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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/bcd.h>
19#include <linux/i2c.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/rtc.h>
24#include <linux/slab.h>
25#include <linux/mutex.h>
26#include <linux/string.h>
27#ifdef CONFIG_RTC_DRV_M41T80_WDT
28#include <linux/fs.h>
29#include <linux/ioctl.h>
30#include <linux/miscdevice.h>
31#include <linux/reboot.h>
32#include <linux/watchdog.h>
33#endif
34
35#define M41T80_REG_SSEC 0
36#define M41T80_REG_SEC 1
37#define M41T80_REG_MIN 2
38#define M41T80_REG_HOUR 3
39#define M41T80_REG_WDAY 4
40#define M41T80_REG_DAY 5
41#define M41T80_REG_MON 6
42#define M41T80_REG_YEAR 7
43#define M41T80_REG_ALARM_MON 0xa
44#define M41T80_REG_ALARM_DAY 0xb
45#define M41T80_REG_ALARM_HOUR 0xc
46#define M41T80_REG_ALARM_MIN 0xd
47#define M41T80_REG_ALARM_SEC 0xe
48#define M41T80_REG_FLAGS 0xf
49#define M41T80_REG_SQW 0x13
50
51#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
52#define M41T80_ALARM_REG_SIZE \
53 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
54
55#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
56#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
57#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
58#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
59#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
60#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
61#define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */
62#define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */
63#define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */
64
65#define M41T80_FEATURE_HT (1 << 0) /* Halt feature */
66#define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */
67#define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */
68#define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */
69#define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */
70
71static DEFINE_MUTEX(m41t80_rtc_mutex);
72static const struct i2c_device_id m41t80_id[] = {
73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
75 { "m41t80", M41T80_FEATURE_SQ },
76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
84 { }
85};
86MODULE_DEVICE_TABLE(i2c, m41t80_id);
87
88struct m41t80_data {
89 u8 features;
90 struct rtc_device *rtc;
91};
92
93static int m41t80_get_datetime(struct i2c_client *client,
94 struct rtc_time *tm)
95{
96 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
97 struct i2c_msg msgs[] = {
98 {
99 .addr = client->addr,
100 .flags = 0,
101 .len = 1,
102 .buf = dt_addr,
103 },
104 {
105 .addr = client->addr,
106 .flags = I2C_M_RD,
107 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
108 .buf = buf + M41T80_REG_SEC,
109 },
110 };
111
112 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
113 dev_err(&client->dev, "read error\n");
114 return -EIO;
115 }
116
117 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
118 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
119 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
120 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
121 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
122 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
123
124 /* assume 20YY not 19YY, and ignore the Century Bit */
125 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
126 return rtc_valid_tm(tm);
127}
128
129/* Sets the given date and time to the real time clock. */
130static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
131{
132 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
133 u8 *buf = &wbuf[1];
134 u8 dt_addr[1] = { M41T80_REG_SEC };
135 struct i2c_msg msgs_in[] = {
136 {
137 .addr = client->addr,
138 .flags = 0,
139 .len = 1,
140 .buf = dt_addr,
141 },
142 {
143 .addr = client->addr,
144 .flags = I2C_M_RD,
145 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
146 .buf = buf + M41T80_REG_SEC,
147 },
148 };
149 struct i2c_msg msgs[] = {
150 {
151 .addr = client->addr,
152 .flags = 0,
153 .len = 1 + M41T80_DATETIME_REG_SIZE,
154 .buf = wbuf,
155 },
156 };
157
158 /* Read current reg values into buf[1..7] */
159 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
160 dev_err(&client->dev, "read error\n");
161 return -EIO;
162 }
163
164 wbuf[0] = 0; /* offset into rtc's regs */
165 /* Merge time-data and register flags into buf[0..7] */
166 buf[M41T80_REG_SSEC] = 0;
167 buf[M41T80_REG_SEC] =
168 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
169 buf[M41T80_REG_MIN] =
170 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
171 buf[M41T80_REG_HOUR] =
172 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f);
173 buf[M41T80_REG_WDAY] =
174 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
175 buf[M41T80_REG_DAY] =
176 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
177 buf[M41T80_REG_MON] =
178 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
179
180 /* assume 20YY not 19YY */
181 if (tm->tm_year < 100 || tm->tm_year > 199) {
182 dev_err(&client->dev, "Year must be between 2000 and 2099. It's %d.\n",
183 tm->tm_year + 1900);
184 return -EINVAL;
185 }
186 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
187
188 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
189 dev_err(&client->dev, "write error\n");
190 return -EIO;
191 }
192 return 0;
193}
194
195#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
196static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
197{
198 struct i2c_client *client = to_i2c_client(dev);
199 struct m41t80_data *clientdata = i2c_get_clientdata(client);
200 u8 reg;
201
202 if (clientdata->features & M41T80_FEATURE_BL) {
203 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
204 seq_printf(seq, "battery\t\t: %s\n",
205 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
206 }
207 return 0;
208}
209#else
210#define m41t80_rtc_proc NULL
211#endif
212
213static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
214{
215 return m41t80_get_datetime(to_i2c_client(dev), tm);
216}
217
218static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
219{
220 return m41t80_set_datetime(to_i2c_client(dev), tm);
221}
222
223/*
224 * XXX - m41t80 alarm functionality is reported broken.
