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avr32: Reduce DataFlash bus speed to 8 MHz on ATNGW100
[linux-2.6/pdupreez.git] / drivers / rtc / rtc-isl1208.c
blobfbb90b1e40981f6fadfd4542e468ad35a3d70f4d
1 /*
2 * Intersil ISL1208 rtc class driver
3 *
4 * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 *
11 */
12
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/bcd.h>
16 #include <linux/rtc.h>
17
18 #define DRV_VERSION "0.3"
19
20 /* Register map */
21 /* rtc section */
22 #define ISL1208_REG_SC 0x00
23 #define ISL1208_REG_MN 0x01
24 #define ISL1208_REG_HR 0x02
25 #define ISL1208_REG_HR_MIL (1<<7) /* 24h/12h mode */
26 #define ISL1208_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
27 #define ISL1208_REG_DT 0x03
28 #define ISL1208_REG_MO 0x04
29 #define ISL1208_REG_YR 0x05
30 #define ISL1208_REG_DW 0x06
31 #define ISL1208_RTC_SECTION_LEN 7
32
33 /* control/status section */
34 #define ISL1208_REG_SR 0x07
35 #define ISL1208_REG_SR_ARST (1<<7) /* auto reset */
36 #define ISL1208_REG_SR_XTOSCB (1<<6) /* crystal oscillator */
37 #define ISL1208_REG_SR_WRTC (1<<4) /* write rtc */
38 #define ISL1208_REG_SR_ALM (1<<2) /* alarm */
39 #define ISL1208_REG_SR_BAT (1<<1) /* battery */
40 #define ISL1208_REG_SR_RTCF (1<<0) /* rtc fail */
41 #define ISL1208_REG_INT 0x08
42 #define ISL1208_REG_09 0x09 /* reserved */
43 #define ISL1208_REG_ATR 0x0a
44 #define ISL1208_REG_DTR 0x0b
45
46 /* alarm section */
47 #define ISL1208_REG_SCA 0x0c
48 #define ISL1208_REG_MNA 0x0d
49 #define ISL1208_REG_HRA 0x0e
50 #define ISL1208_REG_DTA 0x0f
51 #define ISL1208_REG_MOA 0x10
52 #define ISL1208_REG_DWA 0x11
53 #define ISL1208_ALARM_SECTION_LEN 6
54
55 /* user section */
56 #define ISL1208_REG_USR1 0x12
57 #define ISL1208_REG_USR2 0x13
58 #define ISL1208_USR_SECTION_LEN 2
59
60 static struct i2c_driver isl1208_driver;
61
62 /* block read */
63 static int
64 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
65 unsigned len)
66 {
67 u8 reg_addr[1] = { reg };
68 struct i2c_msg msgs[2] = {
69 {client->addr, 0, sizeof(reg_addr), reg_addr}
70 ,
71 {client->addr, I2C_M_RD, len, buf}
72 };
73 int ret;
74
75 BUG_ON(reg > ISL1208_REG_USR2);
76 BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
77
78 ret = i2c_transfer(client->adapter, msgs, 2);
79 if (ret > 0)
80 ret = 0;
81 return ret;
82 }
83
84 /* block write */
85 static int
86 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
87 unsigned len)
88 {
89 u8 i2c_buf[ISL1208_REG_USR2 + 2];
90 struct i2c_msg msgs[1] = {
91 {client->addr, 0, len + 1, i2c_buf}
92 };
93 int ret;
94
95 BUG_ON(reg > ISL1208_REG_USR2);
96 BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
97
98 i2c_buf[0] = reg;
99 memcpy(&i2c_buf[1], &buf[0], len);
100
101 ret = i2c_transfer(client->adapter, msgs, 1);
102 if (ret > 0)
103 ret = 0;
104 return ret;
105 }
106
107 /* simple check to see wether we have a isl1208 */
108 static int
109 isl1208_i2c_validate_client(struct i2c_client *client)
110 {
111 u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
112 u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
113 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
114 };
115 int i;
116 int ret;
117
118 ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
119 if (ret < 0)
120 return ret;
121
122 for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
123 if (regs[i] & zero_mask[i]) /* check if bits are cleared */
124 return -ENODEV;
125 }
126
127 return 0;
128 }
129
130 static int
131 isl1208_i2c_get_sr(struct i2c_client *client)
132 {
133 int sr = i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
134 if (sr < 0)
135 return -EIO;
136
137 return sr;
138 }
139
140 static int
141 isl1208_i2c_get_atr(struct i2c_client *client)
142 {
143 int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
144 if (atr < 0)
