rtc: ds1307: refactor chip_desc table
[linux-2.6.git] / drivers / rtc / rtc-ds1307.c
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
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 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
63  * start at 7, and they differ a LOT. Only control and status matter for
64  * basic RTC date and time functionality; be careful using them.
65  */
66 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
67 #       define DS1307_BIT_OUT           0x80
68 #       define DS1338_BIT_OSF           0x20
69 #       define DS1307_BIT_SQWE          0x10
70 #       define DS1307_BIT_RS1           0x02
71 #       define DS1307_BIT_RS0           0x01
72 #define DS1337_REG_CONTROL      0x0e
73 #       define DS1337_BIT_nEOSC         0x80
74 #       define DS1339_BIT_BBSQI         0x20
75 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
76 #       define DS1337_BIT_RS2           0x10
77 #       define DS1337_BIT_RS1           0x08
78 #       define DS1337_BIT_INTCN         0x04
79 #       define DS1337_BIT_A2IE          0x02
80 #       define DS1337_BIT_A1IE          0x01
81 #define DS1340_REG_CONTROL      0x07
82 #       define DS1340_BIT_OUT           0x80
83 #       define DS1340_BIT_FT            0x40
84 #       define DS1340_BIT_CALIB_SIGN    0x20
85 #       define DS1340_M_CALIBRATION     0x1f
86 #define DS1340_REG_FLAG         0x09
87 #       define DS1340_BIT_OSF           0x80
88 #define DS1337_REG_STATUS       0x0f
89 #       define DS1337_BIT_OSF           0x80
90 #       define DS1337_BIT_A2I           0x02
91 #       define DS1337_BIT_A1I           0x01
92 #define DS1339_REG_ALARM1_SECS  0x07
93 #define DS1339_REG_TRICKLE      0x10
94
95 #define RX8025_REG_CTRL1        0x0e
96 #       define RX8025_BIT_2412          0x20
97 #define RX8025_REG_CTRL2        0x0f
98 #       define RX8025_BIT_PON           0x10
99 #       define RX8025_BIT_VDET          0x40
100 #       define RX8025_BIT_XST           0x20
101
102
103 struct ds1307 {
104         u8                      offset; /* register's offset */
105         u8                      regs[11];
106         enum ds_type            type;
107         unsigned long           flags;
108 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
109 #define HAS_ALARM       1               /* bit 1 == irq claimed */
110         struct i2c_client       *client;
111         struct rtc_device       *rtc;
112         struct work_struct      work;
113         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
114                                u8 length, u8 *values);
115         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
116                                 u8 length, const u8 *values);
117 };
118
119 struct chip_desc {
120         unsigned                nvram56:1;
121         unsigned                alarm:1;
122 };
123
124 static const struct chip_desc chips[last_ds_type] = {
125         [ds_1307] = {
126                 .nvram56        = 1,
127         },
128         [ds_1337] = {
129                 .alarm          = 1,
130         },
131         [ds_1338] = {
132                 .nvram56        = 1,
133         },
134         [ds_1339] = {
135                 .alarm          = 1,
136         },
137         [ds_3231] = {
138                 .alarm          = 1,
139         },
140 };
141
142 static const struct i2c_device_id ds1307_id[] = {
143         { "ds1307", ds_1307 },
144         { "ds1337", ds_1337 },
145         { "ds1338", ds_1338 },
146         { "ds1339", ds_1339 },
147         { "ds1388", ds_1388 },
148         { "ds1340", ds_1340 },
149         { "ds3231", ds_3231 },
150         { "m41t00", m41t00 },
151         { "mcp7941x", mcp7941x },
152         { "pt7c4338", ds_1307 },
153         { "rx8025", rx_8025 },
154         { }
155 };
156 MODULE_DEVICE_TABLE(i2c, ds1307_id);
157
158 /*----------------------------------------------------------------------*/
159
160 #define BLOCK_DATA_MAX_TRIES 10
161
162 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
163                                        u8 command, u8 length, u8 *values)
164 {
165         s32 i, data;
166
167         for (i = 0; i < length; i++) {
168                 data = i2c_smbus_read_byte_data(client, command + i);
169                 if (data < 0)
170                         return data;
171                 values[i] = data;
172         }
173         return i;
174 }
175
176 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
177                                   u8 length, u8 *values)
178 {
179         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
180         s32 ret;
181         int tries = 0;
182
183         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
