rtc: ds1307: generalise ram size and offset
[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 /*
24  * We can't determine type by probing, but if we expect pre-Linux code
25  * to have set the chip up as a clock (turning on the oscillator and
26  * setting the date and time), Linux can ignore the non-clock features.
27  * That's a natural job for a factory or repair bench.
28  */
29 enum ds_type {
30         ds_1307,
31         ds_1337,
32         ds_1338,
33         ds_1339,
34         ds_1340,
35         ds_1388,
36         ds_3231,
37         m41t00,
38         mcp7941x,
39         rx_8025,
40         last_ds_type /* always last */
41         /* rs5c372 too?  different address... */
42 };
43
44
45 /* RTC registers don't differ much, except for the century flag */
46 #define DS1307_REG_SECS         0x00    /* 00-59 */
47 #       define DS1307_BIT_CH            0x80
48 #       define DS1340_BIT_nEOSC         0x80
49 #       define MCP7941X_BIT_ST          0x80
50 #define DS1307_REG_MIN          0x01    /* 00-59 */
51 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
52 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
53 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
54 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
55 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
56 #define DS1307_REG_WDAY         0x03    /* 01-07 */
57 #       define MCP7941X_BIT_VBATEN      0x08
58 #define DS1307_REG_MDAY         0x04    /* 01-31 */
59 #define DS1307_REG_MONTH        0x05    /* 01-12 */
60 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
61 #define DS1307_REG_YEAR         0x06    /* 00-99 */
62
63 /*
64  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
65  * start at 7, and they differ a LOT. Only control and status matter for
66  * basic RTC date and time functionality; be careful using them.
67  */
68 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
69 #       define DS1307_BIT_OUT           0x80
70 #       define DS1338_BIT_OSF           0x20
71 #       define DS1307_BIT_SQWE          0x10
72 #       define DS1307_BIT_RS1           0x02
73 #       define DS1307_BIT_RS0           0x01
74 #define DS1337_REG_CONTROL      0x0e
75 #       define DS1337_BIT_nEOSC         0x80
76 #       define DS1339_BIT_BBSQI         0x20
77 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
78 #       define DS1337_BIT_RS2           0x10
79 #       define DS1337_BIT_RS1           0x08
80 #       define DS1337_BIT_INTCN         0x04
81 #       define DS1337_BIT_A2IE          0x02
82 #       define DS1337_BIT_A1IE          0x01
83 #define DS1340_REG_CONTROL      0x07
84 #       define DS1340_BIT_OUT           0x80
85 #       define DS1340_BIT_FT            0x40
86 #       define DS1340_BIT_CALIB_SIGN    0x20
87 #       define DS1340_M_CALIBRATION     0x1f
88 #define DS1340_REG_FLAG         0x09
89 #       define DS1340_BIT_OSF           0x80
90 #define DS1337_REG_STATUS       0x0f
91 #       define DS1337_BIT_OSF           0x80
92 #       define DS1337_BIT_A2I           0x02
93 #       define DS1337_BIT_A1I           0x01
94 #define DS1339_REG_ALARM1_SECS  0x07
95 #define DS1339_REG_TRICKLE      0x10
96
97 #define RX8025_REG_CTRL1        0x0e
98 #       define RX8025_BIT_2412          0x20
99 #define RX8025_REG_CTRL2        0x0f
100 #       define RX8025_BIT_PON           0x10
101 #       define RX8025_BIT_VDET          0x40
102 #       define RX8025_BIT_XST           0x20
103
104
105 struct ds1307 {
106         u8                      offset; /* register's offset */
107         u8                      regs[11];
108         u16                     nvram_offset;
109         struct bin_attribute    *nvram;
110         enum ds_type            type;
111         unsigned long           flags;
112 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
113 #define HAS_ALARM       1               /* bit 1 == irq claimed */
114         struct i2c_client       *client;
115         struct rtc_device       *rtc;
116         struct work_struct      work;
117         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
118                                u8 length, u8 *values);
119         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
120                                 u8 length, const u8 *values);
121 };
122
123 struct chip_desc {
124         unsigned                alarm:1;
125         u16                     nvram_offset;
126         u16                     nvram_size;
127 };
128
129 static const struct chip_desc chips[last_ds_type] = {
130         [ds_1307] = {
131                 .nvram_offset   = 8,
132                 .nvram_size     = 56,
