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) | |
23 | return -EBUSY; | |
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) | |
49 | return -EBUSY; | |
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) | |
69 | return -EBUSY; | |
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) | |
109 | return -EBUSY; | |
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; | |
129 | ||
130 | /* The lower level RTC driver may not be capable of filling | |
131 | * in all fields of the rtc_time struct (eg. rtc-cmos), | |
132 | * and so might instead return -1 in some fields. | |
133 | * We deal with that here by grabbing a current RTC timestamp | |
134 | * and using values from that for any missing (-1) values. | |
135 | * | |
136 | * But this can be racey, because some fields of the RTC timestamp | |
137 | * may have wrapped in the interval since we read the RTC alarm, | |
138 | * which would lead to us inserting inconsistent values in place | |
139 | * of the -1 fields. | |
140 | * | |
141 | * Reading the alarm and timestamp in the reverse sequence | |
142 | * would have the same race condition, and not solve the issue. | |
143 | * | |
144 | * So, we must first read the RTC timestamp, | |
145 | * then read the RTC alarm value, | |
146 | * and then read a second RTC timestamp. | |
147 | * | |
148 | * If any fields of the second timestamp have changed | |
149 | * when compared with the first timestamp, then we know | |
150 | * our timestamp may be inconsistent with that used by | |
151 | * the low-level rtc_read_alarm_internal() function. | |
152 | * | |
153 | * So, when the two timestamps disagree, we just loop and do | |
154 | * the process again to get a fully consistent set of values. | |
155 | * | |
156 | * This could all instead be done in the lower level driver, | |
157 | * but since more than one lower level RTC implementation needs it, | |
158 | * then it's probably best best to do it here instead of there.. | |
159 | */ | |
160 | ||
161 | /* Get the "before" timestamp */ | |
162 | err = rtc_read_time(rtc, &before); | |
163 | if (err < 0) | |
164 | return err; | |
165 | do { | |
166 | if (!first_time) | |
167 | memcpy(&before, &now, sizeof(struct rtc_time)); | |
168 | first_time = 0; | |
169 | ||
170 | /* get the RTC alarm values, which may be incomplete */ | |
171 | err = rtc_read_alarm_internal(rtc, alarm); | |
172 | if (err) | |
173 | return err; | |
174 | if (!alarm->enabled) | |
175 | return 0; | |
176 | ||
177 | /* get the "after" timestamp, to detect wrapped fields */ | |
178 | err = rtc_read_time(rtc, &now); | |
179 | if (err < 0) | |
180 | return err; | |
181 | ||
182 | /* note that tm_sec is a "don't care" value here: */ | |
183 | } while ( before.tm_min != now.tm_min | |
184 | || before.tm_hour != now.tm_hour | |
185 | || before.tm_mon != now.tm_mon | |
186 | || before.tm_year != now.tm_year | |
187 | || before.tm_isdst != now.tm_isdst); | |
188 | ||
189 | /* Fill in any missing alarm fields using the timestamp */ | |
190 | if (alarm->time.tm_sec == -1) | |
191 | alarm->time.tm_sec = now.tm_sec; | |
192 | if (alarm->time.tm_min == -1) | |
193 | alarm->time.tm_min = now.tm_min; | |
194 | if (alarm->time.tm_hour == -1) | |
195 | alarm->time.tm_hour = now.tm_hour; | |
196 | if (alarm->time.tm_mday == -1) | |
197 | alarm->time.tm_mday = now.tm_mday; | |
198 | if (alarm->time.tm_mon == -1) | |
199 | alarm->time.tm_mon = now.tm_mon; | |
200 | if (alarm->time.tm_year == -1) | |
