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rtc-ds1307.c
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1 /*
2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
3  *
4  * Copyright (C) 2005 James Chapman (ds1337 core)
5  * Copyright (C) 2006 David Brownell
6  * Copyright (C) 2009 Matthias Fuchs (rx8025 support)
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/i2c.h>
17 #include <linux/string.h>
18 #include <linux/rtc.h>
19 #include <linux/bcd.h>
20 #include <linux/rtc/ds1307.h>
21 
22 /*
23  * We can't determine type by probing, but if we expect pre-Linux code
24  * to have set the chip up as a clock (turning on the oscillator and
25  * setting the date and time), Linux can ignore the non-clock features.
26  * That's a natural job for a factory or repair bench.
27  */
28 enum ds_type {
29  ds_1307,
30  ds_1337,
31  ds_1338,
32  ds_1339,
33  ds_1340,
34  ds_1388,
35  ds_3231,
36  m41t00,
37  mcp7941x,
38  rx_8025,
39  last_ds_type /* always last */
40  /* rs5c372 too? different address... */
41 };
42 
43 
44 /* RTC registers don't differ much, except for the century flag */
45 #define DS1307_REG_SECS 0x00 /* 00-59 */
46 # define DS1307_BIT_CH 0x80
47 # define DS1340_BIT_nEOSC 0x80
48 # define MCP7941X_BIT_ST 0x80
49 #define DS1307_REG_MIN 0x01 /* 00-59 */
50 #define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
51 # define DS1307_BIT_12HR 0x40 /* in REG_HOUR */
52 # define DS1307_BIT_PM 0x20 /* in REG_HOUR */
53 # define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
54 # define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */
55 #define DS1307_REG_WDAY 0x03 /* 01-07 */
56 # define MCP7941X_BIT_VBATEN 0x08
57 #define DS1307_REG_MDAY 0x04 /* 01-31 */
58 #define DS1307_REG_MONTH 0x05 /* 01-12 */
59 # define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */
60 #define DS1307_REG_YEAR 0x06 /* 00-99 */
61 
62 /*
63  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
64  * start at 7, and they differ a LOT. Only control and status matter for
65  * basic RTC date and time functionality; be careful using them.
66  */
67 #define DS1307_REG_CONTROL 0x07 /* or ds1338 */
68 # define DS1307_BIT_OUT 0x80
69 # define DS1338_BIT_OSF 0x20
70 # define DS1307_BIT_SQWE 0x10
71 # define DS1307_BIT_RS1 0x02
72 # define DS1307_BIT_RS0 0x01
73 #define DS1337_REG_CONTROL 0x0e
74 # define DS1337_BIT_nEOSC 0x80
75 # define DS1339_BIT_BBSQI 0x20
76 # define DS3231_BIT_BBSQW 0x40 /* same as BBSQI */
77 # define DS1337_BIT_RS2 0x10
78 # define DS1337_BIT_RS1 0x08
79 # define DS1337_BIT_INTCN 0x04
80 # define DS1337_BIT_A2IE 0x02
81 # define DS1337_BIT_A1IE 0x01
82 #define DS1340_REG_CONTROL 0x07
83 # define DS1340_BIT_OUT 0x80
84 # define DS1340_BIT_FT 0x40
85 # define DS1340_BIT_CALIB_SIGN 0x20
86 # define DS1340_M_CALIBRATION 0x1f
87 #define DS1340_REG_FLAG 0x09
88 # define DS1340_BIT_OSF 0x80
89 #define DS1337_REG_STATUS 0x0f
90 # define DS1337_BIT_OSF 0x80
91 # define DS1337_BIT_A2I 0x02
92 # define DS1337_BIT_A1I 0x01
93 #define DS1339_REG_ALARM1_SECS 0x07
94 
95 #define DS13XX_TRICKLE_CHARGER_MAGIC 0xa0
96 
97 #define RX8025_REG_CTRL1 0x0e
98 # define RX8025_BIT_2412 0x20
99 #define RX8025_REG_CTRL2 0x0f
100 # define RX8025_BIT_PON 0x10
101 # define RX8025_BIT_VDET 0x40
102 # define RX8025_BIT_XST 0x20
103 
104 
105 struct ds1307 {
106  u8 offset; /* register's offset */
107  u8 regs[11];
108  u16 nvram_offset;
109  struct bin_attribute *nvram;
110  enum ds_type type;
111  unsigned long flags;
112 #define HAS_NVRAM 0 /* bit 0 == sysfs file active */
113 #define HAS_ALARM 1 /* bit 1 == irq claimed */
114  struct i2c_client *client;
115  struct rtc_device *rtc;
116  struct work_struct work;
117  s32 (*read_block_data)(const struct i2c_client *client, u8 command,
