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[PATCH] kdump: introduce "reset_devices" command line option
[usb.git] / drivers / rtc / rtc-x1205.c
blob788b6d1f8f2fd282cac69e6b8a5c0e9a3698c9f2
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 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 */
16
17 #include <linux/i2c.h>
18 #include <linux/bcd.h>
19 #include <linux/rtc.h>
20 #include <linux/delay.h>
21
22 #define DRV_VERSION "1.0.7"
23
24 /* Addresses to scan: none. This chip is located at
25 * 0x6f and uses a two bytes register addressing.
26 * Two bytes need to be written to read a single register,
27 * while most other chips just require one and take the second
28 * one as the data to be written. To prevent corrupting
29 * unknown chips, the user must explicitely set the probe parameter.
30 */
31
32 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
33
34 /* Insmod parameters */
35 I2C_CLIENT_INSMOD;
36
37 /* offsets into CCR area */
38
39 #define CCR_SEC 0
40 #define CCR_MIN 1
41 #define CCR_HOUR 2
42 #define CCR_MDAY 3
43 #define CCR_MONTH 4
44 #define CCR_YEAR 5
45 #define CCR_WDAY 6
46 #define CCR_Y2K 7
47
48 #define X1205_REG_SR 0x3F /* status register */
49 #define X1205_REG_Y2K 0x37
50 #define X1205_REG_DW 0x36
51 #define X1205_REG_YR 0x35
52 #define X1205_REG_MO 0x34
53 #define X1205_REG_DT 0x33
54 #define X1205_REG_HR 0x32
55 #define X1205_REG_MN 0x31
56 #define X1205_REG_SC 0x30
57 #define X1205_REG_DTR 0x13
58 #define X1205_REG_ATR 0x12
59 #define X1205_REG_INT 0x11
60 #define X1205_REG_0 0x10
61 #define X1205_REG_Y2K1 0x0F
62 #define X1205_REG_DWA1 0x0E
63 #define X1205_REG_YRA1 0x0D
64 #define X1205_REG_MOA1 0x0C
65 #define X1205_REG_DTA1 0x0B
66 #define X1205_REG_HRA1 0x0A
67 #define X1205_REG_MNA1 0x09
68 #define X1205_REG_SCA1 0x08
69 #define X1205_REG_Y2K0 0x07
70 #define X1205_REG_DWA0 0x06
71 #define X1205_REG_YRA0 0x05
72 #define X1205_REG_MOA0 0x04
73 #define X1205_REG_DTA0 0x03
74 #define X1205_REG_HRA0 0x02
75 #define X1205_REG_MNA0 0x01
76 #define X1205_REG_SCA0 0x00
77
78 #define X1205_CCR_BASE 0x30 /* Base address of CCR */
79 #define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */
80
81 #define X1205_SR_RTCF 0x01 /* Clock failure */
82 #define X1205_SR_WEL 0x02 /* Write Enable Latch */
83 #define X1205_SR_RWEL 0x04 /* Register Write Enable */
84
85 #define X1205_DTR_DTR0 0x01
86 #define X1205_DTR_DTR1 0x02
87 #define X1205_DTR_DTR2 0x04
88
89 #define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */
90
91 /* Prototypes */
92 static int x1205_attach(struct i2c_adapter *adapter);
93 static int x1205_detach(struct i2c_client *client);
94 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
95
96 static struct i2c_driver x1205_driver = {
97 .driver = {
98 .name = "x1205",
99 },
100 .id = I2C_DRIVERID_X1205,
101 .attach_adapter = &x1205_attach,
102 .detach_client = &x1205_detach,
103 };
104
105 /*
106 * In the routines that deal directly with the x1205 hardware, we use
107 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
108 * Epoch is initialized as 2000. Time is set to UTC.
