2 * RTC subsystem, interface functions
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 * based on arch/arm/common/rtctime.c
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.
14 #include <linux/rtc.h>
15 #include <linux/sched.h>
16 #include <linux/log2.h>
18 int rtc_read_time(struct rtc_device
*rtc
, struct rtc_time
*tm
)
22 err
= mutex_lock_interruptible(&rtc
->ops_lock
);
28 else if (!rtc
->ops
->read_time
)
31 memset(tm
, 0, sizeof(struct rtc_time
));
32 err
= rtc
->ops
->read_time(rtc
->dev
.parent
, tm
);
35 mutex_unlock(&rtc
->ops_lock
);
38 EXPORT_SYMBOL_GPL(rtc_read_time
);
40 int rtc_set_time(struct rtc_device
*rtc
, struct rtc_time
*tm
)
44 err
= rtc_valid_tm(tm
);
48 err
= mutex_lock_interruptible(&rtc
->ops_lock
);
54 else if (rtc
->ops
->set_time
)
55 err
= rtc
->ops
->set_time(rtc
->dev
.parent
, tm
);
56 else if (rtc
->ops
->set_mmss
) {
58 err
= rtc_tm_to_time(tm
, &secs
);
60 err
= rtc
->ops
->set_mmss(rtc
->dev
.parent
, secs
);
64 mutex_unlock(&rtc
->ops_lock
);
67 EXPORT_SYMBOL_GPL(rtc_set_time
);
69 int rtc_set_mmss(struct rtc_device
*rtc
, unsigned long secs
)
73 err
= mutex_lock_interruptible(&rtc
->ops_lock
);
79 else if (rtc
->ops
->set_mmss
)
80 err
= rtc
->ops
->set_mmss(rtc
->dev
.parent
, secs
);
81 else if (rtc
->ops
->read_time
&& rtc
->ops
->set_time
) {
82 struct rtc_time
new, old
;
84 err
= rtc
->ops
->read_time(rtc
->dev
.parent
, &old
);
86 rtc_time_to_tm(secs
, &new);
89 * avoid writing when we're going to change the day of
90 * the month. We will retry in the next minute. This
91 * basically means that if the RTC must not drift
92 * by more than 1 minute in 11 minutes.
94 if (!((old
.tm_hour
== 23 && old
.tm_min
== 59) ||
95 (new.tm_hour
== 23 && new.tm_min
== 59)))
96 err
= rtc
->ops
->set_time(rtc
->dev
.parent
,
103 mutex_unlock(&rtc
->ops_lock
);
107 EXPORT_SYMBOL_GPL(rtc_set_mmss
);
109 static int rtc_read_alarm_internal(struct rtc_device
*rtc
, struct rtc_wkalrm
*alarm
)
113 err
= mutex_lock_interruptible(&rtc
->ops_lock
);
117 if (rtc
->ops
== NULL
)
119 else if (!rtc
->ops
->read_alarm
)
122 memset(alarm
, 0, sizeof(struct rtc_wkalrm
));
123 err
= rtc
->ops
->read_alarm(rtc
->dev
.parent
, alarm
);
126 mutex_unlock(&rtc
->ops_lock
);
130 int rtc_read_alarm(struct rtc_device
*rtc
, struct rtc_wkalrm
*alarm
)
133 struct rtc_time before
, now
;
135 unsigned long t_now
, t_alm
;
136 enum { none
, day
, month
, year
} missing
= none
;
139 /* The lower level RTC driver may return -1 in some fields,
140 * creating invalid alarm->time values, for reasons like:
142 * - The hardware may not be capable of filling them in;
143 * many alarms match only on time-of-day fields, not
144 * day/month/year calendar data.
146 * - Some hardware uses illegal values as "wildcard" match
147 * values, which non-Linux firmware (like a BIOS) may try
148 * to set up as e.g. "alarm 15 minutes after each hour".
149 * Linux uses only oneshot alarms.
151 * When we see that here, we deal with it by using values from
152 * a current RTC timestamp for any missing (-1) values. The
153 * RTC driver prevents "periodic alarm" modes.
155 * But this can be racey, because some fields of the RTC timestamp
156 * may have wrapped in the interval since we read the RTC alarm,
157 * which would lead to us inserting inconsistent values in place
160 * Reading the alarm and timestamp in the reverse sequence
161 * would have the same race condition, and not solve the issue.
163 * So, we must first read the RTC timestamp,
164 * then read the RTC alarm value,
165 * and then read a second RTC timestamp.
167 * If any fields of the second timestamp have changed
168 * when compared with the first timestamp, then we know
169 * our timestamp may be inconsistent with that used by
170 * the low-level rtc_read_alarm_internal() function.
172 * So, when the two timestamps disagree, we just loop and do
173 * the process again to get a fully consistent set of values.
175 * This could all instead be done in the lower level driver,
176 * but since more than one lower level RTC implementation needs it,
177 * then it's probably best best to do it here instead of there..
