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path: root/drivers/rtc/rtc-m41t80.c
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-rw-r--r--drivers/rtc/rtc-m41t80.c629
1 files changed, 629 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
new file mode 100644
index 000000000000..4875a4444216
--- /dev/null
+++ b/drivers/rtc/rtc-m41t80.c
@@ -0,0 +1,629 @@
1/*
2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
3 *
4 * Author: Alexander Bigga <ab@mycable.de>
5 *
6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
7 *
8 * 2006 (c) mycable GmbH
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 */
15
16#include <linux/module.h>
17#include <linux/init.h>
18#include <linux/slab.h>
19#include <linux/string.h>
20#include <linux/i2c.h>
21#include <linux/rtc.h>
22#include <linux/bcd.h>
23
24#define M41T80_REG_SSEC 0
25#define M41T80_REG_SEC 1
26#define M41T80_REG_MIN 2
27#define M41T80_REG_HOUR 3
28#define M41T80_REG_WDAY 4
29#define M41T80_REG_DAY 5
30#define M41T80_REG_MON 6
31#define M41T80_REG_YEAR 7
32#define M41T80_REG_ALARM_MON 0xa
33#define M41T80_REG_ALARM_DAY 0xb
34#define M41T80_REG_ALARM_HOUR 0xc
35#define M41T80_REG_ALARM_MIN 0xd
36#define M41T80_REG_ALARM_SEC 0xe
37#define M41T80_REG_FLAGS 0xf
38#define M41T80_REG_SQW 0x13
39
40#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
41#define M41T80_ALARM_REG_SIZE \
42 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
43
44#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
45#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
46#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
47#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
48#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
49#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
50
51#define M41T80_FEATURE_HT (1 << 0)
52#define M41T80_FEATURE_BL (1 << 1)
53
54#define DRV_VERSION "0.05"
55
56struct m41t80_chip_info {
57 const char *name;
58 u8 features;
59};
60
61static const struct m41t80_chip_info m41t80_chip_info_tbl[] = {
62 {
63 .name = "m41t80",
64 .features = 0,
65 },
66 {
67 .name = "m41t81",
68 .features = M41T80_FEATURE_HT,
69 },
70 {
71 .name = "m41t81s",
72 .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
73 },
74 {
75 .name = "m41t82",
76 .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
77 },
78 {
79 .name = "m41t83",
80 .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
81 },
82 {
83 .name = "m41st84",
84 .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
85 },
86 {
87 .name = "m41st85",
88 .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
89 },
90 {
91 .name = "m41st87",
92 .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
93 },
94};
95
96struct m41t80_data {
97 const struct m41t80_chip_info *chip;
98 struct rtc_device *rtc;
99};
100
101static int m41t80_get_datetime(struct i2c_client *client,
102 struct rtc_time *tm)
103{
104 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
105 struct i2c_msg msgs[] = {
106 {
107 .addr = client->addr,
108 .flags = 0,
109 .len = 1,
110 .buf = dt_addr,
111 },
112 {
113 .addr = client->addr,
114 .flags = I2C_M_RD,
115 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
116 .buf = buf + M41T80_REG_SEC,
117 },
118 };
119
120 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
121 dev_err(&client->dev, "read error\n");
122 return -EIO;
123 }
124
125 tm->tm_sec = BCD2BIN(buf[M41T80_REG_SEC] & 0x7f);
126 tm->tm_min = BCD2BIN(buf[M41T80_REG_MIN] & 0x7f);
127 tm->tm_hour = BCD2BIN(buf[M41T80_REG_HOUR] & 0x3f);
128 tm->tm_mday = BCD2BIN(buf[M41T80_REG_DAY] & 0x3f);
129 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
130 tm->tm_mon = BCD2BIN(buf[M41T80_REG_MON] & 0x1f) - 1;
131
132 /* assume 20YY not 19YY, and ignore the Century Bit */
133 tm->tm_year = BCD2BIN(buf[M41T80_REG_YEAR]) + 100;
134 return 0;
135}
136
137/* Sets the given date and time to the real time clock. */
138static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
139{
140 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
141 u8 *buf = &wbuf[1];
142 u8 dt_addr[1] = { M41T80_REG_SEC };
143 struct i2c_msg msgs_in[] = {
144 {
145 .addr = client->addr,
146 .flags = 0,
147 .len = 1,
148 .buf = dt_addr,
149 },
150 {
151 .addr = client->addr,
152 .flags = I2C_M_RD,
153 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
