8a6f9a9f9cb83d98c8e5b6e20a8da8c8374bb004
[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         rx_8025,
38         // rs5c372 too?  different address...
39 };
40
41
42 /* RTC registers don't differ much, except for the century flag */
43 #define DS1307_REG_SECS         0x00    /* 00-59 */
44 #       define DS1307_BIT_CH            0x80
45 #       define DS1340_BIT_nEOSC         0x80
46 #define DS1307_REG_MIN          0x01    /* 00-59 */
47 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
48 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
49 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
50 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
51 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
52 #define DS1307_REG_WDAY         0x03    /* 01-07 */
53 #define DS1307_REG_MDAY         0x04    /* 01-31 */
54 #define DS1307_REG_MONTH        0x05    /* 01-12 */
55 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
56 #define DS1307_REG_YEAR         0x06    /* 00-99 */
57
58 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
59  * start at 7, and they differ a LOT. Only control and status matter for
60  * basic RTC date and time functionality; be careful using them.
61  */
62 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
63 #       define DS1307_BIT_OUT           0x80
64 #       define DS1338_BIT_OSF           0x20
65 #       define DS1307_BIT_SQWE          0x10
66 #       define DS1307_BIT_RS1           0x02
67 #       define DS1307_BIT_RS0           0x01
68 #define DS1337_REG_CONTROL      0x0e
69 #       define DS1337_BIT_nEOSC         0x80
70 #       define DS1339_BIT_BBSQI         0x20
71 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
72 #       define DS1337_BIT_RS2           0x10
73 #       define DS1337_BIT_RS1           0x08
74 #       define DS1337_BIT_INTCN         0x04
75 #       define DS1337_BIT_A2IE          0x02
76 #       define DS1337_BIT_A1IE          0x01
77 #define DS1340_REG_CONTROL      0x07
78 #       define DS1340_BIT_OUT           0x80
79 #       define DS1340_BIT_FT            0x40
80 #       define DS1340_BIT_CALIB_SIGN    0x20
81 #       define DS1340_M_CALIBRATION     0x1f
82 #define DS1340_REG_FLAG         0x09
83 #       define DS1340_BIT_OSF           0x80
84 #define DS1337_REG_STATUS       0x0f
85 #       define DS1337_BIT_OSF           0x80
86 #       define DS1337_BIT_A2I           0x02
87 #       define DS1337_BIT_A1I           0x01
88 #define DS1339_REG_ALARM1_SECS  0x07
89 #define DS1339_REG_TRICKLE      0x10
90
91 #define RX8025_REG_CTRL1        0x0e
92 #       define RX8025_BIT_2412          0x20
93 #define RX8025_REG_CTRL2        0x0f
94 #       define RX8025_BIT_PON           0x10
95 #       define RX8025_BIT_VDET          0x40
96 #       define RX8025_BIT_XST           0x20
97
98
99 struct ds1307 {
100         u8                      offset; /* register's offset */
101         u8                      regs[11];
102         enum ds_type            type;
103         unsigned long           flags;
104 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
105 #define HAS_ALARM       1               /* bit 1 == irq claimed */
106         struct i2c_client       *client;
107         struct rtc_device       *rtc;
108         struct work_struct      work;
109         s32 (*read_block_data)(struct i2c_client *client, u8 command,
110                                u8 length, u8 *values);
111         s32 (*write_block_data)(struct i2c_client *client, u8 command,
112                                 u8 length, const u8 *values);
113 };
114
115 struct chip_desc {
116         unsigned                nvram56:1;
117         unsigned                alarm:1;
118 };
119
120 static const struct chip_desc chips[] = {
121 [ds_1307] = {
122         .nvram56        = 1,
123 },
124 [ds_1337] = {
125         .alarm          = 1,
126 },
127 [ds_1338] = {
128         .nvram56        = 1,
129 },
130 [ds_1339] = {
131         .alarm          = 1,
132 },
133 [ds_1340] = {
134 },
135 [ds_3231] = {
136         .alarm          = 1,
137 },
138 [m41t00] = {
139 },
140 [rx_8025] = {
141 }, };
142
143 static const struct i2c_device_id ds1307_id[] = {
144         { "ds1307", ds_1307 },
145         { "ds1337", ds_1337 },
146         { "ds1338", ds_1338 },
147         { "ds1339", ds_1339 },
148         { "ds1388", ds_1388 },
149         { "ds1340", ds_1340 },
150         { "ds3231", ds_3231 },
151         { "m41t00", m41t00 },
152         { "rx8025", rx_8025 },
153         { }
154 };
155 MODULE_DEVICE_TABLE(i2c, ds1307_id);
156
157 /*----------------------------------------------------------------------*/
