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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / drivers / rtc / rtc-isl1208.c
blob725b0c73c33399e1ccf9000fb0066af25914a15b
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_NAME "isl1208"
19 #define DRV_VERSION "0.2"
20
21 /* Register map */
22 /* rtc section */
23 #define ISL1208_REG_SC 0x00
24 #define ISL1208_REG_MN 0x01
25 #define ISL1208_REG_HR 0x02
26 #define ISL1208_REG_HR_MIL (1<<7) /* 24h/12h mode */
27 #define ISL1208_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
28 #define ISL1208_REG_DT 0x03
29 #define ISL1208_REG_MO 0x04
30 #define ISL1208_REG_YR 0x05
31 #define ISL1208_REG_DW 0x06
32 #define ISL1208_RTC_SECTION_LEN 7
33
34 /* control/status section */
35 #define ISL1208_REG_SR 0x07
36 #define ISL1208_REG_SR_ARST (1<<7) /* auto reset */
37 #define ISL1208_REG_SR_XTOSCB (1<<6) /* crystal oscillator */
38 #define ISL1208_REG_SR_WRTC (1<<4) /* write rtc */
39 #define ISL1208_REG_SR_ALM (1<<2) /* alarm */
40 #define ISL1208_REG_SR_BAT (1<<1) /* battery */
41 #define ISL1208_REG_SR_RTCF (1<<0) /* rtc fail */
42 #define ISL1208_REG_INT 0x08
43 #define ISL1208_REG_09 0x09 /* reserved */
44 #define ISL1208_REG_ATR 0x0a
45 #define ISL1208_REG_DTR 0x0b
46
47 /* alarm section */
48 #define ISL1208_REG_SCA 0x0c
49 #define ISL1208_REG_MNA 0x0d
50 #define ISL1208_REG_HRA 0x0e
51 #define ISL1208_REG_DTA 0x0f
52 #define ISL1208_REG_MOA 0x10
53 #define ISL1208_REG_DWA 0x11
54 #define ISL1208_ALARM_SECTION_LEN 6
55
56 /* user section */
57 #define ISL1208_REG_USR1 0x12
58 #define ISL1208_REG_USR2 0x13
59 #define ISL1208_USR_SECTION_LEN 2
60
61 /* i2c configuration */
62 #define ISL1208_I2C_ADDR 0xde
63
64 static const unsigned short normal_i2c[] = {
65 ISL1208_I2C_ADDR>>1, I2C_CLIENT_END
66 };
67 I2C_CLIENT_INSMOD; /* defines addr_data */
68
69 static int isl1208_attach_adapter(struct i2c_adapter *adapter);
70 static int isl1208_detach_client(struct i2c_client *client);
71
72 static struct i2c_driver isl1208_driver = {
73 .driver = {
74 .name = DRV_NAME,
75 },
76 .id = I2C_DRIVERID_ISL1208,
77 .attach_adapter = &isl1208_attach_adapter,
78 .detach_client = &isl1208_detach_client,
79 };
80
81 /* block read */
82 static int
83 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
84 unsigned len)
85 {
86 u8 reg_addr[1] = { reg };
87 struct i2c_msg msgs[2] = {
88 { client->addr, client->flags, sizeof(reg_addr), reg_addr },
89 { client->addr, client->flags | I2C_M_RD, len, buf }
90 };
91 int ret;
92
93 BUG_ON(len == 0);
94 BUG_ON(reg > ISL1208_REG_USR2);
95 BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
96
97 ret = i2c_transfer(client->adapter, msgs, 2);
98 if (ret > 0)
99 ret = 0;
100 return ret;
101 }
102
103 /* block write */
104 static int
105 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
106 unsigned len)
107 {
108 u8 i2c_buf[ISL1208_REG_USR2 + 2];
109 struct i2c_msg msgs[1] = {
110 { client->addr, client->flags, len + 1, i2c_buf }
111 };
112 int ret;
113
114 BUG_ON(len == 0);
115 BUG_ON(reg > ISL1208_REG_USR2);
116 BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
117
118 i2c_buf[0] = reg;
119 memcpy(&i2c_buf[1], &buf[0], len);
120
121 ret = i2c_transfer(client->adapter, msgs, 1);
122 if (ret > 0)
123 ret = 0;
124 return ret;
125 }
126
127 /* simple check to see wether we have a isl1208 */
128 static int isl1208_i2c_validate_client(struct i2c_client *client)
129 {
130 u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
131 u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
132 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
133 };
134 int i;
135 int ret;
136
137 ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
138 if (ret < 0)
139 return ret;
140
141 for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
142 if (regs[i] & zero_mask[i]) /* check if bits are cleared */
143 return -ENODEV;
144 }
145
146 return 0;
147 }
148
149 static int isl1208_i2c_get_sr(struct i2c_client *client)
150 {
