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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)
54#define M41T80_ALMON_AFE (1 << 7)
55#define M41T80_ALMON_SQWE (1 << 6)
56#define M41T80_ALHOUR_HT (1 << 6)
57#define M41T80_FLAGS_AF (1 << 6)
58#define M41T80_FLAGS_BATT_LOW (1 << 4)
59#define M41T80_WATCHDOG_RB2 (1 << 7)
60#define M41T80_WATCHDOG_RB1 (1 << 1)
61#define M41T80_WATCHDOG_RB0 (1 << 0)
62
63#define M41T80_FEATURE_HT (1 << 0)
64#define M41T80_FEATURE_BL (1 << 1)
65#define M41T80_FEATURE_SQ (1 << 2)
66#define M41T80_FEATURE_WD (1 << 3)
67#define M41T80_FEATURE_SQ_ALT (1 << 4)
68
69static DEFINE_MUTEX(m41t80_rtc_mutex);
70static 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 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
82 { }
83};
84MODULE_DEVICE_TABLE(i2c, m41t80_id);
85
86struct m41t80_data {
87 u8 features;
88 struct rtc_device *rtc;
89};
90
91static int m41t80_get_datetime(struct i2c_client *client,
92 struct rtc_time *tm)
93{
94 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
95 struct i2c_msg msgs[] = {
96 {
97 .addr = client->addr,
98 .flags = 0,
99 .len = 1,
100 .buf = dt_addr,
101 },
102 {
103 .addr = client->addr,
104 .flags = I2C_M_RD,
105 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
106 .buf = buf + M41T80_REG_SEC,
107 },
108 };
109
110 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
111 dev_err(&client->dev, "read error\n");
112 return -EIO;
113 }
114
115 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
116 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
117 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
118 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
119 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
120 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
121
122
123 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
124 return rtc_valid_tm(tm);
125}
126
127
128static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
129{
130 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
131 u8 *buf = &wbuf[1];
132 u8 dt_addr[1] = { M41T80_REG_SEC };
133 struct i2c_msg msgs_in[] = {
134 {
135 .addr = client->addr,
136 .flags = 0,
137 .len = 1,
138 .buf = dt_addr,
139 },
140 {
141 .addr = client->addr,
142 .flags = I2C_M_RD,
143 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
144 .buf = buf + M41T80_REG_SEC,
145 },
146 };
147 struct i2c_msg msgs[] = {
148 {
149 .addr = client->addr,
150 .flags = 0,
151 .len = 1 + M41T80_DATETIME_REG_SIZE,
152 .buf = wbuf,
153 },
154 };
155
156
157 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
158 dev_err(&client->dev, "read error\n");
159 return -EIO;
160 }
161
162 wbuf[0] = 0;
163
164 buf[M41T80_REG_SSEC] = 0;
165 buf[M41T80_REG_SEC] =
166 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
167 buf[M41T80_REG_MIN] =
168 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
169 buf[M41T80_REG_HOUR] =
170 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f);
171 buf[M41T80_REG_WDAY] =
172 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
173 buf[M41T80_REG_DAY] =
174 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
175 buf[M41T80_REG_MON] =
176 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
177
178 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
179
180 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
181 dev_err(&client->dev, "write error\n");
182 return -EIO;
183 }
184 return 0;
185}
186
187#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
188static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
189{
190 struct i2c_client *client = to_i2c_client(dev);
191 struct m41t80_data *clientdata = i2c_get_clientdata(client);
192 u8 reg;
193
194 if (clientdata->features & M41T80_FEATURE_BL) {
195 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
