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v6.8
  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
 45struct 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};
 55static const struct i2c_device_id fm3130_id[] = {
 56	{ "fm3130", 0 },
 57	{ }
 58};
 59MODULE_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
 65static 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
 92static 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
139static 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
182static 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
239static 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
301static 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
333static 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
341static struct i2c_driver fm3130_driver;
342
343static int fm3130_probe(struct i2c_client *client)
 
344{
345	struct fm3130		*fm3130;
346	int			err = -ENODEV;
347	int			tmp;
348	struct i2c_adapter	*adapter = client->adapter;
349
350	if (!i2c_check_functionality(adapter,
351			I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
352		return -EIO;
353
354	fm3130 = devm_kzalloc(&client->dev, sizeof(struct fm3130), GFP_KERNEL);
355
356	if (!fm3130)
357		return -ENOMEM;
358
359	fm3130->client = client;
360	i2c_set_clientdata(client, fm3130);
361	fm3130->reg_addr_time = FM3130_RTC_SECONDS;
362	fm3130->reg_addr_alarm = FM3130_ALARM_SECONDS;
363
364	/* Messages to read time */
365	fm3130->msg[0].addr = client->addr;
366	fm3130->msg[0].flags = 0;
367	fm3130->msg[0].len = 1;
368	fm3130->msg[0].buf = &fm3130->reg_addr_time;
369
370	fm3130->msg[1].addr = client->addr;
371	fm3130->msg[1].flags = I2C_M_RD;
372	fm3130->msg[1].len = FM3130_CLOCK_REGS;
373	fm3130->msg[1].buf = &fm3130->regs[FM3130_RTC_SECONDS];
374
375	/* Messages to read alarm */
376	fm3130->msg[2].addr = client->addr;
377	fm3130->msg[2].flags = 0;
378	fm3130->msg[2].len = 1;
379	fm3130->msg[2].buf = &fm3130->reg_addr_alarm;
380
381	fm3130->msg[3].addr = client->addr;
382	fm3130->msg[3].flags = I2C_M_RD;
383	fm3130->msg[3].len = FM3130_ALARM_REGS;
384	fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];
385
386	fm3130->alarm_valid = 0;
387	fm3130->data_valid = 0;
388
389	tmp = i2c_transfer(adapter, fm3130->msg, 4);
390	if (tmp != 4) {
391		dev_dbg(&client->dev, "read error %d\n", tmp);
392		err = -EIO;
393		goto exit_free;
394	}
395
396	fm3130->regs[FM3130_RTC_CONTROL] =
397		i2c_smbus_read_byte_data(client, FM3130_RTC_CONTROL);
398	fm3130->regs[FM3130_CAL_CONTROL] =
399		i2c_smbus_read_byte_data(client, FM3130_CAL_CONTROL);
400
401	/* Disabling calibration mode */
402	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_CAL) {
403		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
404			fm3130->regs[FM3130_RTC_CONTROL] &
405				~(FM3130_RTC_CONTROL_BIT_CAL));
406		dev_warn(&client->dev, "Disabling calibration mode!\n");
407	}
408
409	/* Disabling read and write modes */
410	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_WRITE ||
411	    fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_READ) {
412		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
413			fm3130->regs[FM3130_RTC_CONTROL] &
414				~(FM3130_RTC_CONTROL_BIT_READ |
415					FM3130_RTC_CONTROL_BIT_WRITE));
416		dev_warn(&client->dev, "Disabling READ or WRITE mode!\n");
417	}
