2c4a65302a9dbf55c5a73af88146aeb3e80dd872
[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         m41t00,
35         rx_8025,
36         // rs5c372 too?  different address...
37 };
38
39
40 /* RTC registers don't differ much, except for the century flag */
41 #define DS1307_REG_SECS         0x00    /* 00-59 */
42 #       define DS1307_BIT_CH            0x80
43 #       define DS1340_BIT_nEOSC         0x80
44 #define DS1307_REG_MIN          0x01    /* 00-59 */
45 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
46 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
47 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
48 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
49 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
50 #define DS1307_REG_WDAY         0x03    /* 01-07 */
51 #define DS1307_REG_MDAY         0x04    /* 01-31 */
52 #define DS1307_REG_MONTH        0x05    /* 01-12 */
53 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
54 #define DS1307_REG_YEAR         0x06    /* 00-99 */
55
56 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
57  * start at 7, and they differ a LOT. Only control and status matter for
58  * basic RTC date and time functionality; be careful using them.
59  */
60 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
61 #       define DS1307_BIT_OUT           0x80
62 #       define DS1338_BIT_OSF           0x20
63 #       define DS1307_BIT_SQWE          0x10
64 #       define DS1307_BIT_RS1           0x02
65 #       define DS1307_BIT_RS0           0x01
66 #define DS1337_REG_CONTROL      0x0e
67 #       define DS1337_BIT_nEOSC         0x80
68 #       define DS1339_BIT_BBSQI         0x20
69 #       define DS1337_BIT_RS2           0x10
70 #       define DS1337_BIT_RS1           0x08
71 #       define DS1337_BIT_INTCN         0x04
72 #       define DS1337_BIT_A2IE          0x02
73 #       define DS1337_BIT_A1IE          0x01
74 #define DS1340_REG_CONTROL      0x07
75 #       define DS1340_BIT_OUT           0x80
76 #       define DS1340_BIT_FT            0x40
77 #       define DS1340_BIT_CALIB_SIGN    0x20
78 #       define DS1340_M_CALIBRATION     0x1f
79 #define DS1340_REG_FLAG         0x09
80 #       define DS1340_BIT_OSF           0x80
81 #define DS1337_REG_STATUS       0x0f
82 #       define DS1337_BIT_OSF           0x80
83 #       define DS1337_BIT_A2I           0x02
84 #       define DS1337_BIT_A1I           0x01
85 #define DS1339_REG_ALARM1_SECS  0x07
86 #define DS1339_REG_TRICKLE      0x10
87
88 #define RX8025_REG_CTRL1        0x0e
89 #       define RX8025_BIT_2412          0x20
90 #define RX8025_REG_CTRL2        0x0f
91 #       define RX8025_BIT_PON           0x10
92 #       define RX8025_BIT_VDET          0x40
93 #       define RX8025_BIT_XST           0x20
94
95
96 struct ds1307 {
97         u8                      regs[11];
98         enum ds_type            type;
99         unsigned long           flags;
100 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
101 #define HAS_ALARM       1               /* bit 1 == irq claimed */
102         struct i2c_client       *client;
103         struct rtc_device       *rtc;
104         struct work_struct      work;
105         s32 (*read_block_data)(struct i2c_client *client, u8 command,
106                                u8 length, u8 *values);
107         s32 (*write_block_data)(struct i2c_client *client, u8 command,
108                                 u8 length, const u8 *values);
109 };
110
111 struct chip_desc {
112         unsigned                nvram56:1;
113         unsigned                alarm:1;
114 };
115
116 static const struct chip_desc chips[] = {
117 [ds_1307] = {
118         .nvram56        = 1,
119 },
120 [ds_1337] = {
121         .alarm          = 1,
122 },
123 [ds_1338] = {
124         .nvram56        = 1,
125 },
126 [ds_1339] = {
127         .alarm          = 1,
128 },
129 [ds_1340] = {
130 },
131 [m41t00] = {
132 },
133 [rx_8025] = {
134 }, };
135
136 static const struct i2c_device_id ds1307_id[] = {
137         { "ds1307", ds_1307 },
138         { "ds1337", ds_1337 },
139         { "ds1338", ds_1338 },
140         { "ds1339", ds_1339 },
141         { "ds1340", ds_1340 },
142         { "m41t00", m41t00 },
143         { "rx8025", rx_8025 },
144         { }
145 };
146 MODULE_DEVICE_TABLE(i2c, ds1307_id);
147
148 /*----------------------------------------------------------------------*/
149
150 #define BLOCK_DATA_MAX_TRIES 10
151
152 static s32 ds1307_read_block_data_once(struct i2c_client *client, u8 command,
