projects/linux·blob v2.6.17 · refs

387 lines · 8.4 KiB

1/*
2 * RTC subsystem, dev interface
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
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
17static struct class *rtc_dev_class;
18static dev_t rtc_devt;
19
20#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
21
22static 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 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->class_dev;
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
52static ssize_t
53rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
54{
55 struct rtc_device *rtc = to_rtc_device(file->private_data);
56
57 DECLARE_WAITQUEUE(wait, current);
58 unsigned long data;
59 ssize_t ret;
60
61 if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
62 return -EINVAL;
63
64 add_wait_queue(&rtc->irq_queue, &wait);
65 do {
66 __set_current_state(TASK_INTERRUPTIBLE);
67
68 spin_lock_irq(&rtc->irq_lock);
69 data = rtc->irq_data;
70 rtc->irq_data = 0;
71 spin_unlock_irq(&rtc->irq_lock);
72
73 if (data != 0) {
74 ret = 0;
75 break;
76 }
77 if (file->f_flags & O_NONBLOCK) {
78 ret = -EAGAIN;
79 break;
80 }
81 if (signal_pending(current)) {
82 ret = -ERESTARTSYS;
83 break;
84 }
85 schedule();
86 } while (1);
87 set_current_state(TASK_RUNNING);
88 remove_wait_queue(&rtc->irq_queue, &wait);
89
90 if (ret == 0) {
91 /* Check for any data updates */
92 if (rtc->ops->read_callback)
93 data = rtc->ops->read_callback(rtc->class_dev.dev,
94 data);
95
96 if (sizeof(int) != sizeof(long) &&
97 count == sizeof(unsigned int))
98 ret = put_user(data, (unsigned int __user *)buf) ?:
99 sizeof(unsigned int);
100 else
101 ret = put_user(data, (unsigned long __user *)buf) ?:
102 sizeof(unsigned long);
103 }
104 return ret;
105}
106
107static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
108{
109 struct rtc_device *rtc = to_rtc_device(file->private_data);
110 unsigned long data;
111
112 poll_wait(file, &rtc->irq_queue, wait);
113
114 data = rtc->irq_data;
115
116 return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
117}
118
119static int rtc_dev_ioctl(struct inode *inode, struct file *file,
120 unsigned int cmd, unsigned long arg)
121{
122 int err = 0;
123 struct class_device *class_dev = file->private_data;
124 struct rtc_device *rtc = to_rtc_device(class_dev);
125 struct rtc_class_ops *ops = rtc->ops;
126 struct rtc_time tm;
127 struct rtc_wkalrm alarm;
128 void __user *uarg = (void __user *) arg;
129
130 /* avoid conflicting IRQ users */
131 if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
132 spin_lock(&rtc->irq_task_lock);
133 if (rtc->irq_task)
134 err = -EBUSY;
135 spin_unlock(&rtc->irq_task_lock);
136
137 if (err < 0)
138 return err;
139 }
140
141 /* try the driver's ioctl interface */
142 if (ops->ioctl) {
143 err = ops->ioctl(class_dev->dev, cmd, arg);
144 if (err != -ENOIOCTLCMD)
145 return err;
146 }
147
148 /* if the driver does not provide the ioctl interface
149 * or if that particular ioctl was not implemented
150 * (-ENOIOCTLCMD), we will try to emulate here.
151 */
152
153 switch (cmd) {
154 case RTC_ALM_READ:
155 err = rtc_read_alarm(class_dev, &alarm);
156 if (err < 0)
157 return err;
158
159 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
160 return -EFAULT;
161 break;
162
163 case RTC_ALM_SET:
164 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
165 return -EFAULT;
166
167 alarm.enabled = 0;
168 alarm.pending = 0;
169 alarm.time.tm_mday = -1;
170 alarm.time.tm_mon = -1;
171 alarm.time.tm_year = -1;
172 alarm.time.tm_wday = -1;
173 alarm.time.tm_yday = -1;
174 alarm.time.tm_isdst = -1;
175 err = rtc_set_alarm(class_dev, &alarm);
176 break;
177
178 case RTC_RD_TIME:
179 err = rtc_read_time(class_dev, &tm);
180 if (err < 0)
181 return err;
182
183 if (copy_to_user(uarg, &tm, sizeof(tm)))
184 return -EFAULT;
185 break;
186
187 case RTC_SET_TIME:
188 if (!capable(CAP_SYS_TIME))
189 return -EACCES;
190
191 if (copy_from_user(&tm, uarg, sizeof(tm)))
192 return -EFAULT;
193
194 err = rtc_set_time(class_dev, &tm);
195 break;
196#if 0
197 case RTC_EPOCH_SET:
198#ifndef rtc_epoch
199 /*
200 * There were no RTC clocks before 1900.