109 */
110 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
111 unsigned char reg_base)
112 {
113 unsigned char dt_addr[2] = { 0, reg_base };
114
115 unsigned char buf[8];
116
117 struct i2c_msg msgs[] = {
118 { client->addr, 0, 2, dt_addr }, /* setup read ptr */
119 { client->addr, I2C_M_RD, 8, buf }, /* read date */
120 };
121
122 /* read date registers */
123 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
124 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
125 return -EIO;
126 }
127
128 dev_dbg(&client->dev,
129 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
130 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
131 __FUNCTION__,
132 buf[0], buf[1], buf[2], buf[3],
133 buf[4], buf[5], buf[6], buf[7]);
134
135 tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
136 tm->tm_min = BCD2BIN(buf[CCR_MIN]);
137 tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
138 tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
139 tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
140 tm->tm_year = BCD2BIN(buf[CCR_YEAR])
141 + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
142 tm->tm_wday = buf[CCR_WDAY];
143
144 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
145 "mday=%d, mon=%d, year=%d, wday=%d\n",
146 __FUNCTION__,
147 tm->tm_sec, tm->tm_min, tm->tm_hour,
148 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
149
150 return 0;
151 }
152
153 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
154 {
155 static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
156
157 struct i2c_msg msgs[] = {
158 { client->addr, 0, 2, sr_addr }, /* setup read ptr */
159 { client->addr, I2C_M_RD, 1, sr }, /* read status */
160 };
161
162 /* read status register */
163 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
164 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
165 return -EIO;
166 }
167
168 return 0;
169 }
170
171 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
172 int datetoo, u8 reg_base)
173 {
174 int i, xfer;
175 unsigned char buf[8];
176
177 static const unsigned char wel[3] = { 0, X1205_REG_SR,
178 X1205_SR_WEL };
179
180 static const unsigned char rwel[3] = { 0, X1205_REG_SR,
181 X1205_SR_WEL | X1205_SR_RWEL };
182
183 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
184
185 dev_dbg(&client->dev,
186 "%s: secs=%d, mins=%d, hours=%d\n",
187 __FUNCTION__,
188 tm->tm_sec, tm->tm_min, tm->tm_hour);
189
190 buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
191 buf[CCR_MIN] = BIN2BCD(tm->tm_min);
192
193 /* set hour and 24hr bit */
194 buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
195
196 /* should we also set the date? */
197 if (datetoo) {
198 dev_dbg(&client->dev,
199 "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
200 __FUNCTION__,
201 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
202
203 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
204
205 /* month, 1 - 12 */
206 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
207
208 /* year, since the rtc epoch*/
209 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
210 buf[CCR_WDAY] = tm->tm_wday & 0x07;
211 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
212 }
213
214 /* this sequence is required to unlock the chip */
215 if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
216 dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
217 return -EIO;
218 }
219
220 if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
221 dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
222 return -EIO;
223 }
224
225 /* write register's data */
226 for (i = 0; i < (datetoo ? 8 : 3); i++) {
227 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
228
229 xfer = i2c_master_send(client, rdata, 3);
230 if (xfer != 3) {
231 dev_err(&client->dev,
232 "%s: xfer=%d addr=%02x, data=%02x\n",
233 __FUNCTION__,
234 xfer, rdata[1], rdata[2]);
235 return -EIO;
236 }
237 };
238
239 /* disable further writes */
240 if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
241 dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
242 return -EIO;
243 }
244
245 return 0;
246 }
247
248 static int x1205_fix_osc(struct i2c_client *client)
249 {
250 int err;
251 struct rtc_time tm;
252
253 tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
254
255 if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
256 dev_err(&client->dev,
257 "unable to restart the oscillator\n");
258
259 return err;
260 }
261
262 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
263 {
264 unsigned char dtr;
265 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
266
267 struct i2c_msg msgs[] = {
268 { client->addr, 0, 2, dtr_addr }, /* setup read ptr */
269 { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */
270 };
271
272 /* read dtr register */
273 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
274 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
275 return -EIO;
276 }
277
278 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
279
280 *trim = 0;
281
282 if (dtr & X1205_DTR_DTR0)
283 *trim += 20;
284
285 if (dtr & X1205_DTR_DTR1)
286 *trim += 10;
287
288 if (dtr & X1205_DTR_DTR2)
289 *trim = -*trim;
290
291 return 0;
292 }
293
294 static int x1205_get_atrim(struct i2c_client *client, int *trim)
295 {
296 s8 atr;
297 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
298
299 struct i2c_msg msgs[] = {
300 { client->addr, 0, 2, atr_addr }, /* setup read ptr */
301 { client->addr, I2C_M_RD, 1, &atr }, /* read atr */
302 };
303
304 /* read atr register */
305 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
306 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
307 return -EIO;
308 }
309
310 dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
311
312 /* atr is a two's complement value on 6 bits,
313 * perform sign extension. The formula is
314 * Catr = (atr * 0.25pF) + 11.00pF.
