summaryrefslogtreecommitdiffstats
path: root/drivers/char/vr41xx_rtc.c
blob: 5e3292df69d8d794a1a0c4a5ccf5f1becbb38591 (plain)
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
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
/*
 *  Driver for NEC VR4100 series  Real Time Clock unit.
 *
 *  Copyright (C) 2003-2005  Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/platform_device.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/mc146818rtc.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/wait.h>

#include <asm/div64.h>
#include <asm/io.h>
#include <asm/time.h>
#include <asm/uaccess.h>
#include <asm/vr41xx/vr41xx.h>

MODULE_AUTHOR("Yoichi Yuasa <yuasa@hh.iij4u.or.jp>");
MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
MODULE_LICENSE("GPL");

#define RTC1_TYPE1_START	0x0b0000c0UL
#define RTC1_TYPE1_END		0x0b0000dfUL
#define RTC2_TYPE1_START	0x0b0001c0UL
#define RTC2_TYPE1_END		0x0b0001dfUL

#define RTC1_TYPE2_START	0x0f000100UL
#define RTC1_TYPE2_END		0x0f00011fUL
#define RTC2_TYPE2_START	0x0f000120UL
#define RTC2_TYPE2_END		0x0f00013fUL

#define RTC1_SIZE		0x20
#define RTC2_SIZE		0x20

/* RTC 1 registers */
#define ETIMELREG		0x00
#define ETIMEMREG		0x02
#define ETIMEHREG		0x04
/* RFU */
#define ECMPLREG		0x08
#define ECMPMREG		0x0a
#define ECMPHREG		0x0c
/* RFU */
#define RTCL1LREG		0x10
#define RTCL1HREG		0x12
#define RTCL1CNTLREG		0x14
#define RTCL1CNTHREG		0x16
#define RTCL2LREG		0x18
#define RTCL2HREG		0x1a
#define RTCL2CNTLREG		0x1c
#define RTCL2CNTHREG		0x1e

/* RTC 2 registers */
#define TCLKLREG		0x00
#define TCLKHREG		0x02
#define TCLKCNTLREG		0x04
#define TCLKCNTHREG		0x06
/* RFU */
#define RTCINTREG		0x1e
 #define TCLOCK_INT		0x08
 #define RTCLONG2_INT		0x04
 #define RTCLONG1_INT		0x02
 #define ELAPSEDTIME_INT	0x01

#define RTC_FREQUENCY		32768
#define MAX_PERIODIC_RATE	6553
#define MAX_USER_PERIODIC_RATE	64

static void __iomem *rtc1_base;
static void __iomem *rtc2_base;

#define rtc1_read(offset)		readw(rtc1_base + (offset))
#define rtc1_write(offset, value)	writew((value), rtc1_base + (offset))

#define rtc2_read(offset)		readw(rtc2_base + (offset))
#define rtc2_write(offset, value)	writew((value), rtc2_base + (offset))

static unsigned long epoch = 1970;	/* Jan 1 1970 00:00:00 */

static spinlock_t rtc_task_lock;
static wait_queue_head_t rtc_wait;
static unsigned long rtc_irq_data;
static struct fasync_struct *rtc_async_queue;
static rtc_task_t *rtc_callback;
static char rtc_name[] = "RTC";
static unsigned long periodic_frequency;
static unsigned long periodic_count;

typedef enum {
	RTC_RELEASE,
	RTC_OPEN,
} rtc_status_t;

static rtc_status_t rtc_status;

typedef enum {
	FUNCTION_RTC_IOCTL,
	FUNCTION_RTC_CONTROL,
} rtc_callfrom_t;

struct resource rtc_resource[2] = {
	{	.name	= rtc_name,
		.flags	= IORESOURCE_MEM,	},
	{	.name	= rtc_name,
		.flags	= IORESOURCE_MEM,	},
};

