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Commit | Line | Data |
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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> | |
97144c67 | 15 | #include <linux/log2.h> |
0c86edc0 | 16 | |
ab6a2d70 | 17 | int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) |
0c86edc0 AZ |
18 | { |
19 | int err; | |
0c86edc0 AZ |
20 | |
21 | err = mutex_lock_interruptible(&rtc->ops_lock); | |
22 | if (err) | |
b68bb263 | 23 | return err; |
0c86edc0 AZ |
24 | |
25 | if (!rtc->ops) | |
26 | err = -ENODEV; | |
27 | else if (!rtc->ops->read_time) | |
28 | err = -EINVAL; | |
29 | else { | |
30 | memset(tm, 0, sizeof(struct rtc_time)); | |
cd966209 | 31 | err = rtc->ops->read_time(rtc->dev.parent, tm); |
0c86edc0 AZ |
32 | } |
33 | ||
34 | mutex_unlock(&rtc->ops_lock); | |
35 | return err; | |
36 | } | |
37 | EXPORT_SYMBOL_GPL(rtc_read_time); | |
38 | ||
ab6a2d70 | 39 | int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) |
0c86edc0 AZ |
40 | { |
41 | int err; | |
0c86edc0 AZ |
42 | |
43 | err = rtc_valid_tm(tm); | |
44 | if (err != 0) | |
45 | return err; | |
46 | ||
47 | err = mutex_lock_interruptible(&rtc->ops_lock); | |
48 | if (err) | |
b68bb263 | 49 | return err; |
0c86edc0 AZ |
50 | |
51 | if (!rtc->ops) | |
52 | err = -ENODEV; | |
53 | else if (!rtc->ops->set_time) | |
54 | err = -EINVAL; | |
55 | else | |
cd966209 | 56 | err = rtc->ops->set_time(rtc->dev.parent, tm); |
0c86edc0 AZ |
57 | |
58 | mutex_unlock(&rtc->ops_lock); | |
59 | return err; | |
60 | } | |
61 | EXPORT_SYMBOL_GPL(rtc_set_time); | |
62 | ||
ab6a2d70 | 63 | int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) |
0c86edc0 AZ |
64 | { |
65 | int err; | |
0c86edc0 AZ |
66 | |
67 | err = mutex_lock_interruptible(&rtc->ops_lock); | |
68 | if (err) | |
b68bb263 | 69 | return err; |
0c86edc0 AZ |
70 | |
71 | if (!rtc->ops) | |
72 | err = -ENODEV; | |
73 | else if (rtc->ops->set_mmss) | |
cd966209 | 74 | err = rtc->ops->set_mmss(rtc->dev.parent, secs); |
0c86edc0 AZ |
75 | else if (rtc->ops->read_time && rtc->ops->set_time) { |
76 | struct rtc_time new, old; | |
77 | ||
cd966209 | 78 | err = rtc->ops->read_time(rtc->dev.parent, &old); |
0c86edc0 AZ |
79 | if (err == 0) { |
80 | rtc_time_to_tm(secs, &new); | |
81 | ||
82 | /* | |
83 | * avoid writing when we're going to change the day of | |
84 | * the month. We will retry in the next minute. This | |
85 | * basically means that if the RTC must not drift | |
86 | * by more than 1 minute in 11 minutes. | |
87 | */ | |
88 | if (!((old.tm_hour == 23 && old.tm_min == 59) || | |
89 | (new.tm_hour == 23 && new.tm_min == 59))) | |
cd966209 | 90 | err = rtc->ops->set_time(rtc->dev.parent, |
ab6a2d70 | 91 | &new); |
0c86edc0 AZ |
92 | } |
93 | } | |
94 | else | |
95 | err = -EINVAL; | |
96 | ||
97 | mutex_unlock(&rtc->ops_lock); | |
98 | ||
99 | return err; | |
100 | } | |
101 | EXPORT_SYMBOL_GPL(rtc_set_mmss); | |
102 | ||
0e36a9a4 | 103 | static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
0c86edc0 AZ |
104 | { |
105 | int err; | |
0c86edc0 AZ |
106 | |
107 | err = mutex_lock_interruptible(&rtc->ops_lock); | |
108 | if (err) | |
b68bb263 | 109 | return err; |
0c86edc0 AZ |
110 | |
111 | if (rtc->ops == NULL) | |
112 | err = -ENODEV; | |
113 | else if (!rtc->ops->read_alarm) | |
114 | err = -EINVAL; | |
115 | else { | |