145 return atr;
146
147 /* The 6bit value in the ATR register controls the load
148 * capacitance C_load * in steps of 0.25pF
149 *
150 * bit (1<<5) of the ATR register is inverted
151 *
152 * C_load(ATR=0x20) = 4.50pF
153 * C_load(ATR=0x00) = 12.50pF
154 * C_load(ATR=0x1f) = 20.25pF
155 *
156 */
157
158 atr &= 0x3f; /* mask out lsb */
159 atr ^= 1 << 5; /* invert 6th bit */
160 atr += 2 * 9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
161
162 return atr;
163 }
164
165 static int
166 isl1208_i2c_get_dtr(struct i2c_client *client)
167 {
168 int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
169 if (dtr < 0)
170 return -EIO;
171
172 /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
173 dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
174
175 return dtr;
176 }
177
178 static int
179 isl1208_i2c_get_usr(struct i2c_client *client)
180 {
181 u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
182 int ret;
183
184 ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
185 ISL1208_USR_SECTION_LEN);
186 if (ret < 0)
187 return ret;
188
189 return (buf[1] << 8) | buf[0];
190 }
191
192 static int
193 isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
194 {
195 u8 buf[ISL1208_USR_SECTION_LEN];
196
197 buf[0] = usr & 0xff;
198 buf[1] = (usr >> 8) & 0xff;
199
200 return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
201 ISL1208_USR_SECTION_LEN);
202 }
203
204 static int
205 isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
206 {
207 struct i2c_client *const client = to_i2c_client(dev);
208 int sr, dtr, atr, usr;
209
210 sr = isl1208_i2c_get_sr(client);
211 if (sr < 0) {
212 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
213 return sr;
214 }
215
216 seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
217 (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
218 (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
219 (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
220 (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
221 (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
222 (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
223
224 seq_printf(seq, "batt_status\t: %s\n",
225 (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
226
227 dtr = isl1208_i2c_get_dtr(client);
228 if (dtr >= 0 - 1)
229 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
230
231 atr = isl1208_i2c_get_atr(client);
232 if (atr >= 0)
233 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
234 atr >> 2, (atr & 0x3) * 25);
235
236 usr = isl1208_i2c_get_usr(client);
237 if (usr >= 0)
238 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
239
240 return 0;
241 }
242
243 static int
244 isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
245 {
246 int sr;
247 u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
248
249 sr = isl1208_i2c_get_sr(client);
250 if (sr < 0) {
251 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
252 return -EIO;
253 }
254
255 sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
256 if (sr < 0) {
257 dev_err(&client->dev, "%s: reading RTC section failed\n",
258 __func__);
259 return sr;
260 }
261
262 tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SC]);
263 tm->tm_min = BCD2BIN(regs[ISL1208_REG_MN]);
264
265 /* HR field has a more complex interpretation */
266 {
267 const u8 _hr = regs[ISL1208_REG_HR];
268 if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
269 tm->tm_hour = BCD2BIN(_hr & 0x3f);
270 else {
271 /* 12h format */
272 tm->tm_hour = BCD2BIN(_hr & 0x1f);
273 if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
274 tm->tm_hour += 12;
275 }
276 }
277
278 tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DT]);
279 tm->tm_mon = BCD2BIN(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
280 tm->tm_year = BCD2BIN(regs[ISL1208_REG_YR]) + 100;