225 * until it is fixed, don't register alarm functions.
226 */
227static struct rtc_class_ops m41t80_rtc_ops = {
228 .read_time = m41t80_rtc_read_time,
229 .set_time = m41t80_rtc_set_time,
230 .proc = m41t80_rtc_proc,
231};
232
233#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
234static ssize_t m41t80_sysfs_show_flags(struct device *dev,
235 struct device_attribute *attr, char *buf)
236{
237 struct i2c_client *client = to_i2c_client(dev);
238 int val;
239
240 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
241 if (val < 0)
242 return val;
243 return sprintf(buf, "%#x\n", val);
244}
245static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
246
247static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
248 struct device_attribute *attr, char *buf)
249{
250 struct i2c_client *client = to_i2c_client(dev);
251 struct m41t80_data *clientdata = i2c_get_clientdata(client);
252 int val, reg_sqw;
253
254 if (!(clientdata->features & M41T80_FEATURE_SQ))
255 return -EINVAL;
256
257 reg_sqw = M41T80_REG_SQW;
258 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
259 reg_sqw = M41T80_REG_WDAY;
260 val = i2c_smbus_read_byte_data(client, reg_sqw);
261 if (val < 0)
262 return val;
263 val = (val >> 4) & 0xf;
264 switch (val) {
265 case 0:
266 break;
267 case 1:
268 val = 32768;
269 break;
270 default:
271 val = 32768 >> val;
272 }
273 return sprintf(buf, "%d\n", val);
274}
275static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
276 struct device_attribute *attr,
277 const char *buf, size_t count)
278{
279 struct i2c_client *client = to_i2c_client(dev);
280 struct m41t80_data *clientdata = i2c_get_clientdata(client);
281 int almon, sqw, reg_sqw, rc;
282 int val = simple_strtoul(buf, NULL, 0);
283
284 if (!(clientdata->features & M41T80_FEATURE_SQ))
285 return -EINVAL;
286
287 if (val) {
288 if (!is_power_of_2(val))
289 return -EINVAL;
290 val = ilog2(val);
291 if (val == 15)
292 val = 1;
293 else if (val < 14)
294 val = 15 - val;
295 else
296 return -EINVAL;
297 }
298 /* disable SQW, set SQW frequency & re-enable */
299 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
300 if (almon < 0)
301 return almon;
302 reg_sqw = M41T80_REG_SQW;
303 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
304 reg_sqw = M41T80_REG_WDAY;
305 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
306 if (sqw < 0)
307 return sqw;
308 sqw = (sqw & 0x0f) | (val << 4);
309
310 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
311 almon & ~M41T80_ALMON_SQWE);
312 if (rc < 0)
313 return rc;
314
315 if (val) {
316 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
317 if (rc < 0)
318 return rc;
319
320 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
321 almon | M41T80_ALMON_SQWE);
322 if (rc <0)
323 return rc;
324 }
325 return count;
326}
327static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
328 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
329
330static struct attribute *attrs[] = {
331 &dev_attr_flags.attr,
332 &dev_attr_sqwfreq.attr,
333 NULL,
334};
335static struct attribute_group attr_group = {
336 .attrs = attrs,
337};
338
339static int m41t80_sysfs_register(struct device *dev)
340{
341 return sysfs_create_group(&dev->kobj, &attr_group);
342}
343#else
344static int m41t80_sysfs_register(struct device *dev)
345{
346 return 0;
347}
348#endif
349
350#ifdef CONFIG_RTC_DRV_M41T80_WDT
351/*
352 *****************************************************************************
353 *
354 * Watchdog Driver
355 *
356 *****************************************************************************
357 */
358static struct i2c_client *save_client;
359
360/* Default margin */
361#define WD_TIMO 60 /* 1..31 seconds */
362
363static int wdt_margin = WD_TIMO;
364module_param(wdt_margin, int, 0);
365MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
366
367static unsigned long wdt_is_open;
368static int boot_flag;
369
370/**
371 * wdt_ping:
372 *
373 * Reload counter one with the watchdog timeout. We don't bother reloading
374 * the cascade counter.
