aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-dev.c
blob: 6c9ad92747fddd2c35061c5e49a4bcc1ad04e2cd (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
/*
 * RTC subsystem, dev interface
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * based on arch/arm/common/rtctime.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/module.h>
#include <linux/rtc.h>

static struct class *rtc_dev_class;
static dev_t rtc_devt;

#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */

static int rtc_dev_open(struct inode *inode, struct file *file)
{
	int err;
	struct rtc_device *rtc = container_of(inode->i_cdev,
					struct rtc_device, char_dev);
	struct rtc_class_ops *ops = rtc->ops;

	/* We keep the lock as long as the device is in use
	 * and return immediately if busy
	 */
	if (!(mutex_trylock(&rtc->char_lock)))
		return -EBUSY;

	file->private_data = &rtc->class_dev;

	err = ops->open ? ops->open(rtc->class_dev.dev) : 0;
	if (err == 0) {
		spin_lock_irq(&rtc->irq_lock);
		rtc->irq_data = 0;
		spin_unlock_irq(&rtc->irq_lock);

		return 0;
	}

	/* something has gone wrong, release the lock */
	mutex_unlock(&rtc->char_lock);
	return err;
}


static ssize_t
rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	struct rtc_device *rtc = to_rtc_device(file->private_data);

	DECLARE_WAITQUEUE(wait, current);
	unsigned long data;
	ssize_t ret;

	if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
		return -EINVAL;

	add_wait_queue(&rtc->irq_queue, &wait);
	do {
		__set_current_state(TASK_INTERRUPTIBLE);

		spin_lock_irq(&rtc->irq_lock);
		data = rtc->irq_data;
		rtc->irq_data = 0;
		spin_unlock_irq(&rtc->irq_lock);

		if (data != 0) {
			ret = 0;
			break;
		}
		if (file->f_flags & O_NONBLOCK) {
			ret = -EAGAIN;
			break;
		}
		if (signal_pending(current)) {
			ret = -ERESTARTSYS;
			break;
		}
		schedule();
	} while (1);
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&rtc->irq_queue, &wait);

	if (ret == 0) {
		/* Check for any data updates */
		if (rtc->ops->read_callback)
			data = rtc->ops->read_callback(rtc->class_dev.dev,
						       data);

		if (sizeof(int) != sizeof(long) &&
		    count == sizeof(unsigned int))
			ret = put_user(data, (unsigned int __user *)buf) ?:
				sizeof(unsigned int);
		else
			ret = put_user(data, (unsigned long __user *)buf) ?:
				sizeof(unsigned long);
	}
	return ret;
}

static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
{
	struct rtc_device *rtc = to_rtc_device(file->private_data);
	unsigned long data;

	poll_wait(file, &rtc->irq_queue, wait);

	data = rtc->irq_data;

	return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
}

static int rtc_dev_ioctl(struct inode *inode, struct file *file,
		unsigned int cmd, unsigned long arg)
{
	int err = 0;
	struct class_device *class_dev = file->private_data;
	struct rtc_device *rtc = to_rtc_device(class_dev);
	struct rtc_class_ops *ops = rtc->ops;
	struct rtc_time tm;
	struct rtc_wkalrm alarm;
	void __user *uarg = (void __user *) arg;

	/* avoid conflicting IRQ users */
	if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
		spin_lock(&rtc->irq_task_lock);
		if (rtc->irq_task)
			err = -EBUSY;
		spin_unlock(&rtc->irq_task_lock);

		if (err < 0)
			return err;
	}

	/* try the driver's ioctl interface */
	if (ops->ioctl) {
		err = ops->ioctl(class_dev->dev, cmd, arg);
		if (err != -EINVAL)
			return err;
	}

	/* if the driver does not provide the ioctl interface
	 * or if that particular ioctl was not implemented
	 * (-EINVAL), we will try to emulate here.
	 */

	switch (cmd) {
	case RTC_ALM_READ:
		err = rtc_read_alarm(class_dev, &alarm);
		if (err < 0)
			return err;

		if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
			return -EFAULT;
		break;

	case RTC_ALM_SET:
		if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
			return -EFAULT;

		alarm.enabled = 0;
		alarm.pending = 0;
		alarm.time.tm_mday = -1;
		alarm.time.tm_mon = -1;
		alarm.time.tm_year = -1;
		alarm.time.tm_wday = -1;
		alarm.time.tm_yday = -1;
		alarm.time.tm_isdst = -1;
		err = rtc_set_alarm(class_dev, &alarm);
		break;

	case RTC_RD_TIME:
		err = rtc_read_time(class_dev, &tm);
		if (err < 0)
			return err;

		if (copy_to_user(uarg, &tm, sizeof(tm)))
			return -EFAULT;
		break;

	case RTC_SET_TIME:
		if (!capable(CAP_SYS_TIME))
			return -EACCES;

		if (copy_from_user(&tm, uarg, sizeof(tm)))
			return -EFAULT;