151 return i2c_smbus_read_byte_data(client, ISL1208_REG_SR) == -1 ? -EIO:0;
152 }
153
154 static int isl1208_i2c_get_atr(struct i2c_client *client)
155 {
156 int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
157
158 if (atr < 0)
159 return -EIO;
160
161 /* The 6bit value in the ATR register controls the load
162 * capacitance C_load * in steps of 0.25pF
163 *
164 * bit (1<<5) of the ATR register is inverted
165 *
166 * C_load(ATR=0x20) = 4.50pF
167 * C_load(ATR=0x00) = 12.50pF
168 * C_load(ATR=0x1f) = 20.25pF
169 *
170 */
171
172 atr &= 0x3f; /* mask out lsb */
173 atr ^= 1<<5; /* invert 6th bit */
174 atr += 2*9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
175
176 return atr;
177 }
178
179 static int isl1208_i2c_get_dtr(struct i2c_client *client)
180 {
181 int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
182
183 if (dtr < 0)
184 return -EIO;
185
186 /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
187 dtr = ((dtr & 0x3) * 20) * (dtr & (1<<2) ? -1 : 1);
188
189 return dtr;
190 }
191
192 static int isl1208_i2c_get_usr(struct i2c_client *client)
193 {
194 u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
195 int ret;
196
197 ret = isl1208_i2c_read_regs (client, ISL1208_REG_USR1, buf,
198 ISL1208_USR_SECTION_LEN);
199 if (ret < 0)
200 return ret;
201
202 return (buf[1] << 8) | buf[0];
203 }
204
205 static int isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
206 {
207 u8 buf[ISL1208_USR_SECTION_LEN];
208
209 buf[0] = usr & 0xff;
210 buf[1] = (usr >> 8) & 0xff;
211
212 return isl1208_i2c_set_regs (client, ISL1208_REG_USR1, buf,
213 ISL1208_USR_SECTION_LEN);
214 }
215
216 static int isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
217 {
218 struct i2c_client *const client = to_i2c_client(dev);
219 int sr, dtr, atr, usr;
220
221 sr = isl1208_i2c_get_sr(client);
222 if (sr < 0) {
223 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
224 return sr;
225 }
226
227 seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
228 (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
229 (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
230 (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
231 (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
232 (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
233 (sr & ISL1208_REG_SR_ARST) ? " ARST" : "",
234 sr);
235
236 seq_printf(seq, "batt_status\t: %s\n",
237 (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
238
239 dtr = isl1208_i2c_get_dtr(client);
240 if (dtr >= 0 -1)
241 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
242
243 atr = isl1208_i2c_get_atr(client);
244 if (atr >= 0)
245 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
246 atr>>2, (atr&0x3)*25);
247
248 usr = isl1208_i2c_get_usr(client);
249 if (usr >= 0)
250 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
251
252 return 0;
253 }
254
255
256 static int isl1208_i2c_read_time(struct i2c_client *client,
257 struct rtc_time *tm)
258 {
259 int sr;
260 u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
261
262 sr = isl1208_i2c_get_sr(client);
263 if (sr < 0) {
264 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
265 return -EIO;
266 }
267
268 sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
269 if (sr < 0) {
270 dev_err(&client->dev, "%s: reading RTC section failed\n",
271 __func__);
272 return sr;
273 }
274
275 tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SC]);
276 tm->tm_min = BCD2BIN(regs[ISL1208_REG_MN]);
277 { /* HR field has a more complex interpretation */
278 const u8 _hr = regs[ISL1208_REG_HR];
279 if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
280 tm->tm_hour = BCD2BIN(_hr & 0x3f);
281 else { // 12h format
282 tm->tm_hour = BCD2BIN(_hr & 0x1f);
283 if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
284 tm->tm_hour += 12;
285 }
286 }
287
288 tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DT]);
289 tm->tm_mon = BCD2BIN(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
290 tm->tm_year = BCD2BIN(regs[ISL1208_REG_YR]) + 100;