375 */
376static void wdt_ping(void)
377{
378 unsigned char i2c_data[2];
379 struct i2c_msg msgs1[1] = {
380 {
381 .addr = save_client->addr,
382 .flags = 0,
383 .len = 2,
384 .buf = i2c_data,
385 },
386 };
387 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
388
389 i2c_data[0] = 0x09; /* watchdog register */
390
391 if (wdt_margin > 31)
392 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
393 else
394 /*
395 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
396 */
397 i2c_data[1] = wdt_margin<<2 | 0x82;
398
399 /*
400 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
401 * that would be an invalid resolution.
402 */
403 if (clientdata->features & M41T80_FEATURE_WD)
404 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
405
406 i2c_transfer(save_client->adapter, msgs1, 1);
407}
408
409/**
410 * wdt_disable:
411 *
412 * disables watchdog.
413 */
414static void wdt_disable(void)
415{
416 unsigned char i2c_data[2], i2c_buf[0x10];
417 struct i2c_msg msgs0[2] = {
418 {
419 .addr = save_client->addr,
420 .flags = 0,
421 .len = 1,
422 .buf = i2c_data,
423 },
424 {
425 .addr = save_client->addr,
426 .flags = I2C_M_RD,
427 .len = 1,
428 .buf = i2c_buf,
429 },
430 };
431 struct i2c_msg msgs1[1] = {
432 {
433 .addr = save_client->addr,
434 .flags = 0,
435 .len = 2,
436 .buf = i2c_data,
437 },
438 };
439
440 i2c_data[0] = 0x09;
441 i2c_transfer(save_client->adapter, msgs0, 2);
442
443 i2c_data[0] = 0x09;
444 i2c_data[1] = 0x00;
445 i2c_transfer(save_client->adapter, msgs1, 1);
446}
447
448/**
449 * wdt_write:
450 * @file: file handle to the watchdog
451 * @buf: buffer to write (unused as data does not matter here
452 * @count: count of bytes
453 * @ppos: pointer to the position to write. No seeks allowed
454 *
455 * A write to a watchdog device is defined as a keepalive signal. Any
456 * write of data will do, as we we don't define content meaning.
457 */
458static ssize_t wdt_write(struct file *file, const char __user *buf,
459 size_t count, loff_t *ppos)
460{
461 if (count) {
462 wdt_ping();
463 return 1;
464 }
465 return 0;
466}
467
468static ssize_t wdt_read(struct file *file, char __user *buf,
469 size_t count, loff_t *ppos)
470{
471 return 0;
472}
473
474/**
475 * wdt_ioctl:
476 * @inode: inode of the device
477 * @file: file handle to the device
478 * @cmd: watchdog command
479 * @arg: argument pointer
480 *
481 * The watchdog API defines a common set of functions for all watchdogs
482 * according to their available features. We only actually usefully support
483 * querying capabilities and current status.
484 */
485static int wdt_ioctl(struct file *file, unsigned int cmd,
486 unsigned long arg)
487{
488 int new_margin, rv;
489 static struct watchdog_info ident = {
490 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
491 WDIOF_SETTIMEOUT,
492 .firmware_version = 1,
493 .identity = "M41T80 WTD"
494 };
495
496 switch (cmd) {
497 case WDIOC_GETSUPPORT:
498 return copy_to_user((struct watchdog_info __user *)arg, &ident,
499 sizeof(ident)) ? -EFAULT : 0;
500
501 case WDIOC_GETSTATUS:
502 case WDIOC_GETBOOTSTATUS:
503 return put_user(boot_flag, (int __user *)arg);
504 case WDIOC_KEEPALIVE:
505 wdt_ping();
506 return 0;
507 case WDIOC_SETTIMEOUT:
508 if (get_user(new_margin, (int __user *)arg))
509 return -EFAULT;
510 /* Arbitrary, can't find the card's limits */
511 if (new_margin < 1 || new_margin > 124)
512 return -EINVAL;
513 wdt_margin = new_margin;
514 wdt_ping();
515 /* Fall */
516 case WDIOC_GETTIMEOUT:
517 return put_user(wdt_margin, (int __user *)arg);
518
519 case WDIOC_SETOPTIONS:
520 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
521 return -EFAULT;
522
523 if (rv & WDIOS_DISABLECARD) {
524 pr_info("disable watchdog\n");
525 wdt_disable();
526 }
527
528 if (rv & WDIOS_ENABLECARD) {
529 pr_info("enable watchdog\n");
530 wdt_ping();
531 }
532
533 return -EINVAL;
534 }
535 return -ENOTTY;
536}
537
538static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
539 unsigned long arg)
540{
541 int ret;
542
543 mutex_lock(&m41t80_rtc_mutex);
544 ret = wdt_ioctl(file, cmd, arg);
545 mutex_unlock(&m41t80_rtc_mutex);
546
547 return ret;
548}
549
550/**
551 * wdt_open:
552 * @inode: inode of device
553 * @file: file handle to device
554 *
555 */
556static int wdt_open(struct inode *inode, struct file *file)
557{
558 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
559 mutex_lock(&m41t80_rtc_mutex);
560 if (test_and_set_bit(0, &wdt_is_open)) {
561 mutex_unlock(&m41t80_rtc_mutex);
562 return -EBUSY;
563 }
564 /*
565 * Activate
566 */
567 wdt_is_open = 1;
568 mutex_unlock(&m41t80_rtc_mutex);
569 return nonseekable_open(inode, file);
570 }
571 return -ENODEV;
572}
573
574/**
575 * wdt_close:
576 * @inode: inode to board
577 * @file: file handle to board
578 *
579 */
580static int wdt_release(struct inode *inode, struct file *file)
581{
582 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
583 clear_bit(0, &wdt_is_open);
584 return 0;
585}
586
587/**
588 * notify_sys:
589 * @this: our notifier block
590 * @code: the event being reported
591 * @unused: unused
592 *
593 * Our notifier is called on system shutdowns. We want to turn the card
594 * off at reboot otherwise the machine will reboot again during memory
595 * test or worse yet during the following fsck. This would suck, in fact
596 * trust me - if it happens it does suck.