118  u8 length, u8 *values);
119  s32 (*write_block_data)(const struct i2c_client *client, u8 command,
120  u8 length, const u8 *values);
121 };
122 
123 struct chip_desc {
124  unsigned alarm:1;
125  u16 nvram_offset;
126  u16 nvram_size;
127  u16 trickle_charger_reg;
128 };
129 
130 static const struct chip_desc chips[last_ds_type] = {
131  [ds_1307] = {
132  .nvram_offset = 8,
133  .nvram_size = 56,
134  },
135  [ds_1337] = {
136  .alarm = 1,
137  },
138  [ds_1338] = {
139  .nvram_offset = 8,
140  .nvram_size = 56,
141  },
142  [ds_1339] = {
143  .alarm = 1,
144  .trickle_charger_reg = 0x10,
145  },
146  [ds_1340] = {
147  .trickle_charger_reg = 0x08,
148  },
149  [ds_1388] = {
150  .trickle_charger_reg = 0x0a,
151  },
152  [ds_3231] = {
153  .alarm = 1,
154  },
155  [mcp7941x] = {
156  /* this is battery backed SRAM */
157  .nvram_offset = 0x20,
158  .nvram_size = 0x40,
159  },
160 };
161 
162 static const struct i2c_device_id ds1307_id[] = {
163  { "ds1307", ds_1307 },
164  { "ds1337", ds_1337 },
165  { "ds1338", ds_1338 },
166  { "ds1339", ds_1339 },
167  { "ds1388", ds_1388 },
168  { "ds1340", ds_1340 },
169  { "ds3231", ds_3231 },
170  { "m41t00", m41t00 },
171  { "mcp7941x", mcp7941x },
172  { "pt7c4338", ds_1307 },
173  { "rx8025", rx_8025 },
174  { }
175 };
176 MODULE_DEVICE_TABLE(i2c, ds1307_id);
177 
178 /*----------------------------------------------------------------------*/
179 
180 #define BLOCK_DATA_MAX_TRIES 10
181 
182 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
183  u8 command, u8 length, u8 *values)
184 {
185  s32 i, data;
186 
187  for (i = 0; i < length; i++) {
188  data = i2c_smbus_read_byte_data(client, command + i);
189  if (data < 0)
190  return data;
191  values[i] = data;
192  }
193  return i;
194 }
195 
196 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
197  u8 length, u8 *values)
198 {
199  u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
200  s32 ret;
201  int tries = 0;
202 
203  dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
204  ret = ds1307_read_block_data_once(client, command, length, values);
205  if (ret < 0)
206  return ret;
207  do {
208  if (++tries > BLOCK_DATA_MAX_TRIES) {
209  dev_err(&client->dev,
210  "ds1307_read_block_data failed\n");
211  return -EIO;
212  }
213  memcpy(oldvalues, values, length);
214  ret = ds1307_read_block_data_once(client, command, length,
215  values);
216  if (ret < 0)
217  return ret;
218  } while (memcmp(oldvalues, values, length));
219  return length;
220 }
221 
222 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
223  u8 length, const u8 *values)
224 {
225  u8 currvalues[I2C_SMBUS_BLOCK_MAX];
226  int tries = 0;
227 
228  dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
229  do {
230  s32 i, ret;
231 
232  if (++tries > BLOCK_DATA_MAX_TRIES) {
233  dev_err(&client->dev,
234  "ds1307_write_block_data failed\n");
235  return -EIO;
236  }
237  for (i = 0; i < length; i++) {
238  ret = i2c_smbus_write_byte_data(client, command + i,
239  values[i]);
240  if (ret < 0)
241  return ret;
242  }
243  ret = ds1307_read_block_data_once(client, command, length,
244  currvalues);
245  if (ret < 0)
246  return ret;
247  } while (memcmp(currvalues, values, length));
248  return length;
249 }
250 
251 /*----------------------------------------------------------------------*/
252 
253 /*
254  * The IRQ logic includes a "real" handler running in IRQ context just
255  * long enough to schedule this workqueue entry. We need a task context
256  * to talk to the RTC, since I2C I/O calls require that; and disable the
257  * IRQ until we clear its status on the chip, so that this handler can
258  * work with any type of triggering (not just falling edge).