153                                   u8 length, u8 *values)
154 {
155         s32 i, data;
156
157         for (i = 0; i < length; i++) {
158                 data = i2c_smbus_read_byte_data(client, command + i);
159                 if (data < 0)
160                         return data;
161                 values[i] = data;
162         }
163         return i;
164 }
165
166 static s32 ds1307_read_block_data(struct i2c_client *client, u8 command,
167                                   u8 length, u8 *values)
168 {
169         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
170         s32 ret;
171         int tries = 0;
172
173         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
174         ret = ds1307_read_block_data_once(client, command, length, values);
175         if (ret < 0)
176                 return ret;
177         do {
178                 if (++tries > BLOCK_DATA_MAX_TRIES) {
179                         dev_err(&client->dev,
180                                 "ds1307_read_block_data failed\n");
181                         return -EIO;
182                 }
183                 memcpy(oldvalues, values, length);
184                 ret = ds1307_read_block_data_once(client, command, length,
185                                                   values);
186                 if (ret < 0)
187                         return ret;
188         } while (memcmp(oldvalues, values, length));
189         return length;
190 }
191
192 static s32 ds1307_write_block_data(struct i2c_client *client, u8 command,
193                                    u8 length, const u8 *values)
194 {
195         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
196         int tries = 0;
197
198         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
199         do {
200                 s32 i, ret;
201
202                 if (++tries > BLOCK_DATA_MAX_TRIES) {
203                         dev_err(&client->dev,
204                                 "ds1307_write_block_data failed\n");
205                         return -EIO;
206                 }
207                 for (i = 0; i < length; i++) {
208                         ret = i2c_smbus_write_byte_data(client, command + i,
209                                                         values[i]);
210                         if (ret < 0)
211                                 return ret;
212                 }
213                 ret = ds1307_read_block_data_once(client, command, length,
214                                                   currvalues);
215                 if (ret < 0)
216                         return ret;
217         } while (memcmp(currvalues, values, length));
218         return length;
219 }
220
221 /*----------------------------------------------------------------------*/
222
223 /*
224  * The IRQ logic includes a "real" handler running in IRQ context just
225  * long enough to schedule this workqueue entry.   We need a task context
226  * to talk to the RTC, since I2C I/O calls require that; and disable the
227  * IRQ until we clear its status on the chip, so that this handler can
228  * work with any type of triggering (not just falling edge).
229  *
230  * The ds1337 and ds1339 both have two alarms, but we only use the first
231  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
232  * signal; ds1339 chips have only one alarm signal.
233  */
234 static void ds1307_work(struct work_struct *work)
235 {
236         struct ds1307           *ds1307;
237         struct i2c_client       *client;
238         struct mutex            *lock;
239         int                     stat, control;
240
241         ds1307 = container_of(work, struct ds1307, work);
242         client = ds1307->client;
243         lock = &ds1307->rtc->ops_lock;
244
245         mutex_lock(lock);
246         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
247         if (stat < 0)
248                 goto out;
249
250         if (stat & DS1337_BIT_A1I) {
251                 stat &= ~DS1337_BIT_A1I;
252                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
253
254                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
255                 if (control < 0)
256                         goto out;
257
258                 control &= ~DS1337_BIT_A1IE;
259                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
260
261                 /* rtc_update_irq() assumes that it is called
262                  * from IRQ-disabled context.
