i2c: Add support for device alias names
[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  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/i2c.h>
16 #include <linux/string.h>
17 #include <linux/rtc.h>
18 #include <linux/bcd.h>
19
20
21
22 /* We can't determine type by probing, but if we expect pre-Linux code
23  * to have set the chip up as a clock (turning on the oscillator and
24  * setting the date and time), Linux can ignore the non-clock features.
25  * That's a natural job for a factory or repair bench.
26  *
27  * This is currently a simple no-alarms driver.  If your board has the
28  * alarm irq wired up on a ds1337 or ds1339, and you want to use that,
29  * then look at the rtc-rs5c372 driver for code to steal...
30  */
31 enum ds_type {
32         ds_1307,
33         ds_1337,
34         ds_1338,
35         ds_1339,
36         ds_1340,
37         m41t00,
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 DS1337_BIT_RS2           0x10
71 #       define DS1337_BIT_RS1           0x08
72 #       define DS1337_BIT_INTCN         0x04
73 #       define DS1337_BIT_A2IE          0x02
74 #       define DS1337_BIT_A1IE          0x01
75 #define DS1340_REG_CONTROL      0x07
76 #       define DS1340_BIT_OUT           0x80
77 #       define DS1340_BIT_FT            0x40
78 #       define DS1340_BIT_CALIB_SIGN    0x20
79 #       define DS1340_M_CALIBRATION     0x1f
80 #define DS1340_REG_FLAG         0x09
81 #       define DS1340_BIT_OSF           0x80
82 #define DS1337_REG_STATUS       0x0f
83 #       define DS1337_BIT_OSF           0x80
84 #       define DS1337_BIT_A2I           0x02
85 #       define DS1337_BIT_A1I           0x01
86 #define DS1339_REG_TRICKLE      0x10
87
88
89
90 struct ds1307 {
91         u8                      reg_addr;
92         bool                    has_nvram;
93         u8                      regs[8];
94         enum ds_type            type;
95         struct i2c_msg          msg[2];
96         struct i2c_client       *client;
97         struct i2c_client       dev;
98         struct rtc_device       *rtc;
99 };
100
101 struct chip_desc {
102         char                    name[9];
103         unsigned                nvram56:1;
104         unsigned                alarm:1;
105         enum ds_type            type;
106 };
107
108 static const struct chip_desc chips[] = { {
109         .name           = "ds1307",
110         .type           = ds_1307,
111         .nvram56        = 1,
112 }, {
113         .name           = "ds1337",
114         .type           = ds_1337,
115         .alarm          = 1,
116 }, {
117         .name           = "ds1338",
118         .type           = ds_1338,
119         .nvram56        = 1,
120 }, {
121         .name           = "ds1339",
122         .type           = ds_1339,
123         .alarm          = 1,
124 }, {
125         .name           = "ds1340",
126         .type           = ds_1340,
127 }, {
128         .name           = "m41t00",
129         .type           = m41t00,
130 }, };
131
132 static inline const struct chip_desc *find_chip(const char *s)
133 {
134         unsigned i;
135
136         for (i = 0; i < ARRAY_SIZE(chips); i++)
137                 if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
138                         return &chips[i];
139         return NULL;
140 }
141
142 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
143 {
144         struct ds1307   *ds1307 = dev_get_drvdata(dev);
145         int             tmp;
146
147         /* read the RTC date and time registers all at once */
148         ds1307->msg[1].flags = I2C_M_RD;
149         ds1307->msg[1].len = 7;
150
151         tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
152                         ds1307->msg, 2);
153         if (tmp != 2) {
154                 dev_err(dev, "%s error %d\n", "read", tmp);
155                 return -EIO;
156         }
157
158         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
159                         "read",
160                         ds1307->regs[0], ds1307->regs[1],
161                         ds1307->regs[2], ds1307->regs[3],
162                         ds1307->regs[4], ds1307->regs[5],
163                         ds1307->regs[6]);
164
165         t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
166         t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
167         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
168         t->tm_hour = BCD2BIN(tmp);