291 tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DW]);
292
293 return 0;
294 }
295
296 static int isl1208_i2c_read_alarm(struct i2c_client *client,
297 struct rtc_wkalrm *alarm)
298 {
299 struct rtc_time *const tm = &alarm->time;
300 u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
301 int sr;
302
303 sr = isl1208_i2c_get_sr(client);
304 if (sr < 0) {
305 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
306 return sr;
307 }
308
309 sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
310 ISL1208_ALARM_SECTION_LEN);
311 if (sr < 0) {
312 dev_err(&client->dev, "%s: reading alarm section failed\n",
313 __func__);
314 return sr;
315 }
316
317 /* MSB of each alarm register is an enable bit */
318 tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SCA-ISL1208_REG_SCA] & 0x7f);
319 tm->tm_min = BCD2BIN(regs[ISL1208_REG_MNA-ISL1208_REG_SCA] & 0x7f);
320 tm->tm_hour = BCD2BIN(regs[ISL1208_REG_HRA-ISL1208_REG_SCA] & 0x3f);
321 tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DTA-ISL1208_REG_SCA] & 0x3f);
322 tm->tm_mon = BCD2BIN(regs[ISL1208_REG_MOA-ISL1208_REG_SCA] & 0x1f)-1;
323 tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DWA-ISL1208_REG_SCA] & 0x03);
324
325 return 0;
326 }
327
328 static int isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
329 {
330 return isl1208_i2c_read_time(to_i2c_client(dev), tm);
331 }
332
333 static int isl1208_i2c_set_time(struct i2c_client *client,
334 struct rtc_time const *tm)
335 {
336 int sr;
337 u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
338
339 regs[ISL1208_REG_SC] = BIN2BCD(tm->tm_sec);
340 regs[ISL1208_REG_MN] = BIN2BCD(tm->tm_min);
341 regs[ISL1208_REG_HR] = BIN2BCD(tm->tm_hour) | ISL1208_REG_HR_MIL;
342
343 regs[ISL1208_REG_DT] = BIN2BCD(tm->tm_mday);
344 regs[ISL1208_REG_MO] = BIN2BCD(tm->tm_mon + 1);
345 regs[ISL1208_REG_YR] = BIN2BCD(tm->tm_year - 100);
346
347 regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);
348
349 sr = isl1208_i2c_get_sr(client);
350 if (sr < 0) {
351 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
352 return sr;
353 }
354
355 /* set WRTC */
356 sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
357 sr | ISL1208_REG_SR_WRTC);
358 if (sr < 0) {
359 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
360 return sr;
361 }
362
363 /* write RTC registers */
364 sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
365 if (sr < 0) {
366 dev_err(&client->dev, "%s: writing RTC section failed\n",
367 __func__);
368 return sr;
369 }
370
371 /* clear WRTC again */
372 sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
373 sr & ~ISL1208_REG_SR_WRTC);
374 if (sr < 0) {
375 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
376 return sr;
377 }
378
379 return 0;
380 }
381
382
383 static int isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
384 {
385 return isl1208_i2c_set_time(to_i2c_client(dev), tm);
386 }
387
388 static int isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
389 {
390 return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
391 }
392
393 static const struct rtc_class_ops isl1208_rtc_ops = {
394 .proc = isl1208_rtc_proc,
395 .read_time = isl1208_rtc_read_time,
396 .set_time = isl1208_rtc_set_time,
397 .read_alarm = isl1208_rtc_read_alarm,
398 //.set_alarm = isl1208_rtc_set_alarm,
399 };
400
401 /* sysfs interface */
402
403 static ssize_t isl1208_sysfs_show_atrim(struct device *dev,
404 struct device_attribute *attr,
405 char *buf)
406 {
407 int atr;
408
409 atr = isl1208_i2c_get_atr(to_i2c_client(dev));
410 if (atr < 0)
411 return atr;
412
413 return sprintf(buf, "%d.%.2d pF\n", atr>>2, (atr&0x3)*25);
414 }
415 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
416
417 static ssize_t isl1208_sysfs_show_dtrim(struct device *dev,
418 struct device_attribute *attr,
419 char *buf)
420 {
421 int dtr;
422
423 dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
424 if (dtr < 0)
425 return dtr;
426
427 return sprintf(buf, "%d ppm\n", dtr);
428 }