418
419	/* oscillator off?  turn it on, so clock can tick. */
420	if (fm3130->regs[FM3130_CAL_CONTROL] & FM3130_CAL_CONTROL_BIT_nOSCEN)
421		i2c_smbus_write_byte_data(client, FM3130_CAL_CONTROL,
422			fm3130->regs[FM3130_CAL_CONTROL] &
423				~(FM3130_CAL_CONTROL_BIT_nOSCEN));
424
425	/* low battery?  clear flag, and warn */
426	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB) {
427		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
428			fm3130->regs[FM3130_RTC_CONTROL] &
429				~(FM3130_RTC_CONTROL_BIT_LB));
430		dev_warn(&client->dev, "Low battery!\n");
431	}
432
433	/* check if Power On Reset bit is set */
434	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_POR) {
435		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
436			fm3130->regs[FM3130_RTC_CONTROL] &
437				~FM3130_RTC_CONTROL_BIT_POR);
438		dev_dbg(&client->dev, "POR bit is set\n");
439	}
440	/* ACS is controlled by alarm */
441	i2c_smbus_write_byte_data(client, FM3130_ALARM_WP_CONTROL, 0x80);
442
443	/* alarm registers sanity check */
444	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
445	if (tmp > 59)
446		goto bad_alarm;
447
448	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
449	if (tmp > 59)
450		goto bad_alarm;
451
452	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
453	if (tmp > 23)
454		goto bad_alarm;
455
456	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
457	if (tmp == 0 || tmp > 31)
458		goto bad_alarm;
459
460	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
461	if (tmp == 0 || tmp > 12)
462		goto bad_alarm;
463
464	fm3130->alarm_valid = 1;
465
466bad_alarm:
467
468	/* clock registers sanity chek */
469	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
470	if (tmp > 59)
471		goto bad_clock;
472
473	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
474	if (tmp > 59)
475		goto bad_clock;
476
477	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
478	if (tmp > 23)
479		goto bad_clock;
480
481	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x7);
482	if (tmp == 0 || tmp > 7)
483		goto bad_clock;
484
485	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
486	if (tmp == 0 || tmp > 31)
487		goto bad_clock;
488
489	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
490	if (tmp == 0 || tmp > 12)
491		goto bad_clock;
492
493	fm3130->data_valid = 1;
494
495bad_clock:
496
497	if (!fm3130->data_valid || !fm3130->alarm_valid)
498		dev_dbg(&client->dev, "%s: %15ph\n", "bogus registers",
499			fm3130->regs);
500
501	/* We won't bail out here because we just got invalid data.
502	   Time setting from u-boot doesn't work anyway */
503	fm3130->rtc = devm_rtc_device_register(&client->dev, client->name,
504				&fm3130_rtc_ops, THIS_MODULE);
505	if (IS_ERR(fm3130->rtc)) {
506		err = PTR_ERR(fm3130->rtc);
507		dev_err(&client->dev,
508			"unable to register the class device\n");
509		goto exit_free;
510	}
511	return 0;
512exit_free:
513	return err;
514}
515
516static struct i2c_driver fm3130_driver = {
517	.driver = {
518		.name	= "rtc-fm3130",
519	},
520	.probe		= fm3130_probe,
521	.id_table	= fm3130_id,
522};
523
524module_i2c_driver(fm3130_driver);
525
526MODULE_DESCRIPTION("RTC driver for FM3130");
527MODULE_AUTHOR("Sergey Lapin <slapin@ossfans.org>");
528MODULE_LICENSE("GPL");
529
v4.17
 
  1/*
  2 * rtc-fm3130.c - RTC driver for Ramtron FM3130 I2C chip.