597 */
598static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
599 void *unused)
600{
601 if (code == SYS_DOWN || code == SYS_HALT)
602 /* Disable Watchdog */
603 wdt_disable();
604 return NOTIFY_DONE;
605}
606
607static const struct file_operations wdt_fops = {
608 .owner = THIS_MODULE,
609 .read = wdt_read,
610 .unlocked_ioctl = wdt_unlocked_ioctl,
611 .write = wdt_write,
612 .open = wdt_open,
613 .release = wdt_release,
614 .llseek = no_llseek,
615};
616
617static struct miscdevice wdt_dev = {
618 .minor = WATCHDOG_MINOR,
619 .name = "watchdog",
620 .fops = &wdt_fops,
621};
622
623/*
624 * The WDT card needs to learn about soft shutdowns in order to
625 * turn the timebomb registers off.
626 */
627static struct notifier_block wdt_notifier = {
628 .notifier_call = wdt_notify_sys,
629};
630#endif /* CONFIG_RTC_DRV_M41T80_WDT */
631
632/*
633 *****************************************************************************
634 *
635 * Driver Interface
636 *
637 *****************************************************************************
638 */
639static int m41t80_probe(struct i2c_client *client,
640 const struct i2c_device_id *id)
641{
642 int rc = 0;
643 struct rtc_device *rtc = NULL;
644 struct rtc_time tm;
645 struct m41t80_data *clientdata = NULL;
646
647 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
648 | I2C_FUNC_SMBUS_BYTE_DATA))
649 return -ENODEV;
650
651 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata),
652 GFP_KERNEL);
653 if (!clientdata)
654 return -ENOMEM;
655
656 clientdata->features = id->driver_data;
657 i2c_set_clientdata(client, clientdata);
658
659 rtc = devm_rtc_device_register(&client->dev, client->name,
660 &m41t80_rtc_ops, THIS_MODULE);
661 if (IS_ERR(rtc))
662 return PTR_ERR(rtc);
663
664 clientdata->rtc = rtc;
665
666 /* Make sure HT (Halt Update) bit is cleared */
667 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
668
669 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
670 if (clientdata->features & M41T80_FEATURE_HT) {
671 m41t80_get_datetime(client, &tm);
672 dev_info(&client->dev, "HT bit was set!\n");
673 dev_info(&client->dev,
674 "Power Down at "
675 "%04i-%02i-%02i %02i:%02i:%02i\n",
676 tm.tm_year + 1900,
677 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
678 tm.tm_min, tm.tm_sec);
679 }
680 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
681 rc & ~M41T80_ALHOUR_HT);
682 }
683
684 if (rc < 0) {
685 dev_err(&client->dev, "Can't clear HT bit\n");
686 return rc;
687 }
688
689 /* Make sure ST (stop) bit is cleared */
690 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
691
692 if (rc >= 0 && rc & M41T80_SEC_ST)
693 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
694 rc & ~M41T80_SEC_ST);
695 if (rc < 0) {
696 dev_err(&client->dev, "Can't clear ST bit\n");
697 return rc;
698 }
699
700 rc = m41t80_sysfs_register(&client->dev);
701 if (rc)
702 return rc;
703
704#ifdef CONFIG_RTC_DRV_M41T80_WDT
705 if (clientdata->features & M41T80_FEATURE_HT) {
706 save_client = client;
707 rc = misc_register(&wdt_dev);
708 if (rc)
709 return rc;
710 rc = register_reboot_notifier(&wdt_notifier);
711 if (rc) {
712 misc_deregister(&wdt_dev);
713 return rc;
714 }
715 }
716#endif
717 return 0;
718}
719
720static int m41t80_remove(struct i2c_client *client)
721{
722#ifdef CONFIG_RTC_DRV_M41T80_WDT
723 struct m41t80_data *clientdata = i2c_get_clientdata(client);
724
725 if (clientdata->features & M41T80_FEATURE_HT) {
726 misc_deregister(&wdt_dev);
727 unregister_reboot_notifier(&wdt_notifier);
728 }
729#endif
730
731 return 0;
732}
733
734static struct i2c_driver m41t80_driver = {
735 .driver = {
736 .name = "rtc-m41t80",
737 },
738 .probe = m41t80_probe,
739 .remove = m41t80_remove,
740 .id_table = m41t80_id,
741};
742
743module_i2c_driver(m41t80_driver);
744
745MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
746MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
747MODULE_LICENSE("GPL");
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#define DRV_VERSION "0.05"
70
71static DEFINE_MUTEX(m41t80_rtc_mutex);