184         ret = ds1307_read_block_data_once(client, command, length, values);
185         if (ret < 0)
186                 return ret;
187         do {
188                 if (++tries > BLOCK_DATA_MAX_TRIES) {
189                         dev_err(&client->dev,
190                                 "ds1307_read_block_data failed\n");
191                         return -EIO;
192                 }
193                 memcpy(oldvalues, values, length);
194                 ret = ds1307_read_block_data_once(client, command, length,
195                                                   values);
196                 if (ret < 0)
197                         return ret;
198         } while (memcmp(oldvalues, values, length));
199         return length;
200 }
201
202 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
203                                    u8 length, const u8 *values)
204 {
205         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
206         int tries = 0;
207
208         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
209         do {
210                 s32 i, ret;
211
212                 if (++tries > BLOCK_DATA_MAX_TRIES) {
213                         dev_err(&client->dev,
214                                 "ds1307_write_block_data failed\n");
215                         return -EIO;
216                 }
217                 for (i = 0; i < length; i++) {
218                         ret = i2c_smbus_write_byte_data(client, command + i,
219                                                         values[i]);
220                         if (ret < 0)
221                                 return ret;
222                 }
223                 ret = ds1307_read_block_data_once(client, command, length,
224                                                   currvalues);
225                 if (ret < 0)
226                         return ret;
227         } while (memcmp(currvalues, values, length));
228         return length;
229 }
230
231 /*----------------------------------------------------------------------*/
232
233 /*
234  * The IRQ logic includes a "real" handler running in IRQ context just
235  * long enough to schedule this workqueue entry.   We need a task context
236  * to talk to the RTC, since I2C I/O calls require that; and disable the
237  * IRQ until we clear its status on the chip, so that this handler can
238  * work with any type of triggering (not just falling edge).
239  *
240  * The ds1337 and ds1339 both have two alarms, but we only use the first
241  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
242  * signal; ds1339 chips have only one alarm signal.
243  */
244 static void ds1307_work(struct work_struct *work)
245 {
246         struct ds1307           *ds1307;
247         struct i2c_client       *client;
248         struct mutex            *lock;
249         int                     stat, control;
250
251         ds1307 = container_of(work, struct ds1307, work);
252         client = ds1307->client;
253         lock = &ds1307->rtc->ops_lock;
254
255         mutex_lock(lock);
256         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
257         if (stat < 0)
258                 goto out;
259
260         if (stat & DS1337_BIT_A1I) {
261                 stat &= ~DS1337_BIT_A1I;
262                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
263
264                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
265                 if (control < 0)
266                         goto out;
267
268                 control &= ~DS1337_BIT_A1IE;
269                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
270
271                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
272         }
273
274 out:
275         if (test_bit(HAS_ALARM, &ds1307->flags))
276                 enable_irq(client->irq);
277         mutex_unlock(lock);
278 }
279
280 static irqreturn_t ds1307_irq(int irq, void *dev_id)
281 {
282         struct i2c_client       *client = dev_id;
283         struct ds1307           *ds1307 = i2c_get_clientdata(client);
284
285         disable_irq_nosync(irq);
286         schedule_work(&ds1307->work);
287         return IRQ_HANDLED;
288 }
289
290 /*----------------------------------------------------------------------*/
291
292 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
293 {
294         struct ds1307   *ds1307 = dev_get_drvdata(dev);
295         int             tmp;
296
297         /* read the RTC date and time registers all at once */
298         tmp = ds1307->read_block_data(ds1307->client,
299                 ds1307->offset, 7, ds1307->regs);
300         if (tmp != 7) {
301                 dev_err(dev, "%s error %d\n", "read", tmp);
302                 return -EIO;
303         }
304