154 .buf = buf + M41T80_REG_SEC,
155 },
156 };
157 struct i2c_msg msgs[] = {
158 {
159 .addr = client->addr,
160 .flags = 0,
161 .len = 1 + M41T80_DATETIME_REG_SIZE,
162 .buf = wbuf,
163 },
164 };
165
166 /* Read current reg values into buf[1..7] */
167 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
168 dev_err(&client->dev, "read error\n");
169 return -EIO;
170 }
171
172 wbuf[0] = 0; /* offset into rtc's regs */
173 /* Merge time-data and register flags into buf[0..7] */
174 buf[M41T80_REG_SSEC] = 0;
175 buf[M41T80_REG_SEC] =
176 BIN2BCD(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
177 buf[M41T80_REG_MIN] =
178 BIN2BCD(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
179 buf[M41T80_REG_HOUR] =
180 BIN2BCD(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
181 buf[M41T80_REG_WDAY] =
182 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
183 buf[M41T80_REG_DAY] =
184 BIN2BCD(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
185 buf[M41T80_REG_MON] =
186 BIN2BCD(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
187 /* assume 20YY not 19YY */
188 buf[M41T80_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
189
190 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
191 dev_err(&client->dev, "write error\n");
192 return -EIO;
193 }
194 return 0;
195}
196
197#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
198static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
199{
200 struct i2c_client *client = to_i2c_client(dev);
201 struct m41t80_data *clientdata = i2c_get_clientdata(client);
202 u8 reg;
203
204 if (clientdata->chip->features & M41T80_FEATURE_BL) {
205 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
206 seq_printf(seq, "battery\t\t: %s\n",
207 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
208 }
209 return 0;
210}
211#else
212#define m41t80_rtc_proc NULL
213#endif
214
215static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
216{
217 return m41t80_get_datetime(to_i2c_client(dev), tm);
218}
219
220static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
221{
222 return m41t80_set_datetime(to_i2c_client(dev), tm);
223}
224
225#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
226static int
227m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
228{
229 struct i2c_client *client = to_i2c_client(dev);
230 int rc;
231
232 switch (cmd) {
233 case RTC_AIE_OFF:
234 case RTC_AIE_ON:
235 break;
236 default:
237 return -ENOIOCTLCMD;
238 }
239
240 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
241 if (rc < 0)
242 goto err;
243 switch (cmd) {
244 case RTC_AIE_OFF:
245 rc &= ~M41T80_ALMON_AFE;
246 break;
247 case RTC_AIE_ON:
248 rc |= M41T80_ALMON_AFE;
249 break;
250 }
251 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
252 goto err;
253 return 0;
254err:
255 return -EIO;
256}
257#else
258#define m41t80_rtc_ioctl NULL
259#endif
260
261static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
262{
263 struct i2c_client *client = to_i2c_client(dev);
264 u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
265 u8 *buf = &wbuf[1];
266 u8 *reg = buf - M41T80_REG_ALARM_MON;
267 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
268 struct i2c_msg msgs_in[] = {
269 {
270 .addr = client->addr,
271 .flags = 0,
272 .len = 1,
273 .buf = dt_addr,
274 },
275 {
276 .addr = client->addr,
277 .flags = I2C_M_RD,
278 .len = M41T80_ALARM_REG_SIZE,
279 .buf = buf,
280 },
281 };
282 struct i2c_msg msgs[] = {
283 {
284 .addr = client->addr,
285 .flags = 0,
286 .len = 1 + M41T80_ALARM_REG_SIZE,
287 .buf = wbuf,
288 },
289 };
290
291 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
292 dev_err(&client->dev, "read error\n");
293 return -EIO;
294 }
295 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
296 reg[M41T80_REG_ALARM_DAY] = 0;
297 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
298 reg[M41T80_REG_ALARM_MIN] = 0;
299 reg[M41T80_REG_ALARM_SEC] = 0;
300
301 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
302 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
303 BIN2BCD(t->time.tm_sec) : 0x80;
304 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
305 BIN2BCD(t->time.tm_min) : 0x80;
306 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
307 BIN2BCD(t->time.tm_hour) : 0x80;
308 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