133         },
134         [ds_1337] = {
135                 .alarm          = 1,
136         },
137         [ds_1338] = {
138                 .nvram_offset   = 8,
139                 .nvram_size     = 56,
140         },
141         [ds_1339] = {
142                 .alarm          = 1,
143         },
144         [ds_3231] = {
145                 .alarm          = 1,
146         },
147         [mcp7941x] = {
148                 /* this is battery backed SRAM */
149                 .nvram_offset   = 0x20,
150                 .nvram_size     = 0x40,
151         },
152 };
153
154 static const struct i2c_device_id ds1307_id[] = {
155         { "ds1307", ds_1307 },
156         { "ds1337", ds_1337 },
157         { "ds1338", ds_1338 },
158         { "ds1339", ds_1339 },
159         { "ds1388", ds_1388 },
160         { "ds1340", ds_1340 },
161         { "ds3231", ds_3231 },
162         { "m41t00", m41t00 },
163         { "mcp7941x", mcp7941x },
164         { "pt7c4338", ds_1307 },
165         { "rx8025", rx_8025 },
166         { }
167 };
168 MODULE_DEVICE_TABLE(i2c, ds1307_id);
169
170 /*----------------------------------------------------------------------*/
171
172 #define BLOCK_DATA_MAX_TRIES 10
173
174 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
175                                        u8 command, u8 length, u8 *values)
176 {
177         s32 i, data;
178
179         for (i = 0; i < length; i++) {
180                 data = i2c_smbus_read_byte_data(client, command + i);
181                 if (data < 0)
182                         return data;
183                 values[i] = data;
184         }
185         return i;
186 }
187
188 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
189                                   u8 length, u8 *values)
190 {
191         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
192         s32 ret;
193         int tries = 0;
194
195         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
196         ret = ds1307_read_block_data_once(client, command, length, values);
197         if (ret < 0)
198                 return ret;
199         do {
200                 if (++tries > BLOCK_DATA_MAX_TRIES) {
201                         dev_err(&client->dev,
202                                 "ds1307_read_block_data failed\n");
203                         return -EIO;
204                 }
205                 memcpy(oldvalues, values, length);
206                 ret = ds1307_read_block_data_once(client, command, length,
207                                                   values);
208                 if (ret < 0)
209                         return ret;
210         } while (memcmp(oldvalues, values, length));
211         return length;
212 }
213
214 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
215                                    u8 length, const u8 *values)
216 {
217         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
218         int tries = 0;
219
220         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
221         do {
222                 s32 i, ret;
223
224                 if (++tries > BLOCK_DATA_MAX_TRIES) {
225                         dev_err(&client->dev,
226                                 "ds1307_write_block_data failed\n");
227                         return -EIO;
228                 }
229                 for (i = 0; i < length; i++) {
230                         ret = i2c_smbus_write_byte_data(client, command + i,
231                                                         values[i]);
232                         if (ret < 0)
233                                 return ret;
234                 }
235                 ret = ds1307_read_block_data_once(client, command, length,
236                                                   currvalues);
237                 if (ret < 0)
238                         return ret;
239         } while (memcmp(currvalues, values, length));
240         return length;
241 }
242
243 /*----------------------------------------------------------------------*/
244
245 /*
246  * The IRQ logic includes a "real" handler running in IRQ context just
247  * long enough to schedule this workqueue entry.   We need a task context
248  * to talk to the RTC, since I2C I/O calls require that; and disable the
249  * IRQ until we clear its status on the chip, so that this handler can
250  * work with any type of triggering (not just falling edge).
251  *
252  * The ds1337 and ds1339 both have two alarms, but we only use the first
253  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
254  * signal; ds1339 chips have only one alarm signal.