305         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
306                         "read",
307                         ds1307->regs[0], ds1307->regs[1],
308                         ds1307->regs[2], ds1307->regs[3],
309                         ds1307->regs[4], ds1307->regs[5],
310                         ds1307->regs[6]);
311
312         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
313         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
314         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
315         t->tm_hour = bcd2bin(tmp);
316         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
317         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
318         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
319         t->tm_mon = bcd2bin(tmp) - 1;
320
321         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
322         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
323
324         dev_dbg(dev, "%s secs=%d, mins=%d, "
325                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
326                 "read", t->tm_sec, t->tm_min,
327                 t->tm_hour, t->tm_mday,
328                 t->tm_mon, t->tm_year, t->tm_wday);
329
330         /* initial clock setting can be undefined */
331         return rtc_valid_tm(t);
332 }
333
334 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
335 {
336         struct ds1307   *ds1307 = dev_get_drvdata(dev);
337         int             result;
338         int             tmp;
339         u8              *buf = ds1307->regs;
340
341         dev_dbg(dev, "%s secs=%d, mins=%d, "
342                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
343                 "write", t->tm_sec, t->tm_min,
344                 t->tm_hour, t->tm_mday,
345                 t->tm_mon, t->tm_year, t->tm_wday);
346
347         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
348         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
349         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
350         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
351         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
352         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
353
354         /* assume 20YY not 19YY */
355         tmp = t->tm_year - 100;
356         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
357
358         switch (ds1307->type) {
359         case ds_1337:
360         case ds_1339:
361         case ds_3231:
362                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
363                 break;
364         case ds_1340:
365                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
366                                 | DS1340_BIT_CENTURY;
367                 break;
368         case mcp7941x:
369                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
370                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
371                 break;
372         default:
373                 break;
374         }
375
376         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
377                 "write", buf[0], buf[1], buf[2], buf[3],
378                 buf[4], buf[5], buf[6]);
379
380         result = ds1307->write_block_data(ds1307->client,
381                 ds1307->offset, 7, buf);
382         if (result < 0) {
383                 dev_err(dev, "%s error %d\n", "write", result);
384                 return result;
385         }
386         return 0;
387 }
388
389 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
390 {
391         struct i2c_client       *client = to_i2c_client(dev);
392         struct ds1307           *ds1307 = i2c_get_clientdata(client);
393         int                     ret;
394
395         if (!test_bit(HAS_ALARM, &ds1307->flags))
396                 return -EINVAL;
397
398         /* read all ALARM1, ALARM2, and status registers at once */
399         ret = ds1307->read_block_data(client,
400                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
401         if (ret != 9) {
402                 dev_err(dev, "%s error %d\n", "alarm read", ret);
403                 return -EIO;
404         }
405
406         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
407                         "alarm read",
408                         ds1307->regs[0], ds1307->regs[1],
409                         ds1307->regs[2], ds1307->regs[3],
410                         ds1307->regs[4], ds1307->regs[5],
411                         ds1307->regs[6], ds1307->regs[7],
412                         ds1307->regs[8]);
413
414         /* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
415          * and that all four fields are checked matches
416          */
