rtc: rtc interfaces don't use class_device
[linux-2.6.git] / drivers / rtc / rtc-dev.c
1 /*
2  * RTC subsystem, dev interface
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/module.h>
15 #include <linux/rtc.h>
16 #include "rtc-core.h"
17
18 static dev_t rtc_devt;
19
20 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
21
22 static int rtc_dev_open(struct inode *inode, struct file *file)
23 {
24         int err;
25         struct rtc_device *rtc = container_of(inode->i_cdev,
26                                         struct rtc_device, char_dev);
27         const struct rtc_class_ops *ops = rtc->ops;
28
29         /* We keep the lock as long as the device is in use
30          * and return immediately if busy
31          */
32         if (!(mutex_trylock(&rtc->char_lock)))
33                 return -EBUSY;
34
35         file->private_data = rtc;
36
37         err = ops->open ? ops->open(rtc->class_dev.dev) : 0;
38         if (err == 0) {
39                 spin_lock_irq(&rtc->irq_lock);
40                 rtc->irq_data = 0;
41                 spin_unlock_irq(&rtc->irq_lock);
42
43                 return 0;
44         }
45
46         /* something has gone wrong, release the lock */
47         mutex_unlock(&rtc->char_lock);
48         return err;
49 }
50
51 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
52 /*
53  * Routine to poll RTC seconds field for change as often as possible,
54  * after first RTC_UIE use timer to reduce polling
55  */
56 static void rtc_uie_task(struct work_struct *work)
57 {
58         struct rtc_device *rtc =
59                 container_of(work, struct rtc_device, uie_task);
60         struct rtc_time tm;
61         int num = 0;
62         int err;
63
64         err = rtc_read_time(rtc, &tm);
65
66         local_irq_disable();
67         spin_lock(&rtc->irq_lock);
68         if (rtc->stop_uie_polling || err) {
69                 rtc->uie_task_active = 0;
70         } else if (rtc->oldsecs != tm.tm_sec) {
71                 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
72                 rtc->oldsecs = tm.tm_sec;
73                 rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
74                 rtc->uie_timer_active = 1;
75                 rtc->uie_task_active = 0;
76                 add_timer(&rtc->uie_timer);
77         } else if (schedule_work(&rtc->uie_task) == 0) {
78                 rtc->uie_task_active = 0;
79         }
80         spin_unlock(&rtc->irq_lock);
81         if (num)
82                 rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);
83         local_irq_enable();
84 }
85 static void rtc_uie_timer(unsigned long data)
86 {
87         struct rtc_device *rtc = (struct rtc_device *)data;
88         unsigned long flags;
89
90         spin_lock_irqsave(&rtc->irq_lock, flags);
91         rtc->uie_timer_active = 0;
92         rtc->uie_task_active = 1;
93         if ((schedule_work(&rtc->uie_task) == 0))
94                 rtc->uie_task_active = 0;
95         spin_unlock_irqrestore(&rtc->irq_lock, flags);
96 }
97
98 static void clear_uie(struct rtc_device *rtc)
99 {
100         spin_lock_irq(&rtc->irq_lock);
101         if (rtc->irq_active) {
102                 rtc->stop_uie_polling = 1;
103                 if (rtc->uie_timer_active) {
104                         spin_unlock_irq(&rtc->irq_lock);
105                         del_timer_sync(&rtc->uie_timer);
106                         spin_lock_irq(&rtc->irq_lock);
107                         rtc->uie_timer_active = 0;
108                 }
109                 if (rtc->uie_task_active) {
110                         spin_unlock_irq(&rtc->irq_lock);
111                         flush_scheduled_work();
112                         spin_lock_irq(&rtc->irq_lock);
113                 }
114                 rtc->irq_active = 0;
115         }
116         spin_unlock_irq(&rtc->irq_lock);
117 }
118
119 static int set_uie(struct rtc_device *rtc)
120 {
121         struct rtc_time tm;
122         int err;
123
124         err = rtc_read_time(rtc, &tm);
125         if (err)
126                 return err;
127         spin_lock_irq(&rtc->irq_lock);
128         if (!rtc->irq_active) {
129                 rtc->irq_active = 1;
130                 rtc->stop_uie_polling = 0;
131                 rtc->oldsecs = tm.tm_sec;
132                 rtc->uie_task_active = 1;
133                 if (schedule_work(&rtc->uie_task) == 0)
134                         rtc->uie_task_active = 0;
135         }
136         rtc->irq_data = 0;
