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[deliverable/linux.git] / drivers / rtc / rtc-m41t80.c
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/bcd.h>
17 #include <linux/i2c.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/rtc.h>
22 #include <linux/slab.h>
23 #include <linux/mutex.h>
24 #include <linux/string.h>
25 #ifdef CONFIG_RTC_DRV_M41T80_WDT
26 #include <linux/fs.h>
27 #include <linux/ioctl.h>
28 #include <linux/miscdevice.h>
29 #include <linux/reboot.h>
30 #include <linux/watchdog.h>
31 #endif
32
33 #define M41T80_REG_SSEC 0
34 #define M41T80_REG_SEC 1
35 #define M41T80_REG_MIN 2
36 #define M41T80_REG_HOUR 3
37 #define M41T80_REG_WDAY 4
38 #define M41T80_REG_DAY 5
39 #define M41T80_REG_MON 6
40 #define M41T80_REG_YEAR 7
41 #define M41T80_REG_ALARM_MON 0xa
42 #define M41T80_REG_ALARM_DAY 0xb
43 #define M41T80_REG_ALARM_HOUR 0xc
44 #define M41T80_REG_ALARM_MIN 0xd
45 #define M41T80_REG_ALARM_SEC 0xe
46 #define M41T80_REG_FLAGS 0xf
47 #define M41T80_REG_SQW 0x13
48
49 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
50 #define M41T80_ALARM_REG_SIZE \
51 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
52
53 #define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
54 #define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
55 #define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
56 #define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
57 #define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
58 #define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
59 #define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */
60 #define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */
61 #define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */
62
63 #define M41T80_FEATURE_HT (1 << 0) /* Halt feature */
64 #define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */
65 #define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */
66 #define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */
67 #define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */
68
69 static DEFINE_MUTEX(m41t80_rtc_mutex);
70 static const struct i2c_device_id m41t80_id[] = {
71 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
72 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
73 { "m41t80", M41T80_FEATURE_SQ },
74 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
75 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
76 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
77 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { }
82 };
83 MODULE_DEVICE_TABLE(i2c, m41t80_id);
84
85 struct m41t80_data {
86 u8 features;
87 struct rtc_device *rtc;
88 };
89
90 static int m41t80_get_datetime(struct i2c_client *client,
91 struct rtc_time *tm)
92 {
93 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
94 struct i2c_msg msgs[] = {
95 {
96 .addr = client->addr,
97 .flags = 0,
98 .len = 1,
99 .buf = dt_addr,
100 },
101 {
102 .addr = client->addr,
103 .flags = I2C_M_RD,
104 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
105 .buf = buf + M41T80_REG_SEC,
106 },
107 };
108
109 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
110 dev_err(&client->dev, "read error\n");
111 return -EIO;
112 }
113
114 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
115 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
116 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
117 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
118 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
119 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
120
121 /* assume 20YY not 19YY, and ignore the Century Bit */
122 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
123 return rtc_valid_tm(tm);
124 }
125
126 /* Sets the given date and time to the real time clock. */
127 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
128 {
129 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
130 u8 *buf = &wbuf[1];
131 u8 dt_addr[1] = { M41T80_REG_SEC };
132 struct i2c_msg msgs_in[] = {
133 {
134 .addr = client->addr,
135 .flags = 0,
136 .len = 1,
137 .buf = dt_addr,
138 },
139 {
140 .addr = client->addr,
141 .flags = I2C_M_RD,
142 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
143 .buf = buf + M41T80_REG_SEC,
144 },
145 };
146 struct i2c_msg msgs[] = {
147 {
148 .addr = client->addr,