417         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
418         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
419         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
420         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
421         t->time.tm_mon = -1;
422         t->time.tm_year = -1;
423         t->time.tm_wday = -1;
424         t->time.tm_yday = -1;
425         t->time.tm_isdst = -1;
426
427         /* ... and status */
428         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
429         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
430
431         dev_dbg(dev, "%s secs=%d, mins=%d, "
432                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
433                 "alarm read", t->time.tm_sec, t->time.tm_min,
434                 t->time.tm_hour, t->time.tm_mday,
435                 t->enabled, t->pending);
436
437         return 0;
438 }
439
440 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
441 {
442         struct i2c_client       *client = to_i2c_client(dev);
443         struct ds1307           *ds1307 = i2c_get_clientdata(client);
444         unsigned char           *buf = ds1307->regs;
445         u8                      control, status;
446         int                     ret;
447
448         if (!test_bit(HAS_ALARM, &ds1307->flags))
449                 return -EINVAL;
450
451         dev_dbg(dev, "%s secs=%d, mins=%d, "
452                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
453                 "alarm set", t->time.tm_sec, t->time.tm_min,
454                 t->time.tm_hour, t->time.tm_mday,
455                 t->enabled, t->pending);
456
457         /* read current status of both alarms and the chip */
458         ret = ds1307->read_block_data(client,
459                         DS1339_REG_ALARM1_SECS, 9, buf);
460         if (ret != 9) {
461                 dev_err(dev, "%s error %d\n", "alarm write", ret);
462                 return -EIO;
463         }
464         control = ds1307->regs[7];
465         status = ds1307->regs[8];
466
467         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
468                         "alarm set (old status)",
469                         ds1307->regs[0], ds1307->regs[1],
470                         ds1307->regs[2], ds1307->regs[3],
471                         ds1307->regs[4], ds1307->regs[5],
472                         ds1307->regs[6], control, status);
473
474         /* set ALARM1, using 24 hour and day-of-month modes */
475         buf[0] = bin2bcd(t->time.tm_sec);
476         buf[1] = bin2bcd(t->time.tm_min);
477         buf[2] = bin2bcd(t->time.tm_hour);
478         buf[3] = bin2bcd(t->time.tm_mday);
479
480         /* set ALARM2 to non-garbage */
481         buf[4] = 0;
482         buf[5] = 0;
483         buf[6] = 0;
484
485         /* optionally enable ALARM1 */
486         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
487         if (t->enabled) {
488                 dev_dbg(dev, "alarm IRQ armed\n");
489                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
490         }
491         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
492
493         ret = ds1307->write_block_data(client,
494                         DS1339_REG_ALARM1_SECS, 9, buf);
495         if (ret < 0) {
496                 dev_err(dev, "can't set alarm time\n");
497                 return ret;
498         }
499
500         return 0;
501 }
502
503 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
504 {
505         struct i2c_client       *client = to_i2c_client(dev);
506         struct ds1307           *ds1307 = i2c_get_clientdata(client);
507         int                     ret;
508
509         if (!test_bit(HAS_ALARM, &ds1307->flags))
510                 return -ENOTTY;
511
512         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
513         if (ret < 0)
514                 return ret;
515
516         if (enabled)
517                 ret |= DS1337_BIT_A1IE;
518         else
519                 ret &= ~DS1337_BIT_A1IE;
520
521         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
522         if (ret < 0)
523                 return ret;
524
525         return 0;
526 }
527
528 static const struct rtc_class_ops ds13xx_rtc_ops = {
529         .read_time      = ds1307_get_time,
530         .set_time       = ds1307_set_time,
531         .read_alarm     = ds1337_read_alarm,
532         .set_alarm      = ds1337_set_alarm,
533         .alarm_irq_enable = ds1307_alarm_irq_enable,
534 };
535
536 /*----------------------------------------------------------------------*/
537
538 #define NVRAM_SIZE      56
539
540 static ssize_t
541 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
542                 struct bin_attribute *attr,