281 tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DW]);
282
283 return 0;
284 }
285
286 static int
287 isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
288 {
289 struct rtc_time *const tm = &alarm->time;
290 u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
291 int sr;
292
293 sr = isl1208_i2c_get_sr(client);
294 if (sr < 0) {
295 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
296 return sr;
297 }
298
299 sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
300 ISL1208_ALARM_SECTION_LEN);
301 if (sr < 0) {
302 dev_err(&client->dev, "%s: reading alarm section failed\n",
303 __func__);
304 return sr;
305 }
306
307 /* MSB of each alarm register is an enable bit */
308 tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
309 tm->tm_min = BCD2BIN(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
310 tm->tm_hour = BCD2BIN(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
311 tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
312 tm->tm_mon =
313 BCD2BIN(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
314 tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
315
316 return 0;
317 }
318
319 static int
320 isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
321 {
322 return isl1208_i2c_read_time(to_i2c_client(dev), tm);
323 }
324
325 static int
326 isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
327 {
328 int sr;
329 u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
330
331 regs[ISL1208_REG_SC] = BIN2BCD(tm->tm_sec);
332 regs[ISL1208_REG_MN] = BIN2BCD(tm->tm_min);
333 regs[ISL1208_REG_HR] = BIN2BCD(tm->tm_hour) | ISL1208_REG_HR_MIL;
334
335 regs[ISL1208_REG_DT] = BIN2BCD(tm->tm_mday);
336 regs[ISL1208_REG_MO] = BIN2BCD(tm->tm_mon + 1);
337 regs[ISL1208_REG_YR] = BIN2BCD(tm->tm_year - 100);
338
339 regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);
340
341 sr = isl1208_i2c_get_sr(client);
342 if (sr < 0) {
343 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
344 return sr;
345 }
346
347 /* set WRTC */
348 sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
349 sr | ISL1208_REG_SR_WRTC);
350 if (sr < 0) {
351 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
352 return sr;
353 }
354
355 /* write RTC registers */
356 sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
357 if (sr < 0) {
358 dev_err(&client->dev, "%s: writing RTC section failed\n",
359 __func__);
360 return sr;
361 }
362
363 /* clear WRTC again */
364 sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
365 sr & ~ISL1208_REG_SR_WRTC);
366 if (sr < 0) {
367 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
368 return sr;
369 }
370
371 return 0;
372 }
373
374
375 static int
376 isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
377 {
378 return isl1208_i2c_set_time(to_i2c_client(dev), tm);
379 }
380
381 static int
382 isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
383 {
384 return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
385 }
386
387 static const struct rtc_class_ops isl1208_rtc_ops = {
388 .proc = isl1208_rtc_proc,
389 .read_time = isl1208_rtc_read_time,
390 .set_time = isl1208_rtc_set_time,
391 .read_alarm = isl1208_rtc_read_alarm,
392 /*.set_alarm = isl1208_rtc_set_alarm, */
393 };
394
395 /* sysfs interface */
396
397 static ssize_t
398 isl1208_sysfs_show_atrim(struct device *dev,
399 struct device_attribute *attr, char *buf)
400 {
401 int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
402 if (atr < 0)
403 return atr;
404
405 return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
406 }
407
408 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
409
410 static ssize_t
411 isl1208_sysfs_show_dtrim(struct device *dev,
412 struct device_attribute *attr, char *buf)
413 {
414 int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
415 if (dtr < 0)
416 return dtr;