180 /* Get the "before" timestamp */
181 err
= rtc_read_time(rtc
, &before
);
186 memcpy(&before
, &now
, sizeof(struct rtc_time
));
189 /* get the RTC alarm values, which may be incomplete */
190 err
= rtc_read_alarm_internal(rtc
, alarm
);
196 /* full-function RTCs won't have such missing fields */
197 if (rtc_valid_tm(&alarm
->time
) == 0)
200 /* get the "after" timestamp, to detect wrapped fields */
201 err
= rtc_read_time(rtc
, &now
);
205 /* note that tm_sec is a "don't care" value here: */
206 } while ( before
.tm_min
!= now
.tm_min
207 || before
.tm_hour
!= now
.tm_hour
208 || before
.tm_mon
!= now
.tm_mon
209 || before
.tm_year
!= now
.tm_year
);
211 /* Fill in the missing alarm fields using the timestamp; we
212 * know there's at least one since alarm->time is invalid.
214 if (alarm
->time
.tm_sec
== -1)
215 alarm
->time
.tm_sec
= now
.tm_sec
;
216 if (alarm
->time
.tm_min
== -1)
217 alarm
->time
.tm_min
= now
.tm_min
;
218 if (alarm
->time
.tm_hour
== -1)
219 alarm
->time
.tm_hour
= now
.tm_hour
;
221 /* For simplicity, only support date rollover for now */
222 if (alarm
->time
.tm_mday
== -1) {
223 alarm
->time
.tm_mday
= now
.tm_mday
;
226 if (alarm
->time
.tm_mon
== -1) {
227 alarm
->time
.tm_mon
= now
.tm_mon
;
231 if (alarm
->time
.tm_year
== -1) {
232 alarm
->time
.tm_year
= now
.tm_year
;
237 /* with luck, no rollover is needed */
238 rtc_tm_to_time(&now
, &t_now
);
239 rtc_tm_to_time(&alarm
->time
, &t_alm
);
245 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
246 * that will trigger at 5am will do so at 5am Tuesday, which
247 * could also be in the next month or year. This is a common
248 * case, especially for PCs.
251 dev_dbg(&rtc
->dev
, "alarm rollover: %s\n", "day");
252 t_alm
+= 24 * 60 * 60;
253 rtc_time_to_tm(t_alm
, &alarm
->time
);
256 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
257 * be next month. An alarm matching on the 30th, 29th, or 28th
258 * may end up in the month after that! Many newer PCs support
259 * this type of alarm.
262 dev_dbg(&rtc
->dev
, "alarm rollover: %s\n", "month");
264 if (alarm
->time
.tm_mon
< 11)
265 alarm
->time
.tm_mon
++;
267 alarm
->time
.tm_mon
= 0;
268 alarm
->time
.tm_year
++;
270 days
= rtc_month_days(alarm
->time
.tm_mon
,
271 alarm
->time
.tm_year
);
272 } while (days
< alarm
->time
.tm_mday
);
275 /* Year rollover ... easy except for leap years! */
277 dev_dbg(&rtc
->dev
, "alarm rollover: %s\n", "year");
279 alarm
->time
.tm_year
++;
280 } while (rtc_valid_tm(&alarm
->time
) != 0);
284 dev_warn(&rtc
->dev
, "alarm rollover not handled\n");
290 EXPORT_SYMBOL_GPL(rtc_read_alarm
);
292 int rtc_set_alarm(struct rtc_device
*rtc
, struct rtc_wkalrm
*alarm
)
296 err
= rtc_valid_tm(&alarm
->time
);
300 err
= mutex_lock_interruptible(&rtc
->ops_lock
);
306 else if (!rtc
->ops
->set_alarm
)
309 err
= rtc
->ops
->set_alarm(rtc
->dev
.parent
, alarm
);
311 mutex_unlock(&rtc
->ops_lock
);
314 EXPORT_SYMBOL_GPL(rtc_set_alarm
);
316 int rtc_alarm_irq_enable(struct rtc_device
*rtc
, unsigned int enabled
)
318 int err
= mutex_lock_interruptible(&rtc
->ops_lock
);
324 else if (!rtc
->ops
->alarm_irq_enable
)
327 err
= rtc
->ops
->alarm_irq_enable(rtc
->dev
.parent
, enabled
);
329 mutex_unlock(&rtc
->ops_lock
);
332 EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable
);
334 int rtc_update_irq_enable(struct rtc_device
*rtc
, unsigned int enabled
)
336 int err
= mutex_lock_interruptible(&rtc
->ops_lock
);
340 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
341 if (enabled
== 0 && rtc
->uie_irq_active
) {
342 mutex_unlock(&rtc
->ops_lock
);
343 return rtc_dev_update_irq_enable_emul(rtc
, enabled
);
349 else if (!rtc
->ops
->update_irq_enable
)
352 err
= rtc
->ops
->update_irq_enable(rtc
->dev
.parent
, enabled
);
354 mutex_unlock(&rtc
->ops_lock
);
356 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
358 * Enable emulation if the driver did not provide
359 * the update_irq_enable function pointer or if returned
360 * -EINVAL to signal that it has been configured without
361 * interrupts or that are not available at the moment.