169         t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
170         t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
171         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
172         t->tm_mon = BCD2BIN(tmp) - 1;
173
174         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
175         t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;
176
177         dev_dbg(dev, "%s secs=%d, mins=%d, "
178                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
179                 "read", t->tm_sec, t->tm_min,
180                 t->tm_hour, t->tm_mday,
181                 t->tm_mon, t->tm_year, t->tm_wday);
182
183         /* initial clock setting can be undefined */
184         return rtc_valid_tm(t);
185 }
186
187 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
188 {
189         struct ds1307   *ds1307 = dev_get_drvdata(dev);
190         int             result;
191         int             tmp;
192         u8              *buf = ds1307->regs;
193
194         dev_dbg(dev, "%s secs=%d, mins=%d, "
195                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
196                 "write", t->tm_sec, t->tm_min,
197                 t->tm_hour, t->tm_mday,
198                 t->tm_mon, t->tm_year, t->tm_wday);
199
200         *buf++ = 0;             /* first register addr */
201         buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
202         buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
203         buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
204         buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
205         buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
206         buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);
207
208         /* assume 20YY not 19YY */
209         tmp = t->tm_year - 100;
210         buf[DS1307_REG_YEAR] = BIN2BCD(tmp);
211
212         switch (ds1307->type) {
213         case ds_1337:
214         case ds_1339:
215                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
216                 break;
217         case ds_1340:
218                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
219                                 | DS1340_BIT_CENTURY;
220                 break;
221         default:
222                 break;
223         }
224
225         ds1307->msg[1].flags = 0;
226         ds1307->msg[1].len = 8;
227
228         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
229                 "write", buf[0], buf[1], buf[2], buf[3],
230                 buf[4], buf[5], buf[6]);
231
232         result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
233                         &ds1307->msg[1], 1);
234         if (result != 1) {
235                 dev_err(dev, "%s error %d\n", "write", tmp);
236                 return -EIO;
237         }
238         return 0;
239 }
240
241 static const struct rtc_class_ops ds13xx_rtc_ops = {
242         .read_time      = ds1307_get_time,
243         .set_time       = ds1307_set_time,
244 };
245
246 /*----------------------------------------------------------------------*/
247
248 #define NVRAM_SIZE      56
249
250 static ssize_t
251 ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
252                 char *buf, loff_t off, size_t count)
253 {
254         struct i2c_client       *client;
255         struct ds1307           *ds1307;
256         struct i2c_msg          msg[2];
257         int                     result;
258
259         client = kobj_to_i2c_client(kobj);
260         ds1307 = i2c_get_clientdata(client);
261
262         if (unlikely(off >= NVRAM_SIZE))
263                 return 0;
264         if ((off + count) > NVRAM_SIZE)
265                 count = NVRAM_SIZE - off;
266         if (unlikely(!count))
267                 return count;
268
269         msg[0].addr = client->addr;
270         msg[0].flags = 0;
271         msg[0].len = 1;
272         msg[0].buf = buf;
273
274         buf[0] = 8 + off;
275
276         msg[1].addr = client->addr;
277         msg[1].flags = I2C_M_RD;
278         msg[1].len = count;
279         msg[1].buf = buf;
280
281         result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
282         if (result != 2) {
283                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
284                 return -EIO;
285         }
286         return count;
287 }
288
289 static ssize_t
290 ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
291                 char *buf, loff_t off, size_t count)