543                 char *buf, loff_t off, size_t count)
544 {
545         struct i2c_client       *client;
546         struct ds1307           *ds1307;
547         int                     result;
548
549         client = kobj_to_i2c_client(kobj);
550         ds1307 = i2c_get_clientdata(client);
551
552         if (unlikely(off >= NVRAM_SIZE))
553                 return 0;
554         if ((off + count) > NVRAM_SIZE)
555                 count = NVRAM_SIZE - off;
556         if (unlikely(!count))
557                 return count;
558
559         result = ds1307->read_block_data(client, 8 + off, count, buf);
560         if (result < 0)
561                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
562         return result;
563 }
564
565 static ssize_t
566 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
567                 struct bin_attribute *attr,
568                 char *buf, loff_t off, size_t count)
569 {
570         struct i2c_client       *client;
571         struct ds1307           *ds1307;
572         int                     result;
573
574         client = kobj_to_i2c_client(kobj);
575         ds1307 = i2c_get_clientdata(client);
576
577         if (unlikely(off >= NVRAM_SIZE))
578                 return -EFBIG;
579         if ((off + count) > NVRAM_SIZE)
580                 count = NVRAM_SIZE - off;
581         if (unlikely(!count))
582                 return count;
583
584         result = ds1307->write_block_data(client, 8 + off, count, buf);
585         if (result < 0) {
586                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
587                 return result;
588         }
589         return count;
590 }
591
592 static struct bin_attribute nvram = {
593         .attr = {
594                 .name   = "nvram",
595                 .mode   = S_IRUGO | S_IWUSR,
596         },
597
598         .read   = ds1307_nvram_read,
599         .write  = ds1307_nvram_write,
600         .size   = NVRAM_SIZE,
601 };
602
603 /*----------------------------------------------------------------------*/
604
605 static struct i2c_driver ds1307_driver;
606
607 static int __devinit ds1307_probe(struct i2c_client *client,
608                                   const struct i2c_device_id *id)
609 {
610         struct ds1307           *ds1307;
611         int                     err = -ENODEV;
612         int                     tmp;
613         const struct chip_desc  *chip = &chips[id->driver_data];
614         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
615         int                     want_irq = false;
616         unsigned char           *buf;
617         static const int        bbsqi_bitpos[] = {
618                 [ds_1337] = 0,
619                 [ds_1339] = DS1339_BIT_BBSQI,
620                 [ds_3231] = DS3231_BIT_BBSQW,
621         };
622
623         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
624             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
625                 return -EIO;
626
627         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
628                 return -ENOMEM;
629
630         i2c_set_clientdata(client, ds1307);
631
632         ds1307->client  = client;
633         ds1307->type    = id->driver_data;
634         ds1307->offset  = 0;
635
636         buf = ds1307->regs;
637         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
638                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
639                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
640         } else {
641                 ds1307->read_block_data = ds1307_read_block_data;
642                 ds1307->write_block_data = ds1307_write_block_data;
643         }
644
645         switch (ds1307->type) {
646         case ds_1337:
647         case ds_1339:
648         case ds_3231:
649                 /* has IRQ? */
650                 if (ds1307->client->irq > 0 && chip->alarm) {
651                         INIT_WORK(&ds1307->work, ds1307_work);
652                         want_irq = true;
653                 }
654                 /* get registers that the "rtc" read below won't read... */
655                 tmp = ds1307->read_block_data(ds1307->client,
656                                 DS1337_REG_CONTROL, 2, buf);
657                 if (tmp != 2) {
658                         pr_debug("read error %d\n", tmp);
659                         err = -EIO;
660                         goto exit_free;
661                 }
662
663                 /* oscillator off?  turn it on, so clock can tick. */
664                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
665                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
666
667                 /* Using IRQ?  Disable the square wave and both alarms.
