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/log2.h>
17 int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
21 err = mutex_lock_interruptible(&rtc->ops_lock);
27 else if (!rtc->ops->read_time)
30 memset(tm, 0, sizeof(struct rtc_time));
31 err = rtc->ops->read_time(rtc->dev.parent, tm);
34 mutex_unlock(&rtc->ops_lock);
37 EXPORT_SYMBOL_GPL(rtc_read_time);
39 int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
43 err = rtc_valid_tm(tm);
47 err = mutex_lock_interruptible(&rtc->ops_lock);
53 else if (!rtc->ops->set_time)
56 err = rtc->ops->set_time(rtc->dev.parent, tm);
58 mutex_unlock(&rtc->ops_lock);
61 EXPORT_SYMBOL_GPL(rtc_set_time);
63 int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
67 err = mutex_lock_interruptible(&rtc->ops_lock);
73 else if (rtc->ops->set_mmss)
74 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
75 else if (rtc->ops->read_time && rtc->ops->set_time) {
76 struct rtc_time new, old;
78 err = rtc->ops->read_time(rtc->dev.parent, &old);
80 rtc_time_to_tm(secs, &new);
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.
88 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
89 (new.tm_hour == 23 && new.tm_min == 59)))
90 err = rtc->ops->set_time(rtc->dev.parent,
97 mutex_unlock(&rtc->ops_lock);
101 EXPORT_SYMBOL_GPL(rtc_set_mmss);
103 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
107 err = mutex_lock_interruptible(&rtc->ops_lock);
111 if (rtc->ops == NULL)
113 else if (!rtc->ops->read_alarm)
116 memset(alarm, 0, sizeof(struct rtc_wkalrm));
117 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
120 mutex_unlock(&rtc->ops_lock);
123 EXPORT_SYMBOL_GPL(rtc_read_alarm);
125 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
129 err = rtc_valid_tm(&alarm->time);
133 err = mutex_lock_interruptible(&rtc->ops_lock);
139 else if (!rtc->ops->set_alarm)
142 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
144 mutex_unlock(&rtc->ops_lock);
147 EXPORT_SYMBOL_GPL(rtc_set_alarm);
150 * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
151 * @rtc: the rtc device
152 * @num: how many irqs are being reported (usually one)
153 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
154 * Context: in_interrupt(), irqs blocked
156 void rtc_update_irq(struct rtc_device *rtc,
157 unsigned long num, unsigned long events)
159 spin_lock(&rtc->irq_lock);
160 rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
161 spin_unlock(&rtc->irq_lock);
163 spin_lock(&rtc->irq_task_lock);
165 rtc->irq_task->func(rtc->irq_task->private_data);
166 spin_unlock(&rtc->irq_task_lock);
168 wake_up_interruptible(&rtc->irq_queue);
169 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
171 EXPORT_SYMBOL_GPL(rtc_update_irq);
173 struct rtc_device *rtc_class_open(char *name)
176 struct rtc_device *rtc = NULL;
178 down(&rtc_class->sem);
179 list_for_each_entry(dev, &rtc_class->devices, node) {
180 if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0) {
181 dev = get_device(dev);
183 rtc = to_rtc_device(dev);
189 if (!try_module_get(rtc->owner)) {
198 EXPORT_SYMBOL_GPL(rtc_class_open);
200 void rtc_class_close(struct rtc_device *rtc)
202 module_put(rtc->owner);
203 put_device(&rtc->dev);
205 EXPORT_SYMBOL_GPL(rtc_class_close);
207 int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
211 if (task == NULL || task->func == NULL)
214 /* Cannot register while the char dev is in use */
215 if (!(mutex_trylock(&rtc->char_lock)))
218 spin_lock_irq(&rtc->irq_task_lock);
219 if (rtc->irq_task == NULL) {
220 rtc->irq_task = task;
223 spin_unlock_irq(&rtc->irq_task_lock);
225 mutex_unlock(&rtc->char_lock);
229 EXPORT_SYMBOL_GPL(rtc_irq_register);
231 void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
233 spin_lock_irq(&rtc->irq_task_lock);
234 if (rtc->irq_task == task)
235 rtc->irq_task = NULL;
236 spin_unlock_irq(&rtc->irq_task_lock);
238 EXPORT_SYMBOL_GPL(rtc_irq_unregister);
241 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
242 * @rtc: the rtc device
243 * @task: currently registered with rtc_irq_register()
244 * @enabled: true to enable periodic IRQs
247 * Note that rtc_irq_set_freq() should previously have been used to
248 * specify the desired frequency of periodic IRQ task->func() callbacks.
250 int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
255 if (rtc->ops->irq_set_state == NULL)
258 spin_lock_irqsave(&rtc->irq_task_lock, flags);
259 if (rtc->irq_task != NULL && task == NULL)
261 if (rtc->irq_task != task)
263 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
266 err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);
270 EXPORT_SYMBOL_GPL(rtc_irq_set_state);
273 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
274 * @rtc: the rtc device
275 * @task: currently registered with rtc_irq_register()
276 * @freq: positive frequency with which task->func() will be called
279 * Note that rtc_irq_set_state() is used to enable or disable the
282 int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
287 if (rtc->ops->irq_set_freq == NULL)
290 if (!is_power_of_2(freq))
293 spin_lock_irqsave(&rtc->irq_task_lock, flags);
294 if (rtc->irq_task != NULL && task == NULL)
296 if (rtc->irq_task != task)
298 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
301 err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);
303 rtc->irq_freq = freq;
307 EXPORT_SYMBOL_GPL(rtc_irq_set_freq);