72static const struct i2c_device_id m41t80_id[] = {
73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
75 { "m41t80", M41T80_FEATURE_SQ },
76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { }
84};
85MODULE_DEVICE_TABLE(i2c, m41t80_id);
86
87struct m41t80_data {
88 u8 features;
89 struct rtc_device *rtc;
90};
91
92static int m41t80_get_datetime(struct i2c_client *client,
93 struct rtc_time *tm)
94{
95 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
96 struct i2c_msg msgs[] = {
97 {
98 .addr = client->addr,
99 .flags = 0,
100 .len = 1,
101 .buf = dt_addr,
102 },
103 {
104 .addr = client->addr,
105 .flags = I2C_M_RD,
106 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
107 .buf = buf + M41T80_REG_SEC,
108 },
109 };
110
111 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
112 dev_err(&client->dev, "read error\n");
113 return -EIO;
114 }
115
116 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
117 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
118 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
119 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
120 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
121 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
122
123 /* assume 20YY not 19YY, and ignore the Century Bit */
124 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
125 return rtc_valid_tm(tm);
126}
127
128/* Sets the given date and time to the real time clock. */
129static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
130{
131 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
132 u8 *buf = &wbuf[1];
133 u8 dt_addr[1] = { M41T80_REG_SEC };
134 struct i2c_msg msgs_in[] = {
135 {
136 .addr = client->addr,
137 .flags = 0,
138 .len = 1,
139 .buf = dt_addr,
140 },
141 {
142 .addr = client->addr,
143 .flags = I2C_M_RD,
144 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
145 .buf = buf + M41T80_REG_SEC,
146 },
147 };
148 struct i2c_msg msgs[] = {
149 {
150 .addr = client->addr,
151 .flags = 0,
152 .len = 1 + M41T80_DATETIME_REG_SIZE,
153 .buf = wbuf,
154 },
155 };
156
157 /* Read current reg values into buf[1..7] */
158 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
159 dev_err(&client->dev, "read error\n");
160 return -EIO;
161 }
162
163 wbuf[0] = 0; /* offset into rtc's regs */
164 /* Merge time-data and register flags into buf[0..7] */
165 buf[M41T80_REG_SSEC] = 0;
166 buf[M41T80_REG_SEC] =
167 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
168 buf[M41T80_REG_MIN] =
169 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
170 buf[M41T80_REG_HOUR] =
171 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f);
172 buf[M41T80_REG_WDAY] =
173 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
174 buf[M41T80_REG_DAY] =
175 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
176 buf[M41T80_REG_MON] =
177 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
178 /* assume 20YY not 19YY */
179 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
180
181 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
182 dev_err(&client->dev, "write error\n");
183 return -EIO;
184 }
185 return 0;
186}
187
188#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
189static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
190{
191 struct i2c_client *client = to_i2c_client(dev);
192 struct m41t80_data *clientdata = i2c_get_clientdata(client);
193 u8 reg;
194
195 if (clientdata->features & M41T80_FEATURE_BL) {
196 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
197 seq_printf(seq, "battery\t\t: %s\n",
198 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
199 }
200 return 0;
201}
202#else
203#define m41t80_rtc_proc NULL
204#endif
205
206static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
207{
208 return m41t80_get_datetime(to_i2c_client(dev), tm);
209}
210
211static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
212{
213 return m41t80_set_datetime(to_i2c_client(dev), tm);
214}
215
216/*
217 * XXX - m41t80 alarm functionality is reported broken.
218 * until it is fixed, don't register alarm functions.
