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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#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 0x00
36#define M41T80_REG_SEC 0x01
37#define M41T80_REG_MIN 0x02
38#define M41T80_REG_HOUR 0x03
39#define M41T80_REG_WDAY 0x04
40#define M41T80_REG_DAY 0x05
41#define M41T80_REG_MON 0x06
42#define M41T80_REG_YEAR 0x07
43#define M41T80_REG_ALARM_MON 0x0a
44#define M41T80_REG_ALARM_DAY 0x0b
45#define M41T80_REG_ALARM_HOUR 0x0c
46#define M41T80_REG_ALARM_MIN 0x0d
47#define M41T80_REG_ALARM_SEC 0x0e
48#define M41T80_REG_FLAGS 0x0f
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 BIT(7) /* ST: Stop Bit */
56#define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
57#define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
58#define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
59#define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
60#define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
61#define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
62#define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
63#define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
64#define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
65
66#define M41T80_FEATURE_HT BIT(0) /* Halt feature */
67#define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
68#define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
69#define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
70#define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
71
72static DEFINE_MUTEX(m41t80_rtc_mutex);
73static const struct i2c_device_id m41t80_id[] = {
74 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
75 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
76 { "m41t80", M41T80_FEATURE_SQ },
77 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
78 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
84 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
85 { }
86};
87MODULE_DEVICE_TABLE(i2c, m41t80_id);
88
89struct m41t80_data {
90 u8 features;
91 struct rtc_device *rtc;
92};
93
94static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
95{
96 struct i2c_client *client = dev_id;
97 struct m41t80_data *m41t80 = i2c_get_clientdata(client);
98 struct mutex *lock = &m41t80->rtc->ops_lock;
99 unsigned long events = 0;
100 int flags, flags_afe;
101
102 mutex_lock(lock);
103
104 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
105 if (flags_afe < 0) {
106 mutex_unlock(lock);
107 return IRQ_NONE;
108 }
109
110 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
111 if (flags <= 0) {
112 mutex_unlock(lock);
113 return IRQ_NONE;
114 }
115
116 if (flags & M41T80_FLAGS_AF) {
117 flags &= ~M41T80_FLAGS_AF;
118 flags_afe &= ~M41T80_ALMON_AFE;
119 events |= RTC_AF;
120 }
121
122 if (events) {
123 rtc_update_irq(m41t80->rtc, 1, events);
124 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
125 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
126 flags_afe);
127 }
128
129 mutex_unlock(lock);
130
131 return IRQ_HANDLED;
132}
133
134static int m41t80_get_datetime(struct i2c_client *client,
135 struct rtc_time *tm)
136{
137 unsigned char buf[8];
138 int err, flags;
139
140 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
141 if (flags < 0)
142 return flags;
143
144 if (flags & M41T80_FLAGS_OF) {
145 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
146 return -EINVAL;
147 }
148
149 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
150 sizeof(buf), buf);
151 if (err < 0) {
152 dev_err(&client->dev, "Unable to read date\n");
153 return -EIO;
154 }
155
156 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
157 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
158 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
159 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
160 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
161 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
162
163 /* assume 20YY not 19YY, and ignore the Century Bit */
164 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
165 return rtc_valid_tm(tm);
166}
167
168/* Sets the given date and time to the real time clock. */
169static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
170{
171 unsigned char buf[8];
172 int err, flags;
173
174 if (tm->tm_year < 100 || tm->tm_year > 199)
175 return -EINVAL;
176
177 buf[M41T80_REG_SSEC] = 0;
178 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
179 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
180 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
181 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
182 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
183 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
184 buf[M41T80_REG_WDAY] = tm->tm_wday;
185
186 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
187 sizeof(buf), buf);
188 if (err < 0) {
189 dev_err(&client->dev, "Unable to write to date registers\n");