116 | memset(alarm, 0, sizeof(struct rtc_wkalrm)); | |
cd966209 | 117 | err = rtc->ops->read_alarm(rtc->dev.parent, alarm); |
0c86edc0 AZ |
118 | } |
119 | ||
120 | mutex_unlock(&rtc->ops_lock); | |
121 | return err; | |
122 | } | |
0e36a9a4 ML |
123 | |
124 | int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) | |
125 | { | |
126 | int err; | |
127 | struct rtc_time before, now; | |
128 | int first_time = 1; | |
a01cc657 DB |
129 | unsigned long t_now, t_alm; |
130 | enum { none, day, month, year } missing = none; | |
131 | unsigned days; | |
0e36a9a4 | 132 | |
a01cc657 DB |
133 | /* The lower level RTC driver may return -1 in some fields, |
134 | * creating invalid alarm->time values, for reasons like: | |
135 | * | |
136 | * - The hardware may not be capable of filling them in; | |
137 | * many alarms match only on time-of-day fields, not | |
138 | * day/month/year calendar data. | |
139 | * | |
140 | * - Some hardware uses illegal values as "wildcard" match | |
141 | * values, which non-Linux firmware (like a BIOS) may try | |
142 | * to set up as e.g. "alarm 15 minutes after each hour". | |
143 | * Linux uses only oneshot alarms. | |
144 | * | |
145 | * When we see that here, we deal with it by using values from | |
146 | * a current RTC timestamp for any missing (-1) values. The | |
147 | * RTC driver prevents "periodic alarm" modes. | |
0e36a9a4 ML |
148 | * |
149 | * But this can be racey, because some fields of the RTC timestamp | |
150 | * may have wrapped in the interval since we read the RTC alarm, | |
151 | * which would lead to us inserting inconsistent values in place | |
152 | * of the -1 fields. | |
153 | * | |
154 | * Reading the alarm and timestamp in the reverse sequence | |
155 | * would have the same race condition, and not solve the issue. | |
156 | * | |
157 | * So, we must first read the RTC timestamp, | |
158 | * then read the RTC alarm value, | |
159 | * and then read a second RTC timestamp. | |
160 | * | |
161 | * If any fields of the second timestamp have changed | |
162 | * when compared with the first timestamp, then we know | |
163 | * our timestamp may be inconsistent with that used by | |
164 | * the low-level rtc_read_alarm_internal() function. | |
165 | * | |
166 | * So, when the two timestamps disagree, we just loop and do | |
167 | * the process again to get a fully consistent set of values. | |
168 | * | |
169 | * This could all instead be done in the lower level driver, | |
170 | * but since more than one lower level RTC implementation needs it, | |
171 | * then it's probably best best to do it here instead of there.. | |
172 | */ | |
173 | ||
174 | /* Get the "before" timestamp */ | |
175 | err = rtc_read_time(rtc, &before); | |
176 | if (err < 0) | |
177 | return err; | |
178 | do { | |
179 | if (!first_time) | |
180 | memcpy(&before, &now, sizeof(struct rtc_time)); | |
181 | first_time = 0; | |
182 | ||
183 | /* get the RTC alarm values, which may be incomplete */ | |
184 | err = rtc_read_alarm_internal(rtc, alarm); | |
185 | if (err) | |
186 | return err; | |
187 | if (!alarm->enabled) | |
188 | return 0; | |
189 | ||
a01cc657 DB |
190 | /* full-function RTCs won't have such missing fields */ |
191 | if (rtc_valid_tm(&alarm->time) == 0) | |
192 | return 0; | |
193 | ||
0e36a9a4 ML |
194 | /* get the "after" timestamp, to detect wrapped fields */ |