149 .flags = 0,
150 .len = 1 + M41T80_DATETIME_REG_SIZE,
151 .buf = wbuf,
152 },
153 };
154
155 /* Read current reg values into buf[1..7] */
156 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
157 dev_err(&client->dev, "read error\n");
158 return -EIO;
159 }
160
161 wbuf[0] = 0; /* offset into rtc's regs */
162 /* Merge time-data and register flags into buf[0..7] */
163 buf[M41T80_REG_SSEC] = 0;
164 buf[M41T80_REG_SEC] =
165 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
166 buf[M41T80_REG_MIN] =
167 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
168 buf[M41T80_REG_HOUR] =
169 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f);
170 buf[M41T80_REG_WDAY] =
171 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
172 buf[M41T80_REG_DAY] =
173 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
174 buf[M41T80_REG_MON] =
175 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
176 /* assume 20YY not 19YY */
177 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
178
179 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
180 dev_err(&client->dev, "write error\n");
181 return -EIO;
182 }
183 return 0;
184 }
185
186 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
187 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
188 {
189 struct i2c_client *client = to_i2c_client(dev);
190 struct m41t80_data *clientdata = i2c_get_clientdata(client);
191 u8 reg;
192
193 if (clientdata->features & M41T80_FEATURE_BL) {
194 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
195 seq_printf(seq, "battery\t\t: %s\n",
196 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
197 }
198 return 0;
199 }
200 #else
201 #define m41t80_rtc_proc NULL
202 #endif
203
204 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
205 {
206 return m41t80_get_datetime(to_i2c_client(dev), tm);
207 }
208
209 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
210 {
211 return m41t80_set_datetime(to_i2c_client(dev), tm);
212 }
213
214 /*
215 * XXX - m41t80 alarm functionality is reported broken.
216 * until it is fixed, don't register alarm functions.
217 */
218 static struct rtc_class_ops m41t80_rtc_ops = {
219 .read_time = m41t80_rtc_read_time,
220 .set_time = m41t80_rtc_set_time,
221 .proc = m41t80_rtc_proc,
222 };
223
224 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
225 static ssize_t m41t80_sysfs_show_flags(struct device *dev,
226 struct device_attribute *attr, char *buf)
227 {
228 struct i2c_client *client = to_i2c_client(dev);
229 int val;
230
231 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
232 if (val < 0)
233 return val;
234 return sprintf(buf, "%#x\n", val);
235 }
236 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
237
238 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
239 struct device_attribute *attr, char *buf)
240 {
241 struct i2c_client *client = to_i2c_client(dev);
242 struct m41t80_data *clientdata = i2c_get_clientdata(client);
243 int val, reg_sqw;
244
245 if (!(clientdata->features & M41T80_FEATURE_SQ))
246 return -EINVAL;
247
248 reg_sqw = M41T80_REG_SQW;
249 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
250 reg_sqw = M41T80_REG_WDAY;
251 val = i2c_smbus_read_byte_data(client, reg_sqw);
252 if (val < 0)
253 return val;
254 val = (val >> 4) & 0xf;
255 switch (val) {
256 case 0:
257 break;
258 case 1:
259 val = 32768;
260 break;
261 default:
262 val = 32768 >> val;
263 }
264 return sprintf(buf, "%d\n", val);
265 }
266 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
267 struct device_attribute *attr,
268 const char *buf, size_t count)
269 {
270 struct i2c_client *client = to_i2c_client(dev);
271 struct m41t80_data *clientdata = i2c_get_clientdata(client);
272 int almon, sqw, reg_sqw, rc;
273 int val = simple_strtoul(buf, NULL, 0);
274
275 if (!(clientdata->features & M41T80_FEATURE_SQ))
276 return -EINVAL;
277
278 if (val) {
279 if (!is_power_of_2(val))
280 return -EINVAL;
281 val = ilog2(val);
282 if (val == 15)
283 val = 1;
284 else if (val < 14)
285 val = 15 - val;
286 else
287 return -EINVAL;
288 }
289 /* disable SQW, set SQW frequency & re-enable */
290 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
291 if (almon < 0)
292 return almon;
293 reg_sqw = M41T80_REG_SQW;
294 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
295 reg_sqw = M41T80_REG_WDAY;