263                  */
264                 local_irq_disable();
265                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
266                 local_irq_enable();
267         }
268
269 out:
270         if (test_bit(HAS_ALARM, &ds1307->flags))
271                 enable_irq(client->irq);
272         mutex_unlock(lock);
273 }
274
275 static irqreturn_t ds1307_irq(int irq, void *dev_id)
276 {
277         struct i2c_client       *client = dev_id;
278         struct ds1307           *ds1307 = i2c_get_clientdata(client);
279
280         disable_irq_nosync(irq);
281         schedule_work(&ds1307->work);
282         return IRQ_HANDLED;
283 }
284
285 /*----------------------------------------------------------------------*/
286
287 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
288 {
289         struct ds1307   *ds1307 = dev_get_drvdata(dev);
290         int             tmp;
291
292         /* read the RTC date and time registers all at once */
293         tmp = ds1307->read_block_data(ds1307->client,
294                 DS1307_REG_SECS, 7, ds1307->regs);
295         if (tmp != 7) {
296                 dev_err(dev, "%s error %d\n", "read", tmp);
297                 return -EIO;
298         }
299
300         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
301                         "read",
302                         ds1307->regs[0], ds1307->regs[1],
303                         ds1307->regs[2], ds1307->regs[3],
304                         ds1307->regs[4], ds1307->regs[5],
305                         ds1307->regs[6]);
306
307         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
308         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
309         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
310         t->tm_hour = bcd2bin(tmp);
311         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
312         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
313         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
314         t->tm_mon = bcd2bin(tmp) - 1;
315
316         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
317         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
318
319         dev_dbg(dev, "%s secs=%d, mins=%d, "
320                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
321                 "read", t->tm_sec, t->tm_min,
322                 t->tm_hour, t->tm_mday,
323                 t->tm_mon, t->tm_year, t->tm_wday);
324
325         /* initial clock setting can be undefined */
326         return rtc_valid_tm(t);
327 }
328
329 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
330 {
331         struct ds1307   *ds1307 = dev_get_drvdata(dev);
332         int             result;
333         int             tmp;
334         u8              *buf = ds1307->regs;
335
336         dev_dbg(dev, "%s secs=%d, mins=%d, "
337                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
338                 "write", t->tm_sec, t->tm_min,
339                 t->tm_hour, t->tm_mday,
340                 t->tm_mon, t->tm_year, t->tm_wday);
341
342         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
343         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
344         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
345         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
346         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
347         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
348
349         /* assume 20YY not 19YY */
350         tmp = t->tm_year - 100;
351         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
352
353         switch (ds1307->type) {
354         case ds_1337:
355         case ds_1339:
356                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
357                 break;
358         case ds_1340:
359                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
360                                 | DS1340_BIT_CENTURY;
361                 break;
362         default:
363                 break;
364         }
365
366         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
367                 "write", buf[0], buf[1], buf[2], buf[3],
368                 buf[4], buf[5], buf[6]);
369
370         result = ds1307->write_block_data(ds1307->client, 0, 7, buf);
371         if (result < 0) {
372                 dev_err(dev, "%s error %d\n", "write", result);
373                 return result;
374         }
375         return 0;
376 }
377
378 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
379 {
380         struct i2c_client       *client = to_i2c_client(dev);
381         struct ds1307           *ds1307 = i2c_get_clientdata(client);
382         int                     ret;
383
384         if (!test_bit(HAS_ALARM, &ds1307->flags))
385                 return -EINVAL;
386
387         /* read all ALARM1, ALARM2, and status registers at once */
388         ret = ds1307->read_block_data(client,
389                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
390         if (ret != 9) {
391                 dev_err(dev, "%s error %d\n", "alarm read", ret);
392                 return -EIO;
393         }
394
395         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
