err = rtc_valid_tm(tm);
|
| 106 | if (err < 0)
|
| 107 | dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
|
| 108 | }
|
| 109 | return err;
|
| 110 | }
|
| 111 |
|
| 112 | int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
|
| 113 | {
|
| 114 | int err;
|
| 115 |
|
| 116 | err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 117 | if (err)
|
| 118 | return err;
|
| 119 |
|
| 120 | err = __rtc_read_time(rtc, tm);
|
| 121 | mutex_unlock(&rtc->ops_lock);
|
| 122 |
|
| 123 | trace_rtc_read_time(rtc_tm_to_time64(tm), err);
|
| 124 | return err;
|
| 125 | }
|
| 126 | EXPORT_SYMBOL_GPL(rtc_read_time);
|
| 127 |
|
| 128 | int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
|
| 129 | {
|
| 130 | int err;
|
| 131 |
|
| 132 | err = rtc_valid_tm(tm);
|
| 133 | if (err != 0)
|
| 134 | return err;
|
| 135 |
|
| 136 | err = rtc_valid_range(rtc, tm);
|
| 137 | if (err)
|
| 138 | return err;
|
| 139 |
|
| 140 | rtc_subtract_offset(rtc, tm);
|
| 141 |
|
| 142 | err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 143 | if (err)
|
| 144 | return err;
|
| 145 |
|
| 146 | if (!rtc->ops)
|
| 147 | err = -ENODEV;
|
| 148 | else if (rtc->ops->set_time)
|
| 149 | err = rtc->ops->set_time(rtc->dev.parent, tm);
|
| 150 | else if (rtc->ops->set_mmss64) {
|
| 151 | time64_t secs64 = rtc_tm_to_time64(tm);
|
| 152 |
|
| 153 | err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
|
| 154 | } else if (rtc->ops->set_mmss) {
|
| 155 | time64_t secs64 = rtc_tm_to_time64(tm);
|
| 156 | err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
|
| 157 | } else
|
| 158 | err = -EINVAL;
|
| 159 |
|
| 160 | pm_stay_awake(rtc->dev.parent);
|
| 161 | mutex_unlock(&rtc->ops_lock);
|
| 162 |
|
| 163 | schedule_work(&rtc->irqwork);
|
| 164 |
|
| 165 | trace_rtc_set_time(rtc_tm_to_time64(tm), err);
|
| 166 | return err;
|
| 167 | }
|
| 168 | EXPORT_SYMBOL_GPL(rtc_set_time);
|
| 169 |
|
| 170 | static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
| 171 | {
|
| 172 | int err;
|
| 173 |
|
| 174 | err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 175 | if (err)
|
| 176 | return err;
|
| 177 |
|
| 178 | if (rtc->ops == NULL)
|
| 179 | err = -ENODEV;
|
| 180 | else if (!rtc->ops->read_alarm)
|
| 181 | err = -EINVAL;
|
| 182 | else {
|
| 183 | alarm->enabled = 0;
|
| 184 | alarm->pending = 0;
|
| 185 | alarm->time.tm_sec = -1;
|
| 186 | alarm->time.tm_min = -1;
|
| 187 | alarm->time.tm_hour = -1;
|
| 188 | alarm->time.tm_mday = -1;
|
| 189 | alarm->time.tm_mon = -1;
|
| 190 | alarm->time.tm_year = -1;
|
| 191 | alarm->time.tm_wday = -1;
|
| 192 | alarm->time.tm_yday = -1;
|
| 193 | alarm->time.tm_isdst = -1;
|
| 194 | err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
|
| 195 | }
|
| 196 |
|
| 197 | mutex_unlock(&rtc->ops_lock);
|
| 198 |
|
| 199 | trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
|
| 200 | return err;
|
| 201 | }
|
| 202 |
|
| 203 | int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
| 204 | {
|
| 205 | int err;
|
| 206 | struct rtc_time before, now;
|
| 207 | int first_time = 1;
|
| 208 | time64_t t_now, t_alm;
|
| 209 | enum { none, day, month, year } missing = none;
|
| 210 | unsigned days;
|
| 211 |
|
| 212 | |
| 213 | * creating invalid alarm->time values, for reasons like:
|
| 214 | *
|
| 215 | * - The hardware may not be capable of filling them in;
|
| 216 | * many alarms match only on time-of-day fields, not
|
| 217 | * day/month/year calendar data.
|
| 218 | *
|
| 219 | * - Some hardware uses illegal values as "wildcard" match
|
| 220 | * values, which non-Linux firmware (like a BIOS) may try
|
| 221 | * to set up as e.g. "alarm 15 minutes after each hour".
|
| 222 | * Linux uses only oneshot alarms.
|
| 223 | *
|
| 224 | * When we see that here, we deal with it by using values from
|
| 225 | * a current RTC timestamp for any missing (-1) values. The
|
| 226 | * RTC driver prevents "periodic alarm" modes.
|
| 227 | *
|
| 228 | * But this can be racey, because some fields of the RTC timestamp
|
| 229 | * may have wrapped in the interval since we read the RTC alarm,
|
| 230 | * which would lead to us inserting inconsistent values in place
|
| 231 | * of the -1 fields.
|
| 232 | *
|
| 233 | * Reading the alarm and timestamp in the reverse sequence
|
| 234 | * would have the same race condition, and not solve the issue.