  3 *
  4 *  Copyright (C) 2008 Sergey Lapin
  5 *  Based on ds1307 driver by James Chapman and David Brownell
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/i2c.h>
 14#include <linux/rtc.h>
 15#include <linux/bcd.h>
 16#include <linux/slab.h>
 17
 18#define FM3130_RTC_CONTROL	(0x0)
 19#define FM3130_CAL_CONTROL	(0x1)
 20#define FM3130_RTC_SECONDS	(0x2)
 21#define FM3130_RTC_MINUTES	(0x3)
 22#define FM3130_RTC_HOURS	(0x4)
 23#define FM3130_RTC_DAY		(0x5)
 24#define FM3130_RTC_DATE		(0x6)
 25#define FM3130_RTC_MONTHS	(0x7)
 26#define FM3130_RTC_YEARS	(0x8)
 27
 28#define FM3130_ALARM_SECONDS	(0x9)
 29#define FM3130_ALARM_MINUTES	(0xa)
 30#define FM3130_ALARM_HOURS	(0xb)
 31#define FM3130_ALARM_DATE	(0xc)
 32#define FM3130_ALARM_MONTHS	(0xd)
 33#define FM3130_ALARM_WP_CONTROL	(0xe)
 34
 35#define FM3130_CAL_CONTROL_BIT_nOSCEN (1 << 7) /* Osciallator enabled */
 36#define FM3130_RTC_CONTROL_BIT_LB (1 << 7) /* Low battery */
 37#define FM3130_RTC_CONTROL_BIT_AF (1 << 6) /* Alarm flag */
 38#define FM3130_RTC_CONTROL_BIT_CF (1 << 5) /* Century overflow */
 39#define FM3130_RTC_CONTROL_BIT_POR (1 << 4) /* Power on reset */
 40#define FM3130_RTC_CONTROL_BIT_AEN (1 << 3) /* Alarm enable */
 41#define FM3130_RTC_CONTROL_BIT_CAL (1 << 2) /* Calibration mode */
 42#define FM3130_RTC_CONTROL_BIT_WRITE (1 << 1) /* W=1 -> write mode W=0 normal */
 43#define FM3130_RTC_CONTROL_BIT_READ (1 << 0) /* R=1 -> read mode R=0 normal */
 44
 45#define FM3130_CLOCK_REGS 7
 46#define FM3130_ALARM_REGS 5
 47
 48struct fm3130 {
 49	u8			reg_addr_time;
 50	u8			reg_addr_alarm;
 51	u8			regs[15];
 52	struct i2c_msg		msg[4];
 53	struct i2c_client	*client;
 54	struct rtc_device	*rtc;
 55	int			alarm_valid;
 56	int			data_valid;
 57};
 58static const struct i2c_device_id fm3130_id[] = {
 59	{ "fm3130", 0 },
 60	{ }
 61};
 62MODULE_DEVICE_TABLE(i2c, fm3130_id);
 63
 64#define FM3130_MODE_NORMAL		0
 65#define FM3130_MODE_WRITE		1
 66#define FM3130_MODE_READ		2
 67
 68static void fm3130_rtc_mode(struct device *dev, int mode)
 69{
 70	struct fm3130 *fm3130 = dev_get_drvdata(dev);
 71
 72	fm3130->regs[FM3130_RTC_CONTROL] =
 73		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
 74	switch (mode) {
 75	case FM3130_MODE_NORMAL:
 76		fm3130->regs[FM3130_RTC_CONTROL] &=
 77			~(FM3130_RTC_CONTROL_BIT_WRITE |
 78			FM3130_RTC_CONTROL_BIT_READ);
 79		break;
 80	case FM3130_MODE_WRITE:
 81		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_WRITE;
 82		break;
 83	case FM3130_MODE_READ:
 84		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_READ;
 85		break;
 86	default:
 87		dev_dbg(dev, "invalid mode %d\n", mode);
 88		break;
 89	}
 90
 91	i2c_smbus_write_byte_data(fm3130->client,
 92		 FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL]);
 93}
 94
 95static int fm3130_get_time(struct device *dev, struct rtc_time *t)
 96{
 97	struct fm3130 *fm3130 = dev_get_drvdata(dev);
 98	int		tmp;
 99
100	if (!fm3130->data_valid) {
101		/* We have invalid data in RTC, probably due
102		to battery faults or other problems. Return EIO
103		for now, it will allow us to set data later instead
104		of error during probing which disables device */
105		return -EIO;
106	}
107	fm3130_rtc_mode(dev, FM3130_MODE_READ);
108
109	/* read the RTC date and time registers all at once */
110	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
111			fm3130->msg, 2);
