[PATCH] rtc subsystem: use ENOIOCTLCMD and ENOTTY where appropriate
[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
17 static struct class *rtc_dev_class;
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         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
52 static ssize_t
53 rtc_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
107 static 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
119 static 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
243 static 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
254 static 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
260 static 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
273 static 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
314 err_cdev_del:
315
316         cdev_del(&rtc->char_dev);
317         return err;
318 }
319
320 static 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
337 static struct class_interface rtc_dev_interface = {
338         .add = &rtc_dev_add_device,
339         .remove = &rtc_dev_remove_device,
340 };
341
342 static 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
366 err_unregister_chrdev:
367         unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
368
369 err_destroy_class:
370         class_destroy(rtc_dev_class);
371
372         return err;
373 }
374
375 static 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
382 module_init(rtc_dev_init);
383 module_exit(rtc_dev_exit);
384
385 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
386 MODULE_DESCRIPTION("RTC class dev interface");
387 MODULE_LICENSE("GPL");