668                  * For some variants, be sure alarms can trigger when we're
669                  * running on Vbackup (BBSQI/BBSQW)
670                  */
671                 if (want_irq) {
672                         ds1307->regs[0] |= DS1337_BIT_INTCN
673                                         | bbsqi_bitpos[ds1307->type];
674                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
675                 }
676
677                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
678                                                         ds1307->regs[0]);
679
680                 /* oscillator fault?  clear flag, and warn */
681                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
682                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
683                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
684                         dev_warn(&client->dev, "SET TIME!\n");
685                 }
686                 break;
687
688         case rx_8025:
689                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
690                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
691                 if (tmp != 2) {
692                         pr_debug("read error %d\n", tmp);
693                         err = -EIO;
694                         goto exit_free;
695                 }
696
697                 /* oscillator off?  turn it on, so clock can tick. */
698                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
699                         ds1307->regs[1] |= RX8025_BIT_XST;
700                         i2c_smbus_write_byte_data(client,
701                                                   RX8025_REG_CTRL2 << 4 | 0x08,
702                                                   ds1307->regs[1]);
703                         dev_warn(&client->dev,
704                                  "oscillator stop detected - SET TIME!\n");
705                 }
706
707                 if (ds1307->regs[1] & RX8025_BIT_PON) {
708                         ds1307->regs[1] &= ~RX8025_BIT_PON;
709                         i2c_smbus_write_byte_data(client,
710                                                   RX8025_REG_CTRL2 << 4 | 0x08,
711                                                   ds1307->regs[1]);
712                         dev_warn(&client->dev, "power-on detected\n");
713                 }
714
715                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
716                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
717                         i2c_smbus_write_byte_data(client,
718                                                   RX8025_REG_CTRL2 << 4 | 0x08,
719                                                   ds1307->regs[1]);
720                         dev_warn(&client->dev, "voltage drop detected\n");
721                 }
722
723                 /* make sure we are running in 24hour mode */
724                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
725                         u8 hour;
726
727                         /* switch to 24 hour mode */
728                         i2c_smbus_write_byte_data(client,
729                                                   RX8025_REG_CTRL1 << 4 | 0x08,
730                                                   ds1307->regs[0] |
731                                                   RX8025_BIT_2412);
732
733                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
734                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
735                         if (tmp != 2) {
736                                 pr_debug("read error %d\n", tmp);
737                                 err = -EIO;
738                                 goto exit_free;
739                         }
740
741                         /* correct hour */
742                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
743                         if (hour == 12)
744                                 hour = 0;
745                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
746                                 hour += 12;
747
748                         i2c_smbus_write_byte_data(client,
749                                                   DS1307_REG_HOUR << 4 | 0x08,
750                                                   hour);
751                 }
752                 break;
753         case ds_1388:
754                 ds1307->offset = 1; /* Seconds starts at 1 */
755                 break;
756         default:
757                 break;
758         }
759
760 read_rtc:
761         /* read RTC registers */
762         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
763         if (tmp != 8) {
764                 pr_debug("read error %d\n", tmp);
765                 err = -EIO;
766                 goto exit_free;
767         }
768
769         /* minimal sanity checking; some chips (like DS1340) don't
770          * specify the extra bits as must-be-zero, but there are
771          * still a few values that are clearly out-of-range.
