2 * RTC subsystem, dev interface
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/module.h>
15 #include <linux/rtc.h>
16 #include <linux/sched.h>
19 static dev_t rtc_devt;
21 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
23 static int rtc_dev_open(struct inode *inode, struct file *file)
26 struct rtc_device *rtc = container_of(inode->i_cdev,
27 struct rtc_device, char_dev);
28 const struct rtc_class_ops *ops = rtc->ops;
30 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
33 file->private_data = rtc;
35 err = ops->open ? ops->open(rtc->dev.parent) : 0;
37 spin_lock_irq(&rtc->irq_lock);
39 spin_unlock_irq(&rtc->irq_lock);
44 /* something has gone wrong */
45 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
51 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
53 struct rtc_device *rtc = file->private_data;
55 DECLARE_WAITQUEUE(wait, current);
59 if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
62 add_wait_queue(&rtc->irq_queue, &wait);
64 __set_current_state(TASK_INTERRUPTIBLE);
66 spin_lock_irq(&rtc->irq_lock);
69 spin_unlock_irq(&rtc->irq_lock);
75 if (file->f_flags & O_NONBLOCK) {
79 if (signal_pending(current)) {
85 set_current_state(TASK_RUNNING);
86 remove_wait_queue(&rtc->irq_queue, &wait);
89 /* Check for any data updates */
90 if (rtc->ops->read_callback)
91 data = rtc->ops->read_callback(rtc->dev.parent,
94 if (sizeof(int) != sizeof(long) &&
95 count == sizeof(unsigned int))
96 ret = put_user(data, (unsigned int __user *)buf) ?:
99 ret = put_user(data, (unsigned long __user *)buf) ?:
100 sizeof(unsigned long);
105 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
107 struct rtc_device *rtc = file->private_data;
110 poll_wait(file, &rtc->irq_queue, wait);
112 data = rtc->irq_data;
114 return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
117 static long rtc_dev_ioctl(struct file *file,
118 unsigned int cmd, unsigned long arg)
121 struct rtc_device *rtc = file->private_data;
122 const struct rtc_class_ops *ops = rtc->ops;
124 struct rtc_wkalrm alarm;
125 void __user *uarg = (void __user *) arg;
127 err = mutex_lock_interruptible(&rtc->ops_lock);
131 /* check that the calling task has appropriate permissions
132 * for certain ioctls. doing this check here is useful
133 * to avoid duplicate code in each driver.
138 if (!capable(CAP_SYS_TIME))
143 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
148 if (rtc->irq_freq > rtc->max_user_freq &&
149 !capable(CAP_SYS_RESOURCE))
158 * Drivers *SHOULD NOT* provide ioctl implementations
159 * for these requests. Instead, provide methods to
160 * support the following code, so that the RTC's main
161 * features are accessible without using ioctls.
163 * RTC and alarm times will be in UTC, by preference,
164 * but dual-booting with MS-Windows implies RTCs must
165 * use the local wall clock time.
170 mutex_unlock(&rtc->ops_lock);
172 err = rtc_read_alarm(rtc, &alarm);
176 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
181 mutex_unlock(&rtc->ops_lock);
183 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
188 alarm.time.tm_wday = -1;
189 alarm.time.tm_yday = -1;
190 alarm.time.tm_isdst = -1;
192 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
193 * Rather than expecting every RTC to implement "don't care"
194 * for day/month/year fields, just force the alarm to have
195 * the right values for those fields.
197 * RTC_WKALM_SET should be used instead. Not only does it
198 * eliminate the need for a separate RTC_AIE_ON call, it
199 * doesn't have the "alarm 23:59:59 in the future" race.
201 * NOTE: some legacy code may have used invalid fields as
202 * wildcards, exposing hardware "periodic alarm" capabilities.
203 * Not supported here.