259  *
260  * The ds1337 and ds1339 both have two alarms, but we only use the first
261  * one (with a "seconds" field). For ds1337 we expect nINTA is our alarm
262  * signal; ds1339 chips have only one alarm signal.
263  */
264 static void ds1307_work(struct work_struct *work)
265 {
266  struct ds1307 *ds1307;
267  struct i2c_client *client;
268  struct mutex *lock;
269  int stat, control;
270 
271  ds1307 = container_of(work, struct ds1307, work);
272  client = ds1307->client;
273  lock = &ds1307->rtc->ops_lock;
274 
275  mutex_lock(lock);
276  stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
277  if (stat < 0)
278  goto out;
279 
280  if (stat & DS1337_BIT_A1I) {
281  stat &= ~DS1337_BIT_A1I;
282  i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
283 
284  control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
285  if (control < 0)
286  goto out;
287 
288  control &= ~DS1337_BIT_A1IE;
289  i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
290 
291  rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
292  }
293 
294 out:
295  if (test_bit(HAS_ALARM, &ds1307->flags))
296  enable_irq(client->irq);
297  mutex_unlock(lock);
298 }
299 
300 static irqreturn_t ds1307_irq(int irq, void *dev_id)
301 {
302  struct i2c_client *client = dev_id;
303  struct ds1307 *ds1307 = i2c_get_clientdata(client);
304 
305  disable_irq_nosync(irq);
306  schedule_work(&ds1307->work);
307  return IRQ_HANDLED;
308 }
309 
310 /*----------------------------------------------------------------------*/
311 
312 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
313 {
314  struct ds1307 *ds1307 = dev_get_drvdata(dev);
315  int tmp;
316 
317  /* read the RTC date and time registers all at once */
318  tmp = ds1307->read_block_data(ds1307->client,
319  ds1307->offset, 7, ds1307->regs);
320  if (tmp != 7) {
321  dev_err(dev, "%s error %d\n", "read", tmp);
322  return -EIO;
323  }
324 
325  dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
326  "read",
327  ds1307->regs[0], ds1307->regs[1],
328  ds1307->regs[2], ds1307->regs[3],
329  ds1307->regs[4], ds1307->regs[5],
330  ds1307->regs[6]);
331 
332  t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
333  t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
334  tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
335  t->tm_hour = bcd2bin(tmp);
336  t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
337  t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
338  tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
339  t->tm_mon = bcd2bin(tmp) - 1;
340 
341  /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
342  t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
343 
344  dev_dbg(dev, "%s secs=%d, mins=%d, "
345  "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
346  "read", t->tm_sec, t->tm_min,
347  t->tm_hour, t->tm_mday,
348  t->tm_mon, t->tm_year, t->tm_wday);
349 
350  /* initial clock setting can be undefined */
351  return rtc_valid_tm(t);
352 }
353 
354 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
355 {
356  struct ds1307 *ds1307 = dev_get_drvdata(dev);
357  int result;
358  int tmp;
359  u8 *buf = ds1307->regs;
360 
361  dev_dbg(dev, "%s secs=%d, mins=%d, "
362  "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
363  "write", t->tm_sec, t->tm_min,
364  t->tm_hour, t->tm_mday,
365  t->tm_mon, t->tm_year, t->tm_wday);
366 
367  buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
368  buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
369  buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
370  buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
371  buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
372  buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
373 
374  /* assume 20YY not 19YY */
375  tmp = t->tm_year - 100;
376  buf[DS1307_REG_YEAR] = bin2bcd(tmp);
377 
378  switch (ds1307->type) {
379  case ds_1337:
380  case ds_1339:
381  case ds_3231:
382  buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
383  break;
384  case ds_1340:
385  buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
386  | DS1340_BIT_CENTURY;
387  break;
388  case mcp7941x:
389  /*
390  * these bits were cleared when preparing the date/time
391  * values and need to be set again before writing the
392  * buffer out to the device.