#define RTC_NUM_RESOURCES	sizeof(rtc_resource) / sizeof(struct resource)

static inline unsigned long read_elapsed_second(void)
{
	unsigned long first_low, first_mid, first_high;
	unsigned long second_low, second_mid, second_high;

	do {
		first_low = rtc1_read(ETIMELREG);
		first_mid = rtc1_read(ETIMEMREG);
		first_high = rtc1_read(ETIMEHREG);
		second_low = rtc1_read(ETIMELREG);
		second_mid = rtc1_read(ETIMEMREG);
		second_high = rtc1_read(ETIMEHREG);
	} while (first_low != second_low || first_mid != second_mid ||
	         first_high != second_high);

	return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
}

static inline void write_elapsed_second(unsigned long sec)
{
	spin_lock_irq(&rtc_lock);

	rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
	rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
	rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));

	spin_unlock_irq(&rtc_lock);
}

static void set_alarm(struct rtc_time *time)
{
	unsigned long alarm_sec;

	alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
	                   time->tm_hour, time->tm_min, time->tm_sec);

	spin_lock_irq(&rtc_lock);

	rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
	rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
	rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));

	spin_unlock_irq(&rtc_lock);
}

static void read_alarm(struct rtc_time *time)
{
	unsigned long low, mid, high;

	spin_lock_irq(&rtc_lock);

	low = rtc1_read(ECMPLREG);
	mid = rtc1_read(ECMPMREG);
	high = rtc1_read(ECMPHREG);

	spin_unlock_irq(&rtc_lock);

	to_tm((high << 17) | (mid << 1) | (low >> 15), time);
	time->tm_year -= 1900;
}

static void read_time(struct rtc_time *time)
{
	unsigned long epoch_sec, elapsed_sec;

	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
	elapsed_sec = read_elapsed_second();

	to_tm(epoch_sec + elapsed_sec, time);
	time->tm_year -= 1900;
}

static void set_time(struct rtc_time *time)
{
	unsigned long epoch_sec, current_sec;

	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
	current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
	                     time->tm_hour, time->tm_min, time->tm_sec);

	write_elapsed_second(current_sec - epoch_sec);
}

static ssize_t rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long irq_data;
	int retval = 0;

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

	add_wait_queue(&rtc_wait, &wait);

	do {
		__set_current_state(TASK_INTERRUPTIBLE);

		spin_lock_irq(&rtc_lock);
		irq_data = rtc_irq_data;
		rtc_irq_data = 0;
		spin_unlock_irq(&rtc_lock);

		if (irq_data != 0)
			break;

		if (file->f_flags & O_NONBLOCK) {
			retval = -EAGAIN;
			break;
		}

		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
	} while (1);

	if (retval == 0) {
		if (count == sizeof(unsigned int)) {
			retval = put_user(irq_data, (unsigned int __user *)buf);
			if (retval == 0)
				retval = sizeof(unsigned int);
		} else {
			retval = put_user(irq_data, (unsigned long __user *)buf);
			if (retval == 0)
				retval = sizeof(unsigned long);
		}

	}

	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&rtc_wait, &wait);

	return retval;
}

static unsigned int rtc_poll(struct file *file, struct poll_table_struct *table)
{
	poll_wait(file, &rtc_wait, table);

	if (rtc_irq_data != 0)
		return POLLIN | POLLRDNORM;

	return 0;
}

static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, rtc_callfrom_t from)
{
	struct rtc_time time;
	unsigned long count;

	switch (cmd) {
	case RTC_AIE_ON:
		enable_irq(ELAPSEDTIME_IRQ);
		break;
	case RTC_AIE_OFF:
		disable_irq(ELAPSEDTIME_IRQ);
		break;
	case RTC_PIE_ON:
		enable_irq(RTCLONG1_IRQ);
		break;
	case RTC_PIE_OFF:
		disable_irq(RTCLONG1_IRQ);
		break;
	case RTC_ALM_SET:
		if (copy_from_user(&time, (struct rtc_time __user *)arg,
		                   sizeof(struct rtc_time)))
			return -EFAULT;