417
418 return sprintf(buf, "%d ppm\n", dtr);
419 }
420
421 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
422
423 static ssize_t
424 isl1208_sysfs_show_usr(struct device *dev,
425 struct device_attribute *attr, char *buf)
426 {
427 int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
428 if (usr < 0)
429 return usr;
430
431 return sprintf(buf, "0x%.4x\n", usr);
432 }
433
434 static ssize_t
435 isl1208_sysfs_store_usr(struct device *dev,
436 struct device_attribute *attr,
437 const char *buf, size_t count)
438 {
439 int usr = -1;
440
441 if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
442 if (sscanf(buf, "%x", &usr) != 1)
443 return -EINVAL;
444 } else {
445 if (sscanf(buf, "%d", &usr) != 1)
446 return -EINVAL;
447 }
448
449 if (usr < 0 || usr > 0xffff)
450 return -EINVAL;
451
452 return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
453 }
454
455 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
456 isl1208_sysfs_store_usr);
457
458 static int
459 isl1208_sysfs_register(struct device *dev)
460 {
461 int err;
462
463 err = device_create_file(dev, &dev_attr_atrim);
464 if (err)
465 return err;
466
467 err = device_create_file(dev, &dev_attr_dtrim);
468 if (err) {
469 device_remove_file(dev, &dev_attr_atrim);
470 return err;
471 }
472
473 err = device_create_file(dev, &dev_attr_usr);
474 if (err) {
475 device_remove_file(dev, &dev_attr_atrim);
476 device_remove_file(dev, &dev_attr_dtrim);
477 }
478
479 return 0;
480 }
481
482 static int
483 isl1208_sysfs_unregister(struct device *dev)
484 {
485 device_remove_file(dev, &dev_attr_atrim);
486 device_remove_file(dev, &dev_attr_atrim);
487 device_remove_file(dev, &dev_attr_usr);
488
489 return 0;
490 }
491
492 static int
493 isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
494 {
495 int rc = 0;
496 struct rtc_device *rtc;
497
498 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
499 return -ENODEV;
500
501 if (isl1208_i2c_validate_client(client) < 0)
502 return -ENODEV;
503
504 dev_info(&client->dev,
505 "chip found, driver version " DRV_VERSION "\n");
506
507 rtc = rtc_device_register(isl1208_driver.driver.name,
508 &client->dev, &isl1208_rtc_ops,
509 THIS_MODULE);
510 if (IS_ERR(rtc))
511 return PTR_ERR(rtc);
512
513 i2c_set_clientdata(client, rtc);
514
515 rc = isl1208_i2c_get_sr(client);
516 if (rc < 0) {
517 dev_err(&client->dev, "reading status failed\n");
518 goto exit_unregister;
519 }
520
521 if (rc & ISL1208_REG_SR_RTCF)
522 dev_warn(&client->dev, "rtc power failure detected, "
523 "please set clock.\n");
524
525 rc = isl1208_sysfs_register(&client->dev);
526 if (rc)
527 goto exit_unregister;
528
529 return 0;
530
531 exit_unregister:
532 rtc_device_unregister(rtc);
533
534 return rc;
535 }
536
537 static int
538 isl1208_remove(struct i2c_client *client)
539 {
540 struct rtc_device *rtc = i2c_get_clientdata(client);
541
542 isl1208_sysfs_unregister(&client->dev);
543 rtc_device_unregister(rtc);
544
545 return 0;
546 }
547
548 static const struct i2c_device_id isl1208_id[] = {
549 { "isl1208", 0 },
550 { }
551 };
552 MODULE_DEVICE_TABLE(i2c, isl1208_id);
553
554 static struct i2c_driver isl1208_driver = {
555 .driver = {
556 .name = "rtc-isl1208",
557 },
558 .probe = isl1208_probe,
559 .remove = isl1208_remove,
560 .id_table = isl1208_id,
561 };
562
563 static int __init
564 isl1208_init(void)
565 {
566 return i2c_add_driver(&isl1208_driver);
567 }
568
569 static void __exit
570 isl1208_exit(void)
571 {
572 i2c_del_driver(&isl1208_driver);
573 }
574
575 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
576 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
577 MODULE_LICENSE("GPL");
578 MODULE_VERSION(DRV_VERSION);
579
580 module_init(isl1208_init);
581 module_exit(isl1208_exit);
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