137         spin_unlock_irq(&rtc->irq_lock);
138         return 0;
139 }
140 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
141
142 static ssize_t
143 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
144 {
145         struct rtc_device *rtc = to_rtc_device(file->private_data);
146
147         DECLARE_WAITQUEUE(wait, current);
148         unsigned long data;
149         ssize_t ret;
150
151         if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
152                 return -EINVAL;
153
154         add_wait_queue(&rtc->irq_queue, &wait);
155         do {
156                 __set_current_state(TASK_INTERRUPTIBLE);
157
158                 spin_lock_irq(&rtc->irq_lock);
159                 data = rtc->irq_data;
160                 rtc->irq_data = 0;
161                 spin_unlock_irq(&rtc->irq_lock);
162
163                 if (data != 0) {
164                         ret = 0;
165                         break;
166                 }
167                 if (file->f_flags & O_NONBLOCK) {
168                         ret = -EAGAIN;
169                         break;
170                 }
171                 if (signal_pending(current)) {
172                         ret = -ERESTARTSYS;
173                         break;
174                 }
175                 schedule();
176         } while (1);
177         set_current_state(TASK_RUNNING);
178         remove_wait_queue(&rtc->irq_queue, &wait);
179
180         if (ret == 0) {
181                 /* Check for any data updates */
182                 if (rtc->ops->read_callback)
183                         data = rtc->ops->read_callback(rtc->class_dev.dev,
184                                                        data);
185
186                 if (sizeof(int) != sizeof(long) &&
187                     count == sizeof(unsigned int))
188                         ret = put_user(data, (unsigned int __user *)buf) ?:
189                                 sizeof(unsigned int);
190                 else
191                         ret = put_user(data, (unsigned long __user *)buf) ?:
192                                 sizeof(unsigned long);
193         }
194         return ret;
195 }
196
197 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
198 {
199         struct rtc_device *rtc = to_rtc_device(file->private_data);
200         unsigned long data;
201
202         poll_wait(file, &rtc->irq_queue, wait);
203
204         data = rtc->irq_data;
205
206         return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
207 }
208
209 static int rtc_dev_ioctl(struct inode *inode, struct file *file,
210                 unsigned int cmd, unsigned long arg)
211 {
212         int err = 0;
213         struct rtc_device *rtc = file->private_data;
214         const struct rtc_class_ops *ops = rtc->ops;
215         struct rtc_time tm;
216         struct rtc_wkalrm alarm;
217         void __user *uarg = (void __user *) arg;
218
219         /* check that the calling task has appropriate permissions
220          * for certain ioctls. doing this check here is useful
221          * to avoid duplicate code in each driver.
222          */
223         switch (cmd) {
224         case RTC_EPOCH_SET:
225         case RTC_SET_TIME:
226                 if (!capable(CAP_SYS_TIME))
227                         return -EACCES;
228                 break;
229
230         case RTC_IRQP_SET:
231                 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
232                         return -EACCES;
233                 break;
234
235         case RTC_PIE_ON:
236                 if (!capable(CAP_SYS_RESOURCE))
237                         return -EACCES;
238                 break;
239         }
240
241         /* avoid conflicting IRQ users */
242         if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
243                 spin_lock_irq(&rtc->irq_task_lock);
244                 if (rtc->irq_task)
245                         err = -EBUSY;
246                 spin_unlock_irq(&rtc->irq_task_lock);
247
248                 if (err < 0)
249                         return err;
250         }
251
252         /* try the driver's ioctl interface */
253         if (ops->ioctl) {
254                 err = ops->ioctl(rtc->class_dev.dev, cmd, arg);
255                 if (err != -ENOIOCTLCMD)
256                         return err;
257         }
258
259         /* if the driver does not provide the ioctl interface
260          * or if that particular ioctl was not implemented
261          * (-ENOIOCTLCMD), we will try to emulate here.
