Commit | Line | Data |
---|---|---|
0c86edc0 AZ |
1 | /* |
2 | * RTC subsystem, interface functions | |
3 | * | |
4 | * Copyright (C) 2005 Tower Technologies | |
5 | * Author: Alessandro Zummo <a.zummo@towertech.it> | |
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> | |
d43c36dc | 15 | #include <linux/sched.h> |
2113852b | 16 | #include <linux/module.h> |
97144c67 | 17 | #include <linux/log2.h> |
6610e089 | 18 | #include <linux/workqueue.h> |
0c86edc0 | 19 | |
29a1f599 BW |
20 | #define CREATE_TRACE_POINTS |
21 | #include <trace/events/rtc.h> | |
22 | ||
aa0be0f4 JS |
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 | ||
98951564 BW |
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 | ||
4c4e5df1 BW |
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); | |
98951564 BW |
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; | |
4c4e5df1 | 79 | |
98951564 | 80 | if (time < range_min || time > range_max) |
4c4e5df1 BW |
81 | return -ERANGE; |
82 | } | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
6610e089 | 87 | static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) |
0c86edc0 AZ |
88 | { |
89 | int err; | |
0c86edc0 AZ |
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)); | |
cd966209 | 96 | err = rtc->ops->read_time(rtc->dev.parent, tm); |
16682c86 | 97 | if (err < 0) { |
d0bddb51 AK |
98 | dev_dbg(&rtc->dev, "read_time: fail to read: %d\n", |
99 | err); | |
16682c86 HG |
100 | return err; |
101 | } | |
102 | ||
98951564 BW |
103 | rtc_add_offset(rtc, tm); |
104 | ||
16682c86 HG |
105 | err = rtc_valid_tm(tm); |
106 | if (err < 0) | |
d0bddb51 | 107 | dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n"); |
0c86edc0 | 108 | } |
6610e089 JS |
109 | return err; |
110 | } | |
111 | ||
112 | int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) | |
113 | { | |
114 | int err; | |
0c86edc0 | 115 | |
6610e089 JS |
116 | err = mutex_lock_interruptible(&rtc->ops_lock); |
117 | if (err) | |
118 | return err; | |
119 | ||
120 | err = __rtc_read_time(rtc, tm); | |
0c86edc0 | 121 | mutex_unlock(&rtc->ops_lock); |
29a1f599 BW |
122 | |
123 | trace_rtc_read_time(rtc_tm_to_time64(tm), err); | |
0c86edc0 AZ |
124 | return err; |
125 | } | |
126 | EXPORT_SYMBOL_GPL(rtc_read_time); | |
127 | ||
ab6a2d70 | 128 | int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) |
0c86edc0 AZ |
129 | { |
130 | int err; | |
0c86edc0 AZ |
131 | |
132 | err = rtc_valid_tm(tm); | |
133 | if (err != 0) | |
134 | return err; | |
135 | ||
4c4e5df1 BW |
136 | err = rtc_valid_range(rtc, tm); |
137 | if (err) | |
138 | return err; | |
71db049e | 139 | |
98951564 BW |
140 | rtc_subtract_offset(rtc, tm); |
141 | ||
0c86edc0 AZ |
142 | err = mutex_lock_interruptible(&rtc->ops_lock); |
143 | if (err) | |
b68bb263 | 144 | return err; |
0c86edc0 AZ |
145 | |
146 | if (!rtc->ops) | |
147 | err = -ENODEV; | |
bbccf83f | 148 | else if (rtc->ops->set_time) |
cd966209 | 149 | err = rtc->ops->set_time(rtc->dev.parent, tm); |
8e4ff1a8 XP |
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) { | |
bc10aa93 XP |
155 | time64_t secs64 = rtc_tm_to_time64(tm); |
156 | err = rtc->ops->set_mmss(rtc->dev.parent, secs64); | |
bbccf83f AZ |
157 | } else |
158 | err = -EINVAL; | |
0c86edc0 | 159 | |
14d0e347 | 160 | pm_stay_awake(rtc->dev.parent); |
0c86edc0 | 161 | mutex_unlock(&rtc->ops_lock); |
5f9679d2 N |
162 | /* A timer might have just expired */ |
163 | schedule_work(&rtc->irqwork); | |
29a1f599 BW |
164 | |
165 | trace_rtc_set_time(rtc_tm_to_time64(tm), err); | |
0c86edc0 AZ |
166 | return err; |
167 | } | |
168 | EXPORT_SYMBOL_GPL(rtc_set_time); | |
169 | ||
f44f7f96 JS |
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 { | |
d68778b8 UKK |
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; | |
f44f7f96 JS |
194 | err = rtc->ops->read_alarm(rtc->dev.parent, alarm); |
195 | } | |
196 | ||
197 | mutex_unlock(&rtc->ops_lock); | |
29a1f599 BW |
198 | |
199 | trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); | |
f44f7f96 JS |
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; | |
bc10aa93 | 208 | time64_t t_now, t_alm; |
f44f7f96 JS |
209 | enum { none, day, month, year } missing = none; |
210 | unsigned days; | |
211 | ||
212 | /* The lower level RTC driver may return -1 in some fields, | |
