xref: /linux/drivers/rtc/rtc-fm3130.c (revision 693d345818e106318710ac150ae252b73765d0fa)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * rtc-fm3130.c - RTC driver for Ramtron FM3130 I2C chip.
4  *
5  *  Copyright (C) 2008 Sergey Lapin
6  *  Based on ds1307 driver by James Chapman and David Brownell
7  */
8 
9 #include <linux/module.h>
10 #include <linux/i2c.h>
11 #include <linux/rtc.h>
12 #include <linux/bcd.h>
13 #include <linux/slab.h>
14 
15 #define FM3130_RTC_CONTROL	(0x0)
16 #define FM3130_CAL_CONTROL	(0x1)
17 #define FM3130_RTC_SECONDS	(0x2)
18 #define FM3130_RTC_MINUTES	(0x3)
19 #define FM3130_RTC_HOURS	(0x4)
20 #define FM3130_RTC_DAY		(0x5)
21 #define FM3130_RTC_DATE		(0x6)
22 #define FM3130_RTC_MONTHS	(0x7)
23 #define FM3130_RTC_YEARS	(0x8)
24 
25 #define FM3130_ALARM_SECONDS	(0x9)
26 #define FM3130_ALARM_MINUTES	(0xa)
27 #define FM3130_ALARM_HOURS	(0xb)
28 #define FM3130_ALARM_DATE	(0xc)
29 #define FM3130_ALARM_MONTHS	(0xd)
30 #define FM3130_ALARM_WP_CONTROL	(0xe)
31 
32 #define FM3130_CAL_CONTROL_BIT_nOSCEN (1 << 7) /* Osciallator enabled */
33 #define FM3130_RTC_CONTROL_BIT_LB (1 << 7) /* Low battery */
34 #define FM3130_RTC_CONTROL_BIT_AF (1 << 6) /* Alarm flag */
35 #define FM3130_RTC_CONTROL_BIT_CF (1 << 5) /* Century overflow */
36 #define FM3130_RTC_CONTROL_BIT_POR (1 << 4) /* Power on reset */
37 #define FM3130_RTC_CONTROL_BIT_AEN (1 << 3) /* Alarm enable */
38 #define FM3130_RTC_CONTROL_BIT_CAL (1 << 2) /* Calibration mode */
39 #define FM3130_RTC_CONTROL_BIT_WRITE (1 << 1) /* W=1 -> write mode W=0 normal */
40 #define FM3130_RTC_CONTROL_BIT_READ (1 << 0) /* R=1 -> read mode R=0 normal */
41 
42 #define FM3130_CLOCK_REGS 7
43 #define FM3130_ALARM_REGS 5
44 
45 struct fm3130 {
46 	u8			reg_addr_time;
47 	u8			reg_addr_alarm;
48 	u8			regs[15];
49 	struct i2c_msg		msg[4];
50 	struct i2c_client	*client;
51 	struct rtc_device	*rtc;
52 	int			alarm_valid;
53 	int			data_valid;
54 };
55 static const struct i2c_device_id fm3130_id[] = {
56 	{ "fm3130", 0 },
57 	{ }
58 };
59 MODULE_DEVICE_TABLE(i2c, fm3130_id);
60 
61 #define FM3130_MODE_NORMAL		0
62 #define FM3130_MODE_WRITE		1
63 #define FM3130_MODE_READ		2
64 
65 static void fm3130_rtc_mode(struct device *dev, int mode)
66 {
67 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
68 
69 	fm3130->regs[FM3130_RTC_CONTROL] =
70 		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
71 	switch (mode) {
72 	case FM3130_MODE_NORMAL:
73 		fm3130->regs[FM3130_RTC_CONTROL] &=
74 			~(FM3130_RTC_CONTROL_BIT_WRITE |
75 			FM3130_RTC_CONTROL_BIT_READ);
76 		break;
77 	case FM3130_MODE_WRITE:
78 		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_WRITE;
79 		break;
80 	case FM3130_MODE_READ:
81 		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_READ;
82 		break;
83 	default:
84 		dev_dbg(dev, "invalid mode %d\n", mode);
85 		break;
86 	}
87 
88 	i2c_smbus_write_byte_data(fm3130->client,
89 		 FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL]);
90 }
91 
92 static int fm3130_get_time(struct device *dev, struct rtc_time *t)
93 {
94 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
95 	int		tmp;
96 
97 	if (!fm3130->data_valid) {
98 		/* We have invalid data in RTC, probably due
99 		to battery faults or other problems. Return EIO
100 		for now, it will allow us to set data later instead
101 		of error during probing which disables device */
102 		return -EIO;
103 	}
104 	fm3130_rtc_mode(dev, FM3130_MODE_READ);
105 
106 	/* read the RTC date and time registers all at once */