292 {
293         struct i2c_client       *client;
294         u8                      buffer[NVRAM_SIZE + 1];
295         int                     ret;
296
297         client = kobj_to_i2c_client(kobj);
298
299         if (unlikely(off >= NVRAM_SIZE))
300                 return -EFBIG;
301         if ((off + count) > NVRAM_SIZE)
302                 count = NVRAM_SIZE - off;
303         if (unlikely(!count))
304                 return count;
305
306         buffer[0] = 8 + off;
307         memcpy(buffer + 1, buf, count);
308
309         ret = i2c_master_send(client, buffer, count + 1);
310         return (ret < 0) ? ret : (ret - 1);
311 }
312
313 static struct bin_attribute nvram = {
314         .attr = {
315                 .name   = "nvram",
316                 .mode   = S_IRUGO | S_IWUSR,
317                 .owner  = THIS_MODULE,
318         },
319
320         .read   = ds1307_nvram_read,
321         .write  = ds1307_nvram_write,
322         .size   = NVRAM_SIZE,
323 };
324
325 /*----------------------------------------------------------------------*/
326
327 static struct i2c_driver ds1307_driver;
328
329 static int __devinit ds1307_probe(struct i2c_client *client,
330                                   const struct i2c_device_id *id)
331 {
332         struct ds1307           *ds1307;
333         int                     err = -ENODEV;
334         int                     tmp;
335         const struct chip_desc  *chip;
336         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
337
338         chip = find_chip(client->name);
339         if (!chip) {
340                 dev_err(&client->dev, "unknown chip type '%s'\n",
341                                 client->name);
342                 return -ENODEV;
343         }
344
345         if (!i2c_check_functionality(adapter,
346                         I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
347                 return -EIO;
348
349         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
350                 return -ENOMEM;
351
352         ds1307->client = client;
353         i2c_set_clientdata(client, ds1307);
354
355         ds1307->msg[0].addr = client->addr;
356         ds1307->msg[0].flags = 0;
357         ds1307->msg[0].len = 1;
358         ds1307->msg[0].buf = &ds1307->reg_addr;
359
360         ds1307->msg[1].addr = client->addr;
361         ds1307->msg[1].flags = I2C_M_RD;
362         ds1307->msg[1].len = sizeof(ds1307->regs);
363         ds1307->msg[1].buf = ds1307->regs;
364
365         ds1307->type = chip->type;
366
367         switch (ds1307->type) {
368         case ds_1337:
369         case ds_1339:
370                 ds1307->reg_addr = DS1337_REG_CONTROL;
371                 ds1307->msg[1].len = 2;
372
373                 /* get registers that the "rtc" read below won't read... */
374                 tmp = i2c_transfer(adapter, ds1307->msg, 2);
375                 if (tmp != 2) {
376                         pr_debug("read error %d\n", tmp);
377                         err = -EIO;
378                         goto exit_free;
379                 }
380
381                 ds1307->reg_addr = 0;
382                 ds1307->msg[1].len = sizeof(ds1307->regs);
383
384                 /* oscillator off?  turn it on, so clock can tick. */
385                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
386                         i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
387                                 ds1307->regs[0] & ~DS1337_BIT_nEOSC);
388
389                 /* oscillator fault?  clear flag, and warn */
390                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
391                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
392                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
393                         dev_warn(&client->dev, "SET TIME!\n");
394                 }
395                 break;
396         default:
397                 break;
398         }
399
400 read_rtc:
401         /* read RTC registers */
402
403         tmp = i2c_transfer(adapter, ds1307->msg, 2);
404         if (tmp != 2) {
405                 pr_debug("read error %d\n", tmp);
406                 err = -EIO;
407                 goto exit_free;
408         }
409
410         /* minimal sanity checking; some chips (like DS1340) don't
411          * specify the extra bits as must-be-zero, but there are
412          * still a few values that are clearly out-of-range.