364 err
= rtc_dev_update_irq_enable_emul(rtc
, enabled
);
368 EXPORT_SYMBOL_GPL(rtc_update_irq_enable
);
371 * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
372 * @rtc: the rtc device
373 * @num: how many irqs are being reported (usually one)
374 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
377 void rtc_update_irq(struct rtc_device
*rtc
,
378 unsigned long num
, unsigned long events
)
382 spin_lock_irqsave(&rtc
->irq_lock
, flags
);
383 rtc
->irq_data
= (rtc
->irq_data
+ (num
<< 8)) | events
;
384 spin_unlock_irqrestore(&rtc
->irq_lock
, flags
);
386 spin_lock_irqsave(&rtc
->irq_task_lock
, flags
);
388 rtc
->irq_task
->func(rtc
->irq_task
->private_data
);
389 spin_unlock_irqrestore(&rtc
->irq_task_lock
, flags
);
391 wake_up_interruptible(&rtc
->irq_queue
);
392 kill_fasync(&rtc
->async_queue
, SIGIO
, POLL_IN
);
394 EXPORT_SYMBOL_GPL(rtc_update_irq
);
396 static int __rtc_match(struct device
*dev
, void *data
)
398 char *name
= (char *)data
;
400 if (strcmp(dev_name(dev
), name
) == 0)
405 struct rtc_device
*rtc_class_open(char *name
)
408 struct rtc_device
*rtc
= NULL
;
410 dev
= class_find_device(rtc_class
, NULL
, name
, __rtc_match
);
412 rtc
= to_rtc_device(dev
);
415 if (!try_module_get(rtc
->owner
)) {
423 EXPORT_SYMBOL_GPL(rtc_class_open
);
425 void rtc_class_close(struct rtc_device
*rtc
)
427 module_put(rtc
->owner
);
428 put_device(&rtc
->dev
);
430 EXPORT_SYMBOL_GPL(rtc_class_close
);
432 int rtc_irq_register(struct rtc_device
*rtc
, struct rtc_task
*task
)
436 if (task
== NULL
|| task
->func
== NULL
)
439 /* Cannot register while the char dev is in use */
440 if (test_and_set_bit_lock(RTC_DEV_BUSY
, &rtc
->flags
))
443 spin_lock_irq(&rtc
->irq_task_lock
);
444 if (rtc
->irq_task
== NULL
) {
445 rtc
->irq_task
= task
;
448 spin_unlock_irq(&rtc
->irq_task_lock
);
450 clear_bit_unlock(RTC_DEV_BUSY
, &rtc
->flags
);
454 EXPORT_SYMBOL_GPL(rtc_irq_register
);
456 void rtc_irq_unregister(struct rtc_device
*rtc
, struct rtc_task
*task
)
458 spin_lock_irq(&rtc
->irq_task_lock
);
459 if (rtc
->irq_task
== task
)
460 rtc
->irq_task
= NULL
;
461 spin_unlock_irq(&rtc
->irq_task_lock
);
463 EXPORT_SYMBOL_GPL(rtc_irq_unregister
);
466 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
467 * @rtc: the rtc device
468 * @task: currently registered with rtc_irq_register()
469 * @enabled: true to enable periodic IRQs
472 * Note that rtc_irq_set_freq() should previously have been used to
473 * specify the desired frequency of periodic IRQ task->func() callbacks.
475 int rtc_irq_set_state(struct rtc_device
*rtc
, struct rtc_task
*task
, int enabled
)
480 if (rtc
->ops
->irq_set_state
== NULL
)
483 spin_lock_irqsave(&rtc
->irq_task_lock
, flags
);
484 if (rtc
->irq_task
!= NULL
&& task
== NULL
)
486 if (rtc
->irq_task
!= task
)
488 spin_unlock_irqrestore(&rtc
->irq_task_lock
, flags
);
491 err
= rtc
->ops
->irq_set_state(rtc
->dev
.parent
, enabled
);
495 EXPORT_SYMBOL_GPL(rtc_irq_set_state
);
498 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
499 * @rtc: the rtc device
500 * @task: currently registered with rtc_irq_register()
501 * @freq: positive frequency with which task->func() will be called
504 * Note that rtc_irq_set_state() is used to enable or disable the
507 int rtc_irq_set_freq(struct rtc_device
*rtc
, struct rtc_task
*task
, int freq
)
512 if (rtc
->ops
->irq_set_freq
== NULL
)
515 spin_lock_irqsave(&rtc
->irq_task_lock
, flags
);
516 if (rtc
->irq_task
!= NULL
&& task
== NULL
)
518 if (rtc
->irq_task
!= task
)
520 spin_unlock_irqrestore(&rtc
->irq_task_lock
, flags
);
523 err
= rtc
->ops
->irq_set_freq(rtc
->dev
.parent
, freq
);
525 rtc
->irq_freq
= freq
;
529 EXPORT_SYMBOL_GPL(rtc_irq_set_freq
);
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