		err = rtc_set_time(class_dev, &tm);
		break;
#if 0
	case RTC_EPOCH_SET:
#ifndef rtc_epoch
		/*
		 * There were no RTC clocks before 1900.
		 */
		if (arg < 1900) {
			err = -EINVAL;
			break;
		}
		if (!capable(CAP_SYS_TIME)) {
			err = -EACCES;
			break;
		}
		rtc_epoch = arg;
		err = 0;
#endif
		break;

	case RTC_EPOCH_READ:
		err = put_user(rtc_epoch, (unsigned long __user *)uarg);
		break;
#endif
	case RTC_WKALM_SET:
		if (copy_from_user(&alarm, uarg, sizeof(alarm)))
			return -EFAULT;

		err = rtc_set_alarm(class_dev, &alarm);
		break;

	case RTC_WKALM_RD:
		err = rtc_read_alarm(class_dev, &alarm);
		if (err < 0)
			return err;

		if (copy_to_user(uarg, &alarm, sizeof(alarm)))
			return -EFAULT;
		break;

	default:
		err = -EINVAL;
		break;
	}

	return err;
}

static int rtc_dev_release(struct inode *inode, struct file *file)
{
	struct rtc_device *rtc = to_rtc_device(file->private_data);

	if (rtc->ops->release)
		rtc->ops->release(rtc->class_dev.dev);

	mutex_unlock(&rtc->char_lock);
	return 0;
}

static int rtc_dev_fasync(int fd, struct file *file, int on)
{
	struct rtc_device *rtc = to_rtc_device(file->private_data);
	return fasync_helper(fd, file, on, &rtc->async_queue);
}

static struct file_operations rtc_dev_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= rtc_dev_read,
	.poll		= rtc_dev_poll,
	.ioctl		= rtc_dev_ioctl,
	.open		= rtc_dev_open,
	.release	= rtc_dev_release,
	.fasync		= rtc_dev_fasync,
};

/* insertion/removal hooks */

static int rtc_dev_add_device(struct class_device *class_dev,
				struct class_interface *class_intf)
{
	int err = 0;
	struct rtc_device *rtc = to_rtc_device(class_dev);

	if (rtc->id >= RTC_DEV_MAX) {
		dev_err(class_dev->dev, "too many RTCs\n");
		return -EINVAL;
	}

	mutex_init(&rtc->char_lock);
	spin_lock_init(&rtc->irq_lock);
	init_waitqueue_head(&rtc->irq_queue);

	cdev_init(&rtc->char_dev, &rtc_dev_fops);
	rtc->char_dev.owner = rtc->owner;

	if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
		cdev_del(&rtc->char_dev);
		dev_err(class_dev->dev,
			"failed to add char device %d:%d\n",
			MAJOR(rtc_devt), rtc->id);
		return -ENODEV;
	}

	rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
						MKDEV(MAJOR(rtc_devt), rtc->id),
						class_dev->dev, "rtc%d", rtc->id);
	if (IS_ERR(rtc->rtc_dev)) {
		dev_err(class_dev->dev, "cannot create rtc_dev device\n");
		err = PTR_ERR(rtc->rtc_dev);
		goto err_cdev_del;
	}

	dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
		MAJOR(rtc->rtc_dev->devt),
		MINOR(rtc->rtc_dev->devt));

	return 0;

err_cdev_del:

	cdev_del(&rtc->char_dev);
	return err;
}

static void rtc_dev_remove_device(struct class_device *class_dev,
					struct class_interface *class_intf)
{
	struct rtc_device *rtc = to_rtc_device(class_dev);

	if (rtc->rtc_dev) {
		dev_dbg(class_dev->dev, "removing char %d:%d\n",
			MAJOR(rtc->rtc_dev->devt),
			MINOR(rtc->rtc_dev->devt));

		class_device_unregister(rtc->rtc_dev);
		cdev_del(&rtc->char_dev);
	}
}

/* interface registration */

static struct class_interface rtc_dev_interface = {
	.add = &rtc_dev_add_device,
	.remove = &rtc_dev_remove_device,
};

static int __init rtc_dev_init(void)
{
	int err;

	rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
	if (IS_ERR(rtc_dev_class))
		return PTR_ERR(rtc_dev_class);

	err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
	if (err < 0) {
		printk(KERN_ERR "%s: failed to allocate char dev region\n",
			__FILE__);
		goto err_destroy_class;
	}

	err = rtc_interface_register(&rtc_dev_interface);
	if (err < 0) {
		printk(KERN_ERR "%s: failed to register the interface\n",
			__FILE__);
		goto err_unregister_chrdev;
	}

	return 0;

err_unregister_chrdev:
	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);

err_destroy_class:
	class_destroy(rtc_dev_class);

	return err;
}

static void __exit rtc_dev_exit(void)
{
	class_interface_unregister(&rtc_dev_interface);
	class_destroy(rtc_dev_class);
	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
}

module_init(rtc_dev_init);
module_exit(rtc_dev_exit);

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("RTC class dev interface");
MODULE_LICENSE("GPL");