393  */
394  buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
395  buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
396  break;
397  default:
398  break;
399  }
400 
401  dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
402  "write", buf[0], buf[1], buf[2], buf[3],
403  buf[4], buf[5], buf[6]);
404 
405  result = ds1307->write_block_data(ds1307->client,
406  ds1307->offset, 7, buf);
407  if (result < 0) {
408  dev_err(dev, "%s error %d\n", "write", result);
409  return result;
410  }
411  return 0;
412 }
413 
414 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
415 {
416  struct i2c_client *client = to_i2c_client(dev);
417  struct ds1307 *ds1307 = i2c_get_clientdata(client);
418  int ret;
419 
420  if (!test_bit(HAS_ALARM, &ds1307->flags))
421  return -EINVAL;
422 
423  /* read all ALARM1, ALARM2, and status registers at once */
424  ret = ds1307->read_block_data(client,
425  DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
426  if (ret != 9) {
427  dev_err(dev, "%s error %d\n", "alarm read", ret);
428  return -EIO;
429  }
430 
431  dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
432  "alarm read",
433  ds1307->regs[0], ds1307->regs[1],
434  ds1307->regs[2], ds1307->regs[3],
435  ds1307->regs[4], ds1307->regs[5],
436  ds1307->regs[6], ds1307->regs[7],
437  ds1307->regs[8]);
438 
439  /*
440  * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
441  * and that all four fields are checked matches
442  */
443  t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
444  t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
445  t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
446  t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
447  t->time.tm_mon = -1;
448  t->time.tm_year = -1;
449  t->time.tm_wday = -1;
450  t->time.tm_yday = -1;
451  t->time.tm_isdst = -1;
452 
453  /* ... and status */
454  t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
455  t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
456 
457  dev_dbg(dev, "%s secs=%d, mins=%d, "
458  "hours=%d, mday=%d, enabled=%d, pending=%d\n",
459  "alarm read", t->time.tm_sec, t->time.tm_min,
460  t->time.tm_hour, t->time.tm_mday,
461  t->enabled, t->pending);
462 
463  return 0;
464 }
465 
466 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
467 {
468  struct i2c_client *client = to_i2c_client(dev);
469  struct ds1307 *ds1307 = i2c_get_clientdata(client);
470  unsigned char *buf = ds1307->regs;
471  u8 control, status;
472  int ret;
473 
474  if (!test_bit(HAS_ALARM, &ds1307->flags))
475  return -EINVAL;
476 
477  dev_dbg(dev, "%s secs=%d, mins=%d, "
478  "hours=%d, mday=%d, enabled=%d, pending=%d\n",
479  "alarm set", t->time.tm_sec, t->time.tm_min,
480  t->time.tm_hour, t->time.tm_mday,
481  t->enabled, t->pending);
482 
483  /* read current status of both alarms and the chip */
484  ret = ds1307->read_block_data(client,
485  DS1339_REG_ALARM1_SECS, 9, buf);
486  if (ret != 9) {
487  dev_err(dev, "%s error %d\n", "alarm write", ret);
488  return -EIO;
489  }
490  control = ds1307->regs[7];
491  status = ds1307->regs[8];
492 
493  dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
494  "alarm set (old status)",
495  ds1307->regs[0], ds1307->regs[1],
496  ds1307->regs[2], ds1307->regs[3],
497  ds1307->regs[4], ds1307->regs[5],
498  ds1307->regs[6], control, status);
499 
500  /* set ALARM1, using 24 hour and day-of-month modes */
501  buf[0] = bin2bcd(t->time.tm_sec);
502  buf[1] = bin2bcd(t->time.tm_min);
503  buf[2] = bin2bcd(t->time.tm_hour);
504  buf[3] = bin2bcd(t->time.tm_mday);
505 
506  /* set ALARM2 to non-garbage */
507  buf[4] = 0;
508  buf[5] = 0;
509  buf[6] = 0;
510 
511  /* optionally enable ALARM1 */
512  buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
513  if (t->enabled) {
514  dev_dbg(dev, "alarm IRQ armed\n");
515  buf[7] |= DS1337_BIT_A1IE; /* only ALARM1 is used */
516  }
517  buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
518 
519  ret = ds1307->write_block_data(client,
520  DS1339_REG_ALARM1_SECS, 9, buf);
521  if (ret < 0) {
522  dev_err(dev, "can't set alarm time\n");
523  return ret;
524  }
525 
526  return 0;
527 }
528 
529 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
530 {
531  struct i2c_client *client = to_i2c_client(dev);
532  struct ds1307 *ds1307 = i2c_get_clientdata(client);
533  int ret;
