aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-rs5c372.c
blob: 7e63074708ebffa060c1f2b5b405ac37790323b5 (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
/*
 * An I2C driver for Ricoh RS5C372 and RV5C38[67] RTCs
 *
 * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
 * Copyright (C) 2006 Tower Technologies
 *
 * 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/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>

#define DRV_VERSION "0.5"


/*
 * Ricoh has a family of I2C based RTCs, which differ only slightly from
 * each other.  Differences center on pinout (e.g. how many interrupts,
 * output clock, etc) and how the control registers are used.  The '372
 * is significant only because that's the one this driver first supported.
 */
#define RS5C372_REG_SECS	0
#define RS5C372_REG_MINS	1
#define RS5C372_REG_HOURS	2
#define RS5C372_REG_WDAY	3
#define RS5C372_REG_DAY		4
#define RS5C372_REG_MONTH	5
#define RS5C372_REG_YEAR	6
#define RS5C372_REG_TRIM	7
#	define RS5C372_TRIM_XSL		0x80
#	define RS5C372_TRIM_MASK	0x7F

#define RS5C_REG_ALARM_A_MIN	8			/* or ALARM_W */
#define RS5C_REG_ALARM_A_HOURS	9
#define RS5C_REG_ALARM_A_WDAY	10

#define RS5C_REG_ALARM_B_MIN	11			/* or ALARM_D */
#define RS5C_REG_ALARM_B_HOURS	12
#define RS5C_REG_ALARM_B_WDAY	13			/* (ALARM_B only) */

#define RS5C_REG_CTRL1		14
#	define RS5C_CTRL1_AALE		(1 << 7)	/* or WALE */
#	define RS5C_CTRL1_BALE		(1 << 6)	/* or DALE */
#	define RV5C387_CTRL1_24		(1 << 5)
#	define RS5C372A_CTRL1_SL1	(1 << 5)
#	define RS5C_CTRL1_CT_MASK	(7 << 0)
#	define RS5C_CTRL1_CT0		(0 << 0)	/* no periodic irq */
#	define RS5C_CTRL1_CT4		(4 << 0)	/* 1 Hz level irq */
#define RS5C_REG_CTRL2		15
#	define RS5C372_CTRL2_24		(1 << 5)
#	define RS5C_CTRL2_XSTP		(1 << 4)
#	define RS5C_CTRL2_CTFG		(1 << 2)
#	define RS5C_CTRL2_AAFG		(1 << 1)	/* or WAFG */
#	define RS5C_CTRL2_BAFG		(1 << 0)	/* or DAFG */


/* to read (style 1) or write registers starting at R */
#define RS5C_ADDR(R)		(((R) << 4) | 0)


enum rtc_type {
	rtc_undef = 0,
	rtc_rs5c372a,
	rtc_rs5c372b,
	rtc_rv5c386,
	rtc_rv5c387a,
};

/* REVISIT:  this assumes that:
 *  - we're in the 21st century, so it's safe to ignore the century
 *    bit for rv5c38[67] (REG_MONTH bit 7);
 *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
 */
struct rs5c372 {
	struct i2c_client	*client;
	struct rtc_device	*rtc;
	enum rtc_type		type;
	unsigned		time24:1;
	unsigned		has_irq:1;
	char			buf[17];
	char			*regs;
};

static int rs5c_get_regs(struct rs5c372 *rs5c)
{
	struct i2c_client	*client = rs5c->client;
	struct i2c_msg		msgs[] = {
		{ client->addr, I2C_M_RD, sizeof rs5c->buf, rs5c->buf },
	};