201 */
202 if (arg < 1900) {
203 err = -EINVAL;
204 break;
205 }
206 if (!capable(CAP_SYS_TIME)) {
207 err = -EACCES;
208 break;
209 }
210 rtc_epoch = arg;
211 err = 0;
212#endif
213 break;
214
215 case RTC_EPOCH_READ:
216 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
217 break;
218#endif
219 case RTC_WKALM_SET:
220 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
221 return -EFAULT;
222
223 err = rtc_set_alarm(class_dev, &alarm);
224 break;
225
226 case RTC_WKALM_RD:
227 err = rtc_read_alarm(class_dev, &alarm);
228 if (err < 0)
229 return err;
230
231 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
232 return -EFAULT;
233 break;
234
235 default:
236 err = -ENOTTY;
237 break;
238 }
239
240 return err;
241}
242
243static int rtc_dev_release(struct inode *inode, struct file *file)
244{
245 struct rtc_device *rtc = to_rtc_device(file->private_data);
246
247 if (rtc->ops->release)
248 rtc->ops->release(rtc->class_dev.dev);
249
250 mutex_unlock(&rtc->char_lock);
251 return 0;
252}
253
254static int rtc_dev_fasync(int fd, struct file *file, int on)
255{
256 struct rtc_device *rtc = to_rtc_device(file->private_data);
257 return fasync_helper(fd, file, on, &rtc->async_queue);
258}
259
260static struct file_operations rtc_dev_fops = {
261 .owner = THIS_MODULE,
262 .llseek = no_llseek,
263 .read = rtc_dev_read,
264 .poll = rtc_dev_poll,
265 .ioctl = rtc_dev_ioctl,
266 .open = rtc_dev_open,
267 .release = rtc_dev_release,
268 .fasync = rtc_dev_fasync,
269};
270
271/* insertion/removal hooks */
272
273static int rtc_dev_add_device(struct class_device *class_dev,
274 struct class_interface *class_intf)
275{
276 int err = 0;
277 struct rtc_device *rtc = to_rtc_device(class_dev);
278
279 if (rtc->id >= RTC_DEV_MAX) {
280 dev_err(class_dev->dev, "too many RTCs\n");
281 return -EINVAL;
282 }
283
284 mutex_init(&rtc->char_lock);
285 spin_lock_init(&rtc->irq_lock);
286 init_waitqueue_head(&rtc->irq_queue);
287
288 cdev_init(&rtc->char_dev, &rtc_dev_fops);
289 rtc->char_dev.owner = rtc->owner;
290
291 if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
292 cdev_del(&rtc->char_dev);
293 dev_err(class_dev->dev,
294 "failed to add char device %d:%d\n",
295 MAJOR(rtc_devt), rtc->id);
296 return -ENODEV;
297 }
298
299 rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
300 MKDEV(MAJOR(rtc_devt), rtc->id),
301 class_dev->dev, "rtc%d", rtc->id);
302 if (IS_ERR(rtc->rtc_dev)) {
303 dev_err(class_dev->dev, "cannot create rtc_dev device\n");
304 err = PTR_ERR(rtc->rtc_dev);
305 goto err_cdev_del;
306 }
307
308 dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
309 MAJOR(rtc->rtc_dev->devt),
310 MINOR(rtc->rtc_dev->devt));
311
312 return 0;
313
314err_cdev_del:
315
316 cdev_del(&rtc->char_dev);
317 return err;
318}
319
320static void rtc_dev_remove_device(struct class_device *class_dev,
321 struct class_interface *class_intf)
322{
323 struct rtc_device *rtc = to_rtc_device(class_dev);
324
325 if (rtc->rtc_dev) {
326 dev_dbg(class_dev->dev, "removing char %d:%d\n",
327 MAJOR(rtc->rtc_dev->devt),
328 MINOR(rtc->rtc_dev->devt));
329
330 class_device_unregister(rtc->rtc_dev);
331 cdev_del(&rtc->char_dev);
332 }
333}
334
335/* interface registration */
336
337static struct class_interface rtc_dev_interface = {
338 .add = &rtc_dev_add_device,
339 .remove = &rtc_dev_remove_device,
340};
341
342static int __init rtc_dev_init(void)
343{
344 int err;
345
346 rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
347 if (IS_ERR(rtc_dev_class))
348 return PTR_ERR(rtc_dev_class);
349
350 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
351 if (err < 0) {
352 printk(KERN_ERR "%s: failed to allocate char dev region\n",
353 __FILE__);
354 goto err_destroy_class;
355 }
356
357 err = rtc_interface_register(&rtc_dev_interface);
358 if (err < 0) {
359 printk(KERN_ERR "%s: failed to register the interface\n",
360 __FILE__);
361 goto err_unregister_chrdev;
362 }
363
364 return 0;
365
366err_unregister_chrdev:
367 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
368
369err_destroy_class:
370 class_destroy(rtc_dev_class);
371
372 return err;
373}
374
375static void __exit rtc_dev_exit(void)
376{
377 class_interface_unregister(&rtc_dev_interface);
378 class_destroy(rtc_dev_class);
379 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
380}
381
382module_init(rtc_dev_init);
383module_exit(rtc_dev_exit);
384
385MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
386MODULE_DESCRIPTION("RTC class dev interface");
387MODULE_LICENSE("GPL");