429 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
430
431 static ssize_t isl1208_sysfs_show_usr(struct device *dev,
432 struct device_attribute *attr,
433 char *buf)
434 {
435 int usr;
436
437 usr = isl1208_i2c_get_usr(to_i2c_client(dev));
438 if (usr < 0)
439 return usr;
440
441 return sprintf(buf, "0x%.4x\n", usr);
442 }
443
444 static ssize_t isl1208_sysfs_store_usr(struct device *dev,
445 struct device_attribute *attr,
446 const char *buf, size_t count)
447 {
448 int usr = -1;
449
450 if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
451 if (sscanf(buf, "%x", &usr) != 1)
452 return -EINVAL;
453 } else {
454 if (sscanf(buf, "%d", &usr) != 1)
455 return -EINVAL;
456 }
457
458 if (usr < 0 || usr > 0xffff)
459 return -EINVAL;
460
461 return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
462 }
463 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
464 isl1208_sysfs_store_usr);
465
466 static int
467 isl1208_probe(struct i2c_adapter *adapter, int addr, int kind)
468 {
469 int rc = 0;
470 struct i2c_client *new_client = NULL;
471 struct rtc_device *rtc = NULL;
472
473 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
474 rc = -ENODEV;
475 goto failout;
476 }
477
478 new_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
479 if (new_client == NULL) {
480 rc = -ENOMEM;
481 goto failout;
482 }
483
484 new_client->addr = addr;
485 new_client->adapter = adapter;
486 new_client->driver = &isl1208_driver;
487 new_client->flags = 0;
488 strcpy(new_client->name, DRV_NAME);
489
490 if (kind < 0) {
491 rc = isl1208_i2c_validate_client(new_client);
492 if (rc < 0)
493 goto failout;
494 }
495
496 rc = i2c_attach_client(new_client);
497 if (rc < 0)
498 goto failout;
499
500 dev_info(&new_client->dev,
501 "chip found, driver version " DRV_VERSION "\n");
502
503 rtc = rtc_device_register(isl1208_driver.driver.name,
504 &new_client->dev,
505 &isl1208_rtc_ops, THIS_MODULE);
506
507 if (IS_ERR(rtc)) {
508 rc = PTR_ERR(rtc);
509 goto failout_detach;
510 }
511
512 i2c_set_clientdata(new_client, rtc);
513
514 rc = isl1208_i2c_get_sr(new_client);
515 if (rc < 0) {
516 dev_err(&new_client->dev, "reading status failed\n");
517 goto failout_unregister;
518 }
519
520 if (rc & ISL1208_REG_SR_RTCF)
521 dev_warn(&new_client->dev, "rtc power failure detected, "
522 "please set clock.\n");
523
524 rc = device_create_file(&new_client->dev, &dev_attr_atrim);
525 if (rc < 0)
526 goto failout_unregister;
527 rc = device_create_file(&new_client->dev, &dev_attr_dtrim);
528 if (rc < 0)
529 goto failout_atrim;
530 rc = device_create_file(&new_client->dev, &dev_attr_usr);
531 if (rc < 0)
532 goto failout_dtrim;
533
534 return 0;
535
536 failout_dtrim:
537 device_remove_file(&new_client->dev, &dev_attr_dtrim);
538 failout_atrim:
539 device_remove_file(&new_client->dev, &dev_attr_atrim);
540 failout_unregister:
541 rtc_device_unregister(rtc);
542 failout_detach:
543 i2c_detach_client(new_client);
544 failout:
545 kfree(new_client);
546 return rc;
547 }
548
549 static int
550 isl1208_attach_adapter (struct i2c_adapter *adapter)
551 {
552 return i2c_probe(adapter, &addr_data, isl1208_probe);
553 }
554
555 static int
556 isl1208_detach_client(struct i2c_client *client)
557 {
558 int rc;
559 struct rtc_device *const rtc = i2c_get_clientdata(client);
560
561 if (rtc)
562 rtc_device_unregister(rtc); /* do we need to kfree? */
563
564 rc = i2c_detach_client(client);
565 if (rc)
566 return rc;
567
568 kfree(client);
569
570 return 0;
571 }
572
573 /* module management */
574
575 static int __init isl1208_init(void)
576 {
577 return i2c_add_driver(&isl1208_driver);
578 }
579
580 static void __exit isl1208_exit(void)
581 {
582 i2c_del_driver(&isl1208_driver);
583 }
584
585 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
586 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
587 MODULE_LICENSE("GPL");
588 MODULE_VERSION(DRV_VERSION);
589
590 module_init(isl1208_init);
591 module_exit(isl1208_exit);
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