summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/rtc/rtc-fm3130.c
blob: 83c3b3029fa774321332961b7abad8796088686b (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
/*
 * rtc-fm3130.c - RTC driver for Ramtron FM3130 I2C chip.
 *
 *  Copyright (C) 2008 Sergey Lapin
 *  Based on ds1307 driver by James Chapman and David Brownell
 *
 * 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/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/slab.h>

#define FM3130_RTC_CONTROL	(0x0)
#define FM3130_CAL_CONTROL	(0x1)
#define FM3130_RTC_SECONDS	(0x2)
#define FM3130_RTC_MINUTES	(0x3)
#define FM3130_RTC_HOURS	(0x4)
#define FM3130_RTC_DAY		(0x5)
#define FM3130_RTC_DATE		(0x6)
#define FM3130_RTC_MONTHS	(0x7)
#define FM3130_RTC_YEARS	(0x8)

#define FM3130_ALARM_SECONDS	(0x9)
#define FM3130_ALARM_MINUTES	(0xa)
#define FM3130_ALARM_HOURS	(0xb)
#define FM3130_ALARM_DATE	(0xc)
#define FM3130_ALARM_MONTHS	(0xd)
#define FM3130_ALARM_WP_CONTROL	(0xe)

#define FM3130_CAL_CONTROL_BIT_nOSCEN (1 << 7) /* Osciallator enabled */
#define FM3130_RTC_CONTROL_BIT_LB (1 << 7) /* Low battery */
#define FM3130_RTC_CONTROL_BIT_AF (1 << 6) /* Alarm flag */
#define FM3130_RTC_CONTROL_BIT_CF (1 << 5) /* Century overflow */
#define FM3130_RTC_CONTROL_BIT_POR (1 << 4) /* Power on reset */
#define FM3130_RTC_CONTROL_BIT_AEN (1 << 3) /* Alarm enable */
#define FM3130_RTC_CONTROL_BIT_CAL (1 << 2) /* Calibration mode */
#define FM3130_RTC_CONTROL_BIT_WRITE (1 << 1) /* W=1 -> write mode W=0 normal */
#define FM3130_RTC_CONTROL_BIT_READ (1 << 0) /* R=1 -> read mode R=0 normal */

#define FM3130_CLOCK_REGS 7
#define FM3130_ALARM_REGS 5

struct fm3130 {
	u8			reg_addr_time;
	u8			reg_addr_alarm;
	u8			regs[15];
	struct i2c_msg		msg[4];
	struct i2c_client	*client;
	struct rtc_device	*rtc;
	int			alarm_valid;
	int			data_valid;
};
static const struct i2c_device_id fm3130_id[] = {
	{ "fm3130", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, fm3130_id);

#define FM3130_MODE_NORMAL		0
#define FM3130_MODE_WRITE		1
#define FM3130_MODE_READ		2

static void fm3130_rtc_mode(struct device *dev, int mode)
{
	struct fm3130 *fm3130 = dev_get_drvdata(dev);

	fm3130->regs[FM3130_RTC_CONTROL] =
		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
	switch (mode) {
	case FM3130_MODE_NORMAL:
		fm3130->regs[FM3130_RTC_CONTROL] &=
			~(FM3130_RTC_CONTROL_BIT_WRITE |
			FM3130_RTC_CONTROL_BIT_READ);
		break;
	case FM3130_MODE_WRITE:
		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_WRITE;
		break;
	case FM3130_MODE_READ:
		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_READ;
		break;
	default:
		dev_dbg(dev, "invalid mode %d\n", mode);
		break;
	}

	i2c_smbus_write_byte_data(fm3130->client,
		 FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL]);
}

static int fm3130_get_time(struct device *dev, struct rtc_time *t)
{
	struct fm3130 *fm3130 = dev_get_drvdata(dev);
	int		tmp;

	if (!fm3130->data_valid) {
		/* We have invalid data in RTC, probably due
		to battery faults or other problems. Return EIO
		for now, it will allow us to set data later instead
		of error during probing which disables device */
		return -EIO;
	}
	fm3130_rtc_mode(dev, FM3130_MODE_READ);

	/* read the RTC date and time registers all at once */
	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
			fm3130->msg, 2);
	if (tmp != 2) {
		dev_err(dev, "%s error %d\n", "read", tmp);
		return -EIO;
	}

	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);

	dev_dbg(dev, "%s: %15ph\n", "read", fm3130->regs);

	t->tm_sec = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
	t->tm_min = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
	tmp = fm3130->regs[FM3130_RTC_HOURS] & 0x3f;
	t->tm_hour = bcd2bin(tmp);
	t->tm_wday = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x07) - 1;
	t->tm_mday = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
	tmp = fm3130->regs[FM3130_RTC_MONTHS] & 0x1f;
	t->tm_mon = bcd2bin(tmp) - 1;