201 | alarm->time.tm_year = now.tm_year; | |
202 | return 0; | |
203 | } | |
0c86edc0 AZ |
204 | EXPORT_SYMBOL_GPL(rtc_read_alarm); |
205 | ||
ab6a2d70 | 206 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
0c86edc0 AZ |
207 | { |
208 | int err; | |
0c86edc0 | 209 | |
f8245c26 DB |
210 | err = rtc_valid_tm(&alarm->time); |
211 | if (err != 0) | |
212 | return err; | |
213 | ||
0c86edc0 AZ |
214 | err = mutex_lock_interruptible(&rtc->ops_lock); |
215 | if (err) | |
216 | return -EBUSY; | |
217 | ||
218 | if (!rtc->ops) | |
219 | err = -ENODEV; | |
220 | else if (!rtc->ops->set_alarm) | |
221 | err = -EINVAL; | |
222 | else | |
cd966209 | 223 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm); |
0c86edc0 AZ |
224 | |
225 | mutex_unlock(&rtc->ops_lock); | |
226 | return err; | |
227 | } | |
228 | EXPORT_SYMBOL_GPL(rtc_set_alarm); | |
229 | ||
d728b1e6 DB |
230 | /** |
231 | * rtc_update_irq - report RTC periodic, alarm, and/or update irqs | |
ab6a2d70 | 232 | * @rtc: the rtc device |
d728b1e6 DB |
233 | * @num: how many irqs are being reported (usually one) |
234 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF | |
235 | * Context: in_interrupt(), irqs blocked | |
236 | */ | |
ab6a2d70 | 237 | void rtc_update_irq(struct rtc_device *rtc, |
0c86edc0 AZ |
238 | unsigned long num, unsigned long events) |
239 | { | |
0c86edc0 AZ |
240 | spin_lock(&rtc->irq_lock); |
241 | rtc->irq_data = (rtc->irq_data + (num << 8)) | events; | |
242 | spin_unlock(&rtc->irq_lock); | |
243 | ||
244 | spin_lock(&rtc->irq_task_lock); | |
245 | if (rtc->irq_task) | |
246 | rtc->irq_task->func(rtc->irq_task->private_data); | |
247 | spin_unlock(&rtc->irq_task_lock); | |
248 | ||
249 | wake_up_interruptible(&rtc->irq_queue); | |
250 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); | |
251 | } | |
252 | EXPORT_SYMBOL_GPL(rtc_update_irq); | |
253 | ||
71da8905 DY |
254 | static int __rtc_match(struct device *dev, void *data) |
255 | { | |
256 | char *name = (char *)data; | |
257 | ||
258 | if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0) | |
259 | return 1; | |
260 | return 0; | |
261 | } | |
262 | ||
ab6a2d70 | 263 | struct rtc_device *rtc_class_open(char *name) |
0c86edc0 | 264 | { |
cd966209 | 265 | struct device *dev; |
ab6a2d70 | 266 | struct rtc_device *rtc = NULL; |
0c86edc0 | 267 | |
71da8905 DY |
268 | dev = class_find_device(rtc_class, name, __rtc_match); |
269 | if (dev) | |
270 | rtc = to_rtc_device(dev); | |
0c86edc0 | 271 | |
ab6a2d70 DB |
272 | if (rtc) { |
273 | if (!try_module_get(rtc->owner)) { | |
cd966209 | 274 | put_device(dev); |
ab6a2d70 DB |
275 | rtc = NULL; |
276 | } | |
0c86edc0 | 277 | } |
0c86edc0 | 278 | |
ab6a2d70 | 279 | return rtc; |
0c86edc0 AZ |
280 | } |
281 | EXPORT_SYMBOL_GPL(rtc_class_open); | |
282 | ||
ab6a2d70 | 283 | void rtc_class_close(struct rtc_device *rtc) |
0c86edc0 | 284 | { |
ab6a2d70 | 285 | module_put(rtc->owner); |
cd966209 | 286 | put_device(&rtc->dev); |
0c86edc0 AZ |
287 | } |
288 | EXPORT_SYMBOL_GPL(rtc_class_close); | |
289 | ||
ab6a2d70 | 290 | int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) |
0c86edc0 AZ |
291 | { |
292 | int retval = -EBUSY; | |
0c86edc0 AZ |
293 | |
294 | if (task == NULL || task->func == NULL) | |
295 | return -EINVAL; | |
296 | ||
d691eb90 | 297 | /* Cannot register while the char dev is in use */ |
372a302e | 298 | if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) |
d691eb90 AZ |
299 | return -EBUSY; |
