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Alessandro Zummo1fec7c62006-03-27 01:16:42 -08001/*
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 "1.0.6"
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
32static unsigned short normal_i2c[] = { I2C_CLIENT_END };
33
34/* Insmod parameters */
35I2C_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 */
92static int x1205_attach(struct i2c_adapter *adapter);
93static int x1205_detach(struct i2c_client *client);
94static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
95
96static 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 */
110static 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
153static 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
171static 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
248static 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
262static 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
294static 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
328struct x1205_limit
329{
330 unsigned char reg, mask, min, max;
331};
332
333static 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
426static 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
432static 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
438static 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
444static 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
450static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
451{
452 int err, dtrim, atrim;
453
454 seq_printf(seq, "24hr\t\t: yes\n");
455
456 if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
457 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
458
459 if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
460 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
461 atrim / 1000, atrim % 1000);
462 return 0;
463}
464
465static struct rtc_class_ops x1205_rtc_ops = {
466 .proc = x1205_rtc_proc,
467 .read_time = x1205_rtc_read_time,
468 .set_time = x1205_rtc_set_time,
469 .read_alarm = x1205_rtc_read_alarm,
470 .set_alarm = x1205_rtc_set_alarm,
471};
472
473static ssize_t x1205_sysfs_show_atrim(struct device *dev,
474 struct device_attribute *attr, char *buf)
475{
476 int atrim;
477
478 if (x1205_get_atrim(to_i2c_client(dev), &atrim) == 0)
479 return sprintf(buf, "%d.%02d pF\n",
480 atrim / 1000, atrim % 1000);
481 return 0;
482}
483static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
484
485static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
486 struct device_attribute *attr, char *buf)
487{
488 int dtrim;
489
490 if (x1205_get_dtrim(to_i2c_client(dev), &dtrim) == 0)
491 return sprintf(buf, "%d ppm\n", dtrim);
492
493 return 0;
494}
495static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
496
497static int x1205_attach(struct i2c_adapter *adapter)
498{
499 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
500 return i2c_probe(adapter, &addr_data, x1205_probe);
501}
502
503static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
504{
505 int err = 0;
506 unsigned char sr;
507 struct i2c_client *client;
508 struct rtc_device *rtc;
509
510 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
511
512 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
513 err = -ENODEV;
514 goto exit;
515 }
516
517 if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
518 err = -ENOMEM;
519 goto exit;
520 }
521
522 /* I2C client */
523 client->addr = address;
524 client->driver = &x1205_driver;
525 client->adapter = adapter;
526
527 strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);
528
529 /* Verify the chip is really an X1205 */
530 if (kind < 0) {
531 if (x1205_validate_client(client) < 0) {
532 err = -ENODEV;
533 goto exit_kfree;
534 }
535 }
536
537 /* Inform the i2c layer */
538 if ((err = i2c_attach_client(client)))
539 goto exit_kfree;
540
541 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
542
543 rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
544 &x1205_rtc_ops, THIS_MODULE);
545
546 if (IS_ERR(rtc)) {
547 err = PTR_ERR(rtc);
548 dev_err(&client->dev,
549 "unable to register the class device\n");
550 goto exit_detach;
551 }
552
553 i2c_set_clientdata(client, rtc);
554
555 /* Check for power failures and eventualy enable the osc */
556 if ((err = x1205_get_status(client, &sr)) == 0) {
557 if (sr & X1205_SR_RTCF) {
558 dev_err(&client->dev,
559 "power failure detected, "
560 "please set the clock\n");
561 udelay(50);
562 x1205_fix_osc(client);
563 }
564 }
565 else
566 dev_err(&client->dev, "couldn't read status\n");
567
568 device_create_file(&client->dev, &dev_attr_atrim);
569 device_create_file(&client->dev, &dev_attr_dtrim);
570
571 return 0;
572
573exit_detach:
574 i2c_detach_client(client);
575
576exit_kfree:
577 kfree(client);
578
579exit:
580 return err;
581}
582
583static int x1205_detach(struct i2c_client *client)
584{
585 int err;
586 struct rtc_device *rtc = i2c_get_clientdata(client);
587
588 dev_dbg(&client->dev, "%s\n", __FUNCTION__);
589
590 if (rtc)
591 rtc_device_unregister(rtc);
592
593 if ((err = i2c_detach_client(client)))
594 return err;
595
596 kfree(client);
597
598 return 0;
599}
600
601static int __init x1205_init(void)
602{
603 return i2c_add_driver(&x1205_driver);
604}
605
606static void __exit x1205_exit(void)
607{
608 i2c_del_driver(&x1205_driver);
609}
610
611MODULE_AUTHOR(
612 "Karen Spearel <kas111 at gmail dot com>, "
613 "Alessandro Zummo <a.zummo@towertech.it>");
614MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
615MODULE_LICENSE("GPL");
616MODULE_VERSION(DRV_VERSION);
617
618module_init(x1205_init);
619module_exit(x1205_exit);