206 unsigned long now, then;
208 err = rtc_read_time(rtc, &tm);
211 rtc_tm_to_time(&tm, &now);
213 alarm.time.tm_mday = tm.tm_mday;
214 alarm.time.tm_mon = tm.tm_mon;
215 alarm.time.tm_year = tm.tm_year;
216 err = rtc_valid_tm(&alarm.time);
219 rtc_tm_to_time(&alarm.time, &then);
221 /* alarm may need to wrap into tomorrow */
223 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
224 alarm.time.tm_mday = tm.tm_mday;
225 alarm.time.tm_mon = tm.tm_mon;
226 alarm.time.tm_year = tm.tm_year;
230 return rtc_set_alarm(rtc, &alarm);
233 mutex_unlock(&rtc->ops_lock);
235 err = rtc_read_time(rtc, &tm);
239 if (copy_to_user(uarg, &tm, sizeof(tm)))
244 mutex_unlock(&rtc->ops_lock);
246 if (copy_from_user(&tm, uarg, sizeof(tm)))
249 return rtc_set_time(rtc, &tm);
252 err = rtc_irq_set_state(rtc, NULL, 1);
256 err = rtc_irq_set_state(rtc, NULL, 0);
260 mutex_unlock(&rtc->ops_lock);
261 return rtc_alarm_irq_enable(rtc, 1);
264 mutex_unlock(&rtc->ops_lock);
265 return rtc_alarm_irq_enable(rtc, 0);
268 mutex_unlock(&rtc->ops_lock);
269 return rtc_update_irq_enable(rtc, 1);
272 mutex_unlock(&rtc->ops_lock);
273 return rtc_update_irq_enable(rtc, 0);
276 err = rtc_irq_set_freq(rtc, NULL, arg);
280 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
287 * There were no RTC clocks before 1900.
299 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
303 mutex_unlock(&rtc->ops_lock);
304 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
307 return rtc_set_alarm(rtc, &alarm);
310 mutex_unlock(&rtc->ops_lock);
311 err = rtc_read_alarm(rtc, &alarm);
315 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
320 /* Finally try the driver's ioctl interface */
322 err = ops->ioctl(rtc->dev.parent, cmd, arg);
323 if (err == -ENOIOCTLCMD)
330 mutex_unlock(&rtc->ops_lock);
334 static int rtc_dev_fasync(int fd, struct file *file, int on)
336 struct rtc_device *rtc = file->private_data;
337 return fasync_helper(fd, file, on, &rtc->async_queue);
340 static int rtc_dev_release(struct inode *inode, struct file *file)
342 struct rtc_device *rtc = file->private_data;
344 /* We shut down the repeating IRQs that userspace enabled,
345 * since nothing is listening to them.
346 * - Update (UIE) ... currently only managed through ioctls
347 * - Periodic (PIE) ... also used through rtc_*() interface calls
349 * Leave the alarm alone; it may be set to trigger a system wakeup
350 * later, or be used by kernel code, and is a one-shot event anyway.
353 /* Keep ioctl until all drivers are converted */
354 rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
355 rtc_update_irq_enable(rtc, 0);
356 rtc_irq_set_state(rtc, NULL, 0);
358 if (rtc->ops->release)
359 rtc->ops->release(rtc->dev.parent);
361 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
365 static const struct file_operations rtc_dev_fops = {
366 .owner = THIS_MODULE,
368 .read = rtc_dev_read,
369 .poll = rtc_dev_poll,
370 .unlocked_ioctl = rtc_dev_ioctl,
371 .open = rtc_dev_open,
372 .release = rtc_dev_release,
373 .fasync = rtc_dev_fasync,
376 /* insertion/removal hooks */
378 void rtc_dev_prepare(struct rtc_device *rtc)
383 if (rtc->id >= RTC_DEV_MAX) {
384 pr_debug("%s: too many RTC devices\n", rtc->name);
388 rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
390 cdev_init(&rtc->char_dev, &rtc_dev_fops);
391 rtc->char_dev.owner = rtc->owner;
394 void rtc_dev_add_device(struct rtc_device *rtc)
396 if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
397 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
398 rtc->name, MAJOR(rtc_devt), rtc->id);
400 pr_debug("%s: dev (%d:%d)\n", rtc->name,
401 MAJOR(rtc_devt), rtc->id);
404 void rtc_dev_del_device(struct rtc_device *rtc)
407 cdev_del(&rtc->char_dev);
410 void __init rtc_dev_init(void)
414 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
416 printk(KERN_ERR "%s: failed to allocate char dev region\n",
420 void __exit rtc_dev_exit(void)
423 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);