534 
535  if (!test_bit(HAS_ALARM, &ds1307->flags))
536  return -ENOTTY;
537 
538  ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
539  if (ret < 0)
540  return ret;
541 
542  if (enabled)
543  ret |= DS1337_BIT_A1IE;
544  else
545  ret &= ~DS1337_BIT_A1IE;
546 
547  ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
548  if (ret < 0)
549  return ret;
550 
551  return 0;
552 }
553 
554 static const struct rtc_class_ops ds13xx_rtc_ops = {
555  .read_time = ds1307_get_time,
556  .set_time = ds1307_set_time,
557  .read_alarm = ds1337_read_alarm,
558  .set_alarm = ds1337_set_alarm,
559  .alarm_irq_enable = ds1307_alarm_irq_enable,
560 };
561 
562 /*----------------------------------------------------------------------*/
563 
564 static ssize_t
565 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
566  struct bin_attribute *attr,
567  char *buf, loff_t off, size_t count)
568 {
569  struct i2c_client *client;
570  struct ds1307 *ds1307;
571  int result;
572 
573  client = kobj_to_i2c_client(kobj);
574  ds1307 = i2c_get_clientdata(client);
575 
576  if (unlikely(off >= ds1307->nvram->size))
577  return 0;
578  if ((off + count) > ds1307->nvram->size)
579  count = ds1307->nvram->size - off;
580  if (unlikely(!count))
581  return count;
582 
583  result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
584  count, buf);
585  if (result < 0)
586  dev_err(&client->dev, "%s error %d\n", "nvram read", result);
587  return result;
588 }
589 
590 static ssize_t
591 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
592  struct bin_attribute *attr,
593  char *buf, loff_t off, size_t count)
594 {
595  struct i2c_client *client;
596  struct ds1307 *ds1307;
597  int result;
598 
599  client = kobj_to_i2c_client(kobj);
600  ds1307 = i2c_get_clientdata(client);
601 
602  if (unlikely(off >= ds1307->nvram->size))
603  return -EFBIG;
604  if ((off + count) > ds1307->nvram->size)
605  count = ds1307->nvram->size - off;
606  if (unlikely(!count))
607  return count;
608 
609  result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
610  count, buf);
611  if (result < 0) {
612  dev_err(&client->dev, "%s error %d\n", "nvram write", result);
613  return result;
614  }
615  return count;
616 }
617 
618 /*----------------------------------------------------------------------*/
619 
620 static int __devinit ds1307_probe(struct i2c_client *client,
621  const struct i2c_device_id *id)
622 {
623  struct ds1307 *ds1307;
624  int err = -ENODEV;
625  int tmp;
626  const struct chip_desc *chip = &chips[id->driver_data];
627  struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
628  int want_irq = false;
629  unsigned char *buf;
630  struct ds1307_platform_data *pdata = client->dev.platform_data;
631  static const int bbsqi_bitpos[] = {
632  [ds_1337] = 0,
633  [ds_1339] = DS1339_BIT_BBSQI,
634  [ds_3231] = DS3231_BIT_BBSQW,
635  };
636 
637  if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
638  && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
639  return -EIO;
640 
641  ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
642  if (!ds1307)
643  return -ENOMEM;
644 
645  i2c_set_clientdata(client, ds1307);
646 
647  ds1307->client = client;
648  ds1307->type = id->driver_data;
649 
650  if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
651  i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
652  DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
653 
654  buf = ds1307->regs;
655  if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
656  ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
657  ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
658  } else {
659  ds1307->read_block_data = ds1307_read_block_data;
660  ds1307->write_block_data = ds1307_write_block_data;
661  }
662 
663  switch (ds1307->type) {
664  case ds_1337:
665  case ds_1339:
666  case ds_3231:
667  /* get registers that the "rtc" read below won't read... */
668  tmp = ds1307->read_block_data(ds1307->client,
669  DS1337_REG_CONTROL, 2, buf);
670  if (tmp != 2) {
671  pr_debug("read error %d\n", tmp);
672  err = -EIO;
673  goto exit_free;
674  }
675 
676  /* oscillator off? turn it on, so clock can tick. */
677  if (ds1307->regs[0] & DS1337_BIT_nEOSC)
678  ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
679 
680  /*
681  * Using IRQ? Disable the square wave and both alarms.