|
| 235 | *
|
| 236 | * So, we must first read the RTC timestamp,
|
| 237 | * then read the RTC alarm value,
|
| 238 | * and then read a second RTC timestamp.
|
| 239 | *
|
| 240 | * If any fields of the second timestamp have changed
|
| 241 | * when compared with the first timestamp, then we know
|
| 242 | * our timestamp may be inconsistent with that used by
|
| 243 | * the low-level rtc_read_alarm_internal() function.
|
| 244 | *
|
| 245 | * So, when the two timestamps disagree, we just loop and do
|
| 246 | * the process again to get a fully consistent set of values.
|
| 247 | *
|
| 248 | * This could all instead be done in the lower level driver,
|
| 249 | * but since more than one lower level RTC implementation needs it,
|
| 250 | * then it's probably best best to do it here instead of there..
|
| 251 |
|
| 252 |
|
| 253 |
|
| 254 | err = rtc_read_time(rtc, &before);
|
| 255 | if (err < 0)
|
| 256 | return err;
|
| 257 | do {
|
| 258 | if (!first_time)
|
| 259 | memcpy(&before, &now, sizeof(struct rtc_time));
|
| 260 | first_time = 0;
|
| 261 |
|
| 262 |
|
| 263 | err = rtc_read_alarm_internal(rtc, alarm);
|
| 264 | if (err)
|
| 265 | return err;
|
| 266 |
|
| 267 |
|
| 268 | if (rtc_valid_tm(&alarm->time) == 0)
|
| 269 | return 0;
|
| 270 |
|
| 271 |
|
| 272 | err = rtc_read_time(rtc, &now);
|
| 273 | if (err < 0)
|
| 274 | return err;
|
| 275 |
|
| 276 |
|
| 277 | } while ( before.tm_min != now.tm_min
|
| 278 | || before.tm_hour != now.tm_hour
|
| 279 | || before.tm_mon != now.tm_mon
|
| 280 | || before.tm_year != now.tm_year);
|
| 281 |
|
| 282 | |
| 283 | * know there's at least one since alarm->time is invalid.
|
| 284 |
|
| 285 | if (alarm->time.tm_sec == -1)
|
| 286 | alarm->time.tm_sec = now.tm_sec;
|
| 287 | if (alarm->time.tm_min == -1)
|
| 288 | alarm->time.tm_min = now.tm_min;
|
| 289 | if (alarm->time.tm_hour == -1)
|
| 290 | alarm->time.tm_hour = now.tm_hour;
|
| 291 |
|
| 292 |
|
| 293 | if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
|
| 294 | alarm->time.tm_mday = now.tm_mday;
|
| 295 | missing = day;
|
| 296 | }
|
| 297 | if ((unsigned)alarm->time.tm_mon >= 12) {
|
| 298 | alarm->time.tm_mon = now.tm_mon;
|
| 299 | if (missing == none)
|
| 300 | missing = month;
|
| 301 | }
|
| 302 | if (alarm->time.tm_year == -1) {
|
| 303 | alarm->time.tm_year = now.tm_year;
|
| 304 | if (missing == none)
|
| 305 | missing = year;
|
| 306 | }
|
| 307 |
|
| 308 | |
| 309 | * missing fields.
|
| 310 |
|
| 311 | err = rtc_valid_tm(&alarm->time);
|
| 312 | if (err)
|
| 313 | goto done;
|
| 314 |
|
| 315 |
|
| 316 | t_now = rtc_tm_to_time64(&now);
|
| 317 | t_alm = rtc_tm_to_time64(&alarm->time);
|
| 318 | if (t_now < t_alm)
|
| 319 | goto done;
|
| 320 |
|
| 321 | switch (missing) {
|
| 322 |
|
| 323 | |
| 324 | * that will trigger at 5am will do so at 5am Tuesday, which
|
| 325 | * could also be in the next month or year. This is a common
|
| 326 | * case, especially for PCs.
|
| 327 |
|
| 328 | case day:
|
| 329 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
|
| 330 | t_alm += 24 * 60 * 60;
|
| 331 | rtc_time64_to_tm(t_alm, &alarm->time);
|
| 332 | break;
|
| 333 |
|
| 334 | |
| 335 | * be next month. An alarm matching on the 30th, 29th, or 28th
|
| 336 | * may end up in the month after that! Many newer PCs support
|
| 337 | * this type of alarm.