255  */
256 static void ds1307_work(struct work_struct *work)
257 {
258         struct ds1307           *ds1307;
259         struct i2c_client       *client;
260         struct mutex            *lock;
261         int                     stat, control;
262
263         ds1307 = container_of(work, struct ds1307, work);
264         client = ds1307->client;
265         lock = &ds1307->rtc->ops_lock;
266
267         mutex_lock(lock);
268         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
269         if (stat < 0)
270                 goto out;
271
272         if (stat & DS1337_BIT_A1I) {
273                 stat &= ~DS1337_BIT_A1I;
274                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
275
276                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
277                 if (control < 0)
278                         goto out;
279
280                 control &= ~DS1337_BIT_A1IE;
281                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
282
283                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
284         }
285
286 out:
287         if (test_bit(HAS_ALARM, &ds1307->flags))
288                 enable_irq(client->irq);
289         mutex_unlock(lock);
290 }
291
292 static irqreturn_t ds1307_irq(int irq, void *dev_id)
293 {
294         struct i2c_client       *client = dev_id;
295         struct ds1307           *ds1307 = i2c_get_clientdata(client);
296
297         disable_irq_nosync(irq);
298         schedule_work(&ds1307->work);
299         return IRQ_HANDLED;
300 }
301
302 /*----------------------------------------------------------------------*/
303
304 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
305 {
306         struct ds1307   *ds1307 = dev_get_drvdata(dev);
307         int             tmp;
308
309         /* read the RTC date and time registers all at once */
310         tmp = ds1307->read_block_data(ds1307->client,
311                 ds1307->offset, 7, ds1307->regs);
312         if (tmp != 7) {
313                 dev_err(dev, "%s error %d\n", "read", tmp);
314                 return -EIO;
315         }
316
317         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
318                         "read",
319                         ds1307->regs[0], ds1307->regs[1],
320                         ds1307->regs[2], ds1307->regs[3],
321                         ds1307->regs[4], ds1307->regs[5],
322                         ds1307->regs[6]);
323
324         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
325         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
326         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
327         t->tm_hour = bcd2bin(tmp);
328         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
329         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
330         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
331         t->tm_mon = bcd2bin(tmp) - 1;
332
333         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
334         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
335
336         dev_dbg(dev, "%s secs=%d, mins=%d, "
337                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
338                 "read", 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         /* initial clock setting can be undefined */
343         return rtc_valid_tm(t);
344 }
345
346 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
347 {
348         struct ds1307   *ds1307 = dev_get_drvdata(dev);
349         int             result;
350         int             tmp;
351         u8              *buf = ds1307->regs;
352
353         dev_dbg(dev, "%s secs=%d, mins=%d, "
354                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
355                 "write", t->tm_sec, t->tm_min,
356                 t->tm_hour, t->tm_mday,
357                 t->tm_mon, t->tm_year, t->tm_wday);
358
359         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
360         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
361         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
362         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
363         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
364         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
365
366         /* assume 20YY not 19YY */
367         tmp = t->tm_year - 100;
368         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
369
370         switch (ds1307->type) {
371         case ds_1337:
372         case ds_1339:
373         case ds_3231:
374                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
375                 break;
376         case ds_1340:
377                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
378                                 | DS1340_BIT_CENTURY;
379                 break;
380         case mcp7941x:
381                 /*
382                  * these bits were cleared when preparing the date/time
383                  * values and need to be set again before writing the
384                  * buffer out to the device.