158
159 #define BLOCK_DATA_MAX_TRIES 10
160
161 static s32 ds1307_read_block_data_once(struct i2c_client *client, u8 command,
162                                   u8 length, u8 *values)
163 {
164         s32 i, data;
165
166         for (i = 0; i < length; i++) {
167                 data = i2c_smbus_read_byte_data(client, command + i);
168                 if (data < 0)
169                         return data;
170                 values[i] = data;
171         }
172         return i;
173 }
174
175 static s32 ds1307_read_block_data(struct i2c_client *client, u8 command,
176                                   u8 length, u8 *values)
177 {
178         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
179         s32 ret;
180         int tries = 0;
181
182         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
183         ret = ds1307_read_block_data_once(client, command, length, values);
184         if (ret < 0)
185                 return ret;
186         do {
187                 if (++tries > BLOCK_DATA_MAX_TRIES) {
188                         dev_err(&client->dev,
189                                 "ds1307_read_block_data failed\n");
190                         return -EIO;
191                 }
192                 memcpy(oldvalues, values, length);
193                 ret = ds1307_read_block_data_once(client, command, length,
194                                                   values);
195                 if (ret < 0)
196                         return ret;
197         } while (memcmp(oldvalues, values, length));
198         return length;
199 }
200
201 static s32 ds1307_write_block_data(struct i2c_client *client, u8 command,
202                                    u8 length, const u8 *values)
203 {
204         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
205         int tries = 0;
206
207         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
208         do {
209                 s32 i, ret;
210
211                 if (++tries > BLOCK_DATA_MAX_TRIES) {
212                         dev_err(&client->dev,
213                                 "ds1307_write_block_data failed\n");
214                         return -EIO;
215                 }
216                 for (i = 0; i < length; i++) {
217                         ret = i2c_smbus_write_byte_data(client, command + i,
218                                                         values[i]);
219                         if (ret < 0)
220                                 return ret;
221                 }
222                 ret = ds1307_read_block_data_once(client, command, length,
223                                                   currvalues);
224                 if (ret < 0)
225                         return ret;
226         } while (memcmp(currvalues, values, length));
227         return length;
228 }
229
230 /*----------------------------------------------------------------------*/
231
232 /*
233  * The IRQ logic includes a "real" handler running in IRQ context just
234  * long enough to schedule this workqueue entry.   We need a task context
235  * to talk to the RTC, since I2C I/O calls require that; and disable the
236  * IRQ until we clear its status on the chip, so that this handler can
237  * work with any type of triggering (not just falling edge).
238  *
239  * The ds1337 and ds1339 both have two alarms, but we only use the first
240  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
241  * signal; ds1339 chips have only one alarm signal.
242  */
243 static void ds1307_work(struct work_struct *work)
244 {
245         struct ds1307           *ds1307;
246         struct i2c_client       *client;
247         struct mutex            *lock;
248         int                     stat, control;
249
250         ds1307 = container_of(work, struct ds1307, work);
251         client = ds1307->client;
252         lock = &ds1307->rtc->ops_lock;
253
254         mutex_lock(lock);
255         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
256         if (stat < 0)
257                 goto out;
258
259         if (stat & DS1337_BIT_A1I) {
260                 stat &= ~DS1337_BIT_A1I;
261                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
262
263                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
264                 if (control < 0)
265                         goto out;
266
267                 control &= ~DS1337_BIT_A1IE;
268                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
269
270                 /* rtc_update_irq() assumes that it is called
271                  * from IRQ-disabled context.