|
| 338 |
|
| 339 | case month:
|
| 340 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
|
| 341 | do {
|
| 342 | if (alarm->time.tm_mon < 11)
|
| 343 | alarm->time.tm_mon++;
|
| 344 | else {
|
| 345 | alarm->time.tm_mon = 0;
|
| 346 | alarm->time.tm_year++;
|
| 347 | }
|
| 348 | days = rtc_month_days(alarm->time.tm_mon,
|
| 349 | alarm->time.tm_year);
|
| 350 | } while (days < alarm->time.tm_mday);
|
| 351 | break;
|
| 352 |
|
| 353 |
|
| 354 | case year:
|
| 355 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
|
| 356 | do {
|
| 357 | alarm->time.tm_year++;
|
| 358 | } while (!is_leap_year(alarm->time.tm_year + 1900)
|
| 359 | && rtc_valid_tm(&alarm->time) != 0);
|
| 360 | break;
|
| 361 |
|
| 362 | default:
|
| 363 | dev_warn(&rtc->dev, "alarm rollover not handled\n");
|
| 364 | }
|
| 365 |
|
| 366 | err = rtc_valid_tm(&alarm->time);
|
| 367 |
|
| 368 | done:
|
| 369 | if (err) {
|
| 370 | dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
|
| 371 | alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
|
| 372 | alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
|
| 373 | alarm->time.tm_sec);
|
| 374 | }
|
| 375 |
|
| 376 | return err;
|
| 377 | }
|
| 378 |
|
| 379 | int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
| 380 | {
|
| 381 | int err;
|
| 382 |
|
| 383 | err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 384 | if (err)
|
| 385 | return err;
|
| 386 | if (rtc->ops == NULL)
|
| 387 | err = -ENODEV;
|
| 388 | else if (!rtc->ops->read_alarm)
|
| 389 | err = -EINVAL;
|
| 390 | else {
|
| 391 | memset(alarm, 0, sizeof(struct rtc_wkalrm));
|
| 392 | alarm->enabled = rtc->aie_timer.enabled;
|
| 393 | alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
|
| 394 | }
|
| 395 | mutex_unlock(&rtc->ops_lock);
|
| 396 |
|
| 397 | trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
|
| 398 | return err;
|
| 399 | }
|
| 400 | EXPORT_SYMBOL_GPL(rtc_read_alarm);
|
| 401 |
|
| 402 | static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
| 403 | {
|
| 404 | struct rtc_time tm;
|
| 405 | time64_t now, scheduled;
|
| 406 | int err;
|
| 407 |
|
| 408 | err = rtc_valid_tm(&alarm->time);
|
| 409 | if (err)
|
| 410 | return err;
|
| 411 |
|
| 412 | rtc_subtract_offset(rtc, &alarm->time);
|
| 413 | scheduled = rtc_tm_to_time64(&alarm->time);
|
| 414 |
|
| 415 |
|
| 416 | err = __rtc_read_time(rtc, &tm);
|
| 417 | if (err)
|
| 418 | return err;
|
| 419 | now = rtc_tm_to_time64(&tm);
|
| 420 | if (scheduled <= now)
|
| 421 | return -ETIME;
|
| 422 | |
| 423 | * XXX - We just checked to make sure the alarm time is not
|
| 424 | * in the past, but there is still a race window where if
|
| 425 | * the is alarm set for the next second and the second ticks
|
| 426 | * over right here, before we set the alarm.
|
| 427 |
|
| 428 |
|
| 429 | if (!rtc->ops)
|
| 430 | err = -ENODEV;
|
| 431 | else if (!rtc->ops->set_alarm)
|
| 432 | err = -EINVAL;
|
| 433 | else
|
| 434 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
|
| 435 |
|
| 436 | trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
|
| 437 | return err;
|
| 438 | }
|
| 439 |
|
| 440 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
| 441 | {
|
| 442 | int err;
|
| 443 |
|
| 444 | err = rtc_valid_tm(&alarm->time);
|
| 445 | if (err != 0)
|
| 446 | return err;
|
| 447 |
|
| 448 | err = rtc_valid_range(rtc, &alarm->time);
|
| 449 | if (err)
|
| 450 | return err;
|
| 451 |
|
| 452 | err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 453 | if (err)
|
| 454 | return err;
|
| 455 | if (rtc->aie_timer.enabled)
|
| 456 | rtc_timer_remove(rtc, &rtc->aie_timer);
|
| 457 |
|
| 458 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
|
| 459 | rtc->aie_timer.period = 0;
|
| 460 | if (alarm->enabled)
|
| 461 | err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
|
| 462 |
|
| 463 | mutex_unlock(&rtc->ops_lock);
|
| 464 |
|
| 465 | rtc_add_offset(rtc, &alarm->time);
|
| 466 | return err;
|
| 467 | }
|
| 468 | EXPORT_SYMBOL_GPL(rtc_set_alarm);
|
| 469 |
|
| 470 |
|
| 471 | int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
| 472 | {
|
| 473 | int err;
|
| 474 | struct rtc_time now;
|
| 475 |
|
| 476 | err = rtc_valid_tm(&alarm->time);
|
| 477 | if (err != 0)
|
| 478 | return err;
|
| 479 |
|
| 480 | err = rtc_read_time(rtc, &now);
|
| 481 | if (err)
|
| 482 | return err;
|
| 483 |
|
| 484 | err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 485 | if (err)
|
| 486 | return err;
|
| 487 |
|
| 488 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
|
| 489 | rtc->aie_timer.period = 0;
|
| 490 |
|
| 491 |
|
| 492 | if (alarm->enabled && (rtc_tm_to_ktime(now) <
|
| 493 | rtc->aie_timer.node.expires)) {
|
| 494 |
|
| 495 | rtc->aie_timer.enabled = 1;
|
| 496 | timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
|
| 497 | trace_rtc_timer_enqueue(&rtc->aie_timer);
|
| 498 | }
|