385                  */
386                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
387                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
388                 break;
389         default:
390                 break;
391         }
392
393         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
394                 "write", buf[0], buf[1], buf[2], buf[3],
395                 buf[4], buf[5], buf[6]);
396
397         result = ds1307->write_block_data(ds1307->client,
398                 ds1307->offset, 7, buf);
399         if (result < 0) {
400                 dev_err(dev, "%s error %d\n", "write", result);
401                 return result;
402         }
403         return 0;
404 }
405
406 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
407 {
408         struct i2c_client       *client = to_i2c_client(dev);
409         struct ds1307           *ds1307 = i2c_get_clientdata(client);
410         int                     ret;
411
412         if (!test_bit(HAS_ALARM, &ds1307->flags))
413                 return -EINVAL;
414
415         /* read all ALARM1, ALARM2, and status registers at once */
416         ret = ds1307->read_block_data(client,
417                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
418         if (ret != 9) {
419                 dev_err(dev, "%s error %d\n", "alarm read", ret);
420                 return -EIO;
421         }
422
423         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
424                         "alarm read",
425                         ds1307->regs[0], ds1307->regs[1],
426                         ds1307->regs[2], ds1307->regs[3],
427                         ds1307->regs[4], ds1307->regs[5],
428                         ds1307->regs[6], ds1307->regs[7],
429                         ds1307->regs[8]);
430
431         /*
432          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
433          * and that all four fields are checked matches
434          */
435         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
436         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
437         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
438         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
439         t->time.tm_mon = -1;
440         t->time.tm_year = -1;
441         t->time.tm_wday = -1;
442         t->time.tm_yday = -1;
443         t->time.tm_isdst = -1;
444
445         /* ... and status */
446         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
447         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
448
449         dev_dbg(dev, "%s secs=%d, mins=%d, "
450                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
451                 "alarm read", t->time.tm_sec, t->time.tm_min,
452                 t->time.tm_hour, t->time.tm_mday,
453                 t->enabled, t->pending);
454
455         return 0;
456 }
457
458 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
459 {
460         struct i2c_client       *client = to_i2c_client(dev);
461         struct ds1307           *ds1307 = i2c_get_clientdata(client);
462         unsigned char           *buf = ds1307->regs;
463         u8                      control, status;
464         int                     ret;
465
466         if (!test_bit(HAS_ALARM, &ds1307->flags))
467                 return -EINVAL;
468
469         dev_dbg(dev, "%s secs=%d, mins=%d, "
470                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
471                 "alarm set", t->time.tm_sec, t->time.tm_min,
472                 t->time.tm_hour, t->time.tm_mday,
473                 t->enabled, t->pending);
474
475         /* read current status of both alarms and the chip */
476         ret = ds1307->read_block_data(client,
477                         DS1339_REG_ALARM1_SECS, 9, buf);
478         if (ret != 9) {
479                 dev_err(dev, "%s error %d\n", "alarm write", ret);
480                 return -EIO;
481         }
482         control = ds1307->regs[7];
483         status = ds1307->regs[8];
484
485         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
486                         "alarm set (old status)",
487                         ds1307->regs[0], ds1307->regs[1],
488                         ds1307->regs[2], ds1307->regs[3],
489                         ds1307->regs[4], ds1307->regs[5],
490                         ds1307->regs[6], control, status);
491
492         /* set ALARM1, using 24 hour and day-of-month modes */
493         buf[0] = bin2bcd(t->time.tm_sec);
494         buf[1] = bin2bcd(t->time.tm_min);
495         buf[2] = bin2bcd(t->time.tm_hour);
496         buf[3] = bin2bcd(t->time.tm_mday);
497
498         /* set ALARM2 to non-garbage */
499         buf[4] = 0;
500         buf[5] = 0;
501         buf[6] = 0;
502
503         /* optionally enable ALARM1 */
504         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
505         if (t->enabled) {
506                 dev_dbg(dev, "alarm IRQ armed\n");
507                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
508         }
509         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
510
511         ret = ds1307->write_block_data(client,