		set_alarm(&time);
		break;
	case RTC_ALM_READ:
		memset(&time, 0, sizeof(struct rtc_time));
		read_alarm(&time);
		break;
	case RTC_RD_TIME:
		memset(&time, 0, sizeof(struct rtc_time));
		read_time(&time);
		if (copy_to_user((void __user *)arg, &time, sizeof(struct rtc_time)))
			return -EFAULT;
		break;
	case RTC_SET_TIME:
		if (capable(CAP_SYS_TIME) == 0)
			return -EACCES;

		if (copy_from_user(&time, (struct rtc_time __user *)arg,
		                   sizeof(struct rtc_time)))
			return -EFAULT;

		set_time(&time);
		break;
	case RTC_IRQP_READ:
		return put_user(periodic_frequency, (unsigned long __user *)arg);
		break;
	case RTC_IRQP_SET:
		if (arg > MAX_PERIODIC_RATE)
			return -EINVAL;

		if (from == FUNCTION_RTC_IOCTL && arg > MAX_USER_PERIODIC_RATE &&
		    capable(CAP_SYS_RESOURCE) == 0)
			return -EACCES;

		periodic_frequency = arg;

		count = RTC_FREQUENCY;
		do_div(count, arg);

		periodic_count = count;

		spin_lock_irq(&rtc_lock);

		rtc1_write(RTCL1LREG, count);
		rtc1_write(RTCL1HREG, count >> 16);

		spin_unlock_irq(&rtc_lock);
		break;
	case RTC_EPOCH_READ:
		return put_user(epoch, (unsigned long __user *)arg);
	case RTC_EPOCH_SET:
		/* Doesn't support before 1900 */
		if (arg < 1900)
			return -EINVAL;

		if (capable(CAP_SYS_TIME) == 0)
			return -EACCES;

		epoch = arg;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
                     unsigned long arg)
{
	return rtc_do_ioctl(cmd, arg, FUNCTION_RTC_IOCTL);
}

static int rtc_open(struct inode *inode, struct file *file)
{
	spin_lock_irq(&rtc_lock);

	if (rtc_status == RTC_OPEN) {
		spin_unlock_irq(&rtc_lock);
		return -EBUSY;
	}

	rtc_status = RTC_OPEN;
	rtc_irq_data = 0;

	spin_unlock_irq(&rtc_lock);

	return 0;
}

static int rtc_release(struct inode *inode, struct file *file)
{
	if (file->f_flags & FASYNC)
		(void)fasync_helper(-1, file, 0, &rtc_async_queue);

	spin_lock_irq(&rtc_lock);

	rtc1_write(ECMPLREG, 0);
	rtc1_write(ECMPMREG, 0);
	rtc1_write(ECMPHREG, 0);
	rtc1_write(RTCL1LREG, 0);
	rtc1_write(RTCL1HREG, 0);

	rtc_status = RTC_RELEASE;

	spin_unlock_irq(&rtc_lock);

	disable_irq(ELAPSEDTIME_IRQ);
	disable_irq(RTCLONG1_IRQ);

	return 0;
}

static int rtc_fasync(int fd, struct file *file, int on)
{
	return fasync_helper(fd, file, on, &rtc_async_queue);
}

static struct file_operations rtc_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= rtc_read,
	.poll		= rtc_poll,
	.ioctl		= rtc_ioctl,
	.open		= rtc_open,
	.release	= rtc_release,
	.fasync		= rtc_fasync,
};

static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	spin_lock(&rtc_lock);
	rtc2_write(RTCINTREG, ELAPSEDTIME_INT);

	rtc_irq_data += 0x100;
	rtc_irq_data &= ~0xff;
	rtc_irq_data |= RTC_AF;
	spin_unlock(&rtc_lock);

	spin_lock(&rtc_lock);
	if (rtc_callback)
		rtc_callback->func(rtc_callback->private_data);
	spin_unlock(&rtc_lock);

	wake_up_interruptible(&rtc_wait);