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 | /* Get the "before" timestamp */ | |
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 | /* get the RTC alarm values, which may be incomplete */ | |
263 | err = rtc_read_alarm_internal(rtc, alarm); | |
264 | if (err) | |
265 | return err; | |
266 | ||
267 | /* full-function RTCs won't have such missing fields */ | |
fd6792bb AB |
268 | if (rtc_valid_tm(&alarm->time) == 0) { |
269 | rtc_add_offset(rtc, &alarm->time); | |
f44f7f96 | 270 | return 0; |
fd6792bb | 271 | } |
f44f7f96 JS |
272 | |
273 | /* get the "after" timestamp, to detect wrapped fields */ | |
274 | err = rtc_read_time(rtc, &now); | |
275 | if (err < 0) | |
276 | return err; | |
277 | ||
278 | /* note that tm_sec is a "don't care" value here: */ | |
279 | } while ( before.tm_min != now.tm_min | |
280 | || before.tm_hour != now.tm_hour | |
281 | || before.tm_mon != now.tm_mon | |
282 | || before.tm_year != now.tm_year); | |
283 | ||
284 | /* Fill in the missing alarm fields using the timestamp; we | |
285 | * know there's at least one since alarm->time is invalid. | |
286 | */ | |
287 | if (alarm->time.tm_sec == -1) | |
288 | alarm->time.tm_sec = now.tm_sec; | |
289 | if (alarm->time.tm_min == -1) | |
290 | alarm->time.tm_min = now.tm_min; | |
291 | if (alarm->time.tm_hour == -1) | |
292 | alarm->time.tm_hour = now.tm_hour; | |
293 | ||
294 | /* For simplicity, only support date rollover for now */ | |
e74a8f2e | 295 | if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) { |
f44f7f96 JS |
296 | alarm->time.tm_mday = now.tm_mday; |
297 | missing = day; | |
298 | } | |
e74a8f2e | 299 | if ((unsigned)alarm->time.tm_mon >= 12) { |
f44f7f96 JS |
300 | alarm->time.tm_mon = now.tm_mon; |
301 | if (missing == none) | |
302 | missing = month; | |
303 | } | |
304 | if (alarm->time.tm_year == -1) { | |
305 | alarm->time.tm_year = now.tm_year; | |
306 | if (missing == none) | |
307 | missing = year; | |
308 | } | |
309 | ||
da96aea0 VJ |
310 | /* Can't proceed if alarm is still invalid after replacing |
311 | * missing fields. | |
312 | */ | |
313 | err = rtc_valid_tm(&alarm->time); | |
314 | if (err) | |
315 | goto done; | |
316 | ||
f44f7f96 | 317 | /* with luck, no rollover is needed */ |
bc10aa93 XP |
318 | t_now = rtc_tm_to_time64(&now); |
319 | t_alm = rtc_tm_to_time64(&alarm->time); | |
f44f7f96 JS |
320 | if (t_now < t_alm) |
321 | goto done; | |
322 | ||
323 | switch (missing) { | |
324 | ||
325 | /* 24 hour rollover ... if it's now 10am Monday, an alarm that | |
326 | * that will trigger at 5am will do so at 5am Tuesday, which | |
327 | * could also be in the next month or year. This is a common | |
328 | * case, especially for PCs. | |
329 | */ | |
330 | case day: | |
331 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); | |
332 | t_alm += 24 * 60 * 60; | |
bc10aa93 | 333 | rtc_time64_to_tm(t_alm, &alarm->time); |
f44f7f96 JS |
334 | break; |
335 | ||
336 | /* Month rollover ... if it's the 31th, an alarm on the 3rd will | |
337 | * be next month. An alarm matching on the 30th, 29th, or 28th | |
338 | * may end up in the month after that! Many newer PCs support | |
339 | * this type of alarm. | |
340 | */ | |
341 | case month: | |
342 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); | |
343 | do { | |
344 | if (alarm->time.tm_mon < 11) | |
345 | alarm->time.tm_mon++; | |
346 | else { | |
347 | alarm->time.tm_mon = 0; | |
348 | alarm->time.tm_year++; | |
349 | } | |
350 | days = rtc_month_days(alarm->time.tm_mon, | |
351 | alarm->time.tm_year); | |
352 | } while (days < alarm->time.tm_mday); | |
353 | break; | |
354 | ||
355 | /* Year rollover ... easy except for leap years! */ | |
356 | case year: | |
357 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); | |
358 | do { | |
359 | alarm->time.tm_year++; | |
ee1d9014 AN |
360 | } while (!is_leap_year(alarm->time.tm_year + 1900) |
361 | && rtc_valid_tm(&alarm->time) != 0); | |
f44f7f96 JS |
362 | break; |
363 | ||
364 | default: | |
365 | dev_warn(&rtc->dev, "alarm rollover not handled\n"); | |
366 | } | |
367 | ||
ee1d9014 AN |
368 | err = rtc_valid_tm(&alarm->time); |
369 | ||
da96aea0 | 370 | done: |
5548cbf7 AS |
371 | if (err) |
372 | dev_warn(&rtc->dev, "invalid alarm value: %ptR\n", &alarm->time); | |