512                         DS1339_REG_ALARM1_SECS, 9, buf);
513         if (ret < 0) {
514                 dev_err(dev, "can't set alarm time\n");
515                 return ret;
516         }
517
518         return 0;
519 }
520
521 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
522 {
523         struct i2c_client       *client = to_i2c_client(dev);
524         struct ds1307           *ds1307 = i2c_get_clientdata(client);
525         int                     ret;
526
527         if (!test_bit(HAS_ALARM, &ds1307->flags))
528                 return -ENOTTY;
529
530         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
531         if (ret < 0)
532                 return ret;
533
534         if (enabled)
535                 ret |= DS1337_BIT_A1IE;
536         else
537                 ret &= ~DS1337_BIT_A1IE;
538
539         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
540         if (ret < 0)
541                 return ret;
542
543         return 0;
544 }
545
546 static const struct rtc_class_ops ds13xx_rtc_ops = {
547         .read_time      = ds1307_get_time,
548         .set_time       = ds1307_set_time,
549         .read_alarm     = ds1337_read_alarm,
550         .set_alarm      = ds1337_set_alarm,
551         .alarm_irq_enable = ds1307_alarm_irq_enable,
552 };
553
554 /*----------------------------------------------------------------------*/
555
556 static ssize_t
557 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
558                 struct bin_attribute *attr,
559                 char *buf, loff_t off, size_t count)
560 {
561         struct i2c_client       *client;
562         struct ds1307           *ds1307;
563         int                     result;
564
565         client = kobj_to_i2c_client(kobj);
566         ds1307 = i2c_get_clientdata(client);
567
568         if (unlikely(off >= ds1307->nvram->size))
569                 return 0;
570         if ((off + count) > ds1307->nvram->size)
571                 count = ds1307->nvram->size - off;
572         if (unlikely(!count))
573                 return count;
574
575         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
576                                                                 count, buf);
577         if (result < 0)
578                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
579         return result;
580 }
581
582 static ssize_t
583 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
584                 struct bin_attribute *attr,
585                 char *buf, loff_t off, size_t count)
586 {
587         struct i2c_client       *client;
588         struct ds1307           *ds1307;
589         int                     result;
590
591         client = kobj_to_i2c_client(kobj);
592         ds1307 = i2c_get_clientdata(client);
593
594         if (unlikely(off >= ds1307->nvram->size))
595                 return -EFBIG;
596         if ((off + count) > ds1307->nvram->size)
597                 count = ds1307->nvram->size - off;
598         if (unlikely(!count))
599                 return count;
600
601         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
602                                                                 count, buf);
603         if (result < 0) {
604                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
605                 return result;
606         }
607         return count;
608 }
609
610 /*----------------------------------------------------------------------*/
611
612 static int __devinit ds1307_probe(struct i2c_client *client,
613                                   const struct i2c_device_id *id)
614 {
615         struct ds1307           *ds1307;
616         int                     err = -ENODEV;
617         int                     tmp;
618         const struct chip_desc  *chip = &chips[id->driver_data];
619         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
620         int                     want_irq = false;
621         unsigned char           *buf;
622         static const int        bbsqi_bitpos[] = {
623                 [ds_1337] = 0,
624                 [ds_1339] = DS1339_BIT_BBSQI,
625                 [ds_3231] = DS3231_BIT_BBSQW,
626         };
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         ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
633         if (!ds1307)
634                 return -ENOMEM;
635
636         i2c_set_clientdata(client, ds1307);
637
638         ds1307->client  = client;
639         ds1307->type    = id->driver_data;
640         ds1307->offset  = 0;
641
642         buf = ds1307->regs;
643         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
644                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
645                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
646         } else {
647                 ds1307->read_block_data = ds1307_read_block_data;
648                 ds1307->write_block_data = ds1307_write_block_data;
649         }
650
651         switch (ds1307->type) {
652         case ds_1337:
653         case ds_1339:
654         case ds_3231:
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                 /*
669                  * Using IRQ?  Disable the square wave and both alarms.