396                         "alarm read",
397                         ds1307->regs[0], ds1307->regs[1],
398                         ds1307->regs[2], ds1307->regs[3],
399                         ds1307->regs[4], ds1307->regs[5],
400                         ds1307->regs[6], ds1307->regs[7],
401                         ds1307->regs[8]);
402
403         /* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
404          * and that all four fields are checked matches
405          */
406         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
407         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
408         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
409         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
410         t->time.tm_mon = -1;
411         t->time.tm_year = -1;
412         t->time.tm_wday = -1;
413         t->time.tm_yday = -1;
414         t->time.tm_isdst = -1;
415
416         /* ... and status */
417         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
418         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
419
420         dev_dbg(dev, "%s secs=%d, mins=%d, "
421                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
422                 "alarm read", t->time.tm_sec, t->time.tm_min,
423                 t->time.tm_hour, t->time.tm_mday,
424                 t->enabled, t->pending);
425
426         return 0;
427 }
428
429 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
430 {
431         struct i2c_client       *client = to_i2c_client(dev);
432         struct ds1307           *ds1307 = i2c_get_clientdata(client);
433         unsigned char           *buf = ds1307->regs;
434         u8                      control, status;
435         int                     ret;
436
437         if (!test_bit(HAS_ALARM, &ds1307->flags))
438                 return -EINVAL;
439
440         dev_dbg(dev, "%s secs=%d, mins=%d, "
441                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
442                 "alarm set", t->time.tm_sec, t->time.tm_min,
443                 t->time.tm_hour, t->time.tm_mday,
444                 t->enabled, t->pending);
445
446         /* read current status of both alarms and the chip */
447         ret = ds1307->read_block_data(client,
448                         DS1339_REG_ALARM1_SECS, 9, buf);
449         if (ret != 9) {
450                 dev_err(dev, "%s error %d\n", "alarm write", ret);
451                 return -EIO;
452         }
453         control = ds1307->regs[7];
454         status = ds1307->regs[8];
455
456         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
457                         "alarm set (old status)",
458                         ds1307->regs[0], ds1307->regs[1],
459                         ds1307->regs[2], ds1307->regs[3],
460                         ds1307->regs[4], ds1307->regs[5],
461                         ds1307->regs[6], control, status);
462
463         /* set ALARM1, using 24 hour and day-of-month modes */
464         buf[0] = bin2bcd(t->time.tm_sec);
465         buf[1] = bin2bcd(t->time.tm_min);
466         buf[2] = bin2bcd(t->time.tm_hour);
467         buf[3] = bin2bcd(t->time.tm_mday);
468
469         /* set ALARM2 to non-garbage */
470         buf[4] = 0;
471         buf[5] = 0;
472         buf[6] = 0;
473
474         /* optionally enable ALARM1 */
475         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
476         if (t->enabled) {
477                 dev_dbg(dev, "alarm IRQ armed\n");
478                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
479         }
480         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
481
482         ret = ds1307->write_block_data(client,
483                         DS1339_REG_ALARM1_SECS, 9, buf);
484         if (ret < 0) {
485                 dev_err(dev, "can't set alarm time\n");
486                 return ret;
487         }
488
489         return 0;
490 }
491
492 static int ds1307_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
493 {
494         struct i2c_client       *client = to_i2c_client(dev);
495         struct ds1307           *ds1307 = i2c_get_clientdata(client);
496         int                     ret;
497
498         switch (cmd) {
499         case RTC_AIE_OFF:
500                 if (!test_bit(HAS_ALARM, &ds1307->flags))
501                         return -ENOTTY;
502
503                 ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
504                 if (ret < 0)
505                         return ret;
506
507                 ret &= ~DS1337_BIT_A1IE;
508
509                 ret = i2c_smbus_write_byte_data(client,
510                                                 DS1337_REG_CONTROL, ret);
511                 if (ret < 0)
512                         return ret;
513
514                 break;
515
516         case RTC_AIE_ON:
517                 if (!test_bit(HAS_ALARM, &ds1307->flags))
518                         return -ENOTTY;
519
520                 ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
521                 if (ret < 0)
522                         return ret;
523
524                 ret |= DS1337_BIT_A1IE;
525
526                 ret = i2c_smbus_write_byte_data(client,