112	if (tmp != 2) {
113		dev_err(dev, "%s error %d\n", "read", tmp);
114		return -EIO;
115	}
116
117	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
118
119	dev_dbg(dev, "%s: %15ph\n", "read", fm3130->regs);
120
121	t->tm_sec = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
122	t->tm_min = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
123	tmp = fm3130->regs[FM3130_RTC_HOURS] & 0x3f;
124	t->tm_hour = bcd2bin(tmp);
125	t->tm_wday = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x07) - 1;
126	t->tm_mday = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
127	tmp = fm3130->regs[FM3130_RTC_MONTHS] & 0x1f;
128	t->tm_mon = bcd2bin(tmp) - 1;
129
130	/* assume 20YY not 19YY, and ignore CF bit */
131	t->tm_year = bcd2bin(fm3130->regs[FM3130_RTC_YEARS]) + 100;
132
133	dev_dbg(dev, "%s secs=%d, mins=%d, "
134		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
135		"read", t->tm_sec, t->tm_min,
136		t->tm_hour, t->tm_mday,
137		t->tm_mon, t->tm_year, t->tm_wday);
138
139	return 0;
140}
141
142
143static int fm3130_set_time(struct device *dev, struct rtc_time *t)
144{
145	struct fm3130 *fm3130 = dev_get_drvdata(dev);
146	int		tmp, i;
147	u8		*buf = fm3130->regs;
148
149	dev_dbg(dev, "%s secs=%d, mins=%d, "
150		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
151		"write", t->tm_sec, t->tm_min,
152		t->tm_hour, t->tm_mday,
153		t->tm_mon, t->tm_year, t->tm_wday);
154
155	/* first register addr */
156	buf[FM3130_RTC_SECONDS] = bin2bcd(t->tm_sec);
157	buf[FM3130_RTC_MINUTES] = bin2bcd(t->tm_min);
158	buf[FM3130_RTC_HOURS] = bin2bcd(t->tm_hour);
159	buf[FM3130_RTC_DAY] = bin2bcd(t->tm_wday + 1);
160	buf[FM3130_RTC_DATE] = bin2bcd(t->tm_mday);
161	buf[FM3130_RTC_MONTHS] = bin2bcd(t->tm_mon + 1);
162
163	/* assume 20YY not 19YY */
164	tmp = t->tm_year - 100;
165	buf[FM3130_RTC_YEARS] = bin2bcd(tmp);
166
167	dev_dbg(dev, "%s: %15ph\n", "write", buf);
168
169	fm3130_rtc_mode(dev, FM3130_MODE_WRITE);
170
171	/* Writing time registers, we don't support multibyte transfers */
172	for (i = 0; i < FM3130_CLOCK_REGS; i++) {
173		i2c_smbus_write_byte_data(fm3130->client,
174					FM3130_RTC_SECONDS + i,
175					fm3130->regs[FM3130_RTC_SECONDS + i]);
176	}
177
178	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
179
180	/* We assume here that data are valid once written */
181	if (!fm3130->data_valid)
182		fm3130->data_valid = 1;
183	return 0;
184}
185
186static int fm3130_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
187{
188	struct fm3130 *fm3130 = dev_get_drvdata(dev);
189	int tmp;
190	struct rtc_time *tm = &alrm->time;
191
192	if (!fm3130->alarm_valid) {
193		/*
194		 * We have invalid alarm in RTC, probably due to battery faults
195		 * or other problems. Return EIO for now, it will allow us to
196		 * set alarm value later instead of error during probing which
197		 * disables device
198		 */
199		return -EIO;
200	}
201
202	/* read the RTC alarm registers all at once */
203	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
204			&fm3130->msg[2], 2);
205	if (tmp != 2) {
206		dev_err(dev, "%s error %d\n", "read", tmp);
207		return -EIO;
208	}
209	dev_dbg(dev, "alarm read %02x %02x %02x %02x %02x\n",
210			fm3130->regs[FM3130_ALARM_SECONDS],
211			fm3130->regs[FM3130_ALARM_MINUTES],
212			fm3130->regs[FM3130_ALARM_HOURS],
213			fm3130->regs[FM3130_ALARM_DATE],