	/* assume 20YY not 19YY, and ignore CF bit */
	t->tm_year = bcd2bin(fm3130->regs[FM3130_RTC_YEARS]) + 100;

	dev_dbg(dev, "%s secs=%d, mins=%d, "
		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
		"read", t->tm_sec, t->tm_min,
		t->tm_hour, t->tm_mday,
		t->tm_mon, t->tm_year, t->tm_wday);

	/* initial clock setting can be undefined */
	return rtc_valid_tm(t);
}


static int fm3130_set_time(struct device *dev, struct rtc_time *t)
{
	struct fm3130 *fm3130 = dev_get_drvdata(dev);
	int		tmp, i;
	u8		*buf = fm3130->regs;

	dev_dbg(dev, "%s secs=%d, mins=%d, "
		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
		"write", t->tm_sec, t->tm_min,
		t->tm_hour, t->tm_mday,
		t->tm_mon, t->tm_year, t->tm_wday);

	/* first register addr */
	buf[FM3130_RTC_SECONDS] = bin2bcd(t->tm_sec);
	buf[FM3130_RTC_MINUTES] = bin2bcd(t->tm_min);
	buf[FM3130_RTC_HOURS] = bin2bcd(t->tm_hour);
	buf[FM3130_RTC_DAY] = bin2bcd(t->tm_wday + 1);
	buf[FM3130_RTC_DATE] = bin2bcd(t->tm_mday);
	buf[FM3130_RTC_MONTHS] = bin2bcd(t->tm_mon + 1);

	/* assume 20YY not 19YY */
	tmp = t->tm_year - 100;
	buf[FM3130_RTC_YEARS] = bin2bcd(tmp);

	dev_dbg(dev, "%s: %15ph\n", "write", buf);

	fm3130_rtc_mode(dev, FM3130_MODE_WRITE);

	/* Writing time registers, we don't support multibyte transfers */
	for (i = 0; i < FM3130_CLOCK_REGS; i++) {
		i2c_smbus_write_byte_data(fm3130->client,
					FM3130_RTC_SECONDS + i,
					fm3130->regs[FM3130_RTC_SECONDS + i]);
	}

	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);

	/* We assume here that data are valid once written */
	if (!fm3130->data_valid)
		fm3130->data_valid = 1;
	return 0;
}

static int fm3130_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct fm3130 *fm3130 = dev_get_drvdata(dev);
	int tmp;
	struct rtc_time *tm = &alrm->time;

	if (!fm3130->alarm_valid) {
		/*
		 * We have invalid alarm in RTC, probably due to battery faults
		 * or other problems. Return EIO for now, it will allow us to
		 * set alarm value later instead of error during probing which
		 * disables device
		 */
		return -EIO;
	}

	/* read the RTC alarm registers all at once */
	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
			&fm3130->msg[2], 2);
	if (tmp != 2) {
		dev_err(dev, "%s error %d\n", "read", tmp);
		return -EIO;
	}
	dev_dbg(dev, "alarm read %02x %02x %02x %02x %02x\n",
			fm3130->regs[FM3130_ALARM_SECONDS],
			fm3130->regs[FM3130_ALARM_MINUTES],
			fm3130->regs[FM3130_ALARM_HOURS],
			fm3130->regs[FM3130_ALARM_DATE],
			fm3130->regs[FM3130_ALARM_MONTHS]);

	tm->tm_sec	= bcd2bin(fm3130->regs[FM3130_ALARM_SECONDS] & 0x7F);
	tm->tm_min	= bcd2bin(fm3130->regs[FM3130_ALARM_MINUTES] & 0x7F);
	tm->tm_hour	= bcd2bin(fm3130->regs[FM3130_ALARM_HOURS] & 0x3F);
	tm->tm_mday	= bcd2bin(fm3130->regs[FM3130_ALARM_DATE] & 0x3F);
	tm->tm_mon	= bcd2bin(fm3130->regs[FM3130_ALARM_MONTHS] & 0x1F);

	if (tm->tm_mon > 0)
		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */

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

	/* check if alarm enabled */
	fm3130->regs[FM3130_RTC_CONTROL] =
		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);

	if ((fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AEN) &&
		(~fm3130->regs[FM3130_RTC_CONTROL] &
			FM3130_RTC_CONTROL_BIT_CAL)) {
		alrm->enabled = 1;
	}

	return 0;
}

static int fm3130_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct fm3130 *fm3130 = dev_get_drvdata(dev);
	struct rtc_time *tm = &alrm->time;
	int i;