	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);

	return IRQ_HANDLED;
}

static irqreturn_t rtclong1_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	unsigned long count = periodic_count;

	spin_lock(&rtc_lock);
	rtc2_write(RTCINTREG, RTCLONG1_INT);

	rtc1_write(RTCL1LREG, count);
	rtc1_write(RTCL1HREG, count >> 16);

	rtc_irq_data += 0x100;
	rtc_irq_data &= ~0xff;
	rtc_irq_data |= RTC_PF;
	spin_unlock(&rtc_lock);

	spin_lock(&rtc_task_lock);
	if (rtc_callback)
		rtc_callback->func(rtc_callback->private_data);
	spin_unlock(&rtc_task_lock);

	wake_up_interruptible(&rtc_wait);

	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);

	return IRQ_HANDLED;
}

int rtc_register(rtc_task_t *task)
{
	if (task == NULL || task->func == NULL)
		return -EINVAL;

	spin_lock_irq(&rtc_lock);
	if (rtc_status == RTC_OPEN) {
		spin_unlock_irq(&rtc_lock);
		return -EBUSY;
	}

	spin_lock(&rtc_task_lock);
	if (rtc_callback != NULL) {
		spin_unlock(&rtc_task_lock);
		spin_unlock_irq(&rtc_task_lock);
		return -EBUSY;
	}

	rtc_callback = task;
	spin_unlock(&rtc_task_lock);

	rtc_status = RTC_OPEN;

	spin_unlock_irq(&rtc_lock);

	return 0;
}

EXPORT_SYMBOL_GPL(rtc_register);

int rtc_unregister(rtc_task_t *task)
{
	spin_lock_irq(&rtc_task_lock);
	if (task == NULL || rtc_callback != task) {
		spin_unlock_irq(&rtc_task_lock);
		return -ENXIO;
	}

	spin_lock(&rtc_lock);

	rtc1_write(ECMPLREG, 0);
	rtc1_write(ECMPMREG, 0);
	rtc1_write(ECMPHREG, 0);
	rtc1_write(RTCL1LREG, 0);
	rtc1_write(RTCL1HREG, 0);

	rtc_status = RTC_RELEASE;

	spin_unlock(&rtc_lock);

	rtc_callback = NULL;

	spin_unlock_irq(&rtc_task_lock);

	disable_irq(ELAPSEDTIME_IRQ);
	disable_irq(RTCLONG1_IRQ);

	return 0;
}

EXPORT_SYMBOL_GPL(rtc_unregister);

int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
{
	int retval = 0;

	spin_lock_irq(&rtc_task_lock);

	if (rtc_callback != task)
		retval = -ENXIO;
	else
		rtc_do_ioctl(cmd, arg, FUNCTION_RTC_CONTROL);

	spin_unlock_irq(&rtc_task_lock);

	return retval;
}

EXPORT_SYMBOL_GPL(rtc_control);

static struct miscdevice rtc_miscdevice = {
	.minor	= RTC_MINOR,
	.name	= rtc_name,
	.fops	= &rtc_fops,
};

static int rtc_probe(struct device *dev)
{
	struct platform_device *pdev;
	unsigned int irq;
	int retval;

	pdev = to_platform_device(dev);
	if (pdev->num_resources != 2)
		return -EBUSY;

	rtc1_base = ioremap(pdev->resource[0].start, RTC1_SIZE);
	if (rtc1_base == NULL)
		return -EBUSY;

	rtc2_base = ioremap(pdev->resource[1].start, RTC2_SIZE);
	if (rtc2_base == NULL) {
		iounmap(rtc1_base);
		rtc1_base = NULL;
		return -EBUSY;
	}