196 seq_printf(seq, "battery\t\t: %s\n",
197 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
198 }
199 return 0;
200}
201#else
202#define m41t80_rtc_proc NULL
203#endif
204
205static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
206{
207 return m41t80_get_datetime(to_i2c_client(dev), tm);
208}
209
210static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
211{
212 return m41t80_set_datetime(to_i2c_client(dev), tm);
213}
214
215
216
217
218
219static struct rtc_class_ops m41t80_rtc_ops = {
220 .read_time = m41t80_rtc_read_time,
221 .set_time = m41t80_rtc_set_time,
222 .proc = m41t80_rtc_proc,
223};
224
225#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
226static ssize_t m41t80_sysfs_show_flags(struct device *dev,
227 struct device_attribute *attr, char *buf)
228{
229 struct i2c_client *client = to_i2c_client(dev);
230 int val;
231
232 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
233 if (val < 0)
234 return val;
235 return sprintf(buf, "%#x\n", val);
236}
237static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
238
239static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
240 struct device_attribute *attr, char *buf)
241{
242 struct i2c_client *client = to_i2c_client(dev);
243 struct m41t80_data *clientdata = i2c_get_clientdata(client);
244 int val, reg_sqw;
245
246 if (!(clientdata->features & M41T80_FEATURE_SQ))
247 return -EINVAL;
248
249 reg_sqw = M41T80_REG_SQW;
250 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
251 reg_sqw = M41T80_REG_WDAY;
252 val = i2c_smbus_read_byte_data(client, reg_sqw);
253 if (val < 0)
254 return val;
255 val = (val >> 4) & 0xf;
256 switch (val) {
257 case 0:
258 break;
259 case 1:
260 val = 32768;
261 break;
262 default:
263 val = 32768 >> val;
264 }
265 return sprintf(buf, "%d\n", val);
266}
267static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
268 struct device_attribute *attr,
269 const char *buf, size_t count)
270{
271 struct i2c_client *client = to_i2c_client(dev);
272 struct m41t80_data *clientdata = i2c_get_clientdata(client);
273 int almon, sqw, reg_sqw, rc;
274 int val = simple_strtoul(buf, NULL, 0);
275
276 if (!(clientdata->features & M41T80_FEATURE_SQ))
277 return -EINVAL;
278
279 if (val) {
280 if (!is_power_of_2(val))
281 return -EINVAL;
282 val = ilog2(val);
283 if (val == 15)
284 val = 1;
285 else if (val < 14)
286 val = 15 - val;
287 else
288 return -EINVAL;
289 }
290
291 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
292 if (almon < 0)
293 return almon;
294 reg_sqw = M41T80_REG_SQW;
295 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
296 reg_sqw = M41T80_REG_WDAY;
297 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
298 if (sqw < 0)
299 return sqw;
300 sqw = (sqw & 0x0f) | (val << 4);
301
302 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
303 almon & ~M41T80_ALMON_SQWE);
304 if (rc < 0)
305 return rc;
306
307 if (val) {
308 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
309 if (rc < 0)
310 return rc;
311
312 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
313 almon | M41T80_ALMON_SQWE);
314 if (rc <0)
315 return rc;
316 }
317 return count;
318}
319static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
320 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
321
322static struct attribute *attrs[] = {
323 &dev_attr_flags.attr,
324 &dev_attr_sqwfreq.attr,
325 NULL,
326};
327static struct attribute_group attr_group = {
328 .attrs = attrs,
329};
330
331static int m41t80_sysfs_register(struct device *dev)
332{
333 return sysfs_create_group(&dev->kobj, &attr_group);
334}
335#else
336static int m41t80_sysfs_register(struct device *dev)
337{
338 return 0;
339}
340#endif
341
342#ifdef CONFIG_RTC_DRV_M41T80_WDT
343
344
345
346
347
348
349
350static struct i2c_client *save_client;
351
352
353#define WD_TIMO 60
354