309 BIN2BCD(t->time.tm_mday) : 0x80;
310 if (t->time.tm_mon >= 0)
311 reg[M41T80_REG_ALARM_MON] |= BIN2BCD(t->time.tm_mon + 1);
312 else
313 reg[M41T80_REG_ALARM_DAY] |= 0x40;
314
315 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
316 dev_err(&client->dev, "write error\n");
317 return -EIO;
318 }
319
320 if (t->enabled) {
321 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
322 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
323 reg[M41T80_REG_ALARM_MON]) < 0) {
324 dev_err(&client->dev, "write error\n");
325 return -EIO;
326 }
327 }
328 return 0;
329}
330
331static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
332{
333 struct i2c_client *client = to_i2c_client(dev);
334 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
335 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
336 u8 *reg = buf - M41T80_REG_ALARM_MON;
337 struct i2c_msg msgs[] = {
338 {
339 .addr = client->addr,
340 .flags = 0,
341 .len = 1,
342 .buf = dt_addr,
343 },
344 {
345 .addr = client->addr,
346 .flags = I2C_M_RD,
347 .len = M41T80_ALARM_REG_SIZE + 1,
348 .buf = buf,
349 },
350 };
351
352 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
353 dev_err(&client->dev, "read error\n");
354 return -EIO;
355 }
356 t->time.tm_sec = -1;
357 t->time.tm_min = -1;
358 t->time.tm_hour = -1;
359 t->time.tm_mday = -1;
360 t->time.tm_mon = -1;
361 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
362 t->time.tm_sec = BCD2BIN(reg[M41T80_REG_ALARM_SEC] & 0x7f);
363 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
364 t->time.tm_min = BCD2BIN(reg[M41T80_REG_ALARM_MIN] & 0x7f);
365 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
366 t->time.tm_hour = BCD2BIN(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
367 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
368 t->time.tm_mday = BCD2BIN(reg[M41T80_REG_ALARM_DAY] & 0x3f);
369 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
370 t->time.tm_mon = BCD2BIN(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
371 t->time.tm_year = -1;
372 t->time.tm_wday = -1;
373 t->time.tm_yday = -1;
374 t->time.tm_isdst = -1;
375 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
376 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
377 return 0;
378}
379
380static struct rtc_class_ops m41t80_rtc_ops = {
381 .read_time = m41t80_rtc_read_time,
382 .set_time = m41t80_rtc_set_time,
383 .read_alarm = m41t80_rtc_read_alarm,
384 .set_alarm = m41t80_rtc_set_alarm,
385 .proc = m41t80_rtc_proc,
386 .ioctl = m41t80_rtc_ioctl,
387};
388
389#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
390static ssize_t m41t80_sysfs_show_flags(struct device *dev,
391 struct device_attribute *attr, char *buf)
392{
393 struct i2c_client *client = to_i2c_client(dev);
394 int val;
395
396 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
397 if (val < 0)
398 return -EIO;
399 return sprintf(buf, "%#x\n", val);
400}
401static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
402
403static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
404 struct device_attribute *attr, char *buf)
405{
406 struct i2c_client *client = to_i2c_client(dev);
407 int val;
408
409 val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
410 if (val < 0)
411 return -EIO;
412 val = (val >> 4) & 0xf;
413 switch (val) {
414 case 0:
415 break;
416 case 1:
417 val = 32768;
418 break;
419 default:
420 val = 32768 >> val;
421 }
422 return sprintf(buf, "%d\n", val);
423}
424static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
425 struct device_attribute *attr,
426 const char *buf, size_t count)
427{
428 struct i2c_client *client = to_i2c_client(dev);
429 int almon, sqw;
430 int val = simple_strtoul(buf, NULL, 0);
431
432 if (val) {
433 if (!is_power_of_2(val))
434 return -EINVAL;
435 val = ilog2(val);
436 if (val == 15)
437 val = 1;
438 else if (val < 14)
439 val = 15 - val;
440 else
441 return -EINVAL;
442 }
443 /* disable SQW, set SQW frequency & re-enable */
444 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
445 if (almon < 0)
446 return -EIO;
447 sqw = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
448 if (sqw < 0)
449 return -EIO;
450 sqw = (sqw & 0x0f) | (val << 4);
451 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
452 almon & ~M41T80_ALMON_SQWE) < 0 ||