272                  */
273                 local_irq_disable();
274                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
275                 local_irq_enable();
276         }
277
278 out:
279         if (test_bit(HAS_ALARM, &ds1307->flags))
280                 enable_irq(client->irq);
281         mutex_unlock(lock);
282 }
283
284 static irqreturn_t ds1307_irq(int irq, void *dev_id)
285 {
286         struct i2c_client       *client = dev_id;
287         struct ds1307           *ds1307 = i2c_get_clientdata(client);
288
289         disable_irq_nosync(irq);
290         schedule_work(&ds1307->work);
291         return IRQ_HANDLED;
292 }
293
294 /*----------------------------------------------------------------------*/
295
296 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
297 {
298         struct ds1307   *ds1307 = dev_get_drvdata(dev);
299         int             tmp;
300
301         /* read the RTC date and time registers all at once */
302         tmp = ds1307->read_block_data(ds1307->client,
303                 ds1307->offset, 7, ds1307->regs);
304         if (tmp != 7) {
305                 dev_err(dev, "%s error %d\n", "read", tmp);
306                 return -EIO;
307         }
308
309         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
310                         "read",
311                         ds1307->regs[0], ds1307->regs[1],
312                         ds1307->regs[2], ds1307->regs[3],
313                         ds1307->regs[4], ds1307->regs[5],
314                         ds1307->regs[6]);
315
316         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
317         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
318         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
319         t->tm_hour = bcd2bin(tmp);
320         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
321         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
322         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
323         t->tm_mon = bcd2bin(tmp) - 1;
324
325         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
326         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
327
328         dev_dbg(dev, "%s secs=%d, mins=%d, "
329                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
330                 "read", t->tm_sec, t->tm_min,
331                 t->tm_hour, t->tm_mday,
332                 t->tm_mon, t->tm_year, t->tm_wday);
333
334         /* initial clock setting can be undefined */
335         return rtc_valid_tm(t);
336 }
337
338 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
339 {
340         struct ds1307   *ds1307 = dev_get_drvdata(dev);
341         int             result;
342         int             tmp;
343         u8              *buf = ds1307->regs;
344
345         dev_dbg(dev, "%s secs=%d, mins=%d, "
346                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
347                 "write", t->tm_sec, t->tm_min,
348                 t->tm_hour, t->tm_mday,
349                 t->tm_mon, t->tm_year, t->tm_wday);
350
351         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
352         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
353         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
354         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
355         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
356         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
357
358         /* assume 20YY not 19YY */
359         tmp = t->tm_year - 100;
360         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
361
362         switch (ds1307->type) {
363         case ds_1337:
364         case ds_1339:
365         case ds_3231:
366                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
367                 break;
368         case ds_1340:
369                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
370                                 | DS1340_BIT_CENTURY;
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_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
504 {
505         struct i2c_client       *client = to_i2c_client(dev);
506         struct ds1307           *ds1307 = i2c_get_clientdata(client);
507         int                     ret;
508
509         switch (cmd) {
510         case RTC_AIE_OFF:
511                 if (!test_bit(HAS_ALARM, &ds1307->flags))
512                         return -ENOTTY;
513
514                 ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
515                 if (ret < 0)
516                         return ret;
517
518                 ret &= ~DS1337_BIT_A1IE;
519
520                 ret = i2c_smbus_write_byte_data(client,
521                                                 DS1337_REG_CONTROL, ret);
522                 if (ret < 0)
523                         return ret;
524
525                 break;
526
527         case RTC_AIE_ON:
528                 if (!test_bit(HAS_ALARM, &ds1307->flags))
529                         return -ENOTTY;
530
531                 ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
532                 if (ret < 0)
533                         return ret;
534
535                 ret |= DS1337_BIT_A1IE;
536
537                 ret = i2c_smbus_write_byte_data(client,
538                                                 DS1337_REG_CONTROL, ret);
539                 if (ret < 0)