300 | ||
d728b1e6 | 301 | spin_lock_irq(&rtc->irq_task_lock); |
0c86edc0 AZ |
302 | if (rtc->irq_task == NULL) { |
303 | rtc->irq_task = task; | |
304 | retval = 0; | |
305 | } | |
d728b1e6 | 306 | spin_unlock_irq(&rtc->irq_task_lock); |
0c86edc0 | 307 | |
372a302e | 308 | clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); |
d691eb90 | 309 | |
0c86edc0 AZ |
310 | return retval; |
311 | } | |
312 | EXPORT_SYMBOL_GPL(rtc_irq_register); | |
313 | ||
ab6a2d70 | 314 | void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) |
0c86edc0 | 315 | { |
d728b1e6 | 316 | spin_lock_irq(&rtc->irq_task_lock); |
0c86edc0 AZ |
317 | if (rtc->irq_task == task) |
318 | rtc->irq_task = NULL; | |
d728b1e6 | 319 | spin_unlock_irq(&rtc->irq_task_lock); |
0c86edc0 AZ |
320 | } |
321 | EXPORT_SYMBOL_GPL(rtc_irq_unregister); | |
322 | ||
97144c67 DB |
323 | /** |
324 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs | |
325 | * @rtc: the rtc device | |
326 | * @task: currently registered with rtc_irq_register() | |
327 | * @enabled: true to enable periodic IRQs | |
328 | * Context: any | |
329 | * | |
330 | * Note that rtc_irq_set_freq() should previously have been used to | |
331 | * specify the desired frequency of periodic IRQ task->func() callbacks. | |
332 | */ | |
ab6a2d70 | 333 | int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) |
0c86edc0 AZ |
334 | { |
335 | int err = 0; | |
336 | unsigned long flags; | |
0c86edc0 | 337 | |
56f10c63 AZ |
338 | if (rtc->ops->irq_set_state == NULL) |
339 | return -ENXIO; | |
340 | ||
0c86edc0 | 341 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
d691eb90 AZ |
342 | if (rtc->irq_task != NULL && task == NULL) |
343 | err = -EBUSY; | |
0c86edc0 | 344 | if (rtc->irq_task != task) |
d691eb90 | 345 | err = -EACCES; |
0c86edc0 AZ |
346 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
347 | ||
348 | if (err == 0) | |
cd966209 | 349 | err = rtc->ops->irq_set_state(rtc->dev.parent, enabled); |
0c86edc0 AZ |
350 | |
351 | return err; | |
352 | } | |
353 | EXPORT_SYMBOL_GPL(rtc_irq_set_state); | |
354 | ||
97144c67 DB |
355 | /** |
356 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ | |
357 | * @rtc: the rtc device | |
358 | * @task: currently registered with rtc_irq_register() | |
359 | * @freq: positive frequency with which task->func() will be called | |
360 | * Context: any | |
361 | * | |
362 | * Note that rtc_irq_set_state() is used to enable or disable the | |
363 | * periodic IRQs. | |
364 | */ | |
ab6a2d70 | 365 | int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) |
0c86edc0 | 366 | { |
56f10c63 | 367 | int err = 0; |
0c86edc0 | 368 | unsigned long flags; |
0c86edc0 | 369 | |
56f10c63 AZ |
370 | if (rtc->ops->irq_set_freq == NULL) |
371 | return -ENXIO; | |
0c86edc0 | 372 | |
97144c67 DB |
373 | if (!is_power_of_2(freq)) |
374 | return -EINVAL; | |
375 | ||
0c86edc0 | 376 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
d691eb90 AZ |
377 | if (rtc->irq_task != NULL && task == NULL) |
378 | err = -EBUSY; | |
0c86edc0 | 379 | if (rtc->irq_task != task) |
d691eb90 | 380 | err = -EACCES; |
0c86edc0 AZ |
381 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
382 | ||
383 | if (err == 0) { | |
cd966209 | 384 | err = rtc->ops->irq_set_freq(rtc->dev.parent, freq); |
0c86edc0 AZ |
385 | if (err == 0) |
386 | rtc->irq_freq = freq; | |
387 | } | |
388 | return err; | |
389 | } | |
2601a464 | 390 | EXPORT_SYMBOL_GPL(rtc_irq_set_freq); |