i2c: Convert most new-style drivers to use module aliasing
[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         unsigned                nvram56:1;
103         unsigned                alarm:1;
104 };
105
106 static const struct chip_desc chips[] = {
107 [ds_1307] = {
108         .nvram56        = 1,
109 },
110 [ds_1337] = {
111         .alarm          = 1,
112 },
113 [ds_1338] = {
114         .nvram56        = 1,
115 },
116 [ds_1339] = {
117         .alarm          = 1,
118 },
119 [ds_1340] = {
120 },
121 [m41t00] = {
122 }, };
123
124 static const struct i2c_device_id ds1307_id[] = {
125         { "ds1307", ds_1307 },
126         { "ds1337", ds_1337 },
127         { "ds1338", ds_1338 },
128         { "ds1339", ds_1339 },
129         { "ds1340", ds_1340 },
130         { "m41t00", m41t00 },
131         { }
132 };
133 MODULE_DEVICE_TABLE(i2c, ds1307_id);
134
135 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
136 {
137         struct ds1307   *ds1307 = dev_get_drvdata(dev);
138         int             tmp;
139
140         /* read the RTC date and time registers all at once */
141         ds1307->msg[1].flags = I2C_M_RD;
142         ds1307->msg[1].len = 7;
143
144         tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
145                         ds1307->msg, 2);
146         if (tmp != 2) {
147                 dev_err(dev, "%s error %d\n", "read", tmp);
148                 return -EIO;
149         }
150
151         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
152                         "read",
153                         ds1307->regs[0], ds1307->regs[1],
154                         ds1307->regs[2], ds1307->regs[3],
155                         ds1307->regs[4], ds1307->regs[5],
156                         ds1307->regs[6]);
157
158         t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
159         t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
160         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
161         t->tm_hour = BCD2BIN(tmp);
162         t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
163         t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
164         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
165         t->tm_mon = BCD2BIN(tmp) - 1;
166
167         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
168         t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;
169
170         dev_dbg(dev, "%s secs=%d, mins=%d, "
171                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
172                 "read", t->tm_sec, t->tm_min,
173                 t->tm_hour, t->tm_mday,
174                 t->tm_mon, t->tm_year, t->tm_wday);
175
176         /* initial clock setting can be undefined */
177         return rtc_valid_tm(t);
178 }
179
180 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
181 {
182         struct ds1307   *ds1307 = dev_get_drvdata(dev);
183         int             result;
184         int             tmp;
185         u8              *buf = ds1307->regs;
186
187         dev_dbg(dev, "%s secs=%d, mins=%d, "
188                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
189                 "write", t->tm_sec, t->tm_min,
190                 t->tm_hour, t->tm_mday,
191                 t->tm_mon, t->tm_year, t->tm_wday);
192
193         *buf++ = 0;             /* first register addr */
194         buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
195         buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
196         buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
197         buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
198         buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
199         buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);
200
201         /* assume 20YY not 19YY */
202         tmp = t->tm_year - 100;
203         buf[DS1307_REG_YEAR] = BIN2BCD(tmp);
204
205         switch (ds1307->type) {
206         case ds_1337:
207         case ds_1339:
208                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
209                 break;
210         case ds_1340:
211                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
212                                 | DS1340_BIT_CENTURY;
213                 break;
214         default:
215                 break;
216         }
217
218         ds1307->msg[1].flags = 0;
219         ds1307->msg[1].len = 8;
220
221         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
222                 "write", buf[0], buf[1], buf[2], buf[3],
223                 buf[4], buf[5], buf[6]);
224
225         result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
226                         &ds1307->msg[1], 1);
227         if (result != 1) {
228                 dev_err(dev, "%s error %d\n", "write", tmp);
229                 return -EIO;
230         }
231         return 0;
232 }
233
234 static const struct rtc_class_ops ds13xx_rtc_ops = {
235         .read_time      = ds1307_get_time,
236         .set_time       = ds1307_set_time,
237 };
238
239 /*----------------------------------------------------------------------*/
240
241 #define NVRAM_SIZE      56
242
243 static ssize_t
244 ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
245                 char *buf, loff_t off, size_t count)
246 {
247         struct i2c_client       *client;
248         struct ds1307           *ds1307;