| 499 | mutex_unlock(&rtc->ops_lock);
|
| 500 | return err;
|
| 501 | }
|
| 502 | EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
|
| 503 |
|
| 504 | int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
|
| 505 | {
|
| 506 | int err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 507 | if (err)
|
| 508 | return err;
|
| 509 |
|
| 510 | if (rtc->aie_timer.enabled != enabled) {
|
| 511 | if (enabled)
|
| 512 | err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
|
| 513 | else
|
| 514 | rtc_timer_remove(rtc, &rtc->aie_timer);
|
| 515 | }
|
| 516 |
|
| 517 | if (err)
|
| 518 | ;
|
| 519 | else if (!rtc->ops)
|
| 520 | err = -ENODEV;
|
| 521 | else if (!rtc->ops->alarm_irq_enable)
|
| 522 | err = -EINVAL;
|
| 523 | else
|
| 524 | err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
|
| 525 |
|
| 526 | mutex_unlock(&rtc->ops_lock);
|
| 527 |
|
| 528 | trace_rtc_alarm_irq_enable(enabled, err);
|
| 529 | return err;
|
| 530 | }
|
| 531 | EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
|
| 532 |
|
| 533 | int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
|
| 534 | {
|
| 535 | int err = mutex_lock_interruptible(&rtc->ops_lock);
|
| 536 | if (err)
|
| 537 | return err;
|
| 538 |
|
| 539 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
|
| 540 | if (enabled == 0 && rtc->uie_irq_active) {
|
| 541 | mutex_unlock(&rtc->ops_lock);
|
| 542 | return rtc_dev_update_irq_enable_emul(rtc, 0);
|
| 543 | }
|
| 544 | #endif
|
| 545 |
|
| 546 | if (rtc->uie_rtctimer.enabled == enabled)
|
| 547 | goto out;
|
| 548 |
|
| 549 | if (rtc->uie_unsupported) {
|
| 550 | err = -EINVAL;
|
| 551 | goto out;
|
| 552 | }
|
| 553 |
|
| 554 | if (enabled) {
|
| 555 | struct rtc_time tm;
|
| 556 | ktime_t now, onesec;
|
| 557 |
|
| 558 | __rtc_read_time(rtc, &tm);
|
| 559 | onesec = ktime_set(1, 0);
|
| 560 | now = rtc_tm_to_ktime(tm);
|
| 561 | rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
|
| 562 | rtc->uie_rtctimer.period = ktime_set(1, 0);
|
| 563 | err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
|
| 564 | } else
|
| 565 | rtc_timer_remove(rtc, &rtc->uie_rtctimer);
|
| 566 |
|
| 567 | out:
|
| 568 | mutex_unlock(&rtc->ops_lock);
|
| 569 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
|
| 570 | |
| 571 | * Enable emulation if the driver did not provide
|
| 572 | * the update_irq_enable function pointer or if returned
|
| 573 | * -EINVAL to signal that it has been configured without
|
| 574 | * interrupts or that are not available at the moment.
|
| 575 |
|
| 576 | if (err == -EINVAL)
|
| 577 | err = rtc_dev_update_irq_enable_emul(rtc, enabled);
|
| 578 | #endif
|
| 579 | return err;
|
| 580 |
|
| 581 | }
|
| 582 | EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
|
| 583 |
|
| 584 |
|
| 585 | |
| 586 | * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
|
| 587 | * @rtc: pointer to the rtc device
|
| 588 | *
|
| 589 | * This function is called when an AIE, UIE or PIE mode interrupt
|
| 590 | * has occurred (or been emulated).
|
| 591 | *
|
| 592 | * Triggers the registered irq_task function callback.
|
| 593 |
|
| 594 | void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
|
| 595 | {
|
| 596 | unsigned long flags;
|
| 597 |
|
| 598 |
|
| 599 | spin_lock_irqsave(&rtc->irq_lock, flags);
|
| 600 | rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
|
| 601 | spin_unlock_irqrestore(&rtc->irq_lock, flags);
|
| 602 |
|
| 603 |
|
| 604 | spin_lock_irqsave(&rtc->irq_task_lock, flags);
|
| 605 | if (rtc->irq_task)
|
| 606 | rtc->irq_task->func(rtc->irq_task->private_data);
|
| 607 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
| 608 |
|
| 609 | wake_up_interruptible(&rtc->irq_queue);
|
| 610 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
|
| 611 | }
|
| 612 |
|
| 613 |
|
| 614 | |
| 615 | * rtc_aie_update_irq - AIE mode rtctimer hook
|
| 616 | * @private: pointer to the rtc_device
|
| 617 | *
|
| 618 | * This functions is called when the aie_timer expires.
|
| 619 |
|
| 620 | void rtc_aie_update_irq(void *private)
|
| 621 | {
|
| 622 | struct rtc_device *rtc = (struct rtc_device *)private;
|
| 623 | rtc_handle_legacy_irq(rtc, 1, RTC_AF);
|
| 624 | }
|
| 625 |
|
| 626 |
|
| 627 | |
| 628 | * rtc_uie_update_irq - UIE mode rtctimer hook
|
| 629 | * @private: pointer to the rtc_device
|
| 630 | *
|
| 631 | * This functions is called when the uie_timer expires.
|
| 632 |
|
| 633 | void rtc_uie_update_irq(void *private)
|
| 634 | {
|
| 635 | struct rtc_device *rtc = (struct rtc_device *)private;
|
| 636 | rtc_handle_legacy_irq(rtc, 1, RTC_UF);
|
| 637 | }
|
| 638 |
|
| 639 |
|
| 640 | |
| 641 | * rtc_pie_update_irq - PIE mode hrtimer hook
|
| 642 | * @timer: pointer to the pie mode hrtimer
|
| 643 | *
|
| 644 | * This function is used to emulate PIE mode interrupts
|
| 645 | * using an hrtimer. This function is called when the periodic
|
| 646 | * hrtimer expires.