190 return err;
191 }
192
193 /* Clear the OF bit of Flags Register */
194 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
195 if (flags < 0)
196 return flags;
197
198 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
199 flags & ~M41T80_FLAGS_OF)) {
200 dev_err(&client->dev, "Unable to write flags register\n");
201 return -EIO;
202 }
203
204 return err;
205}
206
207static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
208{
209 struct i2c_client *client = to_i2c_client(dev);
210 struct m41t80_data *clientdata = i2c_get_clientdata(client);
211 u8 reg;
212
213 if (clientdata->features & M41T80_FEATURE_BL) {
214 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
215 seq_printf(seq, "battery\t\t: %s\n",
216 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
217 }
218 return 0;
219}
220
221static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
222{
223 return m41t80_get_datetime(to_i2c_client(dev), tm);
224}
225
226static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
227{
228 return m41t80_set_datetime(to_i2c_client(dev), tm);
229}
230
231static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
232{
233 struct i2c_client *client = to_i2c_client(dev);
234 int flags, retval;
235
236 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
237 if (flags < 0)
238 return flags;
239
240 if (enabled)
241 flags |= M41T80_ALMON_AFE;
242 else
243 flags &= ~M41T80_ALMON_AFE;
244
245 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
246 if (retval < 0) {
247 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
248 return retval;
249 }
250 return 0;
251}
252
253static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
254{
255 struct i2c_client *client = to_i2c_client(dev);
256 u8 alarmvals[5];
257 int ret, err;
258
259 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
260 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
261 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
262 alarmvals[3] = bin2bcd(alrm->time.tm_min);
263 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
264
265 /* Clear AF and AFE flags */
266 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
267 if (ret < 0)
268 return ret;
269 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
270 ret & ~(M41T80_ALMON_AFE));
271 if (err < 0) {
272 dev_err(dev, "Unable to clear AFE bit\n");
273 return err;
274 }
275
276 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
277 if (ret < 0)
278 return ret;
279
280 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
281 ret & ~(M41T80_FLAGS_AF));
282 if (err < 0) {
283 dev_err(dev, "Unable to clear AF bit\n");
284 return err;
285 }
286
287 /* Write the alarm */
288 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
289 5, alarmvals);
290 if (err)
291 return err;
292
293 /* Enable the alarm interrupt */
294 if (alrm->enabled) {
295 alarmvals[0] |= M41T80_ALMON_AFE;
296 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
297 alarmvals[0]);
298 if (err)
299 return err;
300 }
301
302 return 0;
303}
304
305static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
306{
307 struct i2c_client *client = to_i2c_client(dev);
308 u8 alarmvals[5];
309 int flags, ret;
310
311 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
312 5, alarmvals);
313 if (ret != 5)
314 return ret < 0 ? ret : -EIO;
315
316 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
317 if (flags < 0)
318 return flags;
319
320 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
321 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
322 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
323 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
324 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f);
325
326 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
327 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
328
329 return 0;
330}
331
332static struct rtc_class_ops m41t80_rtc_ops = {
333 .read_time = m41t80_rtc_read_time,
334 .set_time = m41t80_rtc_set_time,
335 .proc = m41t80_rtc_proc,
336};
337
338#ifdef CONFIG_PM_SLEEP
339static int m41t80_suspend(struct device *dev)
340{
341 struct i2c_client *client = to_i2c_client(dev);
342
343 if (client->irq >= 0 && device_may_wakeup(dev))
344 enable_irq_wake(client->irq);
345
346 return 0;
347}
348
349static int m41t80_resume(struct device *dev)
350{
351 struct i2c_client *client = to_i2c_client(dev);
352
353 if (client->irq >= 0 && device_may_wakeup(dev))
354 disable_irq_wake(client->irq);
355
356 return 0;
357}
358#endif
359
360static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
361
362static ssize_t flags_show(struct device *dev,
363 struct device_attribute *attr, char *buf)
364{
365 struct i2c_client *client = to_i2c_client(dev);
366 int val;
367
368 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
369 if (val < 0)
370 return val;
371 return sprintf(buf, "%#x\n", val);
372}
373static DEVICE_ATTR_RO(flags);
374
375static ssize_t sqwfreq_show(struct device *dev,