540                         return ret;
541
542                 break;
543
544         default:
545                 return -ENOIOCTLCMD;
546         }
547
548         return 0;
549 }
550
551 static const struct rtc_class_ops ds13xx_rtc_ops = {
552         .read_time      = ds1307_get_time,
553         .set_time       = ds1307_set_time,
554         .read_alarm     = ds1337_read_alarm,
555         .set_alarm      = ds1337_set_alarm,
556         .ioctl          = ds1307_ioctl,
557 };
558
559 /*----------------------------------------------------------------------*/
560
561 #define NVRAM_SIZE      56
562
563 static ssize_t
564 ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
565                 char *buf, loff_t off, size_t count)
566 {
567         struct i2c_client       *client;
568         struct ds1307           *ds1307;
569         int                     result;
570
571         client = kobj_to_i2c_client(kobj);
572         ds1307 = i2c_get_clientdata(client);
573
574         if (unlikely(off >= NVRAM_SIZE))
575                 return 0;
576         if ((off + count) > NVRAM_SIZE)
577                 count = NVRAM_SIZE - off;
578         if (unlikely(!count))
579                 return count;
580
581         result = ds1307->read_block_data(client, 8 + off, count, buf);
582         if (result < 0)
583                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
584         return result;
585 }
586
587 static ssize_t
588 ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
589                 char *buf, loff_t off, size_t count)
590 {
591         struct i2c_client       *client;
592         struct ds1307           *ds1307;
593         int                     result;
594
595         client = kobj_to_i2c_client(kobj);
596         ds1307 = i2c_get_clientdata(client);
597
598         if (unlikely(off >= NVRAM_SIZE))
599                 return -EFBIG;
600         if ((off + count) > NVRAM_SIZE)
601                 count = NVRAM_SIZE - off;
602         if (unlikely(!count))
603                 return count;
604
605         result = ds1307->write_block_data(client, 8 + off, count, buf);
606         if (result < 0) {
607                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
608                 return result;
609         }
610         return count;
611 }
612
613 static struct bin_attribute nvram = {
614         .attr = {
615                 .name   = "nvram",
616                 .mode   = S_IRUGO | S_IWUSR,
617         },
618
619         .read   = ds1307_nvram_read,
620         .write  = ds1307_nvram_write,
621         .size   = NVRAM_SIZE,
622 };
623
624 /*----------------------------------------------------------------------*/
625
626 static struct i2c_driver ds1307_driver;
627
628 static int __devinit ds1307_probe(struct i2c_client *client,
629                                   const struct i2c_device_id *id)
630 {
631         struct ds1307           *ds1307;
632         int                     err = -ENODEV;
633         int                     tmp;
634         const struct chip_desc  *chip = &chips[id->driver_data];
635         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
636         int                     want_irq = false;
637         unsigned char           *buf;
638         static const int        bbsqi_bitpos[] = {
639                 [ds_1337] = 0,
640                 [ds_1339] = DS1339_BIT_BBSQI,
641                 [ds_3231] = DS3231_BIT_BBSQW,
642         };
643
644         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
645             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
646                 return -EIO;
647
648         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
649                 return -ENOMEM;
650
651         i2c_set_clientdata(client, ds1307);
652
653         ds1307->client  = client;
654         ds1307->type    = id->driver_data;
655         ds1307->offset  = 0;
656
657         buf = ds1307->regs;
658         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
659                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
660                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
661         } else {
662                 ds1307->read_block_data = ds1307_read_block_data;
663                 ds1307->write_block_data = ds1307_write_block_data;
664         }
665
666         switch (ds1307->type) {
667         case ds_1337:
668         case ds_1339:
669         case ds_3231:
670                 /* has IRQ? */
671                 if (ds1307->client->irq > 0 && chip->alarm) {
672                         INIT_WORK(&ds1307->work, ds1307_work);
673                         want_irq = true;
674                 }
675                 /* get registers that the "rtc" read below won't read... */
676                 tmp = ds1307->read_block_data(ds1307->client,
677                                 DS1337_REG_CONTROL, 2, buf);
678                 if (tmp != 2) {
679                         pr_debug("read error %d\n", tmp);
680                         err = -EIO;
681                         goto exit_free;
682                 }
683
684                 /* oscillator off?  turn it on, so clock can tick. */
685                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
686                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
687
688                 /* Using IRQ?  Disable the square wave and both alarms.
