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Linux 2.6.26-rc5
[linux-2.6/openmoko-kernel/knife-kernel.git] / drivers / rtc / rtc-x1205.c
blobeaf55945f21bbf860318a082b24463caa8648ebc
1 /*
2 * An i2c driver for the Xicor/Intersil X1205 RTC
3 * Copyright 2004 Karen Spearel
4 * Copyright 2005 Alessandro Zummo
5 *
6 * please send all reports to:
7 * Karen Spearel <kas111 at gmail dot com>
8 * Alessandro Zummo <a.zummo@towertech.it>
9 *
10 * based on a lot of other RTC drivers.
11 *
12 * Information and datasheet:
13 * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License version 2 as
17 * published by the Free Software Foundation.
18 */
19
20 #include <linux/i2c.h>
21 #include <linux/bcd.h>
22 #include <linux/rtc.h>
23 #include <linux/delay.h>
24
25 #define DRV_VERSION "1.0.8"
26
27 /* offsets into CCR area */
28
29 #define CCR_SEC 0
30 #define CCR_MIN 1
31 #define CCR_HOUR 2
32 #define CCR_MDAY 3
33 #define CCR_MONTH 4
34 #define CCR_YEAR 5
35 #define CCR_WDAY 6
36 #define CCR_Y2K 7
37
38 #define X1205_REG_SR 0x3F /* status register */
39 #define X1205_REG_Y2K 0x37
40 #define X1205_REG_DW 0x36
41 #define X1205_REG_YR 0x35
42 #define X1205_REG_MO 0x34
43 #define X1205_REG_DT 0x33
44 #define X1205_REG_HR 0x32
45 #define X1205_REG_MN 0x31
46 #define X1205_REG_SC 0x30
47 #define X1205_REG_DTR 0x13
48 #define X1205_REG_ATR 0x12
49 #define X1205_REG_INT 0x11
50 #define X1205_REG_0 0x10
51 #define X1205_REG_Y2K1 0x0F
52 #define X1205_REG_DWA1 0x0E
53 #define X1205_REG_YRA1 0x0D
54 #define X1205_REG_MOA1 0x0C
55 #define X1205_REG_DTA1 0x0B
56 #define X1205_REG_HRA1 0x0A
57 #define X1205_REG_MNA1 0x09
58 #define X1205_REG_SCA1 0x08
59 #define X1205_REG_Y2K0 0x07
60 #define X1205_REG_DWA0 0x06
61 #define X1205_REG_YRA0 0x05
62 #define X1205_REG_MOA0 0x04
63 #define X1205_REG_DTA0 0x03
64 #define X1205_REG_HRA0 0x02
65 #define X1205_REG_MNA0 0x01
66 #define X1205_REG_SCA0 0x00
67
68 #define X1205_CCR_BASE 0x30 /* Base address of CCR */
69 #define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */
70
71 #define X1205_SR_RTCF 0x01 /* Clock failure */
72 #define X1205_SR_WEL 0x02 /* Write Enable Latch */
73 #define X1205_SR_RWEL 0x04 /* Register Write Enable */
74
75 #define X1205_DTR_DTR0 0x01
76 #define X1205_DTR_DTR1 0x02
77 #define X1205_DTR_DTR2 0x04
78
79 #define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */
80
81 static struct i2c_driver x1205_driver;
82
83 /*
84 * In the routines that deal directly with the x1205 hardware, we use
85 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
86 * Epoch is initialized as 2000. Time is set to UTC.