107 	tmp = i2c_transfer(fm3130->client->adapter, fm3130->msg, 2);
108 	if (tmp != 2) {
109 		dev_err(dev, "%s error %d\n", "read", tmp);
110 		return -EIO;
111 	}
112 
113 	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
114 
115 	dev_dbg(dev, "%s: %15ph\n", "read", fm3130->regs);
116 
117 	t->tm_sec = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
118 	t->tm_min = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
119 	tmp = fm3130->regs[FM3130_RTC_HOURS] & 0x3f;
120 	t->tm_hour = bcd2bin(tmp);
121 	t->tm_wday = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x07) - 1;
122 	t->tm_mday = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
123 	tmp = fm3130->regs[FM3130_RTC_MONTHS] & 0x1f;
124 	t->tm_mon = bcd2bin(tmp) - 1;
125 
126 	/* assume 20YY not 19YY, and ignore CF bit */
127 	t->tm_year = bcd2bin(fm3130->regs[FM3130_RTC_YEARS]) + 100;
128 
129 	dev_dbg(dev, "%s secs=%d, mins=%d, "
130 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
131 		"read", t->tm_sec, t->tm_min,
132 		t->tm_hour, t->tm_mday,
133 		t->tm_mon, t->tm_year, t->tm_wday);
134 
135 	return 0;
136 }
137 
138 
139 static int fm3130_set_time(struct device *dev, struct rtc_time *t)
140 {
141 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
142 	int		tmp, i;
143 	u8		*buf = fm3130->regs;
144 
145 	dev_dbg(dev, "%s secs=%d, mins=%d, "
146 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
147 		"write", t->tm_sec, t->tm_min,
148 		t->tm_hour, t->tm_mday,
149 		t->tm_mon, t->tm_year, t->tm_wday);
150 
151 	/* first register addr */
152 	buf[FM3130_RTC_SECONDS] = bin2bcd(t->tm_sec);
153 	buf[FM3130_RTC_MINUTES] = bin2bcd(t->tm_min);
154 	buf[FM3130_RTC_HOURS] = bin2bcd(t->tm_hour);
155 	buf[FM3130_RTC_DAY] = bin2bcd(t->tm_wday + 1);
156 	buf[FM3130_RTC_DATE] = bin2bcd(t->tm_mday);
157 	buf[FM3130_RTC_MONTHS] = bin2bcd(t->tm_mon + 1);
158 
159 	/* assume 20YY not 19YY */
160 	tmp = t->tm_year - 100;
161 	buf[FM3130_RTC_YEARS] = bin2bcd(tmp);
162 
163 	dev_dbg(dev, "%s: %15ph\n", "write", buf);
164 
165 	fm3130_rtc_mode(dev, FM3130_MODE_WRITE);
166 
167 	/* Writing time registers, we don't support multibyte transfers */
168 	for (i = 0; i < FM3130_CLOCK_REGS; i++) {
169 		i2c_smbus_write_byte_data(fm3130->client,
170 					FM3130_RTC_SECONDS + i,
171 					fm3130->regs[FM3130_RTC_SECONDS + i]);
172 	}
173 
174 	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
175 
176 	/* We assume here that data are valid once written */
177 	if (!fm3130->data_valid)
178 		fm3130->data_valid = 1;
179 	return 0;
180 }
181 
182 static int fm3130_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
183 {
184 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
185 	int tmp;
186 	struct rtc_time *tm = &alrm->time;
187 
188 	if (!fm3130->alarm_valid) {
189 		/*
190 		 * We have invalid alarm in RTC, probably due to battery faults
191 		 * or other problems. Return EIO for now, it will allow us to
192 		 * set alarm value later instead of error during probing which
193 		 * disables device
194 		 */
195 		return -EIO;
196 	}
197 
198 	/* read the RTC alarm registers all at once */
199 	tmp = i2c_transfer(fm3130->client->adapter, &fm3130->msg[2], 2);
200 	if (tmp != 2) {
201 		dev_err(dev, "%s error %d\n", "read", tmp);
202 		return -EIO;
203 	}
204 	dev_dbg(dev, "alarm read %02x %02x %02x %02x %02x\n",
205 			fm3130->regs[FM3130_ALARM_SECONDS],
206 			fm3130->regs[FM3130_ALARM_MINUTES],
207 			fm3130->regs[FM3130_ALARM_HOURS],
208 			fm3130->regs[FM3130_ALARM_DATE],