376 struct device_attribute *attr, char *buf)
377{
378 struct i2c_client *client = to_i2c_client(dev);
379 struct m41t80_data *clientdata = i2c_get_clientdata(client);
380 int val, reg_sqw;
381
382 if (!(clientdata->features & M41T80_FEATURE_SQ))
383 return -EINVAL;
384
385 reg_sqw = M41T80_REG_SQW;
386 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
387 reg_sqw = M41T80_REG_WDAY;
388 val = i2c_smbus_read_byte_data(client, reg_sqw);
389 if (val < 0)
390 return val;
391 val = (val >> 4) & 0xf;
392 switch (val) {
393 case 0:
394 break;
395 case 1:
396 val = 32768;
397 break;
398 default:
399 val = 32768 >> val;
400 }
401 return sprintf(buf, "%d\n", val);
402}
403
404static ssize_t sqwfreq_store(struct device *dev,
405 struct device_attribute *attr,
406 const char *buf, size_t count)
407{
408 struct i2c_client *client = to_i2c_client(dev);
409 struct m41t80_data *clientdata = i2c_get_clientdata(client);
410 int almon, sqw, reg_sqw, rc;
411 unsigned long val;
412
413 rc = kstrtoul(buf, 0, &val);
414 if (rc < 0)
415 return rc;
416
417 if (!(clientdata->features & M41T80_FEATURE_SQ))
418 return -EINVAL;
419
420 if (val) {
421 if (!is_power_of_2(val))
422 return -EINVAL;
423 val = ilog2(val);
424 if (val == 15)
425 val = 1;
426 else if (val < 14)
427 val = 15 - val;
428 else
429 return -EINVAL;
430 }
431 /* disable SQW, set SQW frequency & re-enable */
432 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
433 if (almon < 0)
434 return almon;
435 reg_sqw = M41T80_REG_SQW;
436 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
437 reg_sqw = M41T80_REG_WDAY;
438 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
439 if (sqw < 0)
440 return sqw;
441 sqw = (sqw & 0x0f) | (val << 4);
442
443 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
444 almon & ~M41T80_ALMON_SQWE);
445 if (rc < 0)
446 return rc;
447
448 if (val) {
449 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
450 if (rc < 0)
451 return rc;
452
453 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
454 almon | M41T80_ALMON_SQWE);
455 if (rc < 0)
456 return rc;
457 }
458 return count;
459}
460static DEVICE_ATTR_RW(sqwfreq);
461
462static struct attribute *attrs[] = {
463 &dev_attr_flags.attr,
464 &dev_attr_sqwfreq.attr,
465 NULL,
466};
467
468static struct attribute_group attr_group = {
469 .attrs = attrs,
470};
471
472#ifdef CONFIG_RTC_DRV_M41T80_WDT
473/*
474 *****************************************************************************
475 *
476 * Watchdog Driver
477 *
478 *****************************************************************************
479 */
480static struct i2c_client *save_client;
481
482/* Default margin */
483#define WD_TIMO 60 /* 1..31 seconds */
484
485static int wdt_margin = WD_TIMO;
486module_param(wdt_margin, int, 0);
487MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
488
489static unsigned long wdt_is_open;
490static int boot_flag;
491
492/**
493 * wdt_ping:
494 *
495 * Reload counter one with the watchdog timeout. We don't bother reloading
496 * the cascade counter.
497 */
498static void wdt_ping(void)
499{
500 unsigned char i2c_data[2];
501 struct i2c_msg msgs1[1] = {
502 {
503 .addr = save_client->addr,
504 .flags = 0,
505 .len = 2,
506 .buf = i2c_data,
507 },
508 };
509 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
510
511 i2c_data[0] = 0x09; /* watchdog register */
512
513 if (wdt_margin > 31)
514 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
515 else
516 /*
517 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
518 */
519 i2c_data[1] = wdt_margin << 2 | 0x82;
520
521 /*
522 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
523 * that would be an invalid resolution.
524 */
525 if (clientdata->features & M41T80_FEATURE_WD)
526 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
527
528 i2c_transfer(save_client->adapter, msgs1, 1);
529}
530
531/**
532 * wdt_disable:
533 *
534 * disables watchdog.
535 */
536static void wdt_disable(void)
537{
538 unsigned char i2c_data[2], i2c_buf[0x10];
539 struct i2c_msg msgs0[2] = {
540 {
541 .addr = save_client->addr,
542 .flags = 0,
543 .len = 1,
544 .buf = i2c_data,
545 },
546 {
547 .addr = save_client->addr,
548 .flags = I2C_M_RD,
549 .len = 1,
550 .buf = i2c_buf,
551 },
552 };
553 struct i2c_msg msgs1[1] = {
554 {
555 .addr = save_client->addr,
556 .flags = 0,
557 .len = 2,
558 .buf = i2c_data,
559 },
560 };
561
562 i2c_data[0] = 0x09;
563 i2c_transfer(save_client->adapter, msgs0, 2);
564
565 i2c_data[0] = 0x09;
566 i2c_data[1] = 0x00;
567 i2c_transfer(save_client->adapter, msgs1, 1);
568}
569
570/**
571 * wdt_write:
572 * @file: file handle to the watchdog
573 * @buf: buffer to write (unused as data does not matter here
574 * @count: count of bytes
575 * @ppos: pointer to the position to write. No seeks allowed
576 *
577 * A write to a watchdog device is defined as a keepalive signal. Any
578 * write of data will do, as we we don't define content meaning.