262          */
263
264         switch (cmd) {
265         case RTC_ALM_READ:
266                 err = rtc_read_alarm(rtc, &alarm);
267                 if (err < 0)
268                         return err;
269
270                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
271                         return -EFAULT;
272                 break;
273
274         case RTC_ALM_SET:
275                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
276                         return -EFAULT;
277
278                 alarm.enabled = 0;
279                 alarm.pending = 0;
280                 alarm.time.tm_mday = -1;
281                 alarm.time.tm_mon = -1;
282                 alarm.time.tm_year = -1;
283                 alarm.time.tm_wday = -1;
284                 alarm.time.tm_yday = -1;
285                 alarm.time.tm_isdst = -1;
286                 err = rtc_set_alarm(rtc, &alarm);
287                 break;
288
289         case RTC_RD_TIME:
290                 err = rtc_read_time(rtc, &tm);
291                 if (err < 0)
292                         return err;
293
294                 if (copy_to_user(uarg, &tm, sizeof(tm)))
295                         return -EFAULT;
296                 break;
297
298         case RTC_SET_TIME:
299                 if (copy_from_user(&tm, uarg, sizeof(tm)))
300                         return -EFAULT;
301
302                 err = rtc_set_time(rtc, &tm);
303                 break;
304
305         case RTC_IRQP_READ:
306                 if (ops->irq_set_freq)
307                         err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
308                 break;
309
310         case RTC_IRQP_SET:
311                 if (ops->irq_set_freq)
312                         err = rtc_irq_set_freq(rtc, rtc->irq_task, arg);
313                 break;
314
315 #if 0
316         case RTC_EPOCH_SET:
317 #ifndef rtc_epoch
318                 /*
319                  * There were no RTC clocks before 1900.
320                  */
321                 if (arg < 1900) {
322                         err = -EINVAL;
323                         break;
324                 }
325                 rtc_epoch = arg;
326                 err = 0;
327 #endif
328                 break;
329
330         case RTC_EPOCH_READ:
331                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
332                 break;
333 #endif
334         case RTC_WKALM_SET:
335                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
336                         return -EFAULT;
337
338                 err = rtc_set_alarm(rtc, &alarm);
339                 break;
340
341         case RTC_WKALM_RD:
342                 err = rtc_read_alarm(rtc, &alarm);
343                 if (err < 0)
344                         return err;
345
346                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
347                         return -EFAULT;
348                 break;
349
350 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
351         case RTC_UIE_OFF:
352                 clear_uie(rtc);
353                 return 0;
354
355         case RTC_UIE_ON:
356                 return set_uie(rtc);
357 #endif
358         default:
359                 err = -ENOTTY;
360                 break;
361         }
362
363         return err;
364 }
365
366 static int rtc_dev_release(struct inode *inode, struct file *file)
367 {
368         struct rtc_device *rtc = to_rtc_device(file->private_data);
369
370 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
371         clear_uie(rtc);
372 #endif
373         if (rtc->ops->release)
374                 rtc->ops->release(rtc->class_dev.dev);
375
376         mutex_unlock(&rtc->char_lock);
377         return 0;
378 }
379
380 static int rtc_dev_fasync(int fd, struct file *file, int on)
381 {
382         struct rtc_device *rtc = to_rtc_device(file->private_data);
383         return fasync_helper(fd, file, on, &rtc->async_queue);
384 }
385
386 static const struct file_operations rtc_dev_fops = {
387         .owner          = THIS_MODULE,
388         .llseek         = no_llseek,
389         .read           = rtc_dev_read,
390         .poll           = rtc_dev_poll,
391         .ioctl          = rtc_dev_ioctl,
392         .open           = rtc_dev_open,
393         .release        = rtc_dev_release,
394         .fasync         = rtc_dev_fasync,
395 };
396
397 /* insertion/removal hooks */
398
399 void rtc_dev_add_device(struct rtc_device *rtc)
400 {
401         if (!rtc_devt)
402                 return;
403
404         if (rtc->id >= RTC_DEV_MAX) {
405                 pr_debug("%s: too many RTC devices\n", rtc->name);
406                 return;
407         }
408
409         rtc->class_dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
410
411         mutex_init(&rtc->char_lock);
412         spin_lock_init(&rtc->irq_lock);
413         init_waitqueue_head(&rtc->irq_queue);
414 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
415         INIT_WORK(&rtc->uie_task, rtc_uie_task);
416         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
417 #endif
418
419         cdev_init(&rtc->char_dev, &rtc_dev_fops);
420         rtc->char_dev.owner = rtc->owner;
421
422         if (cdev_add(&rtc->char_dev, rtc->class_dev.devt, 1))
423                 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
424                         rtc->name, MAJOR(rtc_devt), rtc->id);
425         else
426                 pr_debug("%s: dev (%d:%d)\n", rtc->name,
427                         MAJOR(rtc_devt), rtc->id);
428 }
429
430 void rtc_dev_del_device(struct rtc_device *rtc)
431 {
432         if (rtc->class_dev.devt)
433                 cdev_del(&rtc->char_dev);
434 }
435
436 void __init rtc_dev_init(void)
437 {
438         int err;
439
440         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
441         if (err < 0)
442                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
443                         __FILE__);
444 }
445
446 void __exit rtc_dev_exit(void)
447 {
448         if (rtc_devt)
449                 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
450 }