209 			fm3130->regs[FM3130_ALARM_MONTHS]);
210 
211 	tm->tm_sec	= bcd2bin(fm3130->regs[FM3130_ALARM_SECONDS] & 0x7F);
212 	tm->tm_min	= bcd2bin(fm3130->regs[FM3130_ALARM_MINUTES] & 0x7F);
213 	tm->tm_hour	= bcd2bin(fm3130->regs[FM3130_ALARM_HOURS] & 0x3F);
214 	tm->tm_mday	= bcd2bin(fm3130->regs[FM3130_ALARM_DATE] & 0x3F);
215 	tm->tm_mon	= bcd2bin(fm3130->regs[FM3130_ALARM_MONTHS] & 0x1F);
216 
217 	if (tm->tm_mon > 0)
218 		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
219 
220 	dev_dbg(dev, "%s secs=%d, mins=%d, "
221 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
222 		"read alarm", tm->tm_sec, tm->tm_min,
223 		tm->tm_hour, tm->tm_mday,
224 		tm->tm_mon, tm->tm_year, tm->tm_wday);
225 
226 	/* check if alarm enabled */
227 	fm3130->regs[FM3130_RTC_CONTROL] =
228 		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
229 
230 	if ((fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AEN) &&
231 		(~fm3130->regs[FM3130_RTC_CONTROL] &
232 			FM3130_RTC_CONTROL_BIT_CAL)) {
233 		alrm->enabled = 1;
234 	}
235 
236 	return 0;
237 }
238 
239 static int fm3130_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
240 {
241 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
242 	struct rtc_time *tm = &alrm->time;
243 	int i;
244 
245 	dev_dbg(dev, "%s secs=%d, mins=%d, "
246 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
247 		"write alarm", tm->tm_sec, tm->tm_min,
248 		tm->tm_hour, tm->tm_mday,
249 		tm->tm_mon, tm->tm_year, tm->tm_wday);
250 
251 	fm3130->regs[FM3130_ALARM_SECONDS] =
252 		(tm->tm_sec != -1) ? bin2bcd(tm->tm_sec) : 0x80;
253 
254 	fm3130->regs[FM3130_ALARM_MINUTES] =
255 		(tm->tm_min != -1) ? bin2bcd(tm->tm_min) : 0x80;
256 
257 	fm3130->regs[FM3130_ALARM_HOURS] =
258 		(tm->tm_hour != -1) ? bin2bcd(tm->tm_hour) : 0x80;
259 
260 	fm3130->regs[FM3130_ALARM_DATE] =
261 		(tm->tm_mday != -1) ? bin2bcd(tm->tm_mday) : 0x80;
262 
263 	fm3130->regs[FM3130_ALARM_MONTHS] =
264 		(tm->tm_mon != -1) ? bin2bcd(tm->tm_mon + 1) : 0x80;
265 
266 	dev_dbg(dev, "alarm write %02x %02x %02x %02x %02x\n",
267 			fm3130->regs[FM3130_ALARM_SECONDS],
268 			fm3130->regs[FM3130_ALARM_MINUTES],
269 			fm3130->regs[FM3130_ALARM_HOURS],
270 			fm3130->regs[FM3130_ALARM_DATE],
271 			fm3130->regs[FM3130_ALARM_MONTHS]);
272 	/* Writing time registers, we don't support multibyte transfers */
273 	for (i = 0; i < FM3130_ALARM_REGS; i++) {
274 		i2c_smbus_write_byte_data(fm3130->client,
275 					FM3130_ALARM_SECONDS + i,
276 					fm3130->regs[FM3130_ALARM_SECONDS + i]);
277 	}
278 	fm3130->regs[FM3130_RTC_CONTROL] =
279 		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
280 
281 	/* enable or disable alarm */
282 	if (alrm->enabled) {
283 		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
284 			(fm3130->regs[FM3130_RTC_CONTROL] &
285 				~(FM3130_RTC_CONTROL_BIT_CAL)) |
286 					FM3130_RTC_CONTROL_BIT_AEN);
287 	} else {
288 		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
289 			fm3130->regs[FM3130_RTC_CONTROL] &
290 				~(FM3130_RTC_CONTROL_BIT_CAL) &
291 					~(FM3130_RTC_CONTROL_BIT_AEN));
292 	}
293 
294 	/* We assume here that data is valid once written */
295 	if (!fm3130->alarm_valid)
296 		fm3130->alarm_valid = 1;
297 
298 	return 0;
299 }
300 
301 static int fm3130_alarm_irq_enable(struct device *dev, unsigned int enabled)
302 {
303 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
304 	int ret = 0;
305 
306 	fm3130->regs[FM3130_RTC_CONTROL] =
307 		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
308 