315 */
316 if (atr & 0x20)
317 atr |= 0xC0;
318
319 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
320
321 *trim = (atr * 250) + 11000;
322
323 dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
324
325 return 0;
326 }
327
328 struct x1205_limit
329 {
330 unsigned char reg, mask, min, max;
331 };
332
333 static int x1205_validate_client(struct i2c_client *client)
334 {
335 int i, xfer;
336
337 /* Probe array. We will read the register at the specified
338 * address and check if the given bits are zero.
339 */
340 static const unsigned char probe_zero_pattern[] = {
341 /* register, mask */
342 X1205_REG_SR, 0x18,
343 X1205_REG_DTR, 0xF8,
344 X1205_REG_ATR, 0xC0,
345 X1205_REG_INT, 0x18,
346 X1205_REG_0, 0xFF,
347 };
348
349 static const struct x1205_limit probe_limits_pattern[] = {
350 /* register, mask, min, max */
351 { X1205_REG_Y2K, 0xFF, 19, 20 },
352 { X1205_REG_DW, 0xFF, 0, 6 },
353 { X1205_REG_YR, 0xFF, 0, 99 },
354 { X1205_REG_MO, 0xFF, 0, 12 },
355 { X1205_REG_DT, 0xFF, 0, 31 },
356 { X1205_REG_HR, 0x7F, 0, 23 },
357 { X1205_REG_MN, 0xFF, 0, 59 },
358 { X1205_REG_SC, 0xFF, 0, 59 },
359 { X1205_REG_Y2K1, 0xFF, 19, 20 },
360 { X1205_REG_Y2K0, 0xFF, 19, 20 },
361 };
362
363 /* check that registers have bits a 0 where expected */
364 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
365 unsigned char buf;
366
367 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
368
369 struct i2c_msg msgs[2] = {
370 { client->addr, 0, 2, addr },
371 { client->addr, I2C_M_RD, 1, &buf },
372 };
373
374 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
375 dev_err(&client->adapter->dev,
376 "%s: could not read register %x\n",
377 __FUNCTION__, probe_zero_pattern[i]);
378
379 return -EIO;
380 }
381
382 if ((buf & probe_zero_pattern[i+1]) != 0) {
383 dev_err(&client->adapter->dev,
384 "%s: register=%02x, zero pattern=%d, value=%x\n",
385 __FUNCTION__, probe_zero_pattern[i], i, buf);
386
387 return -ENODEV;
388 }
389 }
390
391 /* check limits (only registers with bcd values) */
392 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
393 unsigned char reg, value;
394
395 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
396
397 struct i2c_msg msgs[2] = {
398 { client->addr, 0, 2, addr },
399 { client->addr, I2C_M_RD, 1, &reg },
400 };
401
402 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
403 dev_err(&client->adapter->dev,
404 "%s: could not read register %x\n",
405 __FUNCTION__, probe_limits_pattern[i].reg);
406
407 return -EIO;
408 }
409
410 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
411
412 if (value > probe_limits_pattern[i].max ||
413 value < probe_limits_pattern[i].min) {
414 dev_dbg(&client->adapter->dev,
415 "%s: register=%x, lim pattern=%d, value=%d\n",
416 __FUNCTION__, probe_limits_pattern[i].reg,
417 i, value);
418
419 return -ENODEV;
420 }
421 }
422
423 return 0;
424 }
425
426 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
427 {
428 return x1205_get_datetime(to_i2c_client(dev),
429 &alrm->time, X1205_ALM0_BASE);
430 }
431
432 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
433 {
434 return x1205_set_datetime(to_i2c_client(dev),
435 &alrm->time, 1, X1205_ALM0_BASE);
436 }
437
438 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
439 {
440 return x1205_get_datetime(to_i2c_client(dev),
441 tm, X1205_CCR_BASE);
442 }
443
444 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
445 {
446 return x1205_set_datetime(to_i2c_client(dev),
447 tm, 1, X1205_CCR_BASE);
448 }
449
450 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
451 {
452 int err, dtrim, atrim;
453
454 if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
455 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
456
457 if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