ee1d9014 AN |
373 | |
374 | return err; | |
f44f7f96 JS |
375 | } |
376 | ||
6610e089 | 377 | int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
0c86edc0 AZ |
378 | { |
379 | int err; | |
0c86edc0 AZ |
380 | |
381 | err = mutex_lock_interruptible(&rtc->ops_lock); | |
382 | if (err) | |
b68bb263 | 383 | return err; |
d5553a55 JS |
384 | if (rtc->ops == NULL) |
385 | err = -ENODEV; | |
386 | else if (!rtc->ops->read_alarm) | |
387 | err = -EINVAL; | |
388 | else { | |
389 | memset(alarm, 0, sizeof(struct rtc_wkalrm)); | |
390 | alarm->enabled = rtc->aie_timer.enabled; | |
6610e089 | 391 | alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires); |
d5553a55 | 392 | } |
0c86edc0 | 393 | mutex_unlock(&rtc->ops_lock); |
6610e089 | 394 | |
29a1f599 | 395 | trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); |
d5553a55 | 396 | return err; |
0c86edc0 | 397 | } |
6610e089 | 398 | EXPORT_SYMBOL_GPL(rtc_read_alarm); |
0e36a9a4 | 399 | |
d576fe49 | 400 | static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
0e36a9a4 | 401 | { |
6610e089 | 402 | struct rtc_time tm; |
bc10aa93 | 403 | time64_t now, scheduled; |
0e36a9a4 | 404 | int err; |
0e36a9a4 | 405 | |
6610e089 JS |
406 | err = rtc_valid_tm(&alarm->time); |
407 | if (err) | |
0e36a9a4 | 408 | return err; |
98951564 | 409 | |
bc10aa93 | 410 | scheduled = rtc_tm_to_time64(&alarm->time); |
a01cc657 | 411 | |
6610e089 JS |
412 | /* Make sure we're not setting alarms in the past */ |
413 | err = __rtc_read_time(rtc, &tm); | |
ca6dc2da HG |
414 | if (err) |
415 | return err; | |
bc10aa93 | 416 | now = rtc_tm_to_time64(&tm); |
6610e089 JS |
417 | if (scheduled <= now) |
418 | return -ETIME; | |
419 | /* | |
420 | * XXX - We just checked to make sure the alarm time is not | |
421 | * in the past, but there is still a race window where if | |
422 | * the is alarm set for the next second and the second ticks | |
423 | * over right here, before we set the alarm. | |
a01cc657 | 424 | */ |
a01cc657 | 425 | |
fd6792bb AB |
426 | rtc_subtract_offset(rtc, &alarm->time); |
427 | ||
157e8bf8 LT |
428 | if (!rtc->ops) |
429 | err = -ENODEV; | |
430 | else if (!rtc->ops->set_alarm) | |
431 | err = -EINVAL; | |
432 | else | |
433 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm); | |
434 | ||
29a1f599 | 435 | trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err); |
157e8bf8 | 436 | return err; |
0e36a9a4 | 437 | } |
0c86edc0 | 438 | |
ab6a2d70 | 439 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
0c86edc0 AZ |
440 | { |
441 | int err; | |
0c86edc0 | 442 | |
abfdff44 AB |
443 | if (!rtc->ops) |
444 | return -ENODEV; | |
445 | else if (!rtc->ops->set_alarm) | |
446 | return -EINVAL; | |
447 | ||
f8245c26 DB |
448 | err = rtc_valid_tm(&alarm->time); |
449 | if (err != 0) | |
450 | return err; | |
451 | ||
4c4e5df1 BW |
452 | err = rtc_valid_range(rtc, &alarm->time); |
453 | if (err) | |
454 | return err; | |
71db049e | 455 | |
0c86edc0 AZ |
456 | err = mutex_lock_interruptible(&rtc->ops_lock); |
457 | if (err) | |
b68bb263 | 458 | return err; |
3ff2e13c | 459 | if (rtc->aie_timer.enabled) |
96c8f06a | 460 | rtc_timer_remove(rtc, &rtc->aie_timer); |
3ff2e13c | 461 | |
6610e089 | 462 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); |
8b0e1953 | 463 | rtc->aie_timer.period = 0; |
3ff2e13c | 464 | if (alarm->enabled) |
aa0be0f4 | 465 | err = rtc_timer_enqueue(rtc, &rtc->aie_timer); |
3ff2e13c | 466 | |
0c86edc0 | 467 | mutex_unlock(&rtc->ops_lock); |
98951564 | 468 | |
aa0be0f4 | 469 | return err; |
0c86edc0 AZ |
470 | } |
471 | EXPORT_SYMBOL_GPL(rtc_set_alarm); | |
472 | ||
f6d5b331 JS |
473 | /* Called once per device from rtc_device_register */ |
474 | int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) | |
475 | { | |
476 | int err; | |
bd729d72 | 477 | struct rtc_time now; |
f6d5b331 JS |
478 | |
479 | err = rtc_valid_tm(&alarm->time); | |
480 | if (err != 0) | |
481 | return err; | |
482 | ||
bd729d72 JS |
483 | err = rtc_read_time(rtc, &now); |
484 | if (err) | |
485 | return err; | |
486 | ||
f6d5b331 JS |
487 | err = mutex_lock_interruptible(&rtc->ops_lock); |
488 | if (err) | |
489 | return err; | |
490 | ||
491 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); | |
8b0e1953 | 492 | rtc->aie_timer.period = 0; |