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

	fm3130->regs[FM3130_ALARM_SECONDS] =
		(tm->tm_sec != -1) ? bin2bcd(tm->tm_sec) : 0x80;

	fm3130->regs[FM3130_ALARM_MINUTES] =
		(tm->tm_min != -1) ? bin2bcd(tm->tm_min) : 0x80;

	fm3130->regs[FM3130_ALARM_HOURS] =
		(tm->tm_hour != -1) ? bin2bcd(tm->tm_hour) : 0x80;

	fm3130->regs[FM3130_ALARM_DATE] =
		(tm->tm_mday != -1) ? bin2bcd(tm->tm_mday) : 0x80;

	fm3130->regs[FM3130_ALARM_MONTHS] =
		(tm->tm_mon != -1) ? bin2bcd(tm->tm_mon + 1) : 0x80;

	dev_dbg(dev, "alarm write %02x %02x %02x %02x %02x\n",
			fm3130->regs[FM3130_ALARM_SECONDS],
			fm3130->regs[FM3130_ALARM_MINUTES],
			fm3130->regs[FM3130_ALARM_HOURS],
			fm3130->regs[FM3130_ALARM_DATE],
			fm3130->regs[FM3130_ALARM_MONTHS]);
	/* Writing time registers, we don't support multibyte transfers */
	for (i = 0; i < FM3130_ALARM_REGS; i++) {
		i2c_smbus_write_byte_data(fm3130->client,
					FM3130_ALARM_SECONDS + i,
					fm3130->regs[FM3130_ALARM_SECONDS + i]);
	}
	fm3130->regs[FM3130_RTC_CONTROL] =
		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);

	/* enable or disable alarm */
	if (alrm->enabled) {
		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
			(fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_CAL)) |
					FM3130_RTC_CONTROL_BIT_AEN);
	} else {
		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
			fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_CAL) &
					~(FM3130_RTC_CONTROL_BIT_AEN));
	}

	/* We assume here that data is valid once written */
	if (!fm3130->alarm_valid)
		fm3130->alarm_valid = 1;

	return 0;
}

static int fm3130_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct fm3130 *fm3130 = dev_get_drvdata(dev);
	int ret = 0;

	fm3130->regs[FM3130_RTC_CONTROL] =
		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);

	dev_dbg(dev, "alarm_irq_enable: enable=%d, FM3130_RTC_CONTROL=%02x\n",
		enabled, fm3130->regs[FM3130_RTC_CONTROL]);

	switch (enabled) {
	case 0:		/* alarm off */
		ret = i2c_smbus_write_byte_data(fm3130->client,
			FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_CAL) &
					~(FM3130_RTC_CONTROL_BIT_AEN));
		break;
	case 1:		/* alarm on */
		ret = i2c_smbus_write_byte_data(fm3130->client,
			FM3130_RTC_CONTROL, (fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_CAL)) |
					FM3130_RTC_CONTROL_BIT_AEN);
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

static const struct rtc_class_ops fm3130_rtc_ops = {
	.read_time	= fm3130_get_time,
	.set_time	= fm3130_set_time,
	.read_alarm	= fm3130_read_alarm,
	.set_alarm	= fm3130_set_alarm,
	.alarm_irq_enable = fm3130_alarm_irq_enable,
};

static struct i2c_driver fm3130_driver;

static int fm3130_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct fm3130		*fm3130;
	int			err = -ENODEV;
	int			tmp;
	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);

	if (!i2c_check_functionality(adapter,
			I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
		return -EIO;

	fm3130 = devm_kzalloc(&client->dev, sizeof(struct fm3130), GFP_KERNEL);

	if (!fm3130)
		return -ENOMEM;

	fm3130->client = client;
	i2c_set_clientdata(client, fm3130);
	fm3130->reg_addr_time = FM3130_RTC_SECONDS;
	fm3130->reg_addr_alarm = FM3130_ALARM_SECONDS;

	/* Messages to read time */
	fm3130->msg[0].addr = client->addr;
	fm3130->msg[0].flags = 0;
	fm3130->msg[0].len = 1;
	fm3130->msg[0].buf = &fm3130->reg_addr_time;

	fm3130->msg[1].addr = client->addr;
	fm3130->msg[1].flags = I2C_M_RD;
	fm3130->msg[1].len = FM3130_CLOCK_REGS;
	fm3130->msg[1].buf = &fm3130->regs[FM3130_RTC_SECONDS];