	/* This implements the third reading method from the datasheet, using
	 * an internal address that's reset after each transaction (by STOP)
	 * to 0x0f ... so we read extra registers, and skip the first one.
	 *
	 * The first method doesn't work with the iop3xx adapter driver, on at
	 * least 80219 chips; this works around that bug.
	 */
	if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
		dev_warn(&client->dev, "can't read registers\n");
		return -EIO;
	}

	dev_dbg(&client->dev,
		"%02x %02x %02x (%02x) %02x %02x %02x (%02x), "
		"%02x %02x %02x, %02x %02x %02x; %02x %02x\n",
		rs5c->regs[0],  rs5c->regs[1],  rs5c->regs[2],  rs5c->regs[3],
		rs5c->regs[4],  rs5c->regs[5],  rs5c->regs[6],  rs5c->regs[7],
		rs5c->regs[8],  rs5c->regs[9],  rs5c->regs[10], rs5c->regs[11],
		rs5c->regs[12], rs5c->regs[13], rs5c->regs[14], rs5c->regs[15]);

	return 0;
}

static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
{
	unsigned	hour;

	if (rs5c->time24)
		return BCD2BIN(reg & 0x3f);

	hour = BCD2BIN(reg & 0x1f);
	if (hour == 12)
		hour = 0;
	if (reg & 0x20)
		hour += 12;
	return hour;
}

static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
{
	if (rs5c->time24)
		return BIN2BCD(hour);

	if (hour > 12)
		return 0x20 | BIN2BCD(hour - 12);
	if (hour == 12)
		return 0x20 | BIN2BCD(12);
	if (hour == 0)
		return BIN2BCD(12);
	return BIN2BCD(hour);
}

static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	struct rs5c372	*rs5c = i2c_get_clientdata(client);
	int		status = rs5c_get_regs(rs5c);

	if (status < 0)
		return status;

	tm->tm_sec = BCD2BIN(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
	tm->tm_min = BCD2BIN(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);

	tm->tm_wday = BCD2BIN(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
	tm->tm_mday = BCD2BIN(rs5c->regs[RS5C372_REG_DAY] & 0x3f);

	/* tm->tm_mon is zero-based */
	tm->tm_mon = BCD2BIN(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;

	/* year is 1900 + tm->tm_year */
	tm->tm_year = BCD2BIN(rs5c->regs[RS5C372_REG_YEAR]) + 100;

	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
		"mday=%d, mon=%d, year=%d, wday=%d\n",
		__func__,
		tm->tm_sec, tm->tm_min, tm->tm_hour,
		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

	/* rtc might need initialization */
	return rtc_valid_tm(tm);
}

static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	struct rs5c372	*rs5c = i2c_get_clientdata(client);
	unsigned char	buf[8];

	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
		"mday=%d, mon=%d, year=%d, wday=%d\n",
		__func__,
		tm->tm_sec, tm->tm_min, tm->tm_hour,
		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

	buf[0] = RS5C_ADDR(RS5C372_REG_SECS);
	buf[1] = BIN2BCD(tm->tm_sec);
	buf[2] = BIN2BCD(tm->tm_min);
	buf[3] = rs5c_hr2reg(rs5c, tm->tm_hour);
	buf[4] = BIN2BCD(tm->tm_wday);
	buf[5] = BIN2BCD(tm->tm_mday);
	buf[6] = BIN2BCD(tm->tm_mon + 1);
	buf[7] = BIN2BCD(tm->tm_year - 100);

	if ((i2c_master_send(client, buf, 8)) != 8) {
		dev_err(&client->dev, "%s: write error\n", __func__);
		return -EIO;
	}

	return 0;
}

#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
#define	NEED_TRIM
#endif

#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
#define	NEED_TRIM
#endif

#ifdef	NEED_TRIM
static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
{
	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];

	if (osc)
		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;

	if (trim) {
		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
		tmp &= RS5C372_TRIM_MASK;
		if (tmp & 0x3e) {
			int t = tmp & 0x3f;

			if (tmp & 0x40)
				t = (~t | (s8)0xc0) + 1;
			else
				t = t - 1;

			tmp = t * 2;
		} else
			tmp = 0;
		*trim = tmp;
	}

	return 0;
}
#endif

static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return rs5c372_get_datetime(to_i2c_client(dev), tm);
}

static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	return rs5c372_set_datetime(to_i2c_client(dev), tm);
}