579 */
580static ssize_t wdt_write(struct file *file, const char __user *buf,
581 size_t count, loff_t *ppos)
582{
583 if (count) {
584 wdt_ping();
585 return 1;
586 }
587 return 0;
588}
589
590static ssize_t wdt_read(struct file *file, char __user *buf,
591 size_t count, loff_t *ppos)
592{
593 return 0;
594}
595
596/**
597 * wdt_ioctl:
598 * @inode: inode of the device
599 * @file: file handle to the device
600 * @cmd: watchdog command
601 * @arg: argument pointer
602 *
603 * The watchdog API defines a common set of functions for all watchdogs
604 * according to their available features. We only actually usefully support
605 * querying capabilities and current status.
606 */
607static int wdt_ioctl(struct file *file, unsigned int cmd,
608 unsigned long arg)
609{
610 int new_margin, rv;
611 static struct watchdog_info ident = {
612 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
613 WDIOF_SETTIMEOUT,
614 .firmware_version = 1,
615 .identity = "M41T80 WTD"
616 };
617
618 switch (cmd) {
619 case WDIOC_GETSUPPORT:
620 return copy_to_user((struct watchdog_info __user *)arg, &ident,
621 sizeof(ident)) ? -EFAULT : 0;
622
623 case WDIOC_GETSTATUS:
624 case WDIOC_GETBOOTSTATUS:
625 return put_user(boot_flag, (int __user *)arg);
626 case WDIOC_KEEPALIVE:
627 wdt_ping();
628 return 0;
629 case WDIOC_SETTIMEOUT:
630 if (get_user(new_margin, (int __user *)arg))
631 return -EFAULT;
632 /* Arbitrary, can't find the card's limits */
633 if (new_margin < 1 || new_margin > 124)
634 return -EINVAL;
635 wdt_margin = new_margin;
636 wdt_ping();
637 /* Fall */
638 case WDIOC_GETTIMEOUT:
639 return put_user(wdt_margin, (int __user *)arg);
640
641 case WDIOC_SETOPTIONS:
642 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
643 return -EFAULT;
644
645 if (rv & WDIOS_DISABLECARD) {
646 pr_info("disable watchdog\n");
647 wdt_disable();
648 }
649
650 if (rv & WDIOS_ENABLECARD) {
651 pr_info("enable watchdog\n");
652 wdt_ping();
653 }
654
655 return -EINVAL;
656 }
657 return -ENOTTY;
658}
659
660static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
661 unsigned long arg)
662{
663 int ret;
664
665 mutex_lock(&m41t80_rtc_mutex);
666 ret = wdt_ioctl(file, cmd, arg);
667 mutex_unlock(&m41t80_rtc_mutex);
668
669 return ret;
670}
671
672/**
673 * wdt_open:
674 * @inode: inode of device
675 * @file: file handle to device
676 *
677 */
678static int wdt_open(struct inode *inode, struct file *file)
679{
680 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
681 mutex_lock(&m41t80_rtc_mutex);
682 if (test_and_set_bit(0, &wdt_is_open)) {
683 mutex_unlock(&m41t80_rtc_mutex);
684 return -EBUSY;
685 }
686 /*
687 * Activate
688 */
689 wdt_is_open = 1;
690 mutex_unlock(&m41t80_rtc_mutex);
691 return nonseekable_open(inode, file);
692 }
693 return -ENODEV;
694}
695
696/**
697 * wdt_close:
698 * @inode: inode to board
699 * @file: file handle to board
700 *
701 */
702static int wdt_release(struct inode *inode, struct file *file)
703{
704 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
705 clear_bit(0, &wdt_is_open);
706 return 0;
707}
708
709/**
710 * notify_sys:
711 * @this: our notifier block
712 * @code: the event being reported
713 * @unused: unused
714 *
715 * Our notifier is called on system shutdowns. We want to turn the card
716 * off at reboot otherwise the machine will reboot again during memory
717 * test or worse yet during the following fsck. This would suck, in fact
718 * trust me - if it happens it does suck.
719 */
720static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
721 void *unused)
722{
723 if (code == SYS_DOWN || code == SYS_HALT)
724 /* Disable Watchdog */
725 wdt_disable();
726 return NOTIFY_DONE;
727}
728
729static const struct file_operations wdt_fops = {
730 .owner = THIS_MODULE,
731 .read = wdt_read,
732 .unlocked_ioctl = wdt_unlocked_ioctl,
733 .write = wdt_write,
734 .open = wdt_open,
735 .release = wdt_release,
736 .llseek = no_llseek,
737};
738
739static struct miscdevice wdt_dev = {
740 .minor = WATCHDOG_MINOR,
741 .name = "watchdog",
742 .fops = &wdt_fops,
743};
744
745/*
746 * The WDT card needs to learn about soft shutdowns in order to
747 * turn the timebomb registers off.