bd729d72 | 493 | |
6785b3b6 | 494 | /* Alarm has to be enabled & in the future for us to enqueue it */ |
2456e855 TG |
495 | if (alarm->enabled && (rtc_tm_to_ktime(now) < |
496 | rtc->aie_timer.node.expires)) { | |
bd729d72 | 497 | |
f6d5b331 JS |
498 | rtc->aie_timer.enabled = 1; |
499 | timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node); | |
29a1f599 | 500 | trace_rtc_timer_enqueue(&rtc->aie_timer); |
f6d5b331 JS |
501 | } |
502 | mutex_unlock(&rtc->ops_lock); | |
503 | return err; | |
504 | } | |
505 | EXPORT_SYMBOL_GPL(rtc_initialize_alarm); | |
506 | ||
099e6576 AZ |
507 | int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
508 | { | |
509 | int err = mutex_lock_interruptible(&rtc->ops_lock); | |
510 | if (err) | |
511 | return err; | |
512 | ||
6610e089 | 513 | if (rtc->aie_timer.enabled != enabled) { |
aa0be0f4 JS |
514 | if (enabled) |
515 | err = rtc_timer_enqueue(rtc, &rtc->aie_timer); | |
516 | else | |
96c8f06a | 517 | rtc_timer_remove(rtc, &rtc->aie_timer); |
6610e089 JS |
518 | } |
519 | ||
aa0be0f4 | 520 | if (err) |
516373b8 UKK |
521 | /* nothing */; |
522 | else if (!rtc->ops) | |
099e6576 AZ |
523 | err = -ENODEV; |
524 | else if (!rtc->ops->alarm_irq_enable) | |
525 | err = -EINVAL; | |
526 | else | |
527 | err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); | |
528 | ||
529 | mutex_unlock(&rtc->ops_lock); | |
29a1f599 BW |
530 | |
531 | trace_rtc_alarm_irq_enable(enabled, err); | |
099e6576 AZ |
532 | return err; |
533 | } | |
534 | EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); | |
535 | ||
536 | int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) | |
537 | { | |
538 | int err = mutex_lock_interruptible(&rtc->ops_lock); | |
539 | if (err) | |
540 | return err; | |
541 | ||
456d66ec JS |
542 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
543 | if (enabled == 0 && rtc->uie_irq_active) { | |
544 | mutex_unlock(&rtc->ops_lock); | |
545 | return rtc_dev_update_irq_enable_emul(rtc, 0); | |
546 | } | |
547 | #endif | |
6610e089 JS |
548 | /* make sure we're changing state */ |
549 | if (rtc->uie_rtctimer.enabled == enabled) | |
550 | goto out; | |
551 | ||
4a649903 JS |
552 | if (rtc->uie_unsupported) { |
553 | err = -EINVAL; | |
554 | goto out; | |
555 | } | |
556 | ||
6610e089 JS |
557 | if (enabled) { |
558 | struct rtc_time tm; | |
559 | ktime_t now, onesec; | |
560 | ||
561 | __rtc_read_time(rtc, &tm); | |
562 | onesec = ktime_set(1, 0); | |
563 | now = rtc_tm_to_ktime(tm); | |
564 | rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); | |
565 | rtc->uie_rtctimer.period = ktime_set(1, 0); | |
aa0be0f4 JS |
566 | err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); |
567 | } else | |
96c8f06a | 568 | rtc_timer_remove(rtc, &rtc->uie_rtctimer); |
099e6576 | 569 | |
6610e089 | 570 | out: |
099e6576 | 571 | mutex_unlock(&rtc->ops_lock); |
456d66ec JS |
572 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
573 | /* | |
574 | * Enable emulation if the driver did not provide | |
575 | * the update_irq_enable function pointer or if returned | |
576 | * -EINVAL to signal that it has been configured without | |
577 | * interrupts or that are not available at the moment. | |
578 | */ | |
579 | if (err == -EINVAL) | |
580 | err = rtc_dev_update_irq_enable_emul(rtc, enabled); | |
581 | #endif | |
099e6576 | 582 | return err; |
6610e089 | 583 | |
099e6576 AZ |
584 | } |
585 | EXPORT_SYMBOL_GPL(rtc_update_irq_enable); | |
586 | ||
6610e089 | 587 | |
d728b1e6 | 588 | /** |
6610e089 JS |
589 | * rtc_handle_legacy_irq - AIE, UIE and PIE event hook |
590 | * @rtc: pointer to the rtc device | |
591 | * | |
592 | * This function is called when an AIE, UIE or PIE mode interrupt | |
25985edc | 593 | * has occurred (or been emulated). |
6610e089 | 594 | * |
d728b1e6 | 595 | */ |
456d66ec | 596 | void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) |
0c86edc0 | 597 | { |
e6229bec AN |
598 | unsigned long flags; |
599 | ||
6610e089 | 600 | /* mark one irq of the appropriate mode */ |
e6229bec | 601 | spin_lock_irqsave(&rtc->irq_lock, flags); |
6610e089 | 602 | rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode); |
e6229bec | 603 | spin_unlock_irqrestore(&rtc->irq_lock, flags); |
0c86edc0 | 604 | |
0c86edc0 AZ |