670                  * For some variants, be sure alarms can trigger when we're
671                  * running on Vbackup (BBSQI/BBSQW)
672                  */
673                 if (ds1307->client->irq > 0 && chip->alarm) {
674                         INIT_WORK(&ds1307->work, ds1307_work);
675
676                         ds1307->regs[0] |= DS1337_BIT_INTCN
677                                         | bbsqi_bitpos[ds1307->type];
678                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
679
680                         want_irq = true;
681                 }
682
683                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
684                                                         ds1307->regs[0]);
685
686                 /* oscillator fault?  clear flag, and warn */
687                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
688                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
689                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
690                         dev_warn(&client->dev, "SET TIME!\n");
691                 }
692                 break;
693
694         case rx_8025:
695                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
696                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
697                 if (tmp != 2) {
698                         pr_debug("read error %d\n", tmp);
699                         err = -EIO;
700                         goto exit_free;
701                 }
702
703                 /* oscillator off?  turn it on, so clock can tick. */
704                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
705                         ds1307->regs[1] |= RX8025_BIT_XST;
706                         i2c_smbus_write_byte_data(client,
707                                                   RX8025_REG_CTRL2 << 4 | 0x08,
708                                                   ds1307->regs[1]);
709                         dev_warn(&client->dev,
710                                  "oscillator stop detected - SET TIME!\n");
711                 }
712
713                 if (ds1307->regs[1] & RX8025_BIT_PON) {
714                         ds1307->regs[1] &= ~RX8025_BIT_PON;
715                         i2c_smbus_write_byte_data(client,
716                                                   RX8025_REG_CTRL2 << 4 | 0x08,
717                                                   ds1307->regs[1]);
718                         dev_warn(&client->dev, "power-on detected\n");
719                 }
720
721                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
722                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
723                         i2c_smbus_write_byte_data(client,
724                                                   RX8025_REG_CTRL2 << 4 | 0x08,
725                                                   ds1307->regs[1]);
726                         dev_warn(&client->dev, "voltage drop detected\n");
727                 }
728
729                 /* make sure we are running in 24hour mode */
730                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
731                         u8 hour;
732
733                         /* switch to 24 hour mode */
734                         i2c_smbus_write_byte_data(client,
735                                                   RX8025_REG_CTRL1 << 4 | 0x08,
736                                                   ds1307->regs[0] |
737                                                   RX8025_BIT_2412);
738
739                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
740                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
741                         if (tmp != 2) {
742                                 pr_debug("read error %d\n", tmp);
743                                 err = -EIO;
744                                 goto exit_free;
745                         }
746
747                         /* correct hour */
748                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
749                         if (hour == 12)
750                                 hour = 0;
751                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
752                                 hour += 12;
753
754                         i2c_smbus_write_byte_data(client,
755                                                   DS1307_REG_HOUR << 4 | 0x08,
756                                                   hour);
757                 }
758                 break;
759         case ds_1388:
760                 ds1307->offset = 1; /* Seconds starts at 1 */
761                 break;
762         default:
763                 break;
764         }
765
766 read_rtc:
767         /* read RTC registers */
768         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
769         if (tmp != 8) {
770                 pr_debug("read error %d\n", tmp);
771                 err = -EIO;
772                 goto exit_free;
773         }
774
775         /*
776          * minimal sanity checking; some chips (like DS1340) don't
777          * specify the extra bits as must-be-zero, but there are
778          * still a few values that are clearly out-of-range.
779          */
780         tmp = ds1307->regs[DS1307_REG_SECS];
781         switch (ds1307->type) {
782         case ds_1307:
783         case m41t00:
784                 /* clock halted?  turn it on, so clock can tick. */
785                 if (tmp & DS1307_BIT_CH) {
786                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
787                         dev_warn(&client->dev, "SET TIME!\n");
788                         goto read_rtc;
789                 }
790                 break;
791         case ds_1338:
792                 /* clock halted?  turn it on, so clock can tick. */
793                 if (tmp & DS1307_BIT_CH)
794                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
795
796                 /* oscillator fault?  clear flag, and warn */
797                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
798                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
799                                         ds1307->regs[DS1307_REG_CONTROL]
800                                         & ~DS1338_BIT_OSF);
801                         dev_warn(&client->dev, "SET TIME!\n");
802                         goto read_rtc;
803                 }
804                 break;
805         case ds_1340:
806                 /* clock halted?  turn it on, so clock can tick. */
807                 if (tmp & DS1340_BIT_nEOSC)
808                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
809
810                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
811                 if (tmp < 0) {
812                         pr_debug("read error %d\n", tmp);
813                         err = -EIO;
814                         goto exit_free;
815                 }
816
817                 /* oscillator fault?  clear flag, and warn */
818                 if (tmp & DS1340_BIT_OSF) {
819                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
820                         dev_warn(&client->dev, "SET TIME!\n");
821                 }
822                 break;
823         case mcp7941x:
824                 /* make sure that the backup battery is enabled */
825                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
826                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
827                                         ds1307->regs[DS1307_REG_WDAY]
828                                         | MCP7941X_BIT_VBATEN);
829                 }
830
831                 /* clock halted?  turn it on, so clock can tick. */
832                 if (!(tmp & MCP7941X_BIT_ST)) {
833                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
834                                         MCP7941X_BIT_ST);
835                         dev_warn(&client->dev, "SET TIME!\n");
836                         goto read_rtc;
837                 }
838
839                 break;
840         default:
841                 break;
842         }
843
844         tmp = ds1307->regs[DS1307_REG_HOUR];
845         switch (ds1307->type) {
846         case ds_1340:
847         case m41t00:
848                 /*
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                 /*
860                  * Be sure we're in 24 hour mode.  Multi-master systems
861                  * take note...