748 */
749static struct notifier_block wdt_notifier = {
750 .notifier_call = wdt_notify_sys,
751};
752#endif /* CONFIG_RTC_DRV_M41T80_WDT */
753
754/*
755 *****************************************************************************
756 *
757 * Driver Interface
758 *
759 *****************************************************************************
760 */
761
762static void m41t80_remove_sysfs_group(void *_dev)
763{
764 struct device *dev = _dev;
765
766 sysfs_remove_group(&dev->kobj, &attr_group);
767}
768
769static int m41t80_probe(struct i2c_client *client,
770 const struct i2c_device_id *id)
771{
772 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
773 int rc = 0;
774 struct rtc_device *rtc = NULL;
775 struct rtc_time tm;
776 struct m41t80_data *m41t80_data = NULL;
777
778 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
779 I2C_FUNC_SMBUS_BYTE_DATA)) {
780 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
781 return -ENODEV;
782 }
783
784 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
785 GFP_KERNEL);
786 if (!m41t80_data)
787 return -ENOMEM;
788
789 m41t80_data->features = id->driver_data;
790 i2c_set_clientdata(client, m41t80_data);
791
792 if (client->irq > 0) {
793 rc = devm_request_threaded_irq(&client->dev, client->irq,
794 NULL, m41t80_handle_irq,
795 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
796 "m41t80", client);
797 if (rc) {
798 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
799 client->irq = 0;
800 } else {
801 m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
802 m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
803 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
804 /* Enable the wakealarm */
805 device_init_wakeup(&client->dev, true);
806 }
807 }
808
809 rtc = devm_rtc_device_register(&client->dev, client->name,
810 &m41t80_rtc_ops, THIS_MODULE);
811 if (IS_ERR(rtc))
812 return PTR_ERR(rtc);
813
814 m41t80_data->rtc = rtc;
815
816 /* Make sure HT (Halt Update) bit is cleared */
817 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
818
819 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
820 if (m41t80_data->features & M41T80_FEATURE_HT) {
821 m41t80_get_datetime(client, &tm);
822 dev_info(&client->dev, "HT bit was set!\n");
823 dev_info(&client->dev,
824 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
825 tm.tm_year + 1900,
826 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
827 tm.tm_min, tm.tm_sec);
828 }
829 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
830 rc & ~M41T80_ALHOUR_HT);
831 }
832
833 if (rc < 0) {
834 dev_err(&client->dev, "Can't clear HT bit\n");
835 return rc;
836 }
837
838 /* Make sure ST (stop) bit is cleared */
839 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
840
841 if (rc >= 0 && rc & M41T80_SEC_ST)
842 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
843 rc & ~M41T80_SEC_ST);
844 if (rc < 0) {
845 dev_err(&client->dev, "Can't clear ST bit\n");
846 return rc;
847 }
848
849 /* Export sysfs entries */
850 rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group);
851 if (rc) {
852 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc);
853 return rc;
854 }
855
856 rc = devm_add_action_or_reset(&client->dev, m41t80_remove_sysfs_group,
857 &client->dev);
858 if (rc) {
859 dev_err(&client->dev,
860 "Failed to add sysfs cleanup action: %d\n", rc);
861 return rc;
862 }
863
864#ifdef CONFIG_RTC_DRV_M41T80_WDT
865 if (m41t80_data->features & M41T80_FEATURE_HT) {
866 save_client = client;
867 rc = misc_register(&wdt_dev);
868 if (rc)
869 return rc;
870 rc = register_reboot_notifier(&wdt_notifier);
871 if (rc) {
872 misc_deregister(&wdt_dev);
873 return rc;
874 }
875 }
876#endif
877 return 0;
878}
879
880static int m41t80_remove(struct i2c_client *client)
881{
882#ifdef CONFIG_RTC_DRV_M41T80_WDT
883 struct m41t80_data *clientdata = i2c_get_clientdata(client);
884
885 if (clientdata->features & M41T80_FEATURE_HT) {
886 misc_deregister(&wdt_dev);
887 unregister_reboot_notifier(&wdt_notifier);
888 }
889#endif
890
891 return 0;
892}
893
894static struct i2c_driver m41t80_driver = {
895 .driver = {
896 .name = "rtc-m41t80",
897 .pm = &m41t80_pm,
898 },
899 .probe = m41t80_probe,
900 .remove = m41t80_remove,
901 .id_table = m41t80_id,
902};
903
904module_i2c_driver(m41t80_driver);
905
906MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
907MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
908MODULE_LICENSE("GPL");