682  * For some variants, be sure alarms can trigger when we're
683  * running on Vbackup (BBSQI/BBSQW)
684  */
685  if (ds1307->client->irq > 0 && chip->alarm) {
686  INIT_WORK(&ds1307->work, ds1307_work);
687 
688  ds1307->regs[0] |= DS1337_BIT_INTCN
689  | bbsqi_bitpos[ds1307->type];
690  ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
691 
692  want_irq = true;
693  }
694 
695  i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
696  ds1307->regs[0]);
697 
698  /* oscillator fault? clear flag, and warn */
699  if (ds1307->regs[1] & DS1337_BIT_OSF) {
700  i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
701  ds1307->regs[1] & ~DS1337_BIT_OSF);
702  dev_warn(&client->dev, "SET TIME!\n");
703  }
704  break;
705 
706  case rx_8025:
707  tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
708  RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
709  if (tmp != 2) {
710  pr_debug("read error %d\n", tmp);
711  err = -EIO;
712  goto exit_free;
713  }
714 
715  /* oscillator off? turn it on, so clock can tick. */
716  if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
717  ds1307->regs[1] |= RX8025_BIT_XST;
718  i2c_smbus_write_byte_data(client,
719  RX8025_REG_CTRL2 << 4 | 0x08,
720  ds1307->regs[1]);
721  dev_warn(&client->dev,
722  "oscillator stop detected - SET TIME!\n");
723  }
724 
725  if (ds1307->regs[1] & RX8025_BIT_PON) {
726  ds1307->regs[1] &= ~RX8025_BIT_PON;
727  i2c_smbus_write_byte_data(client,
728  RX8025_REG_CTRL2 << 4 | 0x08,
729  ds1307->regs[1]);
730  dev_warn(&client->dev, "power-on detected\n");
731  }
732 
733  if (ds1307->regs[1] & RX8025_BIT_VDET) {
734  ds1307->regs[1] &= ~RX8025_BIT_VDET;
735  i2c_smbus_write_byte_data(client,
736  RX8025_REG_CTRL2 << 4 | 0x08,
737  ds1307->regs[1]);
738  dev_warn(&client->dev, "voltage drop detected\n");
739  }
740 
741  /* make sure we are running in 24hour mode */
742  if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
743  u8 hour;
744 
745  /* switch to 24 hour mode */
746  i2c_smbus_write_byte_data(client,
747  RX8025_REG_CTRL1 << 4 | 0x08,
748  ds1307->regs[0] |
749  RX8025_BIT_2412);
750 
751  tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
752  RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
753  if (tmp != 2) {
754  pr_debug("read error %d\n", tmp);
755  err = -EIO;
756  goto exit_free;
757  }
758 
759  /* correct hour */
760  hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
761  if (hour == 12)
762  hour = 0;
763  if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
764  hour += 12;
765 
766  i2c_smbus_write_byte_data(client,
767  DS1307_REG_HOUR << 4 | 0x08,
768  hour);
769  }
770  break;
771  case ds_1388:
772  ds1307->offset = 1; /* Seconds starts at 1 */
773  break;
774  default:
775  break;
776  }
777 
778 read_rtc:
779  /* read RTC registers */
780  tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
781  if (tmp != 8) {
782  pr_debug("read error %d\n", tmp);
783  err = -EIO;
784  goto exit_free;
785  }
786 
787  /*
788  * minimal sanity checking; some chips (like DS1340) don't
789  * specify the extra bits as must-be-zero, but there are
790  * still a few values that are clearly out-of-range.