#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)

static int
rs5c_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
	struct i2c_client	*client = to_i2c_client(dev);
	struct rs5c372		*rs5c = i2c_get_clientdata(client);
	unsigned char		buf[2];
	int			status;

	buf[1] = rs5c->regs[RS5C_REG_CTRL1];
	switch (cmd) {
	case RTC_UIE_OFF:
	case RTC_UIE_ON:
		/* some 327a modes use a different IRQ pin for 1Hz irqs */
		if (rs5c->type == rtc_rs5c372a
				&& (buf[1] & RS5C372A_CTRL1_SL1))
			return -ENOIOCTLCMD;
	case RTC_AIE_OFF:
	case RTC_AIE_ON:
		/* these irq management calls only make sense for chips
		 * which are wired up to an IRQ.
		 */
		if (!rs5c->has_irq)
			return -ENOIOCTLCMD;
		break;
	default:
		return -ENOIOCTLCMD;
	}

	status = rs5c_get_regs(rs5c);
	if (status < 0)
		return status;

	buf[0] = RS5C_ADDR(RS5C_REG_CTRL1);
	switch (cmd) {
	case RTC_AIE_OFF:	/* alarm off */
		buf[1] &= ~RS5C_CTRL1_AALE;
		break;
	case RTC_AIE_ON:	/* alarm on */
		buf[1] |= RS5C_CTRL1_AALE;
		break;
	case RTC_UIE_OFF:	/* update off */
		buf[1] &= ~RS5C_CTRL1_CT_MASK;
		break;
	case RTC_UIE_ON:	/* update on */
		buf[1] &= ~RS5C_CTRL1_CT_MASK;
		buf[1] |= RS5C_CTRL1_CT4;
		break;
	}
	if ((i2c_master_send(client, buf, 2)) != 2) {
		printk(KERN_WARNING "%s: can't update alarm\n",
			rs5c->rtc->name);
		status = -EIO;
	} else
		rs5c->regs[RS5C_REG_CTRL1] = buf[1];
	return status;
}

#else
#define	rs5c_rtc_ioctl	NULL
#endif


/* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
 * which only exposes a polled programming interface; and since
 * these calls map directly to those EFI requests; we don't demand
 * we have an IRQ for this chip when we go through this API.
 *
 * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
 * though, managed through RTC_AIE_{ON,OFF} requests.
 */

static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
	struct i2c_client	*client = to_i2c_client(dev);
	struct rs5c372		*rs5c = i2c_get_clientdata(client);
	int			status;

	status = rs5c_get_regs(rs5c);
	if (status < 0)
		return status;

	/* report alarm time */
	t->time.tm_sec = 0;
	t->time.tm_min = BCD2BIN(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
	t->time.tm_mday = -1;
	t->time.tm_mon = -1;
	t->time.tm_year = -1;
	t->time.tm_wday = -1;
	t->time.tm_yday = -1;
	t->time.tm_isdst = -1;

	/* ... and status */
	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);

	return 0;
}

static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
	struct i2c_client	*client = to_i2c_client(dev);
	struct rs5c372		*rs5c = i2c_get_clientdata(client);
	int			status;
	unsigned char		buf[4];

	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
	if (t->time.tm_mday != -1
			|| t->time.tm_mon != -1
			|| t->time.tm_year != -1)
		return -EINVAL;

	/* REVISIT: round up tm_sec */

	/* if needed, disable irq (clears pending status) */
	status = rs5c_get_regs(rs5c);
	if (status < 0)
		return status;
	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
		buf[0] = RS5C_ADDR(RS5C_REG_CTRL1);
		buf[1] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
		if (i2c_master_send(client, buf, 2) != 2) {
			pr_debug("%s: can't disable alarm\n", rs5c->rtc->name);
			return -EIO;
		}
		rs5c->regs[RS5C_REG_CTRL1] = buf[1];
	}