309 	dev_dbg(dev, "alarm_irq_enable: enable=%d, FM3130_RTC_CONTROL=%02x\n",
310 		enabled, fm3130->regs[FM3130_RTC_CONTROL]);
311 
312 	switch (enabled) {
313 	case 0:		/* alarm off */
314 		ret = i2c_smbus_write_byte_data(fm3130->client,
315 			FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL] &
316 				~(FM3130_RTC_CONTROL_BIT_CAL) &
317 					~(FM3130_RTC_CONTROL_BIT_AEN));
318 		break;
319 	case 1:		/* alarm on */
320 		ret = i2c_smbus_write_byte_data(fm3130->client,
321 			FM3130_RTC_CONTROL, (fm3130->regs[FM3130_RTC_CONTROL] &
322 				~(FM3130_RTC_CONTROL_BIT_CAL)) |
323 					FM3130_RTC_CONTROL_BIT_AEN);
324 		break;
325 	default:
326 		ret = -EINVAL;
327 		break;
328 	}
329 
330 	return ret;
331 }
332 
333 static const struct rtc_class_ops fm3130_rtc_ops = {
334 	.read_time	= fm3130_get_time,
335 	.set_time	= fm3130_set_time,
336 	.read_alarm	= fm3130_read_alarm,
337 	.set_alarm	= fm3130_set_alarm,
338 	.alarm_irq_enable = fm3130_alarm_irq_enable,
339 };
340 
341 static struct i2c_driver fm3130_driver;
342 
343 static int fm3130_probe(struct i2c_client *client,
344 			const struct i2c_device_id *id)
345 {
346 	struct fm3130		*fm3130;
347 	int			err = -ENODEV;
348 	int			tmp;
349 	struct i2c_adapter	*adapter = client->adapter;
350 
351 	if (!i2c_check_functionality(adapter,
352 			I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
353 		return -EIO;
354 
355 	fm3130 = devm_kzalloc(&client->dev, sizeof(struct fm3130), GFP_KERNEL);
356 
357 	if (!fm3130)
358 		return -ENOMEM;
359 
360 	fm3130->client = client;
361 	i2c_set_clientdata(client, fm3130);
362 	fm3130->reg_addr_time = FM3130_RTC_SECONDS;
363 	fm3130->reg_addr_alarm = FM3130_ALARM_SECONDS;
364 
365 	/* Messages to read time */
366 	fm3130->msg[0].addr = client->addr;
367 	fm3130->msg[0].flags = 0;
368 	fm3130->msg[0].len = 1;
369 	fm3130->msg[0].buf = &fm3130->reg_addr_time;
370 
371 	fm3130->msg[1].addr = client->addr;
372 	fm3130->msg[1].flags = I2C_M_RD;
373 	fm3130->msg[1].len = FM3130_CLOCK_REGS;
374 	fm3130->msg[1].buf = &fm3130->regs[FM3130_RTC_SECONDS];
375 
376 	/* Messages to read alarm */
377 	fm3130->msg[2].addr = client->addr;
378 	fm3130->msg[2].flags = 0;
379 	fm3130->msg[2].len = 1;
380 	fm3130->msg[2].buf = &fm3130->reg_addr_alarm;
381 
382 	fm3130->msg[3].addr = client->addr;
383 	fm3130->msg[3].flags = I2C_M_RD;
384 	fm3130->msg[3].len = FM3130_ALARM_REGS;
385 	fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];
386 
387 	fm3130->alarm_valid = 0;
388 	fm3130->data_valid = 0;
389 
390 	tmp = i2c_transfer(adapter, fm3130->msg, 4);
391 	if (tmp != 4) {
392 		dev_dbg(&client->dev, "read error %d\n", tmp);
393 		err = -EIO;
394 		goto exit_free;
395 	}
396 
397 	fm3130->regs[FM3130_RTC_CONTROL] =
398 		i2c_smbus_read_byte_data(client, FM3130_RTC_CONTROL);
399 	fm3130->regs[FM3130_CAL_CONTROL] =
400 		i2c_smbus_read_byte_data(client, FM3130_CAL_CONTROL);
401 
402 	/* Disabling calibration mode */
403 	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_CAL) {
404 		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
405 			fm3130->regs[FM3130_RTC_CONTROL] &
406 				~(FM3130_RTC_CONTROL_BIT_CAL));
407 		dev_warn(&client->dev, "Disabling calibration mode!\n");
408 	}
409 
410 	/* Disabling read and write modes */
411 	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_WRITE ||
412 	    fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_READ) {
413 		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
414 			fm3130->regs[FM3130_RTC_CONTROL] &
