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e824290e AZ |
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 | ||
3418ff76 | 61 | if (count != sizeof(unsigned int) && count < sizeof(unsigned long)) |
e824290e AZ |
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) | |
3418ff76 AN |
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); | |
e824290e AZ |
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); | |
b3969e58 | 144 | if (err != -ENOIOCTLCMD) |
e824290e AZ |
145 | return err; |
146 | } | |
147 | ||
148 | /* if the driver does not provide the ioctl interface | |
149 | * or if that particular ioctl was not implemented | |
b3969e58 | 150 | * (-ENOIOCTLCMD), we will try to emulate here. |
e824290e AZ |
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: | |
b3969e58 | 236 | err = -ENOTTY; |
e824290e AZ |
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"); |