	/* set alarm */
	buf[0] = RS5C_ADDR(RS5C_REG_ALARM_A_MIN);
	buf[1] = BIN2BCD(t->time.tm_min);
	buf[2] = rs5c_hr2reg(rs5c, t->time.tm_hour);
	buf[3] = 0x7f;	/* any/all days */
	if ((i2c_master_send(client, buf, 4)) != 4) {
		pr_debug("%s: can't set alarm time\n", rs5c->rtc->name);
		return -EIO;
	}

	/* ... and maybe enable its irq */
	if (t->enabled) {
		buf[0] = RS5C_ADDR(RS5C_REG_CTRL1);
		buf[1] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
		if ((i2c_master_send(client, buf, 2)) != 2)
			printk(KERN_WARNING "%s: can't enable alarm\n",
				rs5c->rtc->name);
		rs5c->regs[RS5C_REG_CTRL1] = buf[1];
	}

	return 0;
}

#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)

static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
{
	int err, osc, trim;

	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
	if (err == 0) {
		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
				osc / 1000, osc % 1000);
		seq_printf(seq, "trim\t\t: %d\n", trim);
	}

	return 0;
}

#else
#define	rs5c372_rtc_proc	NULL
#endif

static const struct rtc_class_ops rs5c372_rtc_ops = {
	.proc		= rs5c372_rtc_proc,
	.ioctl		= rs5c_rtc_ioctl,
	.read_time	= rs5c372_rtc_read_time,
	.set_time	= rs5c372_rtc_set_time,
	.read_alarm	= rs5c_read_alarm,
	.set_alarm	= rs5c_set_alarm,
};

#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)

static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	int err, trim;

	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
	if (err)
		return err;

	return sprintf(buf, "%d\n", trim);
}
static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);

static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	int err, osc;

	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
	if (err)
		return err;

	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
}
static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);

static int rs5c_sysfs_register(struct device *dev)
{
	int err;

	err = device_create_file(dev, &dev_attr_trim);
	if (err)
		return err;
	err = device_create_file(dev, &dev_attr_osc);
	if (err)
		device_remove_file(dev, &dev_attr_trim);

	return err;
}

static void rs5c_sysfs_unregister(struct device *dev)
{
	device_remove_file(dev, &dev_attr_trim);
	device_remove_file(dev, &dev_attr_osc);
}

#else
static int rs5c_sysfs_register(struct device *dev)
{
	return 0;
}

static void rs5c_sysfs_unregister(struct device *dev)
{
	/* nothing */
}
#endif	/* SYSFS */

static struct i2c_driver rs5c372_driver;

static int rs5c372_probe(struct i2c_client *client)
{
	int err = 0;
	struct rs5c372 *rs5c372;
	struct rtc_time tm;

	dev_dbg(&client->dev, "%s\n", __func__);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		err = -ENODEV;
		goto exit;
	}

	if (!(rs5c372 = kzalloc(sizeof(struct rs5c372), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}

	rs5c372->client = client;
	i2c_set_clientdata(client, rs5c372);

	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
	rs5c372->regs = &rs5c372->buf[1];

	err = rs5c_get_regs(rs5c372);
	if (err < 0)
		goto exit_kfree;

	if (strcmp(client->name, "rs5c372a") == 0)
		rs5c372->type = rtc_rs5c372a;
	else if (strcmp(client->name, "rs5c372b") == 0)
		rs5c372->type = rtc_rs5c372b;
	else if (strcmp(client->name, "rv5c386") == 0)
		rs5c372->type = rtc_rv5c386;
	else if (strcmp(client->name, "rv5c387a") == 0)
		rs5c372->type = rtc_rv5c387a;
	else {
		rs5c372->type = rtc_rs5c372b;
		dev_warn(&client->dev, "assuming rs5c372b\n");
	}