|
| 647 |
|
| 648 | enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
|
| 649 | {
|
| 650 | struct rtc_device *rtc;
|
| 651 | ktime_t period;
|
| 652 | int count;
|
| 653 | rtc = container_of(timer, struct rtc_device, pie_timer);
|
| 654 |
|
| 655 | period = NSEC_PER_SEC / rtc->irq_freq;
|
| 656 | count = hrtimer_forward_now(timer, period);
|
| 657 |
|
| 658 | rtc_handle_legacy_irq(rtc, count, RTC_PF);
|
| 659 |
|
| 660 | return HRTIMER_RESTART;
|
| 661 | }
|
| 662 |
|
| 663 | |
| 664 | * rtc_update_irq - Triggered when a RTC interrupt occurs.
|
| 665 | * @rtc: the rtc device
|
| 666 | * @num: how many irqs are being reported (usually one)
|
| 667 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
|
| 668 | * Context: any
|
| 669 |
|
| 670 | void rtc_update_irq(struct rtc_device *rtc,
|
| 671 | unsigned long num, unsigned long events)
|
| 672 | {
|
| 673 | if (IS_ERR_OR_NULL(rtc))
|
| 674 | return;
|
| 675 |
|
| 676 | pm_stay_awake(rtc->dev.parent);
|
| 677 | schedule_work(&rtc->irqwork);
|
| 678 | }
|
| 679 | EXPORT_SYMBOL_GPL(rtc_update_irq);
|
| 680 |
|
| 681 | static int __rtc_match(struct device *dev, const void *data)
|
| 682 | {
|
| 683 | const char *name = data;
|
| 684 |
|
| 685 | if (strcmp(dev_name(dev), name) == 0)
|
| 686 | return 1;
|
| 687 | return 0;
|
| 688 | }
|
| 689 |
|
| 690 | struct rtc_device *rtc_class_open(const char *name)
|
| 691 | {
|
| 692 | struct device *dev;
|
| 693 | struct rtc_device *rtc = NULL;
|
| 694 |
|
| 695 | dev = class_find_device(rtc_class, NULL, name, __rtc_match);
|
| 696 | if (dev)
|
| 697 | rtc = to_rtc_device(dev);
|
| 698 |
|
| 699 | if (rtc) {
|
| 700 | if (!try_module_get(rtc->owner)) {
|
| 701 | put_device(dev);
|
| 702 | rtc = NULL;
|
| 703 | }
|
| 704 | }
|
| 705 |
|
| 706 | return rtc;
|
| 707 | }
|
| 708 | EXPORT_SYMBOL_GPL(rtc_class_open);
|
| 709 |
|
| 710 | void rtc_class_close(struct rtc_device *rtc)
|
| 711 | {
|
| 712 | module_put(rtc->owner);
|
| 713 | put_device(&rtc->dev);
|
| 714 | }
|
| 715 | EXPORT_SYMBOL_GPL(rtc_class_close);
|
| 716 |
|
| 717 | int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
|
| 718 | {
|
| 719 | int retval = -EBUSY;
|
| 720 |
|
| 721 | if (task == NULL || task->func == NULL)
|
| 722 | return -EINVAL;
|
| 723 |
|
| 724 |
|
| 725 | if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
|
| 726 | return -EBUSY;
|
| 727 |
|
| 728 | spin_lock_irq(&rtc->irq_task_lock);
|
| 729 | if (rtc->irq_task == NULL) {
|
| 730 | rtc->irq_task = task;
|
| 731 | retval = 0;
|
| 732 | }
|
| 733 | spin_unlock_irq(&rtc->irq_task_lock);
|
| 734 |
|
| 735 | clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
|
| 736 |
|
| 737 | return retval;
|
| 738 | }
|
| 739 | EXPORT_SYMBOL_GPL(rtc_irq_register);
|
| 740 |
|
| 741 | void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
|
| 742 | {
|
| 743 | spin_lock_irq(&rtc->irq_task_lock);
|
| 744 | if (rtc->irq_task == task)
|
| 745 | rtc->irq_task = NULL;
|
| 746 | spin_unlock_irq(&rtc->irq_task_lock);
|
| 747 | }
|
| 748 | EXPORT_SYMBOL_GPL(rtc_irq_unregister);
|
| 749 |
|
| 750 | static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
|
| 751 | {
|
| 752 | |
| 753 | * We always cancel the timer here first, because otherwise
|
| 754 | * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
|
| 755 | * when we manage to start the timer before the callback
|
| 756 | * returns HRTIMER_RESTART.
|
| 757 | *
|
| 758 | * We cannot use hrtimer_cancel() here as a running callback
|
| 759 | * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
|
| 760 | * would spin forever.