214			fm3130->regs[FM3130_ALARM_MONTHS]);
215
216	tm->tm_sec	= bcd2bin(fm3130->regs[FM3130_ALARM_SECONDS] & 0x7F);
217	tm->tm_min	= bcd2bin(fm3130->regs[FM3130_ALARM_MINUTES] & 0x7F);
218	tm->tm_hour	= bcd2bin(fm3130->regs[FM3130_ALARM_HOURS] & 0x3F);
219	tm->tm_mday	= bcd2bin(fm3130->regs[FM3130_ALARM_DATE] & 0x3F);
220	tm->tm_mon	= bcd2bin(fm3130->regs[FM3130_ALARM_MONTHS] & 0x1F);
221
222	if (tm->tm_mon > 0)
223		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
224
225	dev_dbg(dev, "%s secs=%d, mins=%d, "
226		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
227		"read alarm", tm->tm_sec, tm->tm_min,
228		tm->tm_hour, tm->tm_mday,
229		tm->tm_mon, tm->tm_year, tm->tm_wday);
230
231	/* check if alarm enabled */
232	fm3130->regs[FM3130_RTC_CONTROL] =
233		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
234
235	if ((fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AEN) &&
236		(~fm3130->regs[FM3130_RTC_CONTROL] &
237			FM3130_RTC_CONTROL_BIT_CAL)) {
238		alrm->enabled = 1;
239	}
240
241	return 0;
242}
243
244static int fm3130_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
245{
246	struct fm3130 *fm3130 = dev_get_drvdata(dev);
247	struct rtc_time *tm = &alrm->time;
248	int i;
249
250	dev_dbg(dev, "%s secs=%d, mins=%d, "
251		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
252		"write alarm", tm->tm_sec, tm->tm_min,
253		tm->tm_hour, tm->tm_mday,
254		tm->tm_mon, tm->tm_year, tm->tm_wday);
255
256	fm3130->regs[FM3130_ALARM_SECONDS] =
257		(tm->tm_sec != -1) ? bin2bcd(tm->tm_sec) : 0x80;
258
259	fm3130->regs[FM3130_ALARM_MINUTES] =
260		(tm->tm_min != -1) ? bin2bcd(tm->tm_min) : 0x80;
261
262	fm3130->regs[FM3130_ALARM_HOURS] =
263		(tm->tm_hour != -1) ? bin2bcd(tm->tm_hour) : 0x80;
264
265	fm3130->regs[FM3130_ALARM_DATE] =
266		(tm->tm_mday != -1) ? bin2bcd(tm->tm_mday) : 0x80;
267
268	fm3130->regs[FM3130_ALARM_MONTHS] =
269		(tm->tm_mon != -1) ? bin2bcd(tm->tm_mon + 1) : 0x80;
270
271	dev_dbg(dev, "alarm write %02x %02x %02x %02x %02x\n",
272			fm3130->regs[FM3130_ALARM_SECONDS],
273			fm3130->regs[FM3130_ALARM_MINUTES],
274			fm3130->regs[FM3130_ALARM_HOURS],
275			fm3130->regs[FM3130_ALARM_DATE],
276			fm3130->regs[FM3130_ALARM_MONTHS]);
277	/* Writing time registers, we don't support multibyte transfers */
278	for (i = 0; i < FM3130_ALARM_REGS; i++) {
279		i2c_smbus_write_byte_data(fm3130->client,
280					FM3130_ALARM_SECONDS + i,
281					fm3130->regs[FM3130_ALARM_SECONDS + i]);
282	}
283	fm3130->regs[FM3130_RTC_CONTROL] =
284		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
285
286	/* enable or disable alarm */
287	if (alrm->enabled) {
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	} else {
293		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
294			fm3130->regs[FM3130_RTC_CONTROL] &
295				~(FM3130_RTC_CONTROL_BIT_CAL) &
296					~(FM3130_RTC_CONTROL_BIT_AEN));
297	}
298
299	/* We assume here that data is valid once written */
300	if (!fm3130->alarm_valid)
301		fm3130->alarm_valid = 1;
302
303	return 0;
304}
305
306static int fm3130_alarm_irq_enable(struct device *dev, unsigned int enabled)
307{
308	struct fm3130 *fm3130 = dev_get_drvdata(dev);
309	int ret = 0;
310
311	fm3130->regs[FM3130_RTC_CONTROL] =
312		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
313
314	dev_dbg(dev, "alarm_irq_enable: enable=%d, FM3130_RTC_CONTROL=%02x\n",