689                  * For some variants, be sure alarms can trigger when we're
690                  * running on Vbackup (BBSQI/BBSQW)
691                  */
692                 if (want_irq) {
693                         ds1307->regs[0] |= DS1337_BIT_INTCN
694                                         | bbsqi_bitpos[ds1307->type];
695                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
696                 }
697
698                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
699                                                         ds1307->regs[0]);
700
701                 /* oscillator fault?  clear flag, and warn */
702                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
703                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
704                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
705                         dev_warn(&client->dev, "SET TIME!\n");
706                 }
707                 break;
708
709         case rx_8025:
710                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
711                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
712                 if (tmp != 2) {
713                         pr_debug("read error %d\n", tmp);
714                         err = -EIO;
715                         goto exit_free;
716                 }
717
718                 /* oscillator off?  turn it on, so clock can tick. */
719                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
720                         ds1307->regs[1] |= RX8025_BIT_XST;
721                         i2c_smbus_write_byte_data(client,
722                                                   RX8025_REG_CTRL2 << 4 | 0x08,
723                                                   ds1307->regs[1]);
724                         dev_warn(&client->dev,
725                                  "oscillator stop detected - SET TIME!\n");
726                 }
727
728                 if (ds1307->regs[1] & RX8025_BIT_PON) {
729                         ds1307->regs[1] &= ~RX8025_BIT_PON;
730                         i2c_smbus_write_byte_data(client,
731                                                   RX8025_REG_CTRL2 << 4 | 0x08,
732                                                   ds1307->regs[1]);
733                         dev_warn(&client->dev, "power-on detected\n");
734                 }
735
736                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
737                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
738                         i2c_smbus_write_byte_data(client,
739                                                   RX8025_REG_CTRL2 << 4 | 0x08,
740                                                   ds1307->regs[1]);
741                         dev_warn(&client->dev, "voltage drop detected\n");
742                 }
743
744                 /* make sure we are running in 24hour mode */
745                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
746                         u8 hour;
747
748                         /* switch to 24 hour mode */
749                         i2c_smbus_write_byte_data(client,
750                                                   RX8025_REG_CTRL1 << 4 | 0x08,
751                                                   ds1307->regs[0] |
752                                                   RX8025_BIT_2412);
753
754                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
755                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
756                         if (tmp != 2) {
757                                 pr_debug("read error %d\n", tmp);
758                                 err = -EIO;
759                                 goto exit_free;
760                         }
761
762                         /* correct hour */
763                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
764                         if (hour == 12)
765                                 hour = 0;
766                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
767                                 hour += 12;
768
769                         i2c_smbus_write_byte_data(client,
770                                                   DS1307_REG_HOUR << 4 | 0x08,
771                                                   hour);
772                 }
773                 break;
774         case ds_1388:
775                 ds1307->offset = 1; /* Seconds starts at 1 */
776                 break;
777         default:
778                 break;
779         }
780
781 read_rtc:
782         /* read RTC registers */
783         tmp = ds1307->read_block_data(ds1307->client, 0, 8, buf);
784         if (tmp != 8) {
785                 pr_debug("read error %d\n", tmp);
786                 err = -EIO;
787                 goto exit_free;
788         }
789
790         /* minimal sanity checking; some chips (like DS1340) don't
791          * specify the extra bits as must-be-zero, but there are
792          * still a few values that are clearly out-of-range.