|
| 761 |
|
| 762 | if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
|
| 763 | return -1;
|
| 764 |
|
| 765 | if (enabled) {
|
| 766 | ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
|
| 767 |
|
| 768 | hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
|
| 769 | }
|
| 770 | return 0;
|
| 771 | }
|
| 772 |
|
| 773 | |
| 774 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
|
| 775 | * @rtc: the rtc device
|
| 776 | * @task: currently registered with rtc_irq_register()
|
| 777 | * @enabled: true to enable periodic IRQs
|
| 778 | * Context: any
|
| 779 | *
|
| 780 | * Note that rtc_irq_set_freq() should previously have been used to
|
| 781 | * specify the desired frequency of periodic IRQ task->func() callbacks.
|
| 782 |
|
| 783 | int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
|
| 784 | {
|
| 785 | int err = 0;
|
| 786 | unsigned long flags;
|
| 787 |
|
| 788 | retry:
|
| 789 | spin_lock_irqsave(&rtc->irq_task_lock, flags);
|
| 790 | if (rtc->irq_task != NULL && task == NULL)
|
| 791 | err = -EBUSY;
|
| 792 | else if (rtc->irq_task != task)
|
| 793 | err = -EACCES;
|
| 794 | else {
|
| 795 | if (rtc_update_hrtimer(rtc, enabled) < 0) {
|
| 796 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
| 797 | cpu_relax();
|
| 798 | goto retry;
|
| 799 | }
|
| 800 | rtc->pie_enabled = enabled;
|
| 801 | }
|
| 802 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
| 803 |
|
| 804 | trace_rtc_irq_set_state(enabled, err);
|
| 805 | return err;
|
| 806 | }
|
| 807 | EXPORT_SYMBOL_GPL(rtc_irq_set_state);
|
| 808 |
|
| 809 | |
| 810 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
|
| 811 | * @rtc: the rtc device
|
| 812 | * @task: currently registered with rtc_irq_register()
|
| 813 | * @freq: positive frequency with which task->func() will be called
|
| 814 | * Context: any
|
| 815 | *
|
| 816 | * Note that rtc_irq_set_state() is used to enable or disable the
|
| 817 | * periodic IRQs.
|
| 818 |
|
| 819 | int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
|
| 820 | {
|
| 821 | int err = 0;
|
| 822 | unsigned long flags;
|
| 823 |
|
| 824 | if (freq <= 0 || freq > RTC_MAX_FREQ)
|
| 825 | return -EINVAL;
|
| 826 | retry:
|
| 827 | spin_lock_irqsave(&rtc->irq_task_lock, flags);
|
| 828 | if (rtc->irq_task != NULL && task == NULL)
|
| 829 | err = -EBUSY;
|
| 830 | else if (rtc->irq_task != task)
|
| 831 | err = -EACCES;
|
| 832 | else {
|
| 833 | rtc->irq_freq = freq;
|
| 834 | if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
|
| 835 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
| 836 | cpu_relax();
|
| 837 | goto retry;
|
| 838 | }
|
| 839 | }
|
| 840 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
| 841 |
|
| 842 | trace_rtc_irq_set_freq(freq, err);
|
| 843 | return err;
|
| 844 | }
|
| 845 | EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
|
| 846 |
|
| 847 | |
| 848 | * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
|
| 849 | * @rtc rtc device
|
| 850 | * @timer timer being added.
|
| 851 | *
|
| 852 | * Enqueues a timer onto the rtc devices timerqueue and sets
|
| 853 | * the next alarm event appropriately.
|
| 854 | *
|
| 855 | * Sets the enabled bit on the added timer.
|
| 856 | *
|
| 857 | * Must hold ops_lock for proper serialization of timerqueue
|
| 858 |
|
| 859 | static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
|
| 860 | {
|
| 861 | struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
|
| 862 | struct rtc_time tm;
|
| 863 | ktime_t now;
|
| 864 |
|
| 865 | timer->enabled = 1;
|
| 866 | __rtc_read_time(rtc, &tm);
|
| 867 | now = rtc_tm_to_ktime(tm);
|
| 868 |
|
| 869 |
|
| 870 | while (next) {
|
| 871 | if (next->expires >= now)
|
| 872 | break;
|
| 873 | next = timerqueue_iterate_next(next);
|
| 874 | }
|
| 875 |
|
| 876 | timerqueue_add(&rtc->timerqueue, &timer->node);
|
| 877 | trace_rtc_timer_enqueue(timer);
|
| 878 | if (!next || ktime_before(timer->node.expires, next->expires)) {
|
| 879 | struct rtc_wkalrm alarm;
|
| 880 | int err;
|
| 881 | alarm.time = rtc_ktime_to_tm(timer->node.expires);
|
| 882 | alarm.enabled = 1;
|
| 883 | err = __rtc_set_alarm(rtc, &alarm);
|
| 884 | if (err == -ETIME) {
|
| 885 | pm_stay_awake(rtc->dev.parent);
|
| 886 | schedule_work(&rtc->irqwork);
|
| 887 | } else if (err) {
|
| 888 | timerqueue_del(&rtc->timerqueue, &timer->node);
|
| 889 | trace_rtc_timer_dequeue(timer);
|
| 890 | timer->enabled = 0;
|
| 891 | return err;
|
| 892 | }
|
| 893 | }
|
| 894 | return 0;
|
| 895 | }
|
| 896 |
|
| 897 | static void rtc_alarm_disable(struct rtc_device *rtc)
|
| 898 | {
|
| 899 | if (!rtc->ops || !rtc->ops->alarm_irq_enable)
|
| 900 | return;
|
| 901 |
|
| 902 | rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
|
| 903 | trace_rtc_alarm_irq_enable(0, 0);
|
| 904 | }
|
| 905 |
|
| 906 | |
| 907 | * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
|
| 908 | * @rtc rtc device
|
| 909 | * @timer timer being removed.