605 | wake_up_interruptible(&rtc->irq_queue); |
606 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); | |
607 | } | |
6610e089 JS |
608 | |
609 | ||
610 | /** | |
611 | * rtc_aie_update_irq - AIE mode rtctimer hook | |
9a032011 | 612 | * @rtc: pointer to the rtc_device |
6610e089 JS |
613 | * |
614 | * This functions is called when the aie_timer expires. | |
615 | */ | |
9a032011 | 616 | void rtc_aie_update_irq(struct rtc_device *rtc) |
6610e089 | 617 | { |
6610e089 JS |
618 | rtc_handle_legacy_irq(rtc, 1, RTC_AF); |
619 | } | |
620 | ||
621 | ||
622 | /** | |
623 | * rtc_uie_update_irq - UIE mode rtctimer hook | |
9a032011 | 624 | * @rtc: pointer to the rtc_device |
6610e089 JS |
625 | * |
626 | * This functions is called when the uie_timer expires. | |
627 | */ | |
9a032011 | 628 | void rtc_uie_update_irq(struct rtc_device *rtc) |
6610e089 | 629 | { |
6610e089 JS |
630 | rtc_handle_legacy_irq(rtc, 1, RTC_UF); |
631 | } | |
632 | ||
633 | ||
634 | /** | |
635 | * rtc_pie_update_irq - PIE mode hrtimer hook | |
636 | * @timer: pointer to the pie mode hrtimer | |
637 | * | |
638 | * This function is used to emulate PIE mode interrupts | |
639 | * using an hrtimer. This function is called when the periodic | |
640 | * hrtimer expires. | |
641 | */ | |
642 | enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer) | |
643 | { | |
644 | struct rtc_device *rtc; | |
645 | ktime_t period; | |
646 | int count; | |
647 | rtc = container_of(timer, struct rtc_device, pie_timer); | |
648 | ||
8b0e1953 | 649 | period = NSEC_PER_SEC / rtc->irq_freq; |
6610e089 JS |
650 | count = hrtimer_forward_now(timer, period); |
651 | ||
652 | rtc_handle_legacy_irq(rtc, count, RTC_PF); | |
653 | ||
654 | return HRTIMER_RESTART; | |
655 | } | |
656 | ||
657 | /** | |
658 | * rtc_update_irq - Triggered when a RTC interrupt occurs. | |
659 | * @rtc: the rtc device | |
660 | * @num: how many irqs are being reported (usually one) | |
661 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF | |
662 | * Context: any | |
663 | */ | |
664 | void rtc_update_irq(struct rtc_device *rtc, | |
665 | unsigned long num, unsigned long events) | |
666 | { | |
e7cba884 | 667 | if (IS_ERR_OR_NULL(rtc)) |
131c9cc8 AZ |
668 | return; |
669 | ||
7523ceed | 670 | pm_stay_awake(rtc->dev.parent); |
6610e089 JS |
671 | schedule_work(&rtc->irqwork); |
672 | } | |
0c86edc0 AZ |
673 | EXPORT_SYMBOL_GPL(rtc_update_irq); |
674 | ||
9f3b795a | 675 | static int __rtc_match(struct device *dev, const void *data) |
71da8905 | 676 | { |
9f3b795a | 677 | const char *name = data; |
71da8905 | 678 | |
d4afc76c | 679 | if (strcmp(dev_name(dev), name) == 0) |
71da8905 DY |
680 | return 1; |
681 | return 0; | |
682 | } | |
683 | ||
9f3b795a | 684 | struct rtc_device *rtc_class_open(const char *name) |
0c86edc0 | 685 | { |
cd966209 | 686 | struct device *dev; |
ab6a2d70 | 687 | struct rtc_device *rtc = NULL; |
0c86edc0 | 688 | |
695794ae | 689 | dev = class_find_device(rtc_class, NULL, name, __rtc_match); |
71da8905 DY |
690 | if (dev) |
691 | rtc = to_rtc_device(dev); | |
0c86edc0 | 692 | |
ab6a2d70 DB |
693 | if (rtc) { |
694 | if (!try_module_get(rtc->owner)) { | |
cd966209 | 695 | put_device(dev); |
ab6a2d70 DB |
696 | rtc = NULL; |
697 | } | |
0c86edc0 | 698 | } |
0c86edc0 | 699 | |
ab6a2d70 | 700 | return rtc; |
0c86edc0 AZ |
701 | } |
702 | EXPORT_SYMBOL_GPL(rtc_class_open); | |
703 | ||
ab6a2d70 | 704 | void rtc_class_close(struct rtc_device *rtc) |
0c86edc0 | 705 | { |
ab6a2d70 | 706 | module_put(rtc->owner); |
cd966209 | 707 | put_device(&rtc->dev); |
0c86edc0 AZ |
708 | } |
709 | EXPORT_SYMBOL_GPL(rtc_class_close); | |
710 | ||
3c8bb90e TG |
711 | static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled) |
712 | { | |
713 | /* | |
714 | * We always cancel the timer here first, because otherwise | |
715 | * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); | |
716 | * when we manage to start the timer before the callback | |
717 | * returns HRTIMER_RESTART. | |
718 | * | |
719 | * We cannot use hrtimer_cancel() here as a running callback | |
720 | * could be blocked on rtc->irq_task_lock and hrtimer_cancel() | |
721 | * would spin forever. | |
722 | */ | |
723 | if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0) | |
724 | return -1; | |