415 				~(FM3130_RTC_CONTROL_BIT_READ |
416 					FM3130_RTC_CONTROL_BIT_WRITE));
417 		dev_warn(&client->dev, "Disabling READ or WRITE mode!\n");
418 	}
419 
420 	/* oscillator off?  turn it on, so clock can tick. */
421 	if (fm3130->regs[FM3130_CAL_CONTROL] & FM3130_CAL_CONTROL_BIT_nOSCEN)
422 		i2c_smbus_write_byte_data(client, FM3130_CAL_CONTROL,
423 			fm3130->regs[FM3130_CAL_CONTROL] &
424 				~(FM3130_CAL_CONTROL_BIT_nOSCEN));
425 
426 	/* low battery?  clear flag, and warn */
427 	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB) {
428 		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
429 			fm3130->regs[FM3130_RTC_CONTROL] &
430 				~(FM3130_RTC_CONTROL_BIT_LB));
431 		dev_warn(&client->dev, "Low battery!\n");
432 	}
433 
434 	/* check if Power On Reset bit is set */
435 	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_POR) {
436 		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
437 			fm3130->regs[FM3130_RTC_CONTROL] &
438 				~FM3130_RTC_CONTROL_BIT_POR);
439 		dev_dbg(&client->dev, "POR bit is set\n");
440 	}
441 	/* ACS is controlled by alarm */
442 	i2c_smbus_write_byte_data(client, FM3130_ALARM_WP_CONTROL, 0x80);
443 
444 	/* alarm registers sanity check */
445 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
446 	if (tmp > 59)
447 		goto bad_alarm;
448 
449 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
450 	if (tmp > 59)
451 		goto bad_alarm;
452 
453 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
454 	if (tmp > 23)
455 		goto bad_alarm;
456 
457 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
458 	if (tmp == 0 || tmp > 31)
459 		goto bad_alarm;
460 
461 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
462 	if (tmp == 0 || tmp > 12)
463 		goto bad_alarm;
464 
465 	fm3130->alarm_valid = 1;
466 
467 bad_alarm:
468 
469 	/* clock registers sanity chek */
470 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
471 	if (tmp > 59)
472 		goto bad_clock;
473 
474 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
475 	if (tmp > 59)
476 		goto bad_clock;
477 
478 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
479 	if (tmp > 23)
480 		goto bad_clock;
481 
482 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x7);
483 	if (tmp == 0 || tmp > 7)
484 		goto bad_clock;
485 
486 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
487 	if (tmp == 0 || tmp > 31)
488 		goto bad_clock;
489 
490 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
491 	if (tmp == 0 || tmp > 12)
492 		goto bad_clock;
493 
494 	fm3130->data_valid = 1;
495 
496 bad_clock:
497 
498 	if (!fm3130->data_valid || !fm3130->alarm_valid)
499 		dev_dbg(&client->dev, "%s: %15ph\n", "bogus registers",
500 			fm3130->regs);
501 
502 	/* We won't bail out here because we just got invalid data.
503 	   Time setting from u-boot doesn't work anyway */
504 	fm3130->rtc = devm_rtc_device_register(&client->dev, client->name,
505 				&fm3130_rtc_ops, THIS_MODULE);
506 	if (IS_ERR(fm3130->rtc)) {
507 		err = PTR_ERR(fm3130->rtc);
508 		dev_err(&client->dev,
509 			"unable to register the class device\n");
510 		goto exit_free;
511 	}
512 	return 0;
513 exit_free:
514 	return err;
515 }
516 
517 static struct i2c_driver fm3130_driver = {
518 	.driver = {
519 		.name	= "rtc-fm3130",
520 	},
521 	.probe		= fm3130_probe,
522 	.id_table	= fm3130_id,
523 };
524 
525 module_i2c_driver(fm3130_driver);
526 
527 MODULE_DESCRIPTION("RTC driver for FM3130");
528 MODULE_AUTHOR("Sergey Lapin <slapin@ossfans.org>");
529 MODULE_LICENSE("GPL");
530 
531