|
| 910 | *
|
| 911 | * Removes a timer onto the rtc devices timerqueue and sets
|
| 912 | * the next alarm event appropriately.
|
| 913 | *
|
| 914 | * Clears the enabled bit on the removed timer.
|
| 915 | *
|
| 916 | * Must hold ops_lock for proper serialization of timerqueue
|
| 917 |
|
| 918 | static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
|
| 919 | {
|
| 920 | struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
|
| 921 | timerqueue_del(&rtc->timerqueue, &timer->node);
|
| 922 | trace_rtc_timer_dequeue(timer);
|
| 923 | timer->enabled = 0;
|
| 924 | if (next == &timer->node) {
|
| 925 | struct rtc_wkalrm alarm;
|
| 926 | int err;
|
| 927 | next = timerqueue_getnext(&rtc->timerqueue);
|
| 928 | if (!next) {
|
| 929 | rtc_alarm_disable(rtc);
|
| 930 | return;
|
| 931 | }
|
| 932 | alarm.time = rtc_ktime_to_tm(next->expires);
|
| 933 | alarm.enabled = 1;
|
| 934 | err = __rtc_set_alarm(rtc, &alarm);
|
| 935 | if (err == -ETIME) {
|
| 936 | pm_stay_awake(rtc->dev.parent);
|
| 937 | schedule_work(&rtc->irqwork);
|
| 938 | }
|
| 939 | }
|
| 940 | }
|
| 941 |
|
| 942 | |
| 943 | * rtc_timer_do_work - Expires rtc timers
|
| 944 | * @rtc rtc device
|
| 945 | * @timer timer being removed.
|
| 946 | *
|
| 947 | * Expires rtc timers. Reprograms next alarm event if needed.
|
| 948 | * Called via worktask.
|
| 949 | *
|
| 950 | * Serializes access to timerqueue via ops_lock mutex
|
| 951 |
|
| 952 | void rtc_timer_do_work(struct work_struct *work)
|
| 953 | {
|
| 954 | struct rtc_timer *timer;
|
| 955 | struct timerqueue_node *next;
|
| 956 | ktime_t now;
|
| 957 | struct rtc_time tm;
|
| 958 |
|
| 959 | struct rtc_device *rtc =
|
| 960 | container_of(work, struct rtc_device, irqwork);
|
| 961 |
|
| 962 | mutex_lock(&rtc->ops_lock);
|
| 963 | again:
|
| 964 | __rtc_read_time(rtc, &tm);
|
| 965 | now = rtc_tm_to_ktime(tm);
|
| 966 | while ((next = timerqueue_getnext(&rtc->timerqueue))) {
|
| 967 | if (next->expires > now)
|
| 968 | break;
|
| 969 |
|
| 970 |
|
| 971 | timer = container_of(next, struct rtc_timer, node);
|
| 972 | timerqueue_del(&rtc->timerqueue, &timer->node);
|
| 973 | trace_rtc_timer_dequeue(timer);
|
| 974 | timer->enabled = 0;
|
| 975 | if (timer->task.func)
|
| 976 | timer->task.func(timer->task.private_data);
|
| 977 |
|
| 978 | trace_rtc_timer_fired(timer);
|
| 979 |
|
| 980 | if (ktime_to_ns(timer->period)) {
|
| 981 | timer->node.expires = ktime_add(timer->node.expires,
|
| 982 | timer->period);
|
| 983 | timer->enabled = 1;
|
| 984 | timerqueue_add(&rtc->timerqueue, &timer->node);
|
| 985 | trace_rtc_timer_enqueue(timer);
|
| 986 | }
|
| 987 | }
|
| 988 |
|
| 989 |
|
| 990 | if (next) {
|
| 991 | struct rtc_wkalrm alarm;
|
| 992 | int err;
|
| 993 | int retry = 3;
|
| 994 |
|
| 995 | alarm.time = rtc_ktime_to_tm(next->expires);
|
| 996 | alarm.enabled = 1;
|
| 997 | reprogram:
|
| 998 | err = __rtc_set_alarm(rtc, &alarm);
|
| 999 | if (err == -ETIME)
|
| 1000 | goto again;
|
| 1001 | else if (err) {
|
| 1002 | if (retry-- > 0)
|
| 1003 | goto reprogram;
|
| 1004 |
|
| 1005 | timer = container_of(next, struct rtc_timer, node);
|
| 1006 | timerqueue_del(&rtc->timerqueue, &timer->node);
|
| 1007 | trace_rtc_timer_dequeue(timer);
|
| 1008 | timer->enabled = 0;
|
| 1009 | dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
|
| 1010 | goto again;
|
| 1011 | }
|
| 1012 | } else
|
| 1013 | rtc_alarm_disable(rtc);
|
| 1014 |
|
| 1015 | pm_relax(rtc->dev.parent);
|
| 1016 | mutex_unlock(&rtc->ops_lock);
|
| 1017 | }
|
| 1018 |
|
| 1019 |
|
| 1020 | |
| 1021 | * @timer: timer to be intiialized
|
| 1022 | * @f: function pointer to be called when timer fires
|
| 1023 | * @data: private data passed to function pointer
|
| 1024 | *
|
| 1025 | * Kernel interface to initializing an rtc_timer.