355static int wdt_margin = WD_TIMO;
356module_param(wdt_margin, int, 0);
357MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
358
359static unsigned long wdt_is_open;
360static int boot_flag;
361
362
363
364
365
366
367
368static void wdt_ping(void)
369{
370 unsigned char i2c_data[2];
371 struct i2c_msg msgs1[1] = {
372 {
373 .addr = save_client->addr,
374 .flags = 0,
375 .len = 2,
376 .buf = i2c_data,
377 },
378 };
379 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
380
381 i2c_data[0] = 0x09;
382
383 if (wdt_margin > 31)
384 i2c_data[1] = (wdt_margin & 0xFC) | 0x83;
385 else
386
387
388
389 i2c_data[1] = wdt_margin<<2 | 0x82;
390
391
392
393
394
395 if (clientdata->features & M41T80_FEATURE_WD)
396 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
397
398 i2c_transfer(save_client->adapter, msgs1, 1);
399}
400
401
402
403
404
405
406static void wdt_disable(void)
407{
408 unsigned char i2c_data[2], i2c_buf[0x10];
409 struct i2c_msg msgs0[2] = {
410 {
411 .addr = save_client->addr,
412 .flags = 0,
413 .len = 1,
414 .buf = i2c_data,
415 },
416 {
417 .addr = save_client->addr,
418 .flags = I2C_M_RD,
419 .len = 1,
420 .buf = i2c_buf,
421 },
422 };
423 struct i2c_msg msgs1[1] = {
424 {
425 .addr = save_client->addr,
426 .flags = 0,
427 .len = 2,
428 .buf = i2c_data,
429 },
430 };
431
432 i2c_data[0] = 0x09;
433 i2c_transfer(save_client->adapter, msgs0, 2);
434
435 i2c_data[0] = 0x09;
436 i2c_data[1] = 0x00;
437 i2c_transfer(save_client->adapter, msgs1, 1);
438}
439
440
441
442
443
444
445
446
447
448
449
450static ssize_t wdt_write(struct file *file, const char __user *buf,
451 size_t count, loff_t *ppos)
452{
453 if (count) {
454 wdt_ping();
455 return 1;
456 }
457 return 0;
458}
459
460static ssize_t wdt_read(struct file *file, char __user *buf,
461 size_t count, loff_t *ppos)
462{
463 return 0;
464}
465
466
467
468
469
470
471
472
473
474
475
476
477static int wdt_ioctl(struct file *file, unsigned int cmd,
478 unsigned long arg)
479{
480 int new_margin, rv;
481 static struct watchdog_info ident = {
482 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
483 WDIOF_SETTIMEOUT,
484 .firmware_version = 1,
485 .identity = "M41T80 WTD"
486 };
487
488 switch (cmd) {
489 case WDIOC_GETSUPPORT:
490 return copy_to_user((struct watchdog_info __user *)arg, &ident,
491 sizeof(ident)) ? -EFAULT : 0;
492
493 case WDIOC_GETSTATUS:
494 case WDIOC_GETBOOTSTATUS:
495 return put_user(boot_flag, (int __user *)arg);
496 case WDIOC_KEEPALIVE:
497 wdt_ping();
498 return 0;
499 case WDIOC_SETTIMEOUT:
500 if (get_user(new_margin, (int __user *)arg))
501 return -EFAULT;
502
503 if (new_margin < 1 || new_margin > 124)
504 return -EINVAL;
505 wdt_margin = new_margin;
506 wdt_ping();
507
508 case WDIOC_GETTIMEOUT:
509 return put_user(wdt_margin, (int __user *)arg);
510
511 case WDIOC_SETOPTIONS:
512 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
513 return -EFAULT;
514
515 if (rv & WDIOS_DISABLECARD) {
516 pr_info("rtc-m41t80: disable watchdog\n");
517 wdt_disable();
518 }
519
520 if (rv & WDIOS_ENABLECARD) {
521 pr_info("rtc-m41t80: enable watchdog\n");
522 wdt_ping();
523 }
524
525 return -EINVAL;
526 }
527 return -ENOTTY;
528}
529
530static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
531 unsigned long arg)
532{
533 int ret;
534
535 mutex_lock(&m41t80_rtc_mutex);
536 ret = wdt_ioctl(file, cmd, arg);
537 mutex_unlock(&m41t80_rtc_mutex);
538
539 return ret;
540}
541
542
543
544
545
546
547
548static int wdt_open(struct inode *inode, struct file *file)
549{
550 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
551 mutex_lock(&m41t80_rtc_mutex);
552 if (test_and_set_bit(0, &wdt_is_open)) {
553 mutex_unlock(&m41t80_rtc_mutex);
554 return -EBUSY;
555 }
556
557
558
559 wdt_is_open = 1;
560 mutex_unlock(&m41t80_rtc_mutex);