315		enabled, fm3130->regs[FM3130_RTC_CONTROL]);
316
317	switch (enabled) {
318	case 0:		/* alarm off */
319		ret = i2c_smbus_write_byte_data(fm3130->client,
320			FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL] &
321				~(FM3130_RTC_CONTROL_BIT_CAL) &
322					~(FM3130_RTC_CONTROL_BIT_AEN));
323		break;
324	case 1:		/* alarm on */
325		ret = i2c_smbus_write_byte_data(fm3130->client,
326			FM3130_RTC_CONTROL, (fm3130->regs[FM3130_RTC_CONTROL] &
327				~(FM3130_RTC_CONTROL_BIT_CAL)) |
328					FM3130_RTC_CONTROL_BIT_AEN);
329		break;
330	default:
331		ret = -EINVAL;
332		break;
333	}
334
335	return ret;
336}
337
338static const struct rtc_class_ops fm3130_rtc_ops = {
339	.read_time	= fm3130_get_time,
340	.set_time	= fm3130_set_time,
341	.read_alarm	= fm3130_read_alarm,
342	.set_alarm	= fm3130_set_alarm,
343	.alarm_irq_enable = fm3130_alarm_irq_enable,
344};
345
346static struct i2c_driver fm3130_driver;
347
348static int fm3130_probe(struct i2c_client *client,
349			const struct i2c_device_id *id)
350{
351	struct fm3130		*fm3130;
352	int			err = -ENODEV;
353	int			tmp;
354	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
355
356	if (!i2c_check_functionality(adapter,
357			I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
358		return -EIO;
359
360	fm3130 = devm_kzalloc(&client->dev, sizeof(struct fm3130), GFP_KERNEL);
361
362	if (!fm3130)
363		return -ENOMEM;
364
365	fm3130->client = client;
366	i2c_set_clientdata(client, fm3130);
367	fm3130->reg_addr_time = FM3130_RTC_SECONDS;
368	fm3130->reg_addr_alarm = FM3130_ALARM_SECONDS;
369
370	/* Messages to read time */
371	fm3130->msg[0].addr = client->addr;
372	fm3130->msg[0].flags = 0;
373	fm3130->msg[0].len = 1;
374	fm3130->msg[0].buf = &fm3130->reg_addr_time;
375
376	fm3130->msg[1].addr = client->addr;
377	fm3130->msg[1].flags = I2C_M_RD;
378	fm3130->msg[1].len = FM3130_CLOCK_REGS;
379	fm3130->msg[1].buf = &fm3130->regs[FM3130_RTC_SECONDS];
380
381	/* Messages to read alarm */
382	fm3130->msg[2].addr = client->addr;
383	fm3130->msg[2].flags = 0;
384	fm3130->msg[2].len = 1;
385	fm3130->msg[2].buf = &fm3130->reg_addr_alarm;
386
387	fm3130->msg[3].addr = client->addr;
388	fm3130->msg[3].flags = I2C_M_RD;
389	fm3130->msg[3].len = FM3130_ALARM_REGS;
390	fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];
391
392	fm3130->alarm_valid = 0;
393	fm3130->data_valid = 0;
394
395	tmp = i2c_transfer(adapter, fm3130->msg, 4);
396	if (tmp != 4) {
397		dev_dbg(&client->dev, "read error %d\n", tmp);
398		err = -EIO;
399		goto exit_free;
400	}
401
402	fm3130->regs[FM3130_RTC_CONTROL] =
403		i2c_smbus_read_byte_data(client, FM3130_RTC_CONTROL);
404	fm3130->regs[FM3130_CAL_CONTROL] =
405		i2c_smbus_read_byte_data(client, FM3130_CAL_CONTROL);
406
407	/* Disabling calibration mode */
408	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_CAL) {
409		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
410			fm3130->regs[FM3130_RTC_CONTROL] &
411				~(FM3130_RTC_CONTROL_BIT_CAL));
412		dev_warn(&client->dev, "Disabling calibration mode!\n");
413	}
414
415	/* Disabling read and write modes */
416	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_WRITE ||
417	    fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_READ) {
418		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
419			fm3130->regs[FM3130_RTC_CONTROL] &
420				~(FM3130_RTC_CONTROL_BIT_READ |