725 | ||
726 | if (enabled) { | |
8b0e1953 | 727 | ktime_t period = NSEC_PER_SEC / rtc->irq_freq; |
3c8bb90e TG |
728 | |
729 | hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); | |
730 | } | |
731 | return 0; | |
732 | } | |
733 | ||
97144c67 DB |
734 | /** |
735 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs | |
736 | * @rtc: the rtc device | |
97144c67 DB |
737 | * @enabled: true to enable periodic IRQs |
738 | * Context: any | |
739 | * | |
740 | * Note that rtc_irq_set_freq() should previously have been used to | |
acecb3ad | 741 | * specify the desired frequency of periodic IRQ. |
97144c67 | 742 | */ |
8719d3c9 | 743 | int rtc_irq_set_state(struct rtc_device *rtc, int enabled) |
0c86edc0 AZ |
744 | { |
745 | int err = 0; | |
0c86edc0 | 746 | |
acecb3ad AB |
747 | while (rtc_update_hrtimer(rtc, enabled) < 0) |
748 | cpu_relax(); | |
749 | ||
750 | rtc->pie_enabled = enabled; | |
29a1f599 BW |
751 | |
752 | trace_rtc_irq_set_state(enabled, err); | |
0c86edc0 AZ |
753 | return err; |
754 | } | |
0c86edc0 | 755 | |
97144c67 DB |
756 | /** |
757 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ | |
758 | * @rtc: the rtc device | |
acecb3ad | 759 | * @freq: positive frequency |
97144c67 DB |
760 | * Context: any |
761 | * | |
762 | * Note that rtc_irq_set_state() is used to enable or disable the | |
763 | * periodic IRQs. | |
764 | */ | |
8719d3c9 | 765 | int rtc_irq_set_freq(struct rtc_device *rtc, int freq) |
0c86edc0 | 766 | { |
56f10c63 | 767 | int err = 0; |
0c86edc0 | 768 | |
6e7a333e | 769 | if (freq <= 0 || freq > RTC_MAX_FREQ) |
83a06bf5 | 770 | return -EINVAL; |
acecb3ad AB |
771 | |
772 | rtc->irq_freq = freq; | |
773 | while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) | |
774 | cpu_relax(); | |
29a1f599 BW |
775 | |
776 | trace_rtc_irq_set_freq(freq, err); | |
0c86edc0 AZ |
777 | return err; |
778 | } | |
6610e089 JS |
779 | |
780 | /** | |
96c8f06a | 781 | * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue |
6610e089 JS |
782 | * @rtc rtc device |
783 | * @timer timer being added. | |
784 | * | |
785 | * Enqueues a timer onto the rtc devices timerqueue and sets | |
786 | * the next alarm event appropriately. | |
787 | * | |
aa0be0f4 JS |
788 | * Sets the enabled bit on the added timer. |
789 | * | |
6610e089 JS |
790 | * Must hold ops_lock for proper serialization of timerqueue |
791 | */ | |
aa0be0f4 | 792 | static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) |
6610e089 | 793 | { |
2b2f5ff0 CIK |
794 | struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); |
795 | struct rtc_time tm; | |
796 | ktime_t now; | |
797 | ||
aa0be0f4 | 798 | timer->enabled = 1; |
2b2f5ff0 CIK |
799 | __rtc_read_time(rtc, &tm); |
800 | now = rtc_tm_to_ktime(tm); | |
801 | ||
802 | /* Skip over expired timers */ | |
803 | while (next) { | |
2456e855 | 804 | if (next->expires >= now) |
2b2f5ff0 CIK |
805 | break; |
806 | next = timerqueue_iterate_next(next); | |
807 | } | |
808 | ||
6610e089 | 809 | timerqueue_add(&rtc->timerqueue, &timer->node); |
29a1f599 | 810 | trace_rtc_timer_enqueue(timer); |
74717b28 | 811 | if (!next || ktime_before(timer->node.expires, next->expires)) { |
6610e089 JS |
812 | struct rtc_wkalrm alarm; |
813 | int err; | |
814 | alarm.time = rtc_ktime_to_tm(timer->node.expires); | |
815 | alarm.enabled = 1; | |
816 | err = __rtc_set_alarm(rtc, &alarm); | |
14d0e347 ZM |
817 | if (err == -ETIME) { |
818 | pm_stay_awake(rtc->dev.parent); | |
6610e089 | 819 | schedule_work(&rtc->irqwork); |
14d0e347 | 820 | } else if (err) { |
aa0be0f4 | 821 | timerqueue_del(&rtc->timerqueue, &timer->node); |
29a1f599 | 822 | trace_rtc_timer_dequeue(timer); |
aa0be0f4 JS |
823 | timer->enabled = 0; |
824 | return err; | |
825 | } | |
6610e089 | 826 | } |
aa0be0f4 | 827 | return 0; |
6610e089 JS |
828 | } |
829 | ||
41c7f742 RV |
830 | static void rtc_alarm_disable(struct rtc_device *rtc) |
831 | { | |
832 | if (!rtc->ops || !rtc->ops->alarm_irq_enable) | |
833 | return; | |
834 | ||
835 | rtc->ops->alarm_irq_enable(rtc->dev.parent, false); | |
29a1f599 | 836 | trace_rtc_alarm_irq_enable(0, 0); |
41c7f742 RV |
837 | } |
838 | ||
6610e089 | 839 | /** |
96c8f06a | 840 | * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue |
6610e089 JS |