195 | err = rtc_read_time(rtc, &now); | |
196 | if (err < 0) | |
197 | return err; | |
198 | ||
199 | /* note that tm_sec is a "don't care" value here: */ | |
200 | } while ( before.tm_min != now.tm_min | |
201 | || before.tm_hour != now.tm_hour | |
202 | || before.tm_mon != now.tm_mon | |
a01cc657 | 203 | || before.tm_year != now.tm_year); |
0e36a9a4 | 204 | |
a01cc657 DB |
205 | /* Fill in the missing alarm fields using the timestamp; we |
206 | * know there's at least one since alarm->time is invalid. | |
207 | */ | |
0e36a9a4 ML |
208 | if (alarm->time.tm_sec == -1) |
209 | alarm->time.tm_sec = now.tm_sec; | |
210 | if (alarm->time.tm_min == -1) | |
211 | alarm->time.tm_min = now.tm_min; | |
212 | if (alarm->time.tm_hour == -1) | |
213 | alarm->time.tm_hour = now.tm_hour; | |
a01cc657 DB |
214 | |
215 | /* For simplicity, only support date rollover for now */ | |
216 | if (alarm->time.tm_mday == -1) { | |
0e36a9a4 | 217 | alarm->time.tm_mday = now.tm_mday; |
a01cc657 DB |
218 | missing = day; |
219 | } | |
220 | if (alarm->time.tm_mon == -1) { | |
0e36a9a4 | 221 | alarm->time.tm_mon = now.tm_mon; |
a01cc657 DB |
222 | if (missing == none) |
223 | missing = month; | |
224 | } | |
225 | if (alarm->time.tm_year == -1) { | |
0e36a9a4 | 226 | alarm->time.tm_year = now.tm_year; |
a01cc657 DB |
227 | if (missing == none) |
228 | missing = year; | |
229 | } | |
230 | ||
231 | /* with luck, no rollover is needed */ | |
232 | rtc_tm_to_time(&now, &t_now); | |
233 | rtc_tm_to_time(&alarm->time, &t_alm); | |
234 | if (t_now < t_alm) | |
235 | goto done; | |
236 | ||
237 | switch (missing) { | |
238 | ||
239 | /* 24 hour rollover ... if it's now 10am Monday, an alarm that | |
240 | * that will trigger at 5am will do so at 5am Tuesday, which | |
241 | * could also be in the next month or year. This is a common | |
242 | * case, especially for PCs. | |
243 | */ | |
244 | case day: | |
245 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); | |
246 | t_alm += 24 * 60 * 60; | |
247 | rtc_time_to_tm(t_alm, &alarm->time); | |
248 | break; | |
249 | ||
250 | /* Month rollover ... if it's the 31th, an alarm on the 3rd will | |
251 | * be next month. An alarm matching on the 30th, 29th, or 28th | |
252 | * may end up in the month after that! Many newer PCs support | |
253 | * this type of alarm. | |
254 | */ | |
255 | case month: | |
256 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); | |
257 | do { | |
258 | if (alarm->time.tm_mon < 11) | |
259 | alarm->time.tm_mon++; | |
260 | else { | |
261 | alarm->time.tm_mon = 0; | |
262 | alarm->time.tm_year++; | |
263 | } | |
264 | days = rtc_month_days(alarm->time.tm_mon, | |
265 | alarm->time.tm_year); | |
266 | } while (days < alarm->time.tm_mday); | |
267 | break; | |
268 | ||
269 | /* Year rollover ... easy except for leap years! */ | |
270 | case year: | |
271 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); | |
272 | do { | |
273 | alarm->time.tm_year++; | |
9e3a4afd | 274 | } while (rtc_valid_tm(&alarm->time) != 0); |
a01cc657 DB |
275 | break; |
276 | ||
277 | default: | |
278 | dev_warn(&rtc->dev, "alarm rollover not handled\n"); | |
279 | } | |
280 | ||
281 | done: | |
0e36a9a4 ML |
282 | return 0; |
283 | } | |
0c86edc0 AZ |
284 | EXPORT_SYMBOL_GPL(rtc_read_alarm); |
285 | ||
ab6a2d70 | 286 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
0c86edc0 AZ |