296 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
297 if (sqw < 0)
298 return sqw;
299 sqw = (sqw & 0x0f) | (val << 4);
300
301 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
302 almon & ~M41T80_ALMON_SQWE);
303 if (rc < 0)
304 return rc;
305
306 if (val) {
307 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
308 if (rc < 0)
309 return rc;
310
311 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
312 almon | M41T80_ALMON_SQWE);
313 if (rc <0)
314 return rc;
315 }
316 return count;
317 }
318 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
319 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
320
321 static struct attribute *attrs[] = {
322 &dev_attr_flags.attr,
323 &dev_attr_sqwfreq.attr,
324 NULL,
325 };
326 static struct attribute_group attr_group = {
327 .attrs = attrs,
328 };
329
330 static int m41t80_sysfs_register(struct device *dev)
331 {
332 return sysfs_create_group(&dev->kobj, &attr_group);
333 }
334 #else
335 static int m41t80_sysfs_register(struct device *dev)
336 {
337 return 0;
338 }
339 #endif
340
341 #ifdef CONFIG_RTC_DRV_M41T80_WDT
342 /*
343 *****************************************************************************
344 *
345 * Watchdog Driver
346 *
347 *****************************************************************************
348 */
349 static struct i2c_client *save_client;
350
351 /* Default margin */
352 #define WD_TIMO 60 /* 1..31 seconds */
353
354 static int wdt_margin = WD_TIMO;
355 module_param(wdt_margin, int, 0);
356 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
357
358 static unsigned long wdt_is_open;
359 static int boot_flag;
360
361 /**
362 * wdt_ping:
363 *
364 * Reload counter one with the watchdog timeout. We don't bother reloading
365 * the cascade counter.
366 */
367 static void wdt_ping(void)
368 {
369 unsigned char i2c_data[2];
370 struct i2c_msg msgs1[1] = {
371 {
372 .addr = save_client->addr,
373 .flags = 0,
374 .len = 2,
375 .buf = i2c_data,
376 },
377 };
378 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
379
380 i2c_data[0] = 0x09; /* watchdog register */
381
382 if (wdt_margin > 31)
383 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
384 else
385 /*
386 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
387 */
388 i2c_data[1] = wdt_margin<<2 | 0x82;
389
390 /*
391 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
392 * that would be an invalid resolution.
393 */
394 if (clientdata->features & M41T80_FEATURE_WD)
395 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
396
397 i2c_transfer(save_client->adapter, msgs1, 1);
398 }
399
400 /**
401 * wdt_disable:
402 *
403 * disables watchdog.
404 */
405 static void wdt_disable(void)
406 {
407 unsigned char i2c_data[2], i2c_buf[0x10];
408 struct i2c_msg msgs0[2] = {
409 {
410 .addr = save_client->addr,
411 .flags = 0,
412 .len = 1,
413 .buf = i2c_data,
414 },
415 {
416 .addr = save_client->addr,
417 .flags = I2C_M_RD,
418 .len = 1,
419 .buf = i2c_buf,
420 },
421 };
422 struct i2c_msg msgs1[1] = {
423 {
424 .addr = save_client->addr,
425 .flags = 0,
426 .len = 2,
427 .buf = i2c_data,
428 },
429 };
430
431 i2c_data[0] = 0x09;
432 i2c_transfer(save_client->adapter, msgs0, 2);
433
434 i2c_data[0] = 0x09;
435 i2c_data[1] = 0x00;
436 i2c_transfer(save_client->adapter, msgs1, 1);
437 }
438
439 /**
440 * wdt_write:
441 * @file: file handle to the watchdog
442 * @buf: buffer to write (unused as data does not matter here
443 * @count: count of bytes
444 * @ppos: pointer to the position to write. No seeks allowed
445 *
446 * A write to a watchdog device is defined as a keepalive signal. Any
447 * write of data will do, as we we don't define content meaning.
448 */
449 static ssize_t wdt_write(struct file *file, const char __user *buf,
450 size_t count, loff_t *ppos)
451 {
452 if (count) {
453 wdt_ping();
454 return 1;
455 }
456 return 0;
457 }
458
459 static ssize_t wdt_read(struct file *file, char __user *buf,
460 size_t count, loff_t *ppos)
461 {
462 return 0;
463 }
464
465 /**
466 * wdt_ioctl:
467 * @inode: inode of the device
468 * @file: file handle to the device
469 * @cmd: watchdog command
470 * @arg: argument pointer
471 *
472 * The watchdog API defines a common set of functions for all watchdogs
473 * according to their available features. We only actually usefully support
474 * querying capabilities and current status.