	/* Messages to read alarm */
	fm3130->msg[2].addr = client->addr;
	fm3130->msg[2].flags = 0;
	fm3130->msg[2].len = 1;
	fm3130->msg[2].buf = &fm3130->reg_addr_alarm;

	fm3130->msg[3].addr = client->addr;
	fm3130->msg[3].flags = I2C_M_RD;
	fm3130->msg[3].len = FM3130_ALARM_REGS;
	fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];

	fm3130->alarm_valid = 0;
	fm3130->data_valid = 0;

	tmp = i2c_transfer(adapter, fm3130->msg, 4);
	if (tmp != 4) {
		dev_dbg(&client->dev, "read error %d\n", tmp);
		err = -EIO;
		goto exit_free;
	}

	fm3130->regs[FM3130_RTC_CONTROL] =
		i2c_smbus_read_byte_data(client, FM3130_RTC_CONTROL);
	fm3130->regs[FM3130_CAL_CONTROL] =
		i2c_smbus_read_byte_data(client, FM3130_CAL_CONTROL);

	/* Disabling calibration mode */
	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_CAL) {
		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
			fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_CAL));
		dev_warn(&client->dev, "Disabling calibration mode!\n");
	}

	/* Disabling read and write modes */
	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_WRITE ||
	    fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_READ) {
		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
			fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_READ |
					FM3130_RTC_CONTROL_BIT_WRITE));
		dev_warn(&client->dev, "Disabling READ or WRITE mode!\n");
	}

	/* oscillator off?  turn it on, so clock can tick. */
	if (fm3130->regs[FM3130_CAL_CONTROL] & FM3130_CAL_CONTROL_BIT_nOSCEN)
		i2c_smbus_write_byte_data(client, FM3130_CAL_CONTROL,
			fm3130->regs[FM3130_CAL_CONTROL] &
				~(FM3130_CAL_CONTROL_BIT_nOSCEN));

	/* low battery?  clear flag, and warn */
	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB) {
		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
			fm3130->regs[FM3130_RTC_CONTROL] &
				~(FM3130_RTC_CONTROL_BIT_LB));
		dev_warn(&client->dev, "Low battery!\n");
	}

	/* check if Power On Reset bit is set */
	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_POR) {
		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
			fm3130->regs[FM3130_RTC_CONTROL] &
				~FM3130_RTC_CONTROL_BIT_POR);
		dev_dbg(&client->dev, "POR bit is set\n");
	}
	/* ACS is controlled by alarm */
	i2c_smbus_write_byte_data(client, FM3130_ALARM_WP_CONTROL, 0x80);

	/* alarm registers sanity check */
	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
	if (tmp > 59)
		goto bad_alarm;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
	if (tmp > 59)
		goto bad_alarm;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
	if (tmp > 23)
		goto bad_alarm;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
	if (tmp == 0 || tmp > 31)
		goto bad_alarm;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
	if (tmp == 0 || tmp > 12)
		goto bad_alarm;

	fm3130->alarm_valid = 1;

bad_alarm:

	/* clock registers sanity chek */
	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
	if (tmp > 59)
		goto bad_clock;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
	if (tmp > 59)
		goto bad_clock;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
	if (tmp > 23)
		goto bad_clock;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x7);
	if (tmp == 0 || tmp > 7)
		goto bad_clock;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
	if (tmp == 0 || tmp > 31)
		goto bad_clock;

	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
	if (tmp == 0 || tmp > 12)
		goto bad_clock;

	fm3130->data_valid = 1;

bad_clock:

	if (!fm3130->data_valid || !fm3130->alarm_valid)
		dev_dbg(&client->dev, "%s: %15ph\n", "bogus registers",
			fm3130->regs);

	/* We won't bail out here because we just got invalid data.
	   Time setting from u-boot doesn't work anyway */
	fm3130->rtc = devm_rtc_device_register(&client->dev, client->name,
				&fm3130_rtc_ops, THIS_MODULE);
	if (IS_ERR(fm3130->rtc)) {
		err = PTR_ERR(fm3130->rtc);
		dev_err(&client->dev,
			"unable to register the class device\n");
		goto exit_free;
	}
	return 0;
exit_free:
	return err;
}

static struct i2c_driver fm3130_driver = {
	.driver = {
		.name	= "rtc-fm3130",
		.owner	= THIS_MODULE,
	},
	.probe		= fm3130_probe,
	.id_table	= fm3130_id,
};

module_i2c_driver(fm3130_driver);

MODULE_DESCRIPTION("RTC driver for FM3130");
MODULE_AUTHOR("Sergey Lapin <slapin@ossfans.org>");
MODULE_LICENSE("GPL");