453 i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0)
454 return -EIO;
455 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
456 almon | M41T80_ALMON_SQWE) < 0)
457 return -EIO;
458 return count;
459}
460static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
461 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
462
463static struct attribute *attrs[] = {
464 &dev_attr_flags.attr,
465 &dev_attr_sqwfreq.attr,
466 NULL,
467};
468static struct attribute_group attr_group = {
469 .attrs = attrs,
470};
471
472static int m41t80_sysfs_register(struct device *dev)
473{
474 return sysfs_create_group(&dev->kobj, &attr_group);
475}
476#else
477static int m41t80_sysfs_register(struct device *dev)
478{
479 return 0;
480}
481#endif
482
483/*
484 *****************************************************************************
485 *
486 * Driver Interface
487 *
488 *****************************************************************************
489 */
490static int m41t80_probe(struct i2c_client *client)
491{
492 int i, rc = 0;
493 struct rtc_device *rtc = NULL;
494 struct rtc_time tm;
495 const struct m41t80_chip_info *chip;
496 struct m41t80_data *clientdata = NULL;
497
498 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
499 | I2C_FUNC_SMBUS_BYTE_DATA)) {
500 rc = -ENODEV;
501 goto exit;
502 }
503
504 dev_info(&client->dev,
505 "chip found, driver version " DRV_VERSION "\n");
506
507 chip = NULL;
508 for (i = 0; i < ARRAY_SIZE(m41t80_chip_info_tbl); i++) {
509 if (!strcmp(m41t80_chip_info_tbl[i].name, client->name)) {
510 chip = &m41t80_chip_info_tbl[i];
511 break;
512 }
513 }
514 if (!chip) {
515 dev_err(&client->dev, "%s is not supported\n", client->name);
516 rc = -ENODEV;
517 goto exit;
518 }
519
520 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
521 if (!clientdata) {
522 rc = -ENOMEM;
523 goto exit;
524 }
525
526 rtc = rtc_device_register(client->name, &client->dev,
527 &m41t80_rtc_ops, THIS_MODULE);
528 if (IS_ERR(rtc)) {
529 rc = PTR_ERR(rtc);
530 rtc = NULL;
531 goto exit;
532 }
533
534 clientdata->rtc = rtc;
535 clientdata->chip = chip;
536 i2c_set_clientdata(client, clientdata);
537
538 /* Make sure HT (Halt Update) bit is cleared */
539 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
540 if (rc < 0)
541 goto ht_err;
542
543 if (rc & M41T80_ALHOUR_HT) {
544 if (chip->features & M41T80_FEATURE_HT) {
545 m41t80_get_datetime(client, &tm);
546 dev_info(&client->dev, "HT bit was set!\n");
547 dev_info(&client->dev,
548 "Power Down at "
549 "%04i-%02i-%02i %02i:%02i:%02i\n",
550 tm.tm_year + 1900,
551 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
552 tm.tm_min, tm.tm_sec);
553 }
554 if (i2c_smbus_write_byte_data(client,
555 M41T80_REG_ALARM_HOUR,
556 rc & ~M41T80_ALHOUR_HT) < 0)
557 goto ht_err;
558 }
559
560 /* Make sure ST (stop) bit is cleared */
561 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
562 if (rc < 0)
563 goto st_err;
564
565 if (rc & M41T80_SEC_ST) {
566 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
567 rc & ~M41T80_SEC_ST) < 0)
568 goto st_err;
569 }
570
571 rc = m41t80_sysfs_register(&client->dev);
572 if (rc)
573 goto exit;
574
575 return 0;
576
577st_err:
578 rc = -EIO;
579 dev_err(&client->dev, "Can't clear ST bit\n");
580 goto exit;
581ht_err:
582 rc = -EIO;
583 dev_err(&client->dev, "Can't clear HT bit\n");
584 goto exit;
585
586exit:
587 if (rtc)
588 rtc_device_unregister(rtc);
589 kfree(clientdata);
590 return rc;
591}
592
593static int m41t80_remove(struct i2c_client *client)
594{
595 struct m41t80_data *clientdata = i2c_get_clientdata(client);
596 struct rtc_device *rtc = clientdata->rtc;
597
598 if (rtc)
599 rtc_device_unregister(rtc);
600 kfree(clientdata);
601
602 return 0;
603}
604
605static struct i2c_driver m41t80_driver = {
606 .driver = {
607 .name = "m41t80",
608 },
609 .probe = m41t80_probe,
610 .remove = m41t80_remove,
611};
612
613static int __init m41t80_rtc_init(void)
614{
615 return i2c_add_driver(&m41t80_driver);
616}
617
618static void __exit m41t80_rtc_exit(void)
619{
620 i2c_del_driver(&m41t80_driver);
621}
622
623MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
624MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
625MODULE_LICENSE("GPL");
626MODULE_VERSION(DRV_VERSION);
627
628module_init(m41t80_rtc_init);
629module_exit(m41t80_rtc_exit);