421					FM3130_RTC_CONTROL_BIT_WRITE));
422		dev_warn(&client->dev, "Disabling READ or WRITE mode!\n");
423	}
424
425	/* oscillator off?  turn it on, so clock can tick. */
426	if (fm3130->regs[FM3130_CAL_CONTROL] & FM3130_CAL_CONTROL_BIT_nOSCEN)
427		i2c_smbus_write_byte_data(client, FM3130_CAL_CONTROL,
428			fm3130->regs[FM3130_CAL_CONTROL] &
429				~(FM3130_CAL_CONTROL_BIT_nOSCEN));
430
431	/* low battery?  clear flag, and warn */
432	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB) {
433		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
434			fm3130->regs[FM3130_RTC_CONTROL] &
435				~(FM3130_RTC_CONTROL_BIT_LB));
436		dev_warn(&client->dev, "Low battery!\n");
437	}
438
439	/* check if Power On Reset bit is set */
440	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_POR) {
441		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
442			fm3130->regs[FM3130_RTC_CONTROL] &
443				~FM3130_RTC_CONTROL_BIT_POR);
444		dev_dbg(&client->dev, "POR bit is set\n");
445	}
446	/* ACS is controlled by alarm */
447	i2c_smbus_write_byte_data(client, FM3130_ALARM_WP_CONTROL, 0x80);
448
449	/* alarm registers sanity check */
450	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
451	if (tmp > 59)
452		goto bad_alarm;
453
454	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
455	if (tmp > 59)
456		goto bad_alarm;
457
458	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
459	if (tmp > 23)
460		goto bad_alarm;
461
462	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
463	if (tmp == 0 || tmp > 31)
464		goto bad_alarm;
465
466	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
467	if (tmp == 0 || tmp > 12)
468		goto bad_alarm;
469
470	fm3130->alarm_valid = 1;
471
472bad_alarm:
473
474	/* clock registers sanity chek */
475	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
476	if (tmp > 59)
477		goto bad_clock;
478
479	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
480	if (tmp > 59)
481		goto bad_clock;
482
483	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
484	if (tmp > 23)
485		goto bad_clock;
486
487	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x7);
488	if (tmp == 0 || tmp > 7)
489		goto bad_clock;
490
491	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
492	if (tmp == 0 || tmp > 31)
493		goto bad_clock;
494
495	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
496	if (tmp == 0 || tmp > 12)
497		goto bad_clock;
498
499	fm3130->data_valid = 1;
500
501bad_clock:
502
503	if (!fm3130->data_valid || !fm3130->alarm_valid)
504		dev_dbg(&client->dev, "%s: %15ph\n", "bogus registers",
505			fm3130->regs);
506
507	/* We won't bail out here because we just got invalid data.
508	   Time setting from u-boot doesn't work anyway */
509	fm3130->rtc = devm_rtc_device_register(&client->dev, client->name,
510				&fm3130_rtc_ops, THIS_MODULE);
511	if (IS_ERR(fm3130->rtc)) {
512		err = PTR_ERR(fm3130->rtc);
513		dev_err(&client->dev,
514			"unable to register the class device\n");
515		goto exit_free;
516	}
517	return 0;
518exit_free:
519	return err;
520}
521
522static struct i2c_driver fm3130_driver = {
523	.driver = {
524		.name	= "rtc-fm3130",
525	},
526	.probe		= fm3130_probe,
527	.id_table	= fm3130_id,
528};
529
530module_i2c_driver(fm3130_driver);
531
532MODULE_DESCRIPTION("RTC driver for FM3130");
533MODULE_AUTHOR("Sergey Lapin <slapin@ossfans.org>");
534MODULE_LICENSE("GPL");
535