772          */
773         tmp = ds1307->regs[DS1307_REG_SECS];
774         switch (ds1307->type) {
775         case ds_1307:
776         case m41t00:
777                 /* clock halted?  turn it on, so clock can tick. */
778                 if (tmp & DS1307_BIT_CH) {
779                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
780                         dev_warn(&client->dev, "SET TIME!\n");
781                         goto read_rtc;
782                 }
783                 break;
784         case ds_1338:
785                 /* clock halted?  turn it on, so clock can tick. */
786                 if (tmp & DS1307_BIT_CH)
787                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
788
789                 /* oscillator fault?  clear flag, and warn */
790                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
791                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
792                                         ds1307->regs[DS1307_REG_CONTROL]
793                                         & ~DS1338_BIT_OSF);
794                         dev_warn(&client->dev, "SET TIME!\n");
795                         goto read_rtc;
796                 }
797                 break;
798         case ds_1340:
799                 /* clock halted?  turn it on, so clock can tick. */
800                 if (tmp & DS1340_BIT_nEOSC)
801                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
802
803                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
804                 if (tmp < 0) {
805                         pr_debug("read error %d\n", tmp);
806                         err = -EIO;
807                         goto exit_free;
808                 }
809
810                 /* oscillator fault?  clear flag, and warn */
811                 if (tmp & DS1340_BIT_OSF) {
812                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
813                         dev_warn(&client->dev, "SET TIME!\n");
814                 }
815                 break;
816         case mcp7941x:
817                 /* make sure that the backup battery is enabled */
818                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
819                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
820                                         ds1307->regs[DS1307_REG_WDAY]
821                                         | MCP7941X_BIT_VBATEN);
822                 }
823
824                 /* clock halted?  turn it on, so clock can tick. */
825                 if (!(tmp & MCP7941X_BIT_ST)) {
826                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
827                                         MCP7941X_BIT_ST);
828                         dev_warn(&client->dev, "SET TIME!\n");
829                         goto read_rtc;
830                 }
831
832                 break;
833         default:
834                 break;
835         }
836
837         tmp = ds1307->regs[DS1307_REG_HOUR];
838         switch (ds1307->type) {
839         case ds_1340:
840         case m41t00:
841                 /* NOTE: ignores century bits; fix before deploying
842                  * systems that will run through year 2100.
843                  */
844                 break;
845         case rx_8025:
846                 break;
847         default:
848                 if (!(tmp & DS1307_BIT_12HR))
849                         break;
850
851                 /* Be sure we're in 24 hour mode.  Multi-master systems
852                  * take note...
853                  */
854                 tmp = bcd2bin(tmp & 0x1f);
855                 if (tmp == 12)
856                         tmp = 0;
857                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
858                         tmp += 12;
859                 i2c_smbus_write_byte_data(client,
860                                 ds1307->offset + DS1307_REG_HOUR,
861                                 bin2bcd(tmp));
862         }
863
864         ds1307->rtc = rtc_device_register(client->name, &client->dev,
865                                 &ds13xx_rtc_ops, THIS_MODULE);
866         if (IS_ERR(ds1307->rtc)) {
867                 err = PTR_ERR(ds1307->rtc);
868                 dev_err(&client->dev,
869                         "unable to register the class device\n");
870                 goto exit_free;
871         }
872
873         if (want_irq) {
874                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
875                           ds1307->rtc->name, client);
876                 if (err) {
877                         dev_err(&client->dev,
878                                 "unable to request IRQ!\n");
879                         goto exit_irq;
880                 }
881
882                 device_set_wakeup_capable(&client->dev, 1);
883                 set_bit(HAS_ALARM, &ds1307->flags);
884                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
885         }
886
887         if (chip->nvram56) {
888                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
889                 if (err == 0) {
890                         set_bit(HAS_NVRAM, &ds1307->flags);
891                         dev_info(&client->dev, "56 bytes nvram\n");
892                 }
893         }
894
895         return 0;
896
897 exit_irq:
898         rtc_device_unregister(ds1307->rtc);
899 exit_free:
900         kfree(ds1307);
901         return err;
902 }
903
904 static int __devexit ds1307_remove(struct i2c_client *client)
905 {
906         struct ds1307           *ds1307 = i2c_get_clientdata(client);
907
908         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
909                 free_irq(client->irq, client);
910                 cancel_work_sync(&ds1307->work);
911         }
912
913         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
914                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
915
916         rtc_device_unregister(ds1307->rtc);
917         kfree(ds1307);
918         return 0;
919 }
920
921 static struct i2c_driver ds1307_driver = {
922         .driver = {
923                 .name   = "rtc-ds1307",
924                 .owner  = THIS_MODULE,
925         },
926         .probe          = ds1307_probe,
927         .remove         = __devexit_p(ds1307_remove),
928         .id_table       = ds1307_id,
929 };
930
931 module_i2c_driver(ds1307_driver);
932
933 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
934 MODULE_LICENSE("GPL");