791  */
792  tmp = ds1307->regs[DS1307_REG_SECS];
793  switch (ds1307->type) {
794  case ds_1307:
795  case m41t00:
796  /* clock halted? turn it on, so clock can tick. */
797  if (tmp & DS1307_BIT_CH) {
798  i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
799  dev_warn(&client->dev, "SET TIME!\n");
800  goto read_rtc;
801  }
802  break;
803  case ds_1338:
804  /* clock halted? turn it on, so clock can tick. */
805  if (tmp & DS1307_BIT_CH)
806  i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
807 
808  /* oscillator fault? clear flag, and warn */
809  if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
810  i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
811  ds1307->regs[DS1307_REG_CONTROL]
812  & ~DS1338_BIT_OSF);
813  dev_warn(&client->dev, "SET TIME!\n");
814  goto read_rtc;
815  }
816  break;
817  case ds_1340:
818  /* clock halted? turn it on, so clock can tick. */
819  if (tmp & DS1340_BIT_nEOSC)
820  i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
821 
822  tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
823  if (tmp < 0) {
824  pr_debug("read error %d\n", tmp);
825  err = -EIO;
826  goto exit_free;
827  }
828 
829  /* oscillator fault? clear flag, and warn */
830  if (tmp & DS1340_BIT_OSF) {
831  i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
832  dev_warn(&client->dev, "SET TIME!\n");
833  }
834  break;
835  case mcp7941x:
836  /* make sure that the backup battery is enabled */
837  if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
838  i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
839  ds1307->regs[DS1307_REG_WDAY]
840  | MCP7941X_BIT_VBATEN);
841  }
842 
843  /* clock halted? turn it on, so clock can tick. */
844  if (!(tmp & MCP7941X_BIT_ST)) {
845  i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
846  MCP7941X_BIT_ST);
847  dev_warn(&client->dev, "SET TIME!\n");
848  goto read_rtc;
849  }
850 
851  break;
852  default:
853  break;
854  }
855 
856  tmp = ds1307->regs[DS1307_REG_HOUR];
857  switch (ds1307->type) {
858  case ds_1340:
859  case m41t00:
860  /*
861  * NOTE: ignores century bits; fix before deploying
862  * systems that will run through year 2100.
863  */
864  break;
865  case rx_8025:
866  break;
867  default:
868  if (!(tmp & DS1307_BIT_12HR))
869  break;
870 
871  /*
872  * Be sure we're in 24 hour mode. Multi-master systems
873  * take note...
874  */
875  tmp = bcd2bin(tmp & 0x1f);
876  if (tmp == 12)
877  tmp = 0;
878  if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
879  tmp += 12;
880  i2c_smbus_write_byte_data(client,
881  ds1307->offset + DS1307_REG_HOUR,
882  bin2bcd(tmp));
883  }
884 
885  ds1307->rtc = rtc_device_register(client->name, &client->dev,
886  &ds13xx_rtc_ops, THIS_MODULE);
887  if (IS_ERR(ds1307->rtc)) {
888  err = PTR_ERR(ds1307->rtc);
889  dev_err(&client->dev,
890  "unable to register the class device\n");
891  goto exit_free;
892  }
893 
894  if (want_irq) {
895  err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
896  ds1307->rtc->name, client);
897  if (err) {
898  dev_err(&client->dev,
899  "unable to request IRQ!\n");
900  goto exit_irq;
901  }
902 
903  device_set_wakeup_capable(&client->dev, 1);
904  set_bit(HAS_ALARM, &ds1307->flags);
905  dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
906  }
907 
908  if (chip->nvram_size) {
909  ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
910  GFP_KERNEL);
911  if (!ds1307->nvram) {
912  err = -ENOMEM;
913  goto exit_nvram;
914  }
915  ds1307->nvram->attr.name = "nvram";
916  ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
917  sysfs_bin_attr_init(ds1307->nvram);
918  ds1307->nvram->read = ds1307_nvram_read,
919  ds1307->nvram->write = ds1307_nvram_write,
920  ds1307->nvram->size = chip->nvram_size;
921  ds1307->nvram_offset = chip->nvram_offset;
922  err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
923  if (err) {
924  kfree(ds1307->nvram);
925  goto exit_nvram;
926  }
927  set_bit(HAS_NVRAM, &ds1307->flags);
928  dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
929  }
930 
931  return 0;
932 
933 exit_nvram:
934 exit_irq:
935  rtc_device_unregister(ds1307->rtc);
936 exit_free:
937  kfree(ds1307);
938  return err;
939 }
940 
941 static int __devexit ds1307_remove(struct i2c_client *client)
942 {
943  struct ds1307 *ds1307 = i2c_get_clientdata(client);
944 
945  if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
946  free_irq(client->irq, client);
947  cancel_work_sync(&ds1307->work);
948  }
949 
950  if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
951  sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
952  kfree(ds1307->nvram);
953  }
954 
955  rtc_device_unregister(ds1307->rtc);
956  kfree(ds1307);
957  return 0;
958 }
959 
960 static struct i2c_driver ds1307_driver = {
961  .driver = {
962  .name = "rtc-ds1307",
963  .owner = THIS_MODULE,
964  },
965  .probe = ds1307_probe,
966  .remove = __devexit_p(ds1307_remove),
967  .id_table = ds1307_id,
968 };
969 
970 module_i2c_driver(ds1307_driver);
971 
972 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
973 MODULE_LICENSE("GPL");
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