287 | { |
288 | int err; | |
0c86edc0 | 289 | |
f8245c26 DB |
290 | err = rtc_valid_tm(&alarm->time); |
291 | if (err != 0) | |
292 | return err; | |
293 | ||
0c86edc0 AZ |
294 | err = mutex_lock_interruptible(&rtc->ops_lock); |
295 | if (err) | |
b68bb263 | 296 | return err; |
0c86edc0 AZ |
297 | |
298 | if (!rtc->ops) | |
299 | err = -ENODEV; | |
300 | else if (!rtc->ops->set_alarm) | |
301 | err = -EINVAL; | |
302 | else | |
cd966209 | 303 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm); |
0c86edc0 AZ |
304 | |
305 | mutex_unlock(&rtc->ops_lock); | |
306 | return err; | |
307 | } | |
308 | EXPORT_SYMBOL_GPL(rtc_set_alarm); | |
309 | ||
d728b1e6 DB |
310 | /** |
311 | * rtc_update_irq - report RTC periodic, alarm, and/or update irqs | |
ab6a2d70 | 312 | * @rtc: the rtc device |
d728b1e6 DB |
313 | * @num: how many irqs are being reported (usually one) |
314 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF | |
315 | * Context: in_interrupt(), irqs blocked | |
316 | */ | |
ab6a2d70 | 317 | void rtc_update_irq(struct rtc_device *rtc, |
0c86edc0 AZ |
318 | unsigned long num, unsigned long events) |
319 | { | |
0c86edc0 AZ |
320 | spin_lock(&rtc->irq_lock); |
321 | rtc->irq_data = (rtc->irq_data + (num << 8)) | events; | |
322 | spin_unlock(&rtc->irq_lock); | |
323 | ||
324 | spin_lock(&rtc->irq_task_lock); | |
325 | if (rtc->irq_task) | |
326 | rtc->irq_task->func(rtc->irq_task->private_data); | |
327 | spin_unlock(&rtc->irq_task_lock); | |
328 | ||
329 | wake_up_interruptible(&rtc->irq_queue); | |
330 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); | |
331 | } | |
332 | EXPORT_SYMBOL_GPL(rtc_update_irq); | |
333 | ||
71da8905 DY |
334 | static int __rtc_match(struct device *dev, void *data) |
335 | { | |
336 | char *name = (char *)data; | |
337 | ||
338 | if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0) | |
339 | return 1; | |
340 | return 0; | |
341 | } | |
342 | ||
ab6a2d70 | 343 | struct rtc_device *rtc_class_open(char *name) |
0c86edc0 | 344 | { |
cd966209 | 345 | struct device *dev; |
ab6a2d70 | 346 | struct rtc_device *rtc = NULL; |
0c86edc0 | 347 | |
695794ae | 348 | dev = class_find_device(rtc_class, NULL, name, __rtc_match); |
71da8905 DY |
349 | if (dev) |
350 | rtc = to_rtc_device(dev); | |
0c86edc0 | 351 | |
ab6a2d70 DB |
352 | if (rtc) { |
353 | if (!try_module_get(rtc->owner)) { | |
cd966209 | 354 | put_device(dev); |
ab6a2d70 DB |
355 | rtc = NULL; |
356 | } | |
0c86edc0 | 357 | } |
0c86edc0 | 358 | |
ab6a2d70 | 359 | return rtc; |
0c86edc0 AZ |
360 | } |
361 | EXPORT_SYMBOL_GPL(rtc_class_open); | |
362 | ||
ab6a2d70 | 363 | void rtc_class_close(struct rtc_device *rtc) |
0c86edc0 | 364 | { |
ab6a2d70 | 365 | module_put(rtc->owner); |
cd966209 | 366 | put_device(&rtc->dev); |
0c86edc0 AZ |
367 | } |
368 | EXPORT_SYMBOL_GPL(rtc_class_close); | |
369 | ||
ab6a2d70 | 370 | int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) |
0c86edc0 AZ |
371 | { |
372 | int retval = -EBUSY; | |
0c86edc0 AZ |
373 | |
374 | if (task == NULL || task->func == NULL) | |
375 | return -EINVAL; | |
376 | ||
d691eb90 | 377 | /* Cannot register while the char dev is in use */ |
372a302e | 378 | if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) |
d691eb90 AZ |
379 | return -EBUSY; |
380 | ||
d728b1e6 | 381 | spin_lock_irq(&rtc->irq_task_lock); |
0c86edc0 AZ |