841 | * @rtc rtc device |
842 | * @timer timer being removed. | |
843 | * | |
844 | * Removes a timer onto the rtc devices timerqueue and sets | |
845 | * the next alarm event appropriately. | |
846 | * | |
aa0be0f4 JS |
847 | * Clears the enabled bit on the removed timer. |
848 | * | |
6610e089 JS |
849 | * Must hold ops_lock for proper serialization of timerqueue |
850 | */ | |
aa0be0f4 | 851 | static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) |
6610e089 JS |
852 | { |
853 | struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); | |
854 | timerqueue_del(&rtc->timerqueue, &timer->node); | |
29a1f599 | 855 | trace_rtc_timer_dequeue(timer); |
aa0be0f4 | 856 | timer->enabled = 0; |
6610e089 JS |
857 | if (next == &timer->node) { |
858 | struct rtc_wkalrm alarm; | |
859 | int err; | |
860 | next = timerqueue_getnext(&rtc->timerqueue); | |
41c7f742 RV |
861 | if (!next) { |
862 | rtc_alarm_disable(rtc); | |
6610e089 | 863 | return; |
41c7f742 | 864 | } |
6610e089 JS |
865 | alarm.time = rtc_ktime_to_tm(next->expires); |
866 | alarm.enabled = 1; | |
867 | err = __rtc_set_alarm(rtc, &alarm); | |
14d0e347 ZM |
868 | if (err == -ETIME) { |
869 | pm_stay_awake(rtc->dev.parent); | |
6610e089 | 870 | schedule_work(&rtc->irqwork); |
14d0e347 | 871 | } |
6610e089 JS |
872 | } |
873 | } | |
874 | ||
875 | /** | |
96c8f06a | 876 | * rtc_timer_do_work - Expires rtc timers |
6610e089 JS |
877 | * @rtc rtc device |
878 | * @timer timer being removed. | |
879 | * | |
880 | * Expires rtc timers. Reprograms next alarm event if needed. | |
881 | * Called via worktask. | |
882 | * | |
883 | * Serializes access to timerqueue via ops_lock mutex | |
884 | */ | |
96c8f06a | 885 | void rtc_timer_do_work(struct work_struct *work) |
6610e089 JS |
886 | { |
887 | struct rtc_timer *timer; | |
888 | struct timerqueue_node *next; | |
889 | ktime_t now; | |
890 | struct rtc_time tm; | |
891 | ||
892 | struct rtc_device *rtc = | |
893 | container_of(work, struct rtc_device, irqwork); | |
894 | ||
895 | mutex_lock(&rtc->ops_lock); | |
896 | again: | |
897 | __rtc_read_time(rtc, &tm); | |
898 | now = rtc_tm_to_ktime(tm); | |
899 | while ((next = timerqueue_getnext(&rtc->timerqueue))) { | |
2456e855 | 900 | if (next->expires > now) |
6610e089 JS |
901 | break; |
902 | ||
903 | /* expire timer */ | |
904 | timer = container_of(next, struct rtc_timer, node); | |
905 | timerqueue_del(&rtc->timerqueue, &timer->node); | |
29a1f599 | 906 | trace_rtc_timer_dequeue(timer); |
6610e089 | 907 | timer->enabled = 0; |
5a5ba10f | 908 | if (timer->func) |
9a032011 | 909 | timer->func(timer->rtc); |
6610e089 | 910 | |
29a1f599 | 911 | trace_rtc_timer_fired(timer); |
6610e089 JS |
912 | /* Re-add/fwd periodic timers */ |
913 | if (ktime_to_ns(timer->period)) { | |
914 | timer->node.expires = ktime_add(timer->node.expires, | |
915 | timer->period); | |
916 | timer->enabled = 1; | |
917 | timerqueue_add(&rtc->timerqueue, &timer->node); | |
29a1f599 | 918 | trace_rtc_timer_enqueue(timer); |
6610e089 JS |
919 | } |
920 | } | |
921 | ||
922 | /* Set next alarm */ | |
923 | if (next) { | |
924 | struct rtc_wkalrm alarm; | |
925 | int err; | |
6528b889 XP |
926 | int retry = 3; |
927 | ||
6610e089 JS |
928 | alarm.time = rtc_ktime_to_tm(next->expires); |
929 | alarm.enabled = 1; | |
6528b889 | 930 | reprogram: |
6610e089 JS |
931 | err = __rtc_set_alarm(rtc, &alarm); |
932 | if (err == -ETIME) | |
933 | goto again; | |
6528b889 XP |
934 | else if (err) { |
935 | if (retry-- > 0) | |
936 | goto reprogram; | |
937 | ||
938 | timer = container_of(next, struct rtc_timer, node); | |
939 | timerqueue_del(&rtc->timerqueue, &timer->node); | |
29a1f599 | 940 | trace_rtc_timer_dequeue(timer); |
6528b889 XP |
941 | timer->enabled = 0; |
942 | dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err); | |
943 | goto again; | |
944 | } | |
41c7f742 RV |
945 | } else |
946 | rtc_alarm_disable(rtc); | |
6610e089 | 947 | |
14d0e347 | 948 | pm_relax(rtc->dev.parent); |
6610e089 JS |
949 | mutex_unlock(&rtc->ops_lock); |
950 | } | |
951 | ||
952 | ||
96c8f06a | 953 | /* rtc_timer_init - Initializes an rtc_timer |
6610e089 JS |
954 | * @timer: timer to be intiialized |
955 | * @f: function pointer to be called when timer fires | |
9a032011 | 956 | * @rtc: pointer to the rtc_device |