862                  */
863                 tmp = bcd2bin(tmp & 0x1f);
864                 if (tmp == 12)
865                         tmp = 0;
866                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
867                         tmp += 12;
868                 i2c_smbus_write_byte_data(client,
869                                 ds1307->offset + DS1307_REG_HOUR,
870                                 bin2bcd(tmp));
871         }
872
873         ds1307->rtc = rtc_device_register(client->name, &client->dev,
874                                 &ds13xx_rtc_ops, THIS_MODULE);
875         if (IS_ERR(ds1307->rtc)) {
876                 err = PTR_ERR(ds1307->rtc);
877                 dev_err(&client->dev,
878                         "unable to register the class device\n");
879                 goto exit_free;
880         }
881
882         if (want_irq) {
883                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
884                           ds1307->rtc->name, client);
885                 if (err) {
886                         dev_err(&client->dev,
887                                 "unable to request IRQ!\n");
888                         goto exit_irq;
889                 }
890
891                 device_set_wakeup_capable(&client->dev, 1);
892                 set_bit(HAS_ALARM, &ds1307->flags);
893                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
894         }
895
896         if (chip->nvram_size) {
897                 ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
898                                                         GFP_KERNEL);
899                 if (!ds1307->nvram) {
900                         err = -ENOMEM;
901                         goto exit_nvram;
902                 }
903                 ds1307->nvram->attr.name = "nvram";
904                 ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
905                 ds1307->nvram->read = ds1307_nvram_read,
906                 ds1307->nvram->write = ds1307_nvram_write,
907                 ds1307->nvram->size = chip->nvram_size;
908                 ds1307->nvram_offset = chip->nvram_offset;
909                 err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
910                 if (err) {
911                         kfree(ds1307->nvram);
912                         goto exit_nvram;
913                 }
914                 set_bit(HAS_NVRAM, &ds1307->flags);
915                 dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
916         }
917
918         return 0;
919
920 exit_nvram:
921 exit_irq:
922         rtc_device_unregister(ds1307->rtc);
923 exit_free:
924         kfree(ds1307);
925         return err;
926 }
927
928 static int __devexit ds1307_remove(struct i2c_client *client)
929 {
930         struct ds1307 *ds1307 = i2c_get_clientdata(client);
931
932         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
933                 free_irq(client->irq, client);
934                 cancel_work_sync(&ds1307->work);
935         }
936
937         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
938                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
939                 kfree(ds1307->nvram);
940         }
941
942         rtc_device_unregister(ds1307->rtc);
943         kfree(ds1307);
944         return 0;
945 }
946
947 static struct i2c_driver ds1307_driver = {
948         .driver = {
949                 .name   = "rtc-ds1307",
950                 .owner  = THIS_MODULE,
951         },
952         .probe          = ds1307_probe,
953         .remove         = __devexit_p(ds1307_remove),
954         .id_table       = ds1307_id,
955 };
956
957 module_i2c_driver(ds1307_driver);
958
959 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
960 MODULE_LICENSE("GPL");