527                                                 DS1337_REG_CONTROL, ret);
528                 if (ret < 0)
529                         return ret;
530
531                 break;
532
533         default:
534                 return -ENOIOCTLCMD;
535         }
536
537         return 0;
538 }
539
540 static const struct rtc_class_ops ds13xx_rtc_ops = {
541         .read_time      = ds1307_get_time,
542         .set_time       = ds1307_set_time,
543         .read_alarm     = ds1337_read_alarm,
544         .set_alarm      = ds1337_set_alarm,
545         .ioctl          = ds1307_ioctl,
546 };
547
548 /*----------------------------------------------------------------------*/
549
550 #define NVRAM_SIZE      56
551
552 static ssize_t
553 ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
554                 char *buf, loff_t off, size_t count)
555 {
556         struct i2c_client       *client;
557         struct ds1307           *ds1307;
558         int                     result;
559
560         client = kobj_to_i2c_client(kobj);
561         ds1307 = i2c_get_clientdata(client);
562
563         if (unlikely(off >= NVRAM_SIZE))
564                 return 0;
565         if ((off + count) > NVRAM_SIZE)
566                 count = NVRAM_SIZE - off;
567         if (unlikely(!count))
568                 return count;
569
570         result = ds1307->read_block_data(client, 8 + off, count, buf);
571         if (result < 0)
572                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
573         return result;
574 }
575
576 static ssize_t
577 ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
578                 char *buf, loff_t off, size_t count)
579 {
580         struct i2c_client       *client;
581         struct ds1307           *ds1307;
582         int                     result;
583
584         client = kobj_to_i2c_client(kobj);
585         ds1307 = i2c_get_clientdata(client);
586
587         if (unlikely(off >= NVRAM_SIZE))
588                 return -EFBIG;
589         if ((off + count) > NVRAM_SIZE)
590                 count = NVRAM_SIZE - off;
591         if (unlikely(!count))
592                 return count;
593
594         result = ds1307->write_block_data(client, 8 + off, count, buf);
595         if (result < 0) {
596                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
597                 return result;
598         }
599         return count;
600 }
601
602 static struct bin_attribute nvram = {
603         .attr = {
604                 .name   = "nvram",
605                 .mode   = S_IRUGO | S_IWUSR,
606         },
607
608         .read   = ds1307_nvram_read,
609         .write  = ds1307_nvram_write,
610         .size   = NVRAM_SIZE,
611 };
612
613 /*----------------------------------------------------------------------*/
614
615 static struct i2c_driver ds1307_driver;
616
617 static int __devinit ds1307_probe(struct i2c_client *client,
618                                   const struct i2c_device_id *id)
619 {
620         struct ds1307           *ds1307;
621         int                     err = -ENODEV;
622         int                     tmp;
623         const struct chip_desc  *chip = &chips[id->driver_data];
624         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
625         int                     want_irq = false;
626         unsigned char           *buf;
627
628         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
629             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
630                 return -EIO;
631
632         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
633                 return -ENOMEM;
634
635         ds1307->client = client;
636         i2c_set_clientdata(client, ds1307);
637         ds1307->type = id->driver_data;
638         buf = ds1307->regs;
639         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
640                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
641                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
642         } else {
643                 ds1307->read_block_data = ds1307_read_block_data;
644                 ds1307->write_block_data = ds1307_write_block_data;
645         }
646
647         switch (ds1307->type) {
648         case ds_1337:
649         case ds_1339:
650                 /* has IRQ? */
651                 if (ds1307->client->irq > 0 && chip->alarm) {
652                         INIT_WORK(&ds1307->work, ds1307_work);
653                         want_irq = true;
654                 }
655                 /* get registers that the "rtc" read below won't read... */
656                 tmp = ds1307->read_block_data(ds1307->client,
657                                 DS1337_REG_CONTROL, 2, buf);
658                 if (tmp != 2) {
659                         pr_debug("read error %d\n", tmp);
660                         err = -EIO;
661                         goto exit_free;
662                 }
663
664                 /* oscillator off?  turn it on, so clock can tick. */
665                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
666                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
667
668                 /* Using IRQ?  Disable the square wave and both alarms.