87 */
88 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
89 unsigned char reg_base)
90 {
91 unsigned char dt_addr[2] = { 0, reg_base };
92
93 unsigned char buf[8];
94
95 struct i2c_msg msgs[] = {
96 { client->addr, 0, 2, dt_addr }, /* setup read ptr */
97 { client->addr, I2C_M_RD, 8, buf }, /* read date */
98 };
99
100 /* read date registers */
101 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
102 dev_err(&client->dev, "%s: read error\n", __func__);
103 return -EIO;
104 }
105
106 dev_dbg(&client->dev,
107 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
108 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
109 __func__,
110 buf[0], buf[1], buf[2], buf[3],
111 buf[4], buf[5], buf[6], buf[7]);
112
113 tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
114 tm->tm_min = BCD2BIN(buf[CCR_MIN]);
115 tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
116 tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
117 tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
118 tm->tm_year = BCD2BIN(buf[CCR_YEAR])
119 + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
120 tm->tm_wday = buf[CCR_WDAY];
121
122 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
123 "mday=%d, mon=%d, year=%d, wday=%d\n",
124 __func__,
125 tm->tm_sec, tm->tm_min, tm->tm_hour,
126 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
127
128 return 0;
129 }
130
131 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
132 {
133 static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
134
135 struct i2c_msg msgs[] = {
136 { client->addr, 0, 2, sr_addr }, /* setup read ptr */
137 { client->addr, I2C_M_RD, 1, sr }, /* read status */
138 };
139
140 /* read status register */
141 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
142 dev_err(&client->dev, "%s: read error\n", __func__);
143 return -EIO;
144 }
145
146 return 0;
147 }
148
149 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
150 int datetoo, u8 reg_base)
151 {
152 int i, xfer;
153 unsigned char buf[8];
154
155 static const unsigned char wel[3] = { 0, X1205_REG_SR,
156 X1205_SR_WEL };
157
158 static const unsigned char rwel[3] = { 0, X1205_REG_SR,
159 X1205_SR_WEL | X1205_SR_RWEL };
160
161 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
162
163 dev_dbg(&client->dev,
164 "%s: secs=%d, mins=%d, hours=%d\n",
165 __func__,
166 tm->tm_sec, tm->tm_min, tm->tm_hour);
167
168 buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
169 buf[CCR_MIN] = BIN2BCD(tm->tm_min);
170
171 /* set hour and 24hr bit */
172 buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
173
174 /* should we also set the date? */
175 if (datetoo) {
176 dev_dbg(&client->dev,
177 "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
178 __func__,
179 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
180
181 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
182
183 /* month, 1 - 12 */
184 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
185
186 /* year, since the rtc epoch*/
187 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
188 buf[CCR_WDAY] = tm->tm_wday & 0x07;
189 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
190 }
191
192 /* this sequence is required to unlock the chip */
193 if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
194 dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
195 return -EIO;
196 }
197
198 if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
199 dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
200 return -EIO;
201 }
202
203 /* write register's data */
204 for (i = 0; i < (datetoo ? 8 : 3); i++) {
205 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
206
207 xfer = i2c_master_send(client, rdata, 3);
208 if (xfer != 3) {
209 dev_err(&client->dev,
210 "%s: xfer=%d addr=%02x, data=%02x\n",
211 __func__,
212 xfer, rdata[1], rdata[2]);
213 return -EIO;
214 }
215 };
216
217 /* disable further writes */
218 if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
219 dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
220 return -EIO;
221 }
222
223 return 0;
224 }
225
226 static int x1205_fix_osc(struct i2c_client *client)
227 {
228 int err;
229 struct rtc_time tm;
230
231 tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
232
233 if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
234 dev_err(&client->dev,
235 "unable to restart the oscillator\n");
236
237 return err;
238 }
239
240 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
241 {
242 unsigned char dtr;
243 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
244
245 struct i2c_msg msgs[] = {
246 { client->addr, 0, 2, dtr_addr }, /* setup read ptr */
247 { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */
248 };
249
250 /* read dtr register */
251 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
252 dev_err(&client->dev, "%s: read error\n", __func__);
253 return -EIO;
254 }
255
256 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr);
257
258 *trim = 0;
259
260 if (dtr & X1205_DTR_DTR0)
261 *trim += 20;
262
263 if (dtr & X1205_DTR_DTR1)
264 *trim += 10;
265
266 if (dtr & X1205_DTR_DTR2)
267 *trim = -*trim;
268
269 return 0;
270 }
271
272 static int x1205_get_atrim(struct i2c_client *client, int *trim)
273 {
274 s8 atr;
275 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
276
277 struct i2c_msg msgs[] = {
278 { client->addr, 0, 2, atr_addr }, /* setup read ptr */
279 { client->addr, I2C_M_RD, 1, &atr }, /* read atr */
280 };
281
282 /* read atr register */
283 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
284 dev_err(&client->dev, "%s: read error\n", __func__);
285 return -EIO;
286 }
287
288 dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
289
290 /* atr is a two's complement value on 6 bits,
291 * perform sign extension. The formula is
292 * Catr = (atr * 0.25pF) + 11.00pF.