219 */
220static struct rtc_class_ops m41t80_rtc_ops = {
221 .read_time = m41t80_rtc_read_time,
222 .set_time = m41t80_rtc_set_time,
223 .proc = m41t80_rtc_proc,
224};
225
226#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
227static ssize_t m41t80_sysfs_show_flags(struct device *dev,
228 struct device_attribute *attr, char *buf)
229{
230 struct i2c_client *client = to_i2c_client(dev);
231 int val;
232
233 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
234 if (val < 0)
235 return -EIO;
236 return sprintf(buf, "%#x\n", val);
237}
238static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
239
240static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
241 struct device_attribute *attr, char *buf)
242{
243 struct i2c_client *client = to_i2c_client(dev);
244 struct m41t80_data *clientdata = i2c_get_clientdata(client);
245 int val, reg_sqw;
246
247 if (!(clientdata->features & M41T80_FEATURE_SQ))
248 return -EINVAL;
249
250 reg_sqw = M41T80_REG_SQW;
251 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
252 reg_sqw = M41T80_REG_WDAY;
253 val = i2c_smbus_read_byte_data(client, reg_sqw);
254 if (val < 0)
255 return -EIO;
256 val = (val >> 4) & 0xf;
257 switch (val) {
258 case 0:
259 break;
260 case 1:
261 val = 32768;
262 break;
263 default:
264 val = 32768 >> val;
265 }
266 return sprintf(buf, "%d\n", val);
267}
268static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
269 struct device_attribute *attr,
270 const char *buf, size_t count)
271{
272 struct i2c_client *client = to_i2c_client(dev);
273 struct m41t80_data *clientdata = i2c_get_clientdata(client);
274 int almon, sqw, reg_sqw;
275 int val = simple_strtoul(buf, NULL, 0);
276
277 if (!(clientdata->features & M41T80_FEATURE_SQ))
278 return -EINVAL;
279
280 if (val) {
281 if (!is_power_of_2(val))
282 return -EINVAL;
283 val = ilog2(val);
284 if (val == 15)
285 val = 1;
286 else if (val < 14)
287 val = 15 - val;
288 else
289 return -EINVAL;
290 }
291 /* disable SQW, set SQW frequency & re-enable */
292 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
293 if (almon < 0)
294 return -EIO;
295 reg_sqw = M41T80_REG_SQW;
296 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
297 reg_sqw = M41T80_REG_WDAY;
298 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
299 if (sqw < 0)
300 return -EIO;
301 sqw = (sqw & 0x0f) | (val << 4);
302 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
303 almon & ~M41T80_ALMON_SQWE) < 0 ||
304 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
305 return -EIO;
306 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
307 almon | M41T80_ALMON_SQWE) < 0)
308 return -EIO;
309 return count;
310}
311static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
312 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
313
314static struct attribute *attrs[] = {
315 &dev_attr_flags.attr,
316 &dev_attr_sqwfreq.attr,
317 NULL,
318};
319static struct attribute_group attr_group = {
320 .attrs = attrs,
321};
322
323static int m41t80_sysfs_register(struct device *dev)
324{
325 return sysfs_create_group(&dev->kobj, &attr_group);
326}
327#else
328static int m41t80_sysfs_register(struct device *dev)
329{
330 return 0;
331}
332#endif
333
334#ifdef CONFIG_RTC_DRV_M41T80_WDT
335/*
336 *****************************************************************************
337 *
338 * Watchdog Driver
339 *
340 *****************************************************************************
341 */
342static struct i2c_client *save_client;
343
344/* Default margin */
345#define WD_TIMO 60 /* 1..31 seconds */
346
347static int wdt_margin = WD_TIMO;
348module_param(wdt_margin, int, 0);
349MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
350
351static unsigned long wdt_is_open;
352static int boot_flag;
353
354/**
355 * wdt_ping:
356 *
357 * Reload counter one with the watchdog timeout. We don't bother reloading
358 * the cascade counter.
359 */
360static void wdt_ping(void)
361{
362 unsigned char i2c_data[2];
363 struct i2c_msg msgs1[1] = {
364 {
365 .addr = save_client->addr,
366 .flags = 0,
367 .len = 2,
368 .buf = i2c_data,
369 },
370 };
371 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
372
373 i2c_data[0] = 0x09; /* watchdog register */
374
375 if (wdt_margin > 31)
376 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
377 else
378 /*
379 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
380 */
381 i2c_data[1] = wdt_margin<<2 | 0x82;
382
383 /*
384 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
385 * that would be an invalid resolution.
386 */
387 if (clientdata->features & M41T80_FEATURE_WD)
388 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
389
390 i2c_transfer(save_client->adapter, msgs1, 1);
391}
392
393/**
394 * wdt_disable:
395 *
396 * disables watchdog.