413          */
414         tmp = ds1307->regs[DS1307_REG_SECS];
415         switch (ds1307->type) {
416         case ds_1307:
417         case m41t00:
418                 /* clock halted?  turn it on, so clock can tick. */
419                 if (tmp & DS1307_BIT_CH) {
420                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
421                         dev_warn(&client->dev, "SET TIME!\n");
422                         goto read_rtc;
423                 }
424                 break;
425         case ds_1338:
426                 /* clock halted?  turn it on, so clock can tick. */
427                 if (tmp & DS1307_BIT_CH)
428                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
429
430                 /* oscillator fault?  clear flag, and warn */
431                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
432                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
433                                         ds1307->regs[DS1307_REG_CONTROL]
434                                         & ~DS1338_BIT_OSF);
435                         dev_warn(&client->dev, "SET TIME!\n");
436                         goto read_rtc;
437                 }
438                 break;
439         case ds_1340:
440                 /* clock halted?  turn it on, so clock can tick. */
441                 if (tmp & DS1340_BIT_nEOSC)
442                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
443
444                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
445                 if (tmp < 0) {
446                         pr_debug("read error %d\n", tmp);
447                         err = -EIO;
448                         goto exit_free;
449                 }
450
451                 /* oscillator fault?  clear flag, and warn */
452                 if (tmp & DS1340_BIT_OSF) {
453                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
454                         dev_warn(&client->dev, "SET TIME!\n");
455                 }
456                 break;
457         case ds_1337:
458         case ds_1339:
459                 break;
460         }
461
462         tmp = ds1307->regs[DS1307_REG_SECS];
463         tmp = BCD2BIN(tmp & 0x7f);
464         if (tmp > 60)
465                 goto exit_bad;
466         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
467         if (tmp > 60)
468                 goto exit_bad;
469
470         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
471         if (tmp == 0 || tmp > 31)
472                 goto exit_bad;
473
474         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
475         if (tmp == 0 || tmp > 12)
476                 goto exit_bad;
477
478         tmp = ds1307->regs[DS1307_REG_HOUR];
479         switch (ds1307->type) {
480         case ds_1340:
481         case m41t00:
482                 /* NOTE: ignores century bits; fix before deploying
483                  * systems that will run through year 2100.
484                  */
485                 break;
486         default:
487                 if (!(tmp & DS1307_BIT_12HR))
488                         break;
489
490                 /* Be sure we're in 24 hour mode.  Multi-master systems
491                  * take note...
492                  */
493                 tmp = BCD2BIN(tmp & 0x1f);
494                 if (tmp == 12)
495                         tmp = 0;
496                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
497                         tmp += 12;
498                 i2c_smbus_write_byte_data(client,
499                                 DS1307_REG_HOUR,
500                                 BIN2BCD(tmp));
501         }
502
503         ds1307->rtc = rtc_device_register(client->name, &client->dev,
504                                 &ds13xx_rtc_ops, THIS_MODULE);
505         if (IS_ERR(ds1307->rtc)) {
506                 err = PTR_ERR(ds1307->rtc);
507                 dev_err(&client->dev,
508                         "unable to register the class device\n");
509                 goto exit_free;
510         }
511
512         if (chip->nvram56) {
513                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
514                 if (err == 0) {
515                         ds1307->has_nvram = true;
516                         dev_info(&client->dev, "56 bytes nvram\n");
517                 }
518         }
519
520         return 0;
521
522 exit_bad:
523         dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
524                         "bogus register",
525                         ds1307->regs[0], ds1307->regs[1],
526                         ds1307->regs[2], ds1307->regs[3],
527                         ds1307->regs[4], ds1307->regs[5],
528                         ds1307->regs[6]);
529
530 exit_free:
531         kfree(ds1307);
532         return err;
533 }
534
535 static int __devexit ds1307_remove(struct i2c_client *client)
536 {
537         struct ds1307   *ds1307 = i2c_get_clientdata(client);
538
539         if (ds1307->has_nvram)
540                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
541
542         rtc_device_unregister(ds1307->rtc);
543         kfree(ds1307);
544         return 0;
545 }
546
547 static struct i2c_driver ds1307_driver = {
548         .driver = {
549                 .name   = "rtc-ds1307",
550                 .owner  = THIS_MODULE,
551         },
552         .probe          = ds1307_probe,
553         .remove         = __devexit_p(ds1307_remove),
554 };
555
556 static int __init ds1307_init(void)
557 {
558         return i2c_add_driver(&ds1307_driver);
559 }
560 module_init(ds1307_init);
561
562 static void __exit ds1307_exit(void)
563 {
564         i2c_del_driver(&ds1307_driver);
565 }
566 module_exit(ds1307_exit);
567
568 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
569 MODULE_LICENSE("GPL");