293 */
294 if (atr & 0x20)
295 atr |= 0xC0;
296
297 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
298
299 *trim = (atr * 250) + 11000;
300
301 dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim);
302
303 return 0;
304 }
305
306 struct x1205_limit
307 {
308 unsigned char reg, mask, min, max;
309 };
310
311 static int x1205_validate_client(struct i2c_client *client)
312 {
313 int i, xfer;
314
315 /* Probe array. We will read the register at the specified
316 * address and check if the given bits are zero.
317 */
318 static const unsigned char probe_zero_pattern[] = {
319 /* register, mask */
320 X1205_REG_SR, 0x18,
321 X1205_REG_DTR, 0xF8,
322 X1205_REG_ATR, 0xC0,
323 X1205_REG_INT, 0x18,
324 X1205_REG_0, 0xFF,
325 };
326
327 static const struct x1205_limit probe_limits_pattern[] = {
328 /* register, mask, min, max */
329 { X1205_REG_Y2K, 0xFF, 19, 20 },
330 { X1205_REG_DW, 0xFF, 0, 6 },
331 { X1205_REG_YR, 0xFF, 0, 99 },
332 { X1205_REG_MO, 0xFF, 0, 12 },
333 { X1205_REG_DT, 0xFF, 0, 31 },
334 { X1205_REG_HR, 0x7F, 0, 23 },
335 { X1205_REG_MN, 0xFF, 0, 59 },
336 { X1205_REG_SC, 0xFF, 0, 59 },
337 { X1205_REG_Y2K1, 0xFF, 19, 20 },
338 { X1205_REG_Y2K0, 0xFF, 19, 20 },
339 };
340
341 /* check that registers have bits a 0 where expected */
342 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
343 unsigned char buf;
344
345 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
346
347 struct i2c_msg msgs[2] = {
348 { client->addr, 0, 2, addr },
349 { client->addr, I2C_M_RD, 1, &buf },
350 };
351
352 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
353 dev_err(&client->dev,
354 "%s: could not read register %x\n",
355 __func__, probe_zero_pattern[i]);
356
357 return -EIO;
358 }
359
360 if ((buf & probe_zero_pattern[i+1]) != 0) {
361 dev_err(&client->dev,
362 "%s: register=%02x, zero pattern=%d, value=%x\n",
363 __func__, probe_zero_pattern[i], i, buf);
364
365 return -ENODEV;
366 }
367 }
368
369 /* check limits (only registers with bcd values) */
370 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
371 unsigned char reg, value;
372
373 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
374
375 struct i2c_msg msgs[2] = {
376 { client->addr, 0, 2, addr },
377 { client->addr, I2C_M_RD, 1, &reg },
378 };
379
380 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
381 dev_err(&client->dev,
382 "%s: could not read register %x\n",
383 __func__, probe_limits_pattern[i].reg);
384
385 return -EIO;
386 }
387
388 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
389
390 if (value > probe_limits_pattern[i].max ||
391 value < probe_limits_pattern[i].min) {
392 dev_dbg(&client->dev,
393 "%s: register=%x, lim pattern=%d, value=%d\n",
394 __func__, probe_limits_pattern[i].reg,
395 i, value);
396
397 return -ENODEV;
398 }
399 }
400
401 return 0;
402 }
403
404 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
405 {
406 return x1205_get_datetime(to_i2c_client(dev),
407 &alrm->time, X1205_ALM0_BASE);
408 }
409
410 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
411 {
412 return x1205_set_datetime(to_i2c_client(dev),
413 &alrm->time, 1, X1205_ALM0_BASE);
414 }
415
416 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
417 {
418 return x1205_get_datetime(to_i2c_client(dev),
419 tm, X1205_CCR_BASE);
420 }
421
422 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
423 {
424 return x1205_set_datetime(to_i2c_client(dev),
425 tm, 1, X1205_CCR_BASE);
426 }
427
428 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
429 {
430 int err, dtrim, atrim;
431
432 if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
433 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
434
435 if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