|
| 1026 |
|
| 1027 | void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
|
| 1028 | {
|
| 1029 | timerqueue_init(&timer->node);
|
| 1030 | timer->enabled = 0;
|
| 1031 | timer->task.func = f;
|
| 1032 | timer->task.private_data = data;
|
| 1033 | }
|
| 1034 |
|
| 1035 | |
| 1036 | * @ rtc: rtc device to be used
|
| 1037 | * @ timer: timer being set
|
| 1038 | * @ expires: time at which to expire the timer
|
| 1039 | * @ period: period that the timer will recur
|
| 1040 | *
|
| 1041 | * Kernel interface to set an rtc_timer
|
| 1042 |
|
| 1043 | int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
|
| 1044 | ktime_t expires, ktime_t period)
|
| 1045 | {
|
| 1046 | int ret = 0;
|
| 1047 | mutex_lock(&rtc->ops_lock);
|
| 1048 | if (timer->enabled)
|
| 1049 | rtc_timer_remove(rtc, timer);
|
| 1050 |
|
| 1051 | timer->node.expires = expires;
|
| 1052 | timer->period = period;
|
| 1053 |
|
| 1054 | ret = rtc_timer_enqueue(rtc, timer);
|
| 1055 |
|
| 1056 | mutex_unlock(&rtc->ops_lock);
|
| 1057 | return ret;
|
| 1058 | }
|
| 1059 |
|
| 1060 | |
| 1061 | * @ rtc: rtc device to be used
|
| 1062 | * @ timer: timer being set
|
| 1063 | *
|
| 1064 | * Kernel interface to cancel an rtc_timer
|
| 1065 |
|
| 1066 | void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
|
| 1067 | {
|
| 1068 | mutex_lock(&rtc->ops_lock);
|
| 1069 | if (timer->enabled)
|
| 1070 | rtc_timer_remove(rtc, timer);
|
| 1071 | mutex_unlock(&rtc->ops_lock);
|
| 1072 | }
|
| 1073 |
|
| 1074 | |
| 1075 | * rtc_read_offset - Read the amount of rtc offset in parts per billion
|
| 1076 | * @ rtc: rtc device to be used
|
| 1077 | * @ offset: the offset in parts per billion
|
| 1078 | *
|
| 1079 | * see below for details.
|
| 1080 | *
|
| 1081 | * Kernel interface to read rtc clock offset
|
| 1082 | * Returns 0 on success, or a negative number on error.
|
| 1083 | * If read_offset() is not implemented for the rtc, return -EINVAL
|
| 1084 |
|
| 1085 | int rtc_read_offset(struct rtc_device *rtc, long *offset)
|
| 1086 | {
|
| 1087 | int ret;
|
| 1088 |
|
| 1089 | if (!rtc->ops)
|
| 1090 | return -ENODEV;
|
| 1091 |
|
| 1092 | if (!rtc->ops->read_offset)
|
| 1093 | return -EINVAL;
|
| 1094 |
|
| 1095 | mutex_lock(&rtc->ops_lock);
|
| 1096 | ret = rtc->ops->read_offset(rtc->dev.parent, offset);
|
| 1097 | mutex_unlock(&rtc->ops_lock);
|
| 1098 |
|
| 1099 | trace_rtc_read_offset(*offset, ret);
|
| 1100 | return ret;
|
| 1101 | }
|
| 1102 |
|
| 1103 | |
| 1104 | * rtc_set_offset - Adjusts the duration of the average second
|
| 1105 | * @ rtc: rtc device to be used
|
| 1106 | * @ offset: the offset in parts per billion
|
| 1107 | *
|
| 1108 | * Some rtc's allow an adjustment to the average duration of a second
|
| 1109 | * to compensate for differences in the actual clock rate due to temperature,
|
| 1110 | * the crystal, capacitor, etc.
|
| 1111 | *
|
| 1112 | * The adjustment applied is as follows:
|
| 1113 | * t = t0 * (1 + offset * 1e-9)
|
| 1114 | * where t0 is the measured length of 1 RTC second with offset = 0
|
| 1115 | *
|
| 1116 | * Kernel interface to adjust an rtc clock offset.
|
| 1117 | * Return 0 on success, or a negative number on error.
|
| 1118 | * If the rtc offset is not setable (or not implemented), return -EINVAL
|
| 1119 |
|
| 1120 | int rtc_set_offset(struct rtc_device *rtc, long offset)
|
| 1121 | {
|
| 1122 | int ret;
|
| 1123 |
|
| 1124 | if (!rtc->ops)
|
| 1125 | return -ENODEV;
|
| 1126 |
|
| 1127 | if (!rtc->ops->set_offset)
|
| 1128 | return -EINVAL;
|
| 1129 |
|
| 1130 | mutex_lock(&rtc->ops_lock);
|
| 1131 | ret = rtc->ops->set_offset(rtc->dev.parent, offset);
|
| 1132 | mutex_unlock(&rtc->ops_lock);
|
| 1133 |
|
| 1134 | trace_rtc_set_offset(offset, ret);
|
| 1135 | return ret;
|
| 1136 | }
|