561 return nonseekable_open(inode, file);
562 }
563 return -ENODEV;
564}
565
566
567
568
569
570
571
572static int wdt_release(struct inode *inode, struct file *file)
573{
574 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
575 clear_bit(0, &wdt_is_open);
576 return 0;
577}
578
579
580
581
582
583
584
585
586
587
588
589
590static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
591 void *unused)
592{
593 if (code == SYS_DOWN || code == SYS_HALT)
594
595 wdt_disable();
596 return NOTIFY_DONE;
597}
598
599static const struct file_operations wdt_fops = {
600 .owner = THIS_MODULE,
601 .read = wdt_read,
602 .unlocked_ioctl = wdt_unlocked_ioctl,
603 .write = wdt_write,
604 .open = wdt_open,
605 .release = wdt_release,
606 .llseek = no_llseek,
607};
608
609static struct miscdevice wdt_dev = {
610 .minor = WATCHDOG_MINOR,
611 .name = "watchdog",
612 .fops = &wdt_fops,
613};
614
615
616
617
618
619static struct notifier_block wdt_notifier = {
620 .notifier_call = wdt_notify_sys,
621};
622#endif
623
624
625
626
627
628
629
630
631static int m41t80_probe(struct i2c_client *client,
632 const struct i2c_device_id *id)
633{
634 int rc = 0;
635 struct rtc_device *rtc = NULL;
636 struct rtc_time tm;
637 struct m41t80_data *clientdata = NULL;
638
639 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
640 | I2C_FUNC_SMBUS_BYTE_DATA))
641 return -ENODEV;
642
643 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata),
644 GFP_KERNEL);
645 if (!clientdata)
646 return -ENOMEM;
647
648 clientdata->features = id->driver_data;
649 i2c_set_clientdata(client, clientdata);
650
651 rtc = devm_rtc_device_register(&client->dev, client->name,
652 &m41t80_rtc_ops, THIS_MODULE);
653 if (IS_ERR(rtc))
654 return PTR_ERR(rtc);
655
656 clientdata->rtc = rtc;
657
658
659 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
660
661 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
662 if (clientdata->features & M41T80_FEATURE_HT) {
663 m41t80_get_datetime(client, &tm);
664 dev_info(&client->dev, "HT bit was set!\n");
665 dev_info(&client->dev,
666 "Power Down at "
667 "%04i-%02i-%02i %02i:%02i:%02i\n",
668 tm.tm_year + 1900,
669 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
670 tm.tm_min, tm.tm_sec);
671 }
672 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
673 rc & ~M41T80_ALHOUR_HT);
674 }
675
676 if (rc < 0) {
677 dev_err(&client->dev, "Can't clear HT bit\n");
678 return rc;
679 }
680
681
682 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
683
684 if (rc >= 0 && rc & M41T80_SEC_ST)
685 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
686 rc & ~M41T80_SEC_ST);
687 if (rc < 0) {
688 dev_err(&client->dev, "Can't clear ST bit\n");
689 return rc;
690 }
691
692 rc = m41t80_sysfs_register(&client->dev);
693 if (rc)
694 return rc;
695
696#ifdef CONFIG_RTC_DRV_M41T80_WDT
697 if (clientdata->features & M41T80_FEATURE_HT) {
698 save_client = client;
699 rc = misc_register(&wdt_dev);
700 if (rc)
701 return rc;
702 rc = register_reboot_notifier(&wdt_notifier);
703 if (rc) {
704 misc_deregister(&wdt_dev);
705 return rc;
706 }
707 }
708#endif
709 return 0;
710}
711
712static int m41t80_remove(struct i2c_client *client)
713{
714#ifdef CONFIG_RTC_DRV_M41T80_WDT
715 struct m41t80_data *clientdata = i2c_get_clientdata(client);
716
717 if (clientdata->features & M41T80_FEATURE_HT) {
718 misc_deregister(&wdt_dev);
719 unregister_reboot_notifier(&wdt_notifier);
720 }
721#endif
722
723 return 0;
724}
725
726static struct i2c_driver m41t80_driver = {
727 .driver = {
728 .name = "rtc-m41t80",
729 },
730 .probe = m41t80_probe,
731 .remove = m41t80_remove,
732 .id_table = m41t80_id,
733};
734
735module_i2c_driver(m41t80_driver);
736
737MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
738MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
739MODULE_LICENSE("GPL");
740