669                  * For ds1339, be sure alarms can trigger when we're
670                  * running on Vbackup (BBSQI); we assume ds1337 will
671                  * ignore that bit
672                  */
673                 if (want_irq) {
674                         ds1307->regs[0] |= DS1337_BIT_INTCN | DS1339_BIT_BBSQI;
675                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
676                 }
677
678                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
679                                                         ds1307->regs[0]);
680
681                 /* oscillator fault?  clear flag, and warn */
682                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
683                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
684                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
685                         dev_warn(&client->dev, "SET TIME!\n");
686                 }
687                 break;
688
689         case rx_8025:
690                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
691                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
692                 if (tmp != 2) {
693                         pr_debug("read error %d\n", tmp);
694                         err = -EIO;
695                         goto exit_free;
696                 }
697
698                 /* oscillator off?  turn it on, so clock can tick. */
699                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
700                         ds1307->regs[1] |= RX8025_BIT_XST;
701                         i2c_smbus_write_byte_data(client,
702                                                   RX8025_REG_CTRL2 << 4 | 0x08,
703                                                   ds1307->regs[1]);
704                         dev_warn(&client->dev,
705                                  "oscillator stop detected - SET TIME!\n");
706                 }
707
708                 if (ds1307->regs[1] & RX8025_BIT_PON) {
709                         ds1307->regs[1] &= ~RX8025_BIT_PON;
710                         i2c_smbus_write_byte_data(client,
711                                                   RX8025_REG_CTRL2 << 4 | 0x08,
712                                                   ds1307->regs[1]);
713                         dev_warn(&client->dev, "power-on detected\n");
714                 }
715
716                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
717                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
718                         i2c_smbus_write_byte_data(client,
719                                                   RX8025_REG_CTRL2 << 4 | 0x08,
720                                                   ds1307->regs[1]);
721                         dev_warn(&client->dev, "voltage drop detected\n");
722                 }
723
724                 /* make sure we are running in 24hour mode */
725                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
726                         u8 hour;
727
728                         /* switch to 24 hour mode */
729                         i2c_smbus_write_byte_data(client,
730                                                   RX8025_REG_CTRL1 << 4 | 0x08,
731                                                   ds1307->regs[0] |
732                                                   RX8025_BIT_2412);
733
734                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
735                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
736                         if (tmp != 2) {
737                                 pr_debug("read error %d\n", tmp);
738                                 err = -EIO;
739                                 goto exit_free;
740                         }
741
742                         /* correct hour */
743                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
744                         if (hour == 12)
745                                 hour = 0;
746                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
747                                 hour += 12;
748
749                         i2c_smbus_write_byte_data(client,
750                                                   DS1307_REG_HOUR << 4 | 0x08,
751                                                   hour);
752                 }
753                 break;
754         default:
755                 break;
756         }
757
758 read_rtc:
759         /* read RTC registers */
760         tmp = ds1307->read_block_data(ds1307->client, 0, 8, buf);
761         if (tmp != 8) {
762                 pr_debug("read error %d\n", tmp);
763                 err = -EIO;
764                 goto exit_free;
765         }
766
767         /* minimal sanity checking; some chips (like DS1340) don't
768          * specify the extra bits as must-be-zero, but there are
769          * still a few values that are clearly out-of-range.