	retval = misc_register(&rtc_miscdevice);
	if (retval < 0) {
		iounmap(rtc1_base);
		iounmap(rtc2_base);
		rtc1_base = NULL;
		rtc2_base = NULL;
		return retval;
	}

	spin_lock_irq(&rtc_lock);

	rtc1_write(ECMPLREG, 0);
	rtc1_write(ECMPMREG, 0);
	rtc1_write(ECMPHREG, 0);
	rtc1_write(RTCL1LREG, 0);
	rtc1_write(RTCL1HREG, 0);

	rtc_status = RTC_RELEASE;
	rtc_irq_data = 0;

	spin_unlock_irq(&rtc_lock);

	init_waitqueue_head(&rtc_wait);

	irq = ELAPSEDTIME_IRQ;
	retval = request_irq(irq, elapsedtime_interrupt, SA_INTERRUPT,
	                     "elapsed_time", NULL);
	if (retval == 0) {
		irq = RTCLONG1_IRQ;
		retval = request_irq(irq, rtclong1_interrupt, SA_INTERRUPT,
		                     "rtclong1", NULL);
	}

	if (retval < 0) {
		printk(KERN_ERR "rtc: IRQ%d is busy\n", irq);
		if (irq == RTCLONG1_IRQ)
			free_irq(ELAPSEDTIME_IRQ, NULL);
		iounmap(rtc1_base);
		iounmap(rtc2_base);
		rtc1_base = NULL;
		rtc2_base = NULL;
		return retval;
	}

	disable_irq(ELAPSEDTIME_IRQ);
	disable_irq(RTCLONG1_IRQ);

	spin_lock_init(&rtc_task_lock);

	printk(KERN_INFO "rtc: Real Time Clock of NEC VR4100 series\n");

	return 0;
}

static int rtc_remove(struct device *dev)
{
	int retval;

	retval = misc_deregister(&rtc_miscdevice);
	if (retval < 0)
		return retval;

	free_irq(ELAPSEDTIME_IRQ, NULL);
	free_irq(RTCLONG1_IRQ, NULL);
	if (rtc1_base != NULL)
		iounmap(rtc1_base);
	if (rtc2_base != NULL)
		iounmap(rtc2_base);

	return 0;
}

static struct platform_device *rtc_platform_device;

static struct device_driver rtc_device_driver = {
	.name		= rtc_name,
	.bus		= &platform_bus_type,
	.probe		= rtc_probe,
	.remove		= rtc_remove,
};

static int __devinit vr41xx_rtc_init(void)
{
	int retval;

	switch (current_cpu_data.cputype) {
	case CPU_VR4111:
	case CPU_VR4121:
		rtc_resource[0].start = RTC1_TYPE1_START;
		rtc_resource[0].end = RTC1_TYPE1_END;
		rtc_resource[1].start = RTC2_TYPE1_START;
		rtc_resource[1].end = RTC2_TYPE1_END;
		break;
	case CPU_VR4122:
	case CPU_VR4131:
	case CPU_VR4133:
		rtc_resource[0].start = RTC1_TYPE2_START;
		rtc_resource[0].end = RTC1_TYPE2_END;
		rtc_resource[1].start = RTC2_TYPE2_START;
		rtc_resource[1].end = RTC2_TYPE2_END;
		break;
	default:
		return -ENODEV;
		break;
	}

	rtc_platform_device = platform_device_register_simple("RTC", -1, rtc_resource, RTC_NUM_RESOURCES);
	if (IS_ERR(rtc_platform_device))
		return PTR_ERR(rtc_platform_device);

	retval = driver_register(&rtc_device_driver);
	if (retval < 0)
		platform_device_unregister(rtc_platform_device);

	return retval;
}

static void __devexit vr41xx_rtc_exit(void)
{
	driver_unregister(&rtc_device_driver);

	platform_device_unregister(rtc_platform_device);
}

module_init(vr41xx_rtc_init);
module_exit(vr41xx_rtc_exit);