436 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
437 atrim / 1000, atrim % 1000);
438 return 0;
439 }
440
441 static const struct rtc_class_ops x1205_rtc_ops = {
442 .proc = x1205_rtc_proc,
443 .read_time = x1205_rtc_read_time,
444 .set_time = x1205_rtc_set_time,
445 .read_alarm = x1205_rtc_read_alarm,
446 .set_alarm = x1205_rtc_set_alarm,
447 };
448
449 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
450 struct device_attribute *attr, char *buf)
451 {
452 int err, atrim;
453
454 err = x1205_get_atrim(to_i2c_client(dev), &atrim);
455 if (err)
456 return err;
457
458 return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
459 }
460 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
461
462 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
463 struct device_attribute *attr, char *buf)
464 {
465 int err, dtrim;
466
467 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
468 if (err)
469 return err;
470
471 return sprintf(buf, "%d ppm\n", dtrim);
472 }
473 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
474
475 static int x1205_sysfs_register(struct device *dev)
476 {
477 int err;
478
479 err = device_create_file(dev, &dev_attr_atrim);
480 if (err)
481 return err;
482
483 err = device_create_file(dev, &dev_attr_dtrim);
484 if (err)
485 device_remove_file(dev, &dev_attr_atrim);
486
487 return err;
488 }
489
490 static void x1205_sysfs_unregister(struct device *dev)
491 {
492 device_remove_file(dev, &dev_attr_atrim);
493 device_remove_file(dev, &dev_attr_dtrim);
494 }
495
496
497 static int x1205_probe(struct i2c_client *client,
498 const struct i2c_device_id *id)
499 {
500 int err = 0;
501 unsigned char sr;
502 struct rtc_device *rtc;
503
504 dev_dbg(&client->dev, "%s\n", __func__);
505
506 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
507 return -ENODEV;
508
509 if (x1205_validate_client(client) < 0)
510 return -ENODEV;
511
512 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
513
514 rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
515 &x1205_rtc_ops, THIS_MODULE);
516
517 if (IS_ERR(rtc))
518 return PTR_ERR(rtc);
519
520 i2c_set_clientdata(client, rtc);
521
522 /* Check for power failures and eventualy enable the osc */
523 if ((err = x1205_get_status(client, &sr)) == 0) {
524 if (sr & X1205_SR_RTCF) {
525 dev_err(&client->dev,
526 "power failure detected, "
527 "please set the clock\n");
528 udelay(50);
529 x1205_fix_osc(client);
530 }
531 }
532 else
533 dev_err(&client->dev, "couldn't read status\n");
534
535 err = x1205_sysfs_register(&client->dev);
536 if (err)
537 goto exit_devreg;
538
539 return 0;
540
541 exit_devreg:
542 rtc_device_unregister(rtc);
543
544 return err;
545 }
546
547 static int x1205_remove(struct i2c_client *client)
548 {
549 struct rtc_device *rtc = i2c_get_clientdata(client);
550
551 rtc_device_unregister(rtc);
552 x1205_sysfs_unregister(&client->dev);
553 return 0;
554 }
555
556 static const struct i2c_device_id x1205_id[] = {
557 { "x1205", 0 },
558 { }
559 };
560 MODULE_DEVICE_TABLE(i2c, x1205_id);
561
562 static struct i2c_driver x1205_driver = {
563 .driver = {
564 .name = "rtc-x1205",
565 },
566 .probe = x1205_probe,
567 .remove = x1205_remove,
568 .id_table = x1205_id,
569 };
570
571 static int __init x1205_init(void)
572 {
573 return i2c_add_driver(&x1205_driver);
574 }
575
576 static void __exit x1205_exit(void)
577 {
578 i2c_del_driver(&x1205_driver);
579 }
580
581 MODULE_AUTHOR(
582 "Karen Spearel <kas111 at gmail dot com>, "
583 "Alessandro Zummo <a.zummo@towertech.it>");
584 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
585 MODULE_LICENSE("GPL");
586 MODULE_VERSION(DRV_VERSION);
587
588 module_init(x1205_init);
589 module_exit(x1205_exit);
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