397 */
398static void wdt_disable(void)
399{
400 unsigned char i2c_data[2], i2c_buf[0x10];
401 struct i2c_msg msgs0[2] = {
402 {
403 .addr = save_client->addr,
404 .flags = 0,
405 .len = 1,
406 .buf = i2c_data,
407 },
408 {
409 .addr = save_client->addr,
410 .flags = I2C_M_RD,
411 .len = 1,
412 .buf = i2c_buf,
413 },
414 };
415 struct i2c_msg msgs1[1] = {
416 {
417 .addr = save_client->addr,
418 .flags = 0,
419 .len = 2,
420 .buf = i2c_data,
421 },
422 };
423
424 i2c_data[0] = 0x09;
425 i2c_transfer(save_client->adapter, msgs0, 2);
426
427 i2c_data[0] = 0x09;
428 i2c_data[1] = 0x00;
429 i2c_transfer(save_client->adapter, msgs1, 1);
430}
431
432/**
433 * wdt_write:
434 * @file: file handle to the watchdog
435 * @buf: buffer to write (unused as data does not matter here
436 * @count: count of bytes
437 * @ppos: pointer to the position to write. No seeks allowed
438 *
439 * A write to a watchdog device is defined as a keepalive signal. Any
440 * write of data will do, as we we don't define content meaning.
441 */
442static ssize_t wdt_write(struct file *file, const char __user *buf,
443 size_t count, loff_t *ppos)
444{
445 if (count) {
446 wdt_ping();
447 return 1;
448 }
449 return 0;
450}
451
452static ssize_t wdt_read(struct file *file, char __user *buf,
453 size_t count, loff_t *ppos)
454{
455 return 0;
456}
457
458/**
459 * wdt_ioctl:
460 * @inode: inode of the device
461 * @file: file handle to the device
462 * @cmd: watchdog command
463 * @arg: argument pointer
464 *
465 * The watchdog API defines a common set of functions for all watchdogs
466 * according to their available features. We only actually usefully support
467 * querying capabilities and current status.
468 */
469static int wdt_ioctl(struct file *file, unsigned int cmd,
470 unsigned long arg)
471{
472 int new_margin, rv;
473 static struct watchdog_info ident = {
474 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
475 WDIOF_SETTIMEOUT,
476 .firmware_version = 1,
477 .identity = "M41T80 WTD"
478 };
479
480 switch (cmd) {
481 case WDIOC_GETSUPPORT:
482 return copy_to_user((struct watchdog_info __user *)arg, &ident,
483 sizeof(ident)) ? -EFAULT : 0;
484
485 case WDIOC_GETSTATUS:
486 case WDIOC_GETBOOTSTATUS:
487 return put_user(boot_flag, (int __user *)arg);
488 case WDIOC_KEEPALIVE:
489 wdt_ping();
490 return 0;
491 case WDIOC_SETTIMEOUT:
492 if (get_user(new_margin, (int __user *)arg))
493 return -EFAULT;
494 /* Arbitrary, can't find the card's limits */
495 if (new_margin < 1 || new_margin > 124)
496 return -EINVAL;
497 wdt_margin = new_margin;
498 wdt_ping();
499 /* Fall */
500 case WDIOC_GETTIMEOUT:
501 return put_user(wdt_margin, (int __user *)arg);
502
503 case WDIOC_SETOPTIONS:
504 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
505 return -EFAULT;
506
507 if (rv & WDIOS_DISABLECARD) {
508 pr_info("rtc-m41t80: disable watchdog\n");
509 wdt_disable();
510 }
511
512 if (rv & WDIOS_ENABLECARD) {
513 pr_info("rtc-m41t80: enable watchdog\n");
514 wdt_ping();
515 }
516
517 return -EINVAL;
518 }
519 return -ENOTTY;
520}
521
522static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
523 unsigned long arg)
524{
525 int ret;
526
527 mutex_lock(&m41t80_rtc_mutex);
528 ret = wdt_ioctl(file, cmd, arg);
529 mutex_unlock(&m41t80_rtc_mutex);
530
531 return ret;
532}
533
534/**
535 * wdt_open:
536 * @inode: inode of device
537 * @file: file handle to device
538 *
539 */
540static int wdt_open(struct inode *inode, struct file *file)
541{
542 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
543 mutex_lock(&m41t80_rtc_mutex);
544 if (test_and_set_bit(0, &wdt_is_open)) {
545 mutex_unlock(&m41t80_rtc_mutex);
546 return -EBUSY;
547 }
548 /*
549 * Activate
550 */
551 wdt_is_open = 1;
552 mutex_unlock(&m41t80_rtc_mutex);
553 return nonseekable_open(inode, file);
554 }
555 return -ENODEV;
556}
557
558/**
559 * wdt_close:
560 * @inode: inode to board
561 * @file: file handle to board
562 *
563 */
564static int wdt_release(struct inode *inode, struct file *file)
565{
566 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
567 clear_bit(0, &wdt_is_open);
568 return 0;
569}
570
571/**
572 * notify_sys:
573 * @this: our notifier block
574 * @code: the event being reported
575 * @unused: unused
576 *
577 * Our notifier is called on system shutdowns. We want to turn the card
578 * off at reboot otherwise the machine will reboot again during memory
579 * test or worse yet during the following fsck. This would suck, in fact
580 * trust me - if it happens it does suck.
