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rtc-m41t80.c
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1 /*
2  * I2C client/driver for the ST M41T80 family of i2c rtc chips.
3  *
4  * Author: Alexander Bigga <[email protected]>
5  *
6  * Based on m41t00.c by Mark A. Greer <[email protected]>
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 
71 static DEFINE_MUTEX(m41t80_rtc_mutex);
72 static 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 };
85 MODULE_DEVICE_TABLE(i2c, m41t80_id);
86 
87 struct m41t80_data {
88  u8 features;
89  struct rtc_device *rtc;
90 };
91 
92 static 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. */
129 static 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)
189 static 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 
206 static 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 
211 static 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  */
220 static 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)
227 static 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 }
238 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
239 
240 static 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 }
268 static 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 }
311 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
312  m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
313 
314 static struct attribute *attrs[] = {
315  &dev_attr_flags.attr,
316  &dev_attr_sqwfreq.attr,
317  NULL,
318 };
319 static struct attribute_group attr_group = {
320  .attrs = attrs,
321 };
322 
323 static int m41t80_sysfs_register(struct device *dev)
324 {
325  return sysfs_create_group(&dev->kobj, &attr_group);
326 }
327 #else
328 static 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  */
342 static struct i2c_client *save_client;
343 
344 /* Default margin */
345 #define WD_TIMO 60 /* 1..31 seconds */
346 
347 static int wdt_margin = WD_TIMO;
348 module_param(wdt_margin, int, 0);
349 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
350 
351 static unsigned long wdt_is_open;
352 static int boot_flag;
353 
360 static 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 
398 static 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 
442 static 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 
452 static ssize_t wdt_read(struct file *file, char __user *buf,
453  size_t count, loff_t *ppos)
454 {
455  return 0;
456 }
457 
469 static 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 
522 static 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 
540 static 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 
564 static 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 
582 static 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 
591 static 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 
601 static 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  */
611 static 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  */
623 static 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 = kzalloc(sizeof(*clientdata), GFP_KERNEL);
641  if (!clientdata) {
642  rc = -ENOMEM;
643  goto exit;
644  }
645 
646  clientdata->features = id->driver_data;
647  i2c_set_clientdata(client, clientdata);
648 
649  rtc = rtc_device_register(client->name, &client->dev,
650  &m41t80_rtc_ops, THIS_MODULE);
651  if (IS_ERR(rtc)) {
652  rc = PTR_ERR(rtc);
653  rtc = NULL;
654  goto exit;
655  }
656 
657  clientdata->rtc = rtc;
658 
659  /* Make sure HT (Halt Update) bit is cleared */
660  rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
661  if (rc < 0)
662  goto ht_err;
663 
664  if (rc & M41T80_ALHOUR_HT) {
665  if (clientdata->features & M41T80_FEATURE_HT) {
666  m41t80_get_datetime(client, &tm);
667  dev_info(&client->dev, "HT bit was set!\n");
668  dev_info(&client->dev,
669  "Power Down at "
670  "%04i-%02i-%02i %02i:%02i:%02i\n",
671  tm.tm_year + 1900,
672  tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
673  tm.tm_min, tm.tm_sec);
674  }
675  if (i2c_smbus_write_byte_data(client,
676  M41T80_REG_ALARM_HOUR,
677  rc & ~M41T80_ALHOUR_HT) < 0)
678  goto ht_err;
679  }
680 
681  /* Make sure ST (stop) bit is cleared */
682  rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
683  if (rc < 0)
684  goto st_err;
685 
686  if (rc & M41T80_SEC_ST) {
687  if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
688  rc & ~M41T80_SEC_ST) < 0)
689  goto st_err;
690  }
691 
692  rc = m41t80_sysfs_register(&client->dev);
693  if (rc)
694  goto exit;
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  goto exit;
702  rc = register_reboot_notifier(&wdt_notifier);
703  if (rc) {
704  misc_deregister(&wdt_dev);
705  goto exit;
706  }
707  }
708 #endif
709  return 0;
710 
711 st_err:
712  rc = -EIO;
713  dev_err(&client->dev, "Can't clear ST bit\n");
714  goto exit;
715 ht_err:
716  rc = -EIO;
717  dev_err(&client->dev, "Can't clear HT bit\n");
718  goto exit;
719 
720 exit:
721  if (rtc)
722  rtc_device_unregister(rtc);
723  kfree(clientdata);
724  return rc;
725 }
726 
727 static int m41t80_remove(struct i2c_client *client)
728 {
729  struct m41t80_data *clientdata = i2c_get_clientdata(client);
730  struct rtc_device *rtc = clientdata->rtc;
731 
732 #ifdef CONFIG_RTC_DRV_M41T80_WDT
733  if (clientdata->features & M41T80_FEATURE_HT) {
734  misc_deregister(&wdt_dev);
735  unregister_reboot_notifier(&wdt_notifier);
736  }
737 #endif
738  if (rtc)
739  rtc_device_unregister(rtc);
740  kfree(clientdata);
741 
742  return 0;
743 }
744 
745 static struct i2c_driver m41t80_driver = {
746  .driver = {
747  .name = "rtc-m41t80",
748  },
749  .probe = m41t80_probe,
750  .remove = m41t80_remove,
751  .id_table = m41t80_id,
752 };
753 
754 module_i2c_driver(m41t80_driver);
755 
756 MODULE_AUTHOR("Alexander Bigga <[email protected]>");
757 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
758 MODULE_LICENSE("GPL");
759 MODULE_VERSION(DRV_VERSION);
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