475 */
476 static int wdt_ioctl(struct file *file, unsigned int cmd,
477 unsigned long arg)
478 {
479 int new_margin, rv;
480 static struct watchdog_info ident = {
481 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
482 WDIOF_SETTIMEOUT,
483 .firmware_version = 1,
484 .identity = "M41T80 WTD"
485 };
486
487 switch (cmd) {
488 case WDIOC_GETSUPPORT:
489 return copy_to_user((struct watchdog_info __user *)arg, &ident,
490 sizeof(ident)) ? -EFAULT : 0;
491
492 case WDIOC_GETSTATUS:
493 case WDIOC_GETBOOTSTATUS:
494 return put_user(boot_flag, (int __user *)arg);
495 case WDIOC_KEEPALIVE:
496 wdt_ping();
497 return 0;
498 case WDIOC_SETTIMEOUT:
499 if (get_user(new_margin, (int __user *)arg))
500 return -EFAULT;
501 /* Arbitrary, can't find the card's limits */
502 if (new_margin < 1 || new_margin > 124)
503 return -EINVAL;
504 wdt_margin = new_margin;
505 wdt_ping();
506 /* Fall */
507 case WDIOC_GETTIMEOUT:
508 return put_user(wdt_margin, (int __user *)arg);
509
510 case WDIOC_SETOPTIONS:
511 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
512 return -EFAULT;
513
514 if (rv & WDIOS_DISABLECARD) {
515 pr_info("rtc-m41t80: disable watchdog\n");
516 wdt_disable();
517 }
518
519 if (rv & WDIOS_ENABLECARD) {
520 pr_info("rtc-m41t80: enable watchdog\n");
521 wdt_ping();
522 }
523
524 return -EINVAL;
525 }
526 return -ENOTTY;
527 }
528
529 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
530 unsigned long arg)
531 {
532 int ret;
533
534 mutex_lock(&m41t80_rtc_mutex);
535 ret = wdt_ioctl(file, cmd, arg);
536 mutex_unlock(&m41t80_rtc_mutex);
537
538 return ret;
539 }
540
541 /**
542 * wdt_open:
543 * @inode: inode of device
544 * @file: file handle to device
545 *
546 */
547 static int wdt_open(struct inode *inode, struct file *file)
548 {
549 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
550 mutex_lock(&m41t80_rtc_mutex);
551 if (test_and_set_bit(0, &wdt_is_open)) {
552 mutex_unlock(&m41t80_rtc_mutex);
553 return -EBUSY;
554 }
555 /*
556 * Activate
557 */
558 wdt_is_open = 1;
559 mutex_unlock(&m41t80_rtc_mutex);
560 return nonseekable_open(inode, file);
561 }
562 return -ENODEV;
563 }
564
565 /**
566 * wdt_close:
567 * @inode: inode to board
568 * @file: file handle to board
569 *
570 */
571 static int wdt_release(struct inode *inode, struct file *file)
572 {
573 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
574 clear_bit(0, &wdt_is_open);
575 return 0;
576 }
577
578 /**
579 * notify_sys:
580 * @this: our notifier block
581 * @code: the event being reported
582 * @unused: unused
583 *
584 * Our notifier is called on system shutdowns. We want to turn the card
585 * off at reboot otherwise the machine will reboot again during memory
586 * test or worse yet during the following fsck. This would suck, in fact
587 * trust me - if it happens it does suck.