6610e089 JS |
957 | * |
958 | * Kernel interface to initializing an rtc_timer. | |
959 | */ | |
9a032011 AB |
960 | void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r), |
961 | struct rtc_device *rtc) | |
6610e089 JS |
962 | { |
963 | timerqueue_init(&timer->node); | |
964 | timer->enabled = 0; | |
5a5ba10f | 965 | timer->func = f; |
9a032011 | 966 | timer->rtc = rtc; |
6610e089 JS |
967 | } |
968 | ||
96c8f06a | 969 | /* rtc_timer_start - Sets an rtc_timer to fire in the future |
6610e089 JS |
970 | * @ rtc: rtc device to be used |
971 | * @ timer: timer being set | |
972 | * @ expires: time at which to expire the timer | |
973 | * @ period: period that the timer will recur | |
974 | * | |
975 | * Kernel interface to set an rtc_timer | |
976 | */ | |
3ff2e13c | 977 | int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer, |
6610e089 JS |
978 | ktime_t expires, ktime_t period) |
979 | { | |
980 | int ret = 0; | |
981 | mutex_lock(&rtc->ops_lock); | |
982 | if (timer->enabled) | |
96c8f06a | 983 | rtc_timer_remove(rtc, timer); |
6610e089 JS |
984 | |
985 | timer->node.expires = expires; | |
986 | timer->period = period; | |
987 | ||
aa0be0f4 | 988 | ret = rtc_timer_enqueue(rtc, timer); |
6610e089 JS |
989 | |
990 | mutex_unlock(&rtc->ops_lock); | |
991 | return ret; | |
992 | } | |
993 | ||
96c8f06a | 994 | /* rtc_timer_cancel - Stops an rtc_timer |
6610e089 JS |
995 | * @ rtc: rtc device to be used |
996 | * @ timer: timer being set | |
997 | * | |
998 | * Kernel interface to cancel an rtc_timer | |
999 | */ | |
73744a64 | 1000 | void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer) |
6610e089 | 1001 | { |
6610e089 JS |
1002 | mutex_lock(&rtc->ops_lock); |
1003 | if (timer->enabled) | |
96c8f06a | 1004 | rtc_timer_remove(rtc, timer); |
6610e089 | 1005 | mutex_unlock(&rtc->ops_lock); |
6610e089 JS |
1006 | } |
1007 | ||
b3967067 JC |
1008 | /** |
1009 | * rtc_read_offset - Read the amount of rtc offset in parts per billion | |
1010 | * @ rtc: rtc device to be used | |
1011 | * @ offset: the offset in parts per billion | |
1012 | * | |
1013 | * see below for details. | |
1014 | * | |
1015 | * Kernel interface to read rtc clock offset | |
1016 | * Returns 0 on success, or a negative number on error. | |
1017 | * If read_offset() is not implemented for the rtc, return -EINVAL | |
1018 | */ | |
1019 | int rtc_read_offset(struct rtc_device *rtc, long *offset) | |
1020 | { | |
1021 | int ret; | |
1022 | ||
1023 | if (!rtc->ops) | |
1024 | return -ENODEV; | |
1025 | ||
1026 | if (!rtc->ops->read_offset) | |
1027 | return -EINVAL; | |
1028 | ||
1029 | mutex_lock(&rtc->ops_lock); | |
1030 | ret = rtc->ops->read_offset(rtc->dev.parent, offset); | |
1031 | mutex_unlock(&rtc->ops_lock); | |
29a1f599 BW |
1032 | |
1033 | trace_rtc_read_offset(*offset, ret); | |
b3967067 JC |
1034 | return ret; |
1035 | } | |
6610e089 | 1036 | |
b3967067 JC |
1037 | /** |
1038 | * rtc_set_offset - Adjusts the duration of the average second | |
1039 | * @ rtc: rtc device to be used | |
1040 | * @ offset: the offset in parts per billion | |
1041 | * | |
1042 | * Some rtc's allow an adjustment to the average duration of a second | |
1043 | * to compensate for differences in the actual clock rate due to temperature, | |
1044 | * the crystal, capacitor, etc. | |
1045 | * | |
8a25c8f6 RK |
1046 | * The adjustment applied is as follows: |
1047 | * t = t0 * (1 + offset * 1e-9) | |
1048 | * where t0 is the measured length of 1 RTC second with offset = 0 | |
1049 | * | |
b3967067 JC |
1050 | * Kernel interface to adjust an rtc clock offset. |
1051 | * Return 0 on success, or a negative number on error. | |
1052 | * If the rtc offset is not setable (or not implemented), return -EINVAL | |
1053 | */ | |
1054 | int rtc_set_offset(struct rtc_device *rtc, long offset) | |
1055 | { | |
1056 | int ret; | |
1057 | ||
1058 | if (!rtc->ops) | |
1059 | return -ENODEV; | |
1060 | ||
1061 | if (!rtc->ops->set_offset) | |
1062 | return -EINVAL; | |
1063 | ||
1064 | mutex_lock(&rtc->ops_lock); | |
1065 | ret = rtc->ops->set_offset(rtc->dev.parent, offset); | |
1066 | mutex_unlock(&rtc->ops_lock); | |
29a1f599 BW |
1067 | |
1068 | trace_rtc_set_offset(offset, ret); | |
b3967067 JC |
1069 | return ret; |
1070 | } |