249         struct i2c_msg          msg[2];
250         int                     result;
251
252         client = kobj_to_i2c_client(kobj);
253         ds1307 = i2c_get_clientdata(client);
254
255         if (unlikely(off >= NVRAM_SIZE))
256                 return 0;
257         if ((off + count) > NVRAM_SIZE)
258                 count = NVRAM_SIZE - off;
259         if (unlikely(!count))
260                 return count;
261
262         msg[0].addr = client->addr;
263         msg[0].flags = 0;
264         msg[0].len = 1;
265         msg[0].buf = buf;
266
267         buf[0] = 8 + off;
268
269         msg[1].addr = client->addr;
270         msg[1].flags = I2C_M_RD;
271         msg[1].len = count;
272         msg[1].buf = buf;
273
274         result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
275         if (result != 2) {
276                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
277                 return -EIO;
278         }
279         return count;
280 }
281
282 static ssize_t
283 ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
284                 char *buf, loff_t off, size_t count)
285 {
286         struct i2c_client       *client;
287         u8                      buffer[NVRAM_SIZE + 1];
288         int                     ret;
289
290         client = kobj_to_i2c_client(kobj);
291
292         if (unlikely(off >= NVRAM_SIZE))
293                 return -EFBIG;
294         if ((off + count) > NVRAM_SIZE)
295                 count = NVRAM_SIZE - off;
296         if (unlikely(!count))
297                 return count;
298
299         buffer[0] = 8 + off;
300         memcpy(buffer + 1, buf, count);
301
302         ret = i2c_master_send(client, buffer, count + 1);
303         return (ret < 0) ? ret : (ret - 1);
304 }
305
306 static struct bin_attribute nvram = {
307         .attr = {
308                 .name   = "nvram",
309                 .mode   = S_IRUGO | S_IWUSR,
310                 .owner  = THIS_MODULE,
311         },
312
313         .read   = ds1307_nvram_read,
314         .write  = ds1307_nvram_write,
315         .size   = NVRAM_SIZE,
316 };
317
318 /*----------------------------------------------------------------------*/
319
320 static struct i2c_driver ds1307_driver;
321
322 static int __devinit ds1307_probe(struct i2c_client *client,
323                                   const struct i2c_device_id *id)
324 {
325         struct ds1307           *ds1307;
326         int                     err = -ENODEV;
327         int                     tmp;
328         const struct chip_desc  *chip = &chips[id->driver_data];
329         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
330
331         if (!i2c_check_functionality(adapter,
332                         I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
333                 return -EIO;
334
335         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
336                 return -ENOMEM;
337
338         ds1307->client = client;
339         i2c_set_clientdata(client, ds1307);
340
341         ds1307->msg[0].addr = client->addr;
342         ds1307->msg[0].flags = 0;
343         ds1307->msg[0].len = 1;
344         ds1307->msg[0].buf = &ds1307->reg_addr;
345
346         ds1307->msg[1].addr = client->addr;
347         ds1307->msg[1].flags = I2C_M_RD;
348         ds1307->msg[1].len = sizeof(ds1307->regs);
349         ds1307->msg[1].buf = ds1307->regs;
350
351         ds1307->type = id->driver_data;
352
353         switch (ds1307->type) {
354         case ds_1337:
355         case ds_1339:
356                 ds1307->reg_addr = DS1337_REG_CONTROL;
357                 ds1307->msg[1].len = 2;
358
359                 /* get registers that the "rtc" read below won't read... */
360                 tmp = i2c_transfer(adapter, ds1307->msg, 2);
361                 if (tmp != 2) {
362                         pr_debug("read error %d\n", tmp);
363                         err = -EIO;
364                         goto exit_free;
365                 }
366
367                 ds1307->reg_addr = 0;
368                 ds1307->msg[1].len = sizeof(ds1307->regs);
369
370                 /* oscillator off?  turn it on, so clock can tick. */
371                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
372                         i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
373                                 ds1307->regs[0] & ~DS1337_BIT_nEOSC);
374
375                 /* oscillator fault?  clear flag, and warn */
376                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
377                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
378                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
379                         dev_warn(&client->dev, "SET TIME!\n");
380                 }
381                 break;
382         default:
383                 break;
384         }
385
386 read_rtc:
387         /* read RTC registers */
388
389         tmp = i2c_transfer(adapter, ds1307->msg, 2);
390         if (tmp != 2) {
391                 pr_debug("read error %d\n", tmp);
392                 err = -EIO;
393                 goto exit_free;
394         }
395
396         /* minimal sanity checking; some chips (like DS1340) don't
397          * specify the extra bits as must-be-zero, but there are
398          * still a few values that are clearly out-of-range.