793          */
794         tmp = ds1307->regs[DS1307_REG_SECS];
795         switch (ds1307->type) {
796         case ds_1307:
797         case m41t00:
798                 /* clock halted?  turn it on, so clock can tick. */
799                 if (tmp & DS1307_BIT_CH) {
800                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
801                         dev_warn(&client->dev, "SET TIME!\n");
802                         goto read_rtc;
803                 }
804                 break;
805         case ds_1338:
806                 /* clock halted?  turn it on, so clock can tick. */
807                 if (tmp & DS1307_BIT_CH)
808                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
809
810                 /* oscillator fault?  clear flag, and warn */
811                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
812                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
813                                         ds1307->regs[DS1307_REG_CONTROL]
814                                         & ~DS1338_BIT_OSF);
815                         dev_warn(&client->dev, "SET TIME!\n");
816                         goto read_rtc;
817                 }
818                 break;
819         case ds_1340:
820                 /* clock halted?  turn it on, so clock can tick. */
821                 if (tmp & DS1340_BIT_nEOSC)
822                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
823
824                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
825                 if (tmp < 0) {
826                         pr_debug("read error %d\n", tmp);
827                         err = -EIO;
828                         goto exit_free;
829                 }
830
831                 /* oscillator fault?  clear flag, and warn */
832                 if (tmp & DS1340_BIT_OSF) {
833                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
834                         dev_warn(&client->dev, "SET TIME!\n");
835                 }
836                 break;
837         case rx_8025:
838         case ds_1337:
839         case ds_1339:
840         case ds_1388:
841         case ds_3231:
842                 break;
843         }
844
845         tmp = ds1307->regs[DS1307_REG_HOUR];
846         switch (ds1307->type) {
847         case ds_1340:
848         case m41t00:
849                 /* NOTE: ignores century bits; fix before deploying
850                  * systems that will run through year 2100.
851                  */
852                 break;
853         case rx_8025:
854                 break;
855         default:
856                 if (!(tmp & DS1307_BIT_12HR))
857                         break;
858
859                 /* Be sure we're in 24 hour mode.  Multi-master systems
860                  * take note...
861                  */
862                 tmp = bcd2bin(tmp & 0x1f);
863                 if (tmp == 12)
864                         tmp = 0;
865                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
866                         tmp += 12;
867                 i2c_smbus_write_byte_data(client,
868                                 DS1307_REG_HOUR,
869                                 bin2bcd(tmp));
870         }
871
872         ds1307->rtc = rtc_device_register(client->name, &client->dev,
873                                 &ds13xx_rtc_ops, THIS_MODULE);
874         if (IS_ERR(ds1307->rtc)) {
875                 err = PTR_ERR(ds1307->rtc);
876                 dev_err(&client->dev,
877                         "unable to register the class device\n");
878                 goto exit_free;
879         }
880
881         if (want_irq) {
882                 err = request_irq(client->irq, ds1307_irq, 0,
883                           ds1307->rtc->name, client);
884                 if (err) {
885                         dev_err(&client->dev,
886                                 "unable to request IRQ!\n");
887                         goto exit_irq;
888                 }
889                 set_bit(HAS_ALARM, &ds1307->flags);
890                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
891         }
892
893         if (chip->nvram56) {
894                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
895                 if (err == 0) {
896                         set_bit(HAS_NVRAM, &ds1307->flags);
897                         dev_info(&client->dev, "56 bytes nvram\n");
898                 }
899         }
900
901         return 0;
902
903 exit_irq:
904         if (ds1307->rtc)
905                 rtc_device_unregister(ds1307->rtc);
906 exit_free:
907         kfree(ds1307);
908         return err;
909 }
910
911 static int __devexit ds1307_remove(struct i2c_client *client)
912 {
913         struct ds1307           *ds1307 = i2c_get_clientdata(client);
914
915         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
916                 free_irq(client->irq, client);
917                 cancel_work_sync(&ds1307->work);
918         }
919
920         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
921                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
922
923         rtc_device_unregister(ds1307->rtc);
924         kfree(ds1307);
925         return 0;
926 }
927
928 static struct i2c_driver ds1307_driver = {
929         .driver = {
930                 .name   = "rtc-ds1307",
931                 .owner  = THIS_MODULE,
932         },
933         .probe          = ds1307_probe,
934         .remove         = __devexit_p(ds1307_remove),
935         .id_table       = ds1307_id,
936 };
937
938 static int __init ds1307_init(void)
939 {
940         return i2c_add_driver(&ds1307_driver);
941 }
942 module_init(ds1307_init);
943
944 static void __exit ds1307_exit(void)
945 {
946         i2c_del_driver(&ds1307_driver);
947 }
948 module_exit(ds1307_exit);
949
950 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
951 MODULE_LICENSE("GPL");