458 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
459 atrim / 1000, atrim % 1000);
460 return 0;
461 }
462
463 static struct rtc_class_ops x1205_rtc_ops = {
464 .proc = x1205_rtc_proc,
465 .read_time = x1205_rtc_read_time,
466 .set_time = x1205_rtc_set_time,
467 .read_alarm = x1205_rtc_read_alarm,
468 .set_alarm = x1205_rtc_set_alarm,
469 };
470
471 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
472 struct device_attribute *attr, char *buf)
473 {
474 int err, atrim;
475
476 err = x1205_get_atrim(to_i2c_client(dev), &atrim);
477 if (err)
478 return err;
479
480 return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
481 }
482 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
483
484 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
485 struct device_attribute *attr, char *buf)
486 {
487 int err, dtrim;
488
489 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
490 if (err)
491 return err;
492
493 return sprintf(buf, "%d ppm\n", dtrim);
494 }
495 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
496
497 static int x1205_attach(struct i2c_adapter *adapter)
498 {
499 return i2c_probe(adapter, &addr_data, x1205_probe);
500 }
501
502 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
503 {
504 int err = 0;
505 unsigned char sr;
506 struct i2c_client *client;
507 struct rtc_device *rtc;
508
509 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
510
511 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
512 err = -ENODEV;
513 goto exit;
514 }
515
516 if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
517 err = -ENOMEM;
518 goto exit;
519 }
520
521 /* I2C client */
522 client->addr = address;
523 client->driver = &x1205_driver;
524 client->adapter = adapter;
525
526 strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);
527
528 /* Verify the chip is really an X1205 */
529 if (kind < 0) {
530 if (x1205_validate_client(client) < 0) {
531 err = -ENODEV;
532 goto exit_kfree;
533 }
534 }
535
536 /* Inform the i2c layer */
537 if ((err = i2c_attach_client(client)))
538 goto exit_kfree;
539
540 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
541
542 rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
543 &x1205_rtc_ops, THIS_MODULE);
544
545 if (IS_ERR(rtc)) {
546 err = PTR_ERR(rtc);
547 goto exit_detach;
548 }
549
550 i2c_set_clientdata(client, rtc);
551
552 /* Check for power failures and eventualy enable the osc */
553 if ((err = x1205_get_status(client, &sr)) == 0) {
554 if (sr & X1205_SR_RTCF) {
555 dev_err(&client->dev,
556 "power failure detected, "
557 "please set the clock\n");
558 udelay(50);
559 x1205_fix_osc(client);
560 }
561 }
562 else
563 dev_err(&client->dev, "couldn't read status\n");
564
565 device_create_file(&client->dev, &dev_attr_atrim);
566 device_create_file(&client->dev, &dev_attr_dtrim);
567
568 return 0;
569
570 exit_detach:
571 i2c_detach_client(client);
572
573 exit_kfree:
574 kfree(client);
575
576 exit:
577 return err;
578 }
579
580 static int x1205_detach(struct i2c_client *client)
581 {
582 int err;
583 struct rtc_device *rtc = i2c_get_clientdata(client);
584
585 if (rtc)
586 rtc_device_unregister(rtc);
587
588 if ((err = i2c_detach_client(client)))
589 return err;
590
591 kfree(client);
592
593 return 0;
594 }
595
596 static int __init x1205_init(void)
597 {
598 return i2c_add_driver(&x1205_driver);
599 }
600
601 static void __exit x1205_exit(void)
602 {
603 i2c_del_driver(&x1205_driver);
604 }
605
606 MODULE_AUTHOR(
607 "Karen Spearel <kas111 at gmail dot com>, "
608 "Alessandro Zummo <a.zummo@towertech.it>");
609 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
610 MODULE_LICENSE("GPL");
611 MODULE_VERSION(DRV_VERSION);
612
613 module_init(x1205_init);
614 module_exit(x1205_exit);
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