382 | if (rtc->irq_task == NULL) { |
383 | rtc->irq_task = task; | |
384 | retval = 0; | |
385 | } | |
d728b1e6 | 386 | spin_unlock_irq(&rtc->irq_task_lock); |
0c86edc0 | 387 | |
372a302e | 388 | clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); |
d691eb90 | 389 | |
0c86edc0 AZ |
390 | return retval; |
391 | } | |
392 | EXPORT_SYMBOL_GPL(rtc_irq_register); | |
393 | ||
ab6a2d70 | 394 | void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) |
0c86edc0 | 395 | { |
d728b1e6 | 396 | spin_lock_irq(&rtc->irq_task_lock); |
0c86edc0 AZ |
397 | if (rtc->irq_task == task) |
398 | rtc->irq_task = NULL; | |
d728b1e6 | 399 | spin_unlock_irq(&rtc->irq_task_lock); |
0c86edc0 AZ |
400 | } |
401 | EXPORT_SYMBOL_GPL(rtc_irq_unregister); | |
402 | ||
97144c67 DB |
403 | /** |
404 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs | |
405 | * @rtc: the rtc device | |
406 | * @task: currently registered with rtc_irq_register() | |
407 | * @enabled: true to enable periodic IRQs | |
408 | * Context: any | |
409 | * | |
410 | * Note that rtc_irq_set_freq() should previously have been used to | |
411 | * specify the desired frequency of periodic IRQ task->func() callbacks. | |
412 | */ | |
ab6a2d70 | 413 | int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) |
0c86edc0 AZ |
414 | { |
415 | int err = 0; | |
416 | unsigned long flags; | |
0c86edc0 | 417 | |
56f10c63 AZ |
418 | if (rtc->ops->irq_set_state == NULL) |
419 | return -ENXIO; | |
420 | ||
0c86edc0 | 421 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
d691eb90 AZ |
422 | if (rtc->irq_task != NULL && task == NULL) |
423 | err = -EBUSY; | |
0c86edc0 | 424 | if (rtc->irq_task != task) |
d691eb90 | 425 | err = -EACCES; |
0c86edc0 AZ |
426 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
427 | ||
428 | if (err == 0) | |
cd966209 | 429 | err = rtc->ops->irq_set_state(rtc->dev.parent, enabled); |
0c86edc0 AZ |
430 | |
431 | return err; | |
432 | } | |
433 | EXPORT_SYMBOL_GPL(rtc_irq_set_state); | |
434 | ||
97144c67 DB |
435 | /** |
436 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ | |
437 | * @rtc: the rtc device | |
438 | * @task: currently registered with rtc_irq_register() | |
439 | * @freq: positive frequency with which task->func() will be called | |
440 | * Context: any | |
441 | * | |
442 | * Note that rtc_irq_set_state() is used to enable or disable the | |
443 | * periodic IRQs. | |
444 | */ | |
ab6a2d70 | 445 | int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) |
0c86edc0 | 446 | { |
56f10c63 | 447 | int err = 0; |
0c86edc0 | 448 | unsigned long flags; |
0c86edc0 | 449 | |
56f10c63 AZ |
450 | if (rtc->ops->irq_set_freq == NULL) |
451 | return -ENXIO; | |
0c86edc0 | 452 | |
97144c67 DB |
453 | if (!is_power_of_2(freq)) |
454 | return -EINVAL; | |
455 | ||
0c86edc0 | 456 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
d691eb90 AZ |
457 | if (rtc->irq_task != NULL && task == NULL) |
458 | err = -EBUSY; | |
0c86edc0 | 459 | if (rtc->irq_task != task) |
d691eb90 | 460 | err = -EACCES; |
0c86edc0 AZ |
461 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
462 | ||
463 | if (err == 0) { | |
cd966209 | 464 | err = rtc->ops->irq_set_freq(rtc->dev.parent, freq); |
0c86edc0 AZ |
465 | if (err == 0) |
466 | rtc->irq_freq = freq; | |
467 | } | |
468 | return err; | |
469 | } | |
2601a464 | 470 | EXPORT_SYMBOL_GPL(rtc_irq_set_freq); |