	/* clock may be set for am/pm or 24 hr time */
	switch (rs5c372->type) {
	case rtc_rs5c372a:
	case rtc_rs5c372b:
		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
		 * so does periodic irq, except some 327a modes.
		 */
		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
			rs5c372->time24 = 1;
		break;
	case rtc_rv5c386:
	case rtc_rv5c387a:
		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
			rs5c372->time24 = 1;
		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
		 * irq, on both 386 and 387
		 */
		break;
	default:
		dev_err(&client->dev, "unknown RTC type\n");
		goto exit_kfree;
	}

	/* if the oscillator lost power and no other software (like
	 * the bootloader) set it up, do it here.
	 */
	if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP) {
		unsigned char buf[3];

		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;

		buf[0] = RS5C_ADDR(RS5C_REG_CTRL1);
		buf[1] = rs5c372->regs[RS5C_REG_CTRL1];
		buf[2] = rs5c372->regs[RS5C_REG_CTRL2];

		/* use 24hr mode */
		switch (rs5c372->type) {
		case rtc_rs5c372a:
		case rtc_rs5c372b:
			buf[2] |= RS5C372_CTRL2_24;
			rs5c372->time24 = 1;
			break;
		case rtc_rv5c386:
		case rtc_rv5c387a:
			buf[1] |= RV5C387_CTRL1_24;
			rs5c372->time24 = 1;
			break;
		default:
			/* impossible */
			break;
		}

		if ((i2c_master_send(client, buf, 3)) != 3) {
			dev_err(&client->dev, "setup error\n");
			goto exit_kfree;
		}
		rs5c372->regs[RS5C_REG_CTRL1] = buf[1];
		rs5c372->regs[RS5C_REG_CTRL2] = buf[2];
	}

	if (rs5c372_get_datetime(client, &tm) < 0)
		dev_warn(&client->dev, "clock needs to be set\n");

	dev_info(&client->dev, "%s found, %s, driver version " DRV_VERSION "\n",
			({ char *s; switch (rs5c372->type) {
			case rtc_rs5c372a:	s = "rs5c372a"; break;
			case rtc_rs5c372b:	s = "rs5c372b"; break;
			case rtc_rv5c386:	s = "rv5c386"; break;
			case rtc_rv5c387a:	s = "rv5c387a"; break;
			default:		s = "chip"; break;
			}; s;}),
			rs5c372->time24 ? "24hr" : "am/pm"
			);

	/* REVISIT use client->irq to register alarm irq ... */

	rs5c372->rtc = rtc_device_register(rs5c372_driver.driver.name,
				&client->dev, &rs5c372_rtc_ops, THIS_MODULE);

	if (IS_ERR(rs5c372->rtc)) {
		err = PTR_ERR(rs5c372->rtc);
		goto exit_kfree;
	}

	err = rs5c_sysfs_register(&client->dev);
	if (err)
		goto exit_devreg;

	return 0;

exit_devreg:
	rtc_device_unregister(rs5c372->rtc);

exit_kfree:
	kfree(rs5c372);

exit:
	return err;
}

static int rs5c372_remove(struct i2c_client *client)
{
	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);

	rtc_device_unregister(rs5c372->rtc);
	rs5c_sysfs_unregister(&client->dev);
	kfree(rs5c372);
	return 0;
}

static struct i2c_driver rs5c372_driver = {
	.driver		= {
		.name	= "rtc-rs5c372",
	},
	.probe		= rs5c372_probe,
	.remove		= rs5c372_remove,
};

static __init int rs5c372_init(void)
{
	return i2c_add_driver(&rs5c372_driver);
}

static __exit void rs5c372_exit(void)
{
	i2c_del_driver(&rs5c372_driver);
}

module_init(rs5c372_init);
module_exit(rs5c372_exit);

MODULE_AUTHOR(
		"Pavel Mironchik <pmironchik@optifacio.net>, "
		"Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);