581 */
582static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
583 void *unused)
584{
585 if (code == SYS_DOWN || code == SYS_HALT)
586 /* Disable Watchdog */
587 wdt_disable();
588 return NOTIFY_DONE;
589}
590
591static const struct file_operations wdt_fops = {
592 .owner = THIS_MODULE,
593 .read = wdt_read,
594 .unlocked_ioctl = wdt_unlocked_ioctl,
595 .write = wdt_write,
596 .open = wdt_open,
597 .release = wdt_release,
598 .llseek = no_llseek,
599};
600
601static struct miscdevice wdt_dev = {
602 .minor = WATCHDOG_MINOR,
603 .name = "watchdog",
604 .fops = &wdt_fops,
605};
606
607/*
608 * The WDT card needs to learn about soft shutdowns in order to
609 * turn the timebomb registers off.
610 */
611static struct notifier_block wdt_notifier = {
612 .notifier_call = wdt_notify_sys,
613};
614#endif /* CONFIG_RTC_DRV_M41T80_WDT */
615
616/*
617 *****************************************************************************
618 *
619 * Driver Interface
620 *
621 *****************************************************************************
622 */
623static int m41t80_probe(struct i2c_client *client,
624 const struct i2c_device_id *id)
625{
626 int rc = 0;
627 struct rtc_device *rtc = NULL;
628 struct rtc_time tm;
629 struct m41t80_data *clientdata = NULL;
630
631 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
632 | I2C_FUNC_SMBUS_BYTE_DATA)) {
633 rc = -ENODEV;
634 goto exit;
635 }
636
637 dev_info(&client->dev,
638 "chip found, driver version " DRV_VERSION "\n");
639
640 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata),
641 GFP_KERNEL);
642 if (!clientdata) {
643 rc = -ENOMEM;
644 goto exit;
645 }
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 rc = PTR_ERR(rtc);
654 rtc = NULL;
655 goto exit;
656 }
657
658 clientdata->rtc = rtc;
659
660 /* Make sure HT (Halt Update) bit is cleared */
661 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
662 if (rc < 0)
663 goto ht_err;
664
665 if (rc & M41T80_ALHOUR_HT) {
666 if (clientdata->features & M41T80_FEATURE_HT) {
667 m41t80_get_datetime(client, &tm);
668 dev_info(&client->dev, "HT bit was set!\n");
669 dev_info(&client->dev,
670 "Power Down at "
671 "%04i-%02i-%02i %02i:%02i:%02i\n",
672 tm.tm_year + 1900,
673 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
674 tm.tm_min, tm.tm_sec);
675 }
676 if (i2c_smbus_write_byte_data(client,
677 M41T80_REG_ALARM_HOUR,
678 rc & ~M41T80_ALHOUR_HT) < 0)
679 goto ht_err;
680 }
681
682 /* Make sure ST (stop) bit is cleared */
683 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
684 if (rc < 0)
685 goto st_err;
686
687 if (rc & M41T80_SEC_ST) {
688 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
689 rc & ~M41T80_SEC_ST) < 0)
690 goto st_err;
691 }
692
693 rc = m41t80_sysfs_register(&client->dev);
694 if (rc)
695 goto exit;
696
697#ifdef CONFIG_RTC_DRV_M41T80_WDT
698 if (clientdata->features & M41T80_FEATURE_HT) {
699 save_client = client;
700 rc = misc_register(&wdt_dev);
701 if (rc)
702 goto exit;
703 rc = register_reboot_notifier(&wdt_notifier);
704 if (rc) {
705 misc_deregister(&wdt_dev);
706 goto exit;
707 }
708 }
709#endif
710 return 0;
711
712st_err:
713 rc = -EIO;
714 dev_err(&client->dev, "Can't clear ST bit\n");
715 goto exit;
716ht_err:
717 rc = -EIO;
718 dev_err(&client->dev, "Can't clear HT bit\n");
719 goto exit;
720
721exit:
722 return rc;
723}
724
725static int m41t80_remove(struct i2c_client *client)
726{
727#ifdef CONFIG_RTC_DRV_M41T80_WDT
728 struct m41t80_data *clientdata = i2c_get_clientdata(client);
729
730 if (clientdata->features & M41T80_FEATURE_HT) {
731 misc_deregister(&wdt_dev);
732 unregister_reboot_notifier(&wdt_notifier);
733 }
734#endif
735
736 return 0;
737}
738
739static struct i2c_driver m41t80_driver = {
740 .driver = {
741 .name = "rtc-m41t80",
742 },
743 .probe = m41t80_probe,
744 .remove = m41t80_remove,
745 .id_table = m41t80_id,
746};
747
748module_i2c_driver(m41t80_driver);
749
750MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
751MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
752MODULE_LICENSE("GPL");
753MODULE_VERSION(DRV_VERSION);