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Don't trigger softlockup detector on network fs blocked tasks
[linux-2.6/mini2440.git] / drivers / rtc / rtc-ds1307.c
blobbbf97e65202a24327b57beafbba98d6daca738a2
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");
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