399          */
400         tmp = ds1307->regs[DS1307_REG_SECS];
401         switch (ds1307->type) {
402         case ds_1307:
403         case m41t00:
404                 /* clock halted?  turn it on, so clock can tick. */
405                 if (tmp & DS1307_BIT_CH) {
406                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
407                         dev_warn(&client->dev, "SET TIME!\n");
408                         goto read_rtc;
409                 }
410                 break;
411         case ds_1338:
412                 /* clock halted?  turn it on, so clock can tick. */
413                 if (tmp & DS1307_BIT_CH)
414                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
415
416                 /* oscillator fault?  clear flag, and warn */
417                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
418                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
419                                         ds1307->regs[DS1307_REG_CONTROL]
420                                         & ~DS1338_BIT_OSF);
421                         dev_warn(&client->dev, "SET TIME!\n");
422                         goto read_rtc;
423                 }
424                 break;
425         case ds_1340:
426                 /* clock halted?  turn it on, so clock can tick. */
427                 if (tmp & DS1340_BIT_nEOSC)
428                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
429
430                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
431                 if (tmp < 0) {
432                         pr_debug("read error %d\n", tmp);
433                         err = -EIO;
434                         goto exit_free;
435                 }
436
437                 /* oscillator fault?  clear flag, and warn */
438                 if (tmp & DS1340_BIT_OSF) {
439                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
440                         dev_warn(&client->dev, "SET TIME!\n");
441                 }
442                 break;
443         case ds_1337:
444         case ds_1339:
445                 break;
446         }
447
448         tmp = ds1307->regs[DS1307_REG_SECS];
449         tmp = BCD2BIN(tmp & 0x7f);
450         if (tmp > 60)
451                 goto exit_bad;
452         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
453         if (tmp > 60)
454                 goto exit_bad;
455
456         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
457         if (tmp == 0 || tmp > 31)
458                 goto exit_bad;
459
460         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
461         if (tmp == 0 || tmp > 12)
462                 goto exit_bad;
463
464         tmp = ds1307->regs[DS1307_REG_HOUR];
465         switch (ds1307->type) {
466         case ds_1340:
467         case m41t00:
468                 /* NOTE: ignores century bits; fix before deploying
469                  * systems that will run through year 2100.
470                  */
471                 break;
472         default:
473                 if (!(tmp & DS1307_BIT_12HR))
474                         break;
475
476                 /* Be sure we're in 24 hour mode.  Multi-master systems
477                  * take note...
478                  */
479                 tmp = BCD2BIN(tmp & 0x1f);
480                 if (tmp == 12)
481                         tmp = 0;
482                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
483                         tmp += 12;
484                 i2c_smbus_write_byte_data(client,
485                                 DS1307_REG_HOUR,
486                                 BIN2BCD(tmp));
487         }
488
489         ds1307->rtc = rtc_device_register(client->name, &client->dev,
490                                 &ds13xx_rtc_ops, THIS_MODULE);
491         if (IS_ERR(ds1307->rtc)) {
492                 err = PTR_ERR(ds1307->rtc);
493                 dev_err(&client->dev,
494                         "unable to register the class device\n");
495                 goto exit_free;
496         }
497
498         if (chip->nvram56) {
499                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
500                 if (err == 0) {
501                         ds1307->has_nvram = true;
502                         dev_info(&client->dev, "56 bytes nvram\n");
503                 }
504         }
505
506         return 0;
507
508 exit_bad:
509         dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
510                         "bogus register",
511                         ds1307->regs[0], ds1307->regs[1],
512                         ds1307->regs[2], ds1307->regs[3],
513                         ds1307->regs[4], ds1307->regs[5],
514                         ds1307->regs[6]);
515
516 exit_free:
517         kfree(ds1307);
518         return err;
519 }
520
521 static int __devexit ds1307_remove(struct i2c_client *client)
522 {
523         struct ds1307   *ds1307 = i2c_get_clientdata(client);
524
525         if (ds1307->has_nvram)
526                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
527
528         rtc_device_unregister(ds1307->rtc);
529         kfree(ds1307);
530         return 0;
531 }
532
533 static struct i2c_driver ds1307_driver = {
534         .driver = {
535                 .name   = "rtc-ds1307",
536                 .owner  = THIS_MODULE,
537         },
538         .probe          = ds1307_probe,
539         .remove         = __devexit_p(ds1307_remove),
540         .id_table       = ds1307_id,
541 };
542
543 static int __init ds1307_init(void)
544 {
545         return i2c_add_driver(&ds1307_driver);
546 }
547 module_init(ds1307_init);
548
549 static void __exit ds1307_exit(void)
550 {
551         i2c_del_driver(&ds1307_driver);
552 }
553 module_exit(ds1307_exit);
554
555 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
556 MODULE_LICENSE("GPL");