770          */
771         tmp = ds1307->regs[DS1307_REG_SECS];
772         switch (ds1307->type) {
773         case ds_1307:
774         case m41t00:
775                 /* clock halted?  turn it on, so clock can tick. */
776                 if (tmp & DS1307_BIT_CH) {
777                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
778                         dev_warn(&client->dev, "SET TIME!\n");
779                         goto read_rtc;
780                 }
781                 break;
782         case ds_1338:
783                 /* clock halted?  turn it on, so clock can tick. */
784                 if (tmp & DS1307_BIT_CH)
785                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
786
787                 /* oscillator fault?  clear flag, and warn */
788                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
789                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
790                                         ds1307->regs[DS1307_REG_CONTROL]
791                                         & ~DS1338_BIT_OSF);
792                         dev_warn(&client->dev, "SET TIME!\n");
793                         goto read_rtc;
794                 }
795                 break;
796         case ds_1340:
797                 /* clock halted?  turn it on, so clock can tick. */
798                 if (tmp & DS1340_BIT_nEOSC)
799                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
800
801                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
802                 if (tmp < 0) {
803                         pr_debug("read error %d\n", tmp);
804                         err = -EIO;
805                         goto exit_free;
806                 }
807
808                 /* oscillator fault?  clear flag, and warn */
809                 if (tmp & DS1340_BIT_OSF) {
810                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
811                         dev_warn(&client->dev, "SET TIME!\n");
812                 }
813                 break;
814         case rx_8025:
815         case ds_1337:
816         case ds_1339:
817                 break;
818         }
819
820         tmp = ds1307->regs[DS1307_REG_HOUR];
821         switch (ds1307->type) {
822         case ds_1340:
823         case m41t00:
824                 /* NOTE: ignores century bits; fix before deploying
825                  * systems that will run through year 2100.
826                  */
827                 break;
828         case rx_8025:
829                 break;
830         default:
831                 if (!(tmp & DS1307_BIT_12HR))
832                         break;
833
834                 /* Be sure we're in 24 hour mode.  Multi-master systems
835                  * take note...
836                  */
837                 tmp = bcd2bin(tmp & 0x1f);
838                 if (tmp == 12)
839                         tmp = 0;
840                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
841                         tmp += 12;
842                 i2c_smbus_write_byte_data(client,
843                                 DS1307_REG_HOUR,
844                                 bin2bcd(tmp));
845         }
846
847         ds1307->rtc = rtc_device_register(client->name, &client->dev,
848                                 &ds13xx_rtc_ops, THIS_MODULE);
849         if (IS_ERR(ds1307->rtc)) {
850                 err = PTR_ERR(ds1307->rtc);
851                 dev_err(&client->dev,
852                         "unable to register the class device\n");
853                 goto exit_free;
854         }
855
856         if (want_irq) {
857                 err = request_irq(client->irq, ds1307_irq, 0,
858                           ds1307->rtc->name, client);
859                 if (err) {
860                         dev_err(&client->dev,
861                                 "unable to request IRQ!\n");
862                         goto exit_irq;
863                 }
864                 set_bit(HAS_ALARM, &ds1307->flags);
865                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
866         }
867
868         if (chip->nvram56) {
869                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
870                 if (err == 0) {
871                         set_bit(HAS_NVRAM, &ds1307->flags);
872                         dev_info(&client->dev, "56 bytes nvram\n");
873                 }
874         }
875
876         return 0;
877
878 exit_irq:
879         if (ds1307->rtc)
880                 rtc_device_unregister(ds1307->rtc);
881 exit_free:
882         kfree(ds1307);
883         return err;
884 }
885
886 static int __devexit ds1307_remove(struct i2c_client *client)
887 {
888         struct ds1307           *ds1307 = i2c_get_clientdata(client);
889
890         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
891                 free_irq(client->irq, client);
892                 cancel_work_sync(&ds1307->work);
893         }
894
895         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
896                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
897
898         rtc_device_unregister(ds1307->rtc);
899         kfree(ds1307);
900         return 0;
901 }
902
903 static struct i2c_driver ds1307_driver = {
904         .driver = {
905                 .name   = "rtc-ds1307",
906                 .owner  = THIS_MODULE,
907         },
908         .probe          = ds1307_probe,
909         .remove         = __devexit_p(ds1307_remove),
910         .id_table       = ds1307_id,
911 };
912
913 static int __init ds1307_init(void)
914 {
915         return i2c_add_driver(&ds1307_driver);
916 }
917 module_init(ds1307_init);
918
919 static void __exit ds1307_exit(void)
920 {
921         i2c_del_driver(&ds1307_driver);
922 }
923 module_exit(ds1307_exit);
924
925 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
926 MODULE_LICENSE("GPL");