588 */
589 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
590 void *unused)
591 {
592 if (code == SYS_DOWN || code == SYS_HALT)
593 /* Disable Watchdog */
594 wdt_disable();
595 return NOTIFY_DONE;
596 }
597
598 static const struct file_operations wdt_fops = {
599 .owner = THIS_MODULE,
600 .read = wdt_read,
601 .unlocked_ioctl = wdt_unlocked_ioctl,
602 .write = wdt_write,
603 .open = wdt_open,
604 .release = wdt_release,
605 .llseek = no_llseek,
606 };
607
608 static struct miscdevice wdt_dev = {
609 .minor = WATCHDOG_MINOR,
610 .name = "watchdog",
611 .fops = &wdt_fops,
612 };
613
614 /*
615 * The WDT card needs to learn about soft shutdowns in order to
616 * turn the timebomb registers off.
617 */
618 static struct notifier_block wdt_notifier = {
619 .notifier_call = wdt_notify_sys,
620 };
621 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
622
623 /*
624 *****************************************************************************
625 *
626 * Driver Interface
627 *
628 *****************************************************************************
629 */
630 static int m41t80_probe(struct i2c_client *client,
631 const struct i2c_device_id *id)
632 {
633 int rc = 0;
634 struct rtc_device *rtc = NULL;
635 struct rtc_time tm;
636 struct m41t80_data *clientdata = NULL;
637
638 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
639 | I2C_FUNC_SMBUS_BYTE_DATA))
640 return -ENODEV;
641
642 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata),
643 GFP_KERNEL);
644 if (!clientdata)
645 return -ENOMEM;
646
647 clientdata->features = id->driver_data;
648 i2c_set_clientdata(client, clientdata);
649
650 rtc = devm_rtc_device_register(&client->dev, client->name,
651 &m41t80_rtc_ops, THIS_MODULE);
652 if (IS_ERR(rtc))
653 return PTR_ERR(rtc);
654
655 clientdata->rtc = rtc;
656
657 /* Make sure HT (Halt Update) bit is cleared */
658 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
659
660 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
661 if (clientdata->features & M41T80_FEATURE_HT) {
662 m41t80_get_datetime(client, &tm);
663 dev_info(&client->dev, "HT bit was set!\n");
664 dev_info(&client->dev,
665 "Power Down at "
666 "%04i-%02i-%02i %02i:%02i:%02i\n",
667 tm.tm_year + 1900,
668 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
669 tm.tm_min, tm.tm_sec);
670 }
671 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
672 rc & ~M41T80_ALHOUR_HT);
673 }
674
675 if (rc < 0) {
676 dev_err(&client->dev, "Can't clear HT bit\n");
677 return rc;
678 }
679
680 /* Make sure ST (stop) bit is cleared */
681 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
682
683 if (rc >= 0 && rc & M41T80_SEC_ST)
684 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
685 rc & ~M41T80_SEC_ST);
686 if (rc < 0) {
687 dev_err(&client->dev, "Can't clear ST bit\n");
688 return rc;
689 }
690
691 rc = m41t80_sysfs_register(&client->dev);
692 if (rc)
693 return rc;
694
695 #ifdef CONFIG_RTC_DRV_M41T80_WDT
696 if (clientdata->features & M41T80_FEATURE_HT) {
697 save_client = client;
698 rc = misc_register(&wdt_dev);
699 if (rc)
700 return rc;
701 rc = register_reboot_notifier(&wdt_notifier);
702 if (rc) {
703 misc_deregister(&wdt_dev);
704 return rc;
705 }
706 }
707 #endif
708 return 0;
709 }
710
711 static int m41t80_remove(struct i2c_client *client)
712 {
713 #ifdef CONFIG_RTC_DRV_M41T80_WDT
714 struct m41t80_data *clientdata = i2c_get_clientdata(client);
715
716 if (clientdata->features & M41T80_FEATURE_HT) {
717 misc_deregister(&wdt_dev);
718 unregister_reboot_notifier(&wdt_notifier);
719 }
720 #endif
721
722 return 0;
723 }
724
725 static struct i2c_driver m41t80_driver = {
726 .driver = {
727 .name = "rtc-m41t80",
728 },
729 .probe = m41t80_probe,
730 .remove = m41t80_remove,
731 .id_table = m41t80_id,
732 };
733
734 module_i2c_driver(m41t80_driver);
735
736 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
737 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
738 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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