1 /*
2 * Seiko Instruments S-35390A RTC Driver
3 *
4 * Copyright (c) 2007 Byron Bradley
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/module.h>
13 #include <linux/rtc.h>
14 #include <linux/i2c.h>
15 #include <linux/bitrev.h>
16 #include <linux/bcd.h>
17 #include <linux/slab.h>
18 #include <linux/delay.h>
19
20 #define S35390A_CMD_STATUS1 0
21 #define S35390A_CMD_STATUS2 1
22 #define S35390A_CMD_TIME1 2
23 #define S35390A_CMD_TIME2 3
24 #define S35390A_CMD_INT2_REG1 5
25
26 #define S35390A_BYTE_YEAR 0
27 #define S35390A_BYTE_MONTH 1
28 #define S35390A_BYTE_DAY 2
29 #define S35390A_BYTE_WDAY 3
30 #define S35390A_BYTE_HOURS 4
31 #define S35390A_BYTE_MINS 5
32 #define S35390A_BYTE_SECS 6
33
34 #define S35390A_ALRM_BYTE_WDAY 0
35 #define S35390A_ALRM_BYTE_HOURS 1
36 #define S35390A_ALRM_BYTE_MINS 2
37
38 /* flags for STATUS1 */
39 #define S35390A_FLAG_POC 0x01
40 #define S35390A_FLAG_BLD 0x02
41 #define S35390A_FLAG_INT2 0x04
42 #define S35390A_FLAG_24H 0x40
43 #define S35390A_FLAG_RESET 0x80
44
45 /* flag for STATUS2 */
46 #define S35390A_FLAG_TEST 0x01
47
48 #define S35390A_INT2_MODE_MASK 0xF0
49
50 #define S35390A_INT2_MODE_NOINTR 0x00
51 #define S35390A_INT2_MODE_FREQ 0x10
52 #define S35390A_INT2_MODE_ALARM 0x40
53 #define S35390A_INT2_MODE_PMIN_EDG 0x20
54
55 static const struct i2c_device_id s35390a_id[] = {
56 { "s35390a", 0 },
57 { }
58 };
59 MODULE_DEVICE_TABLE(i2c, s35390a_id);
60
61 struct s35390a {
62 struct i2c_client *client[8];
63 struct rtc_device *rtc;
64 int twentyfourhour;
65 };
66
s35390a_set_reg(struct s35390a * s35390a,int reg,char * buf,int len)67 static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
68 {
69 struct i2c_client *client = s35390a->client[reg];
70 struct i2c_msg msg[] = {
71 {
72 .addr = client->addr,
73 .len = len,
74 .buf = buf
75 },
76 };
77
78 if ((i2c_transfer(client->adapter, msg, 1)) != 1)
79 return -EIO;
80
81 return 0;
82 }
83
s35390a_get_reg(struct s35390a * s35390a,int reg,char * buf,int len)84 static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
85 {
86 struct i2c_client *client = s35390a->client[reg];
87 struct i2c_msg msg[] = {
88 {
89 .addr = client->addr,
90 .flags = I2C_M_RD,
91 .len = len,
92 .buf = buf
93 },
94 };
95
96 if ((i2c_transfer(client->adapter, msg, 1)) != 1)
97 return -EIO;
98
99 return 0;
100 }
101
102 /*
103 * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
104 * To keep the information if an irq is pending, pass the value read from
105 * STATUS1 to the caller.
106 */
s35390a_reset(struct s35390a * s35390a,char * status1)107 static int s35390a_reset(struct s35390a *s35390a, char *status1)
108 {
109 char buf;
110 int ret;
111 unsigned initcount = 0;
112
113 ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
114 if (ret < 0)
115 return ret;
116
117 if (*status1 & S35390A_FLAG_POC)
118 /*
119 * Do not communicate for 0.5 seconds since the power-on
120 * detection circuit is in operation.
121 */
122 msleep(500);
123 else if (!(*status1 & S35390A_FLAG_BLD))
124 /*
125 * If both POC and BLD are unset everything is fine.
126 */
127 return 0;
128
129 /*
130 * At least one of POC and BLD are set, so reinitialise chip. Keeping
131 * this information in the hardware to know later that the time isn't
132 * valid is unfortunately not possible because POC and BLD are cleared
133 * on read. So the reset is best done now.
134 *
135 * The 24H bit is kept over reset, so set it already here.
136 */
137 initialize:
138 *status1 = S35390A_FLAG_24H;
139 buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
140 ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
141
142 if (ret < 0)
143 return ret;
144
145 ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
146 if (ret < 0)
147 return ret;
148
149 if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) {
150 /* Try up to five times to reset the chip */
151 if (initcount < 5) {
152 ++initcount;
153 goto initialize;
154 } else
155 return -EIO;
156 }
157
158 return 1;
159 }
160
s35390a_disable_test_mode(struct s35390a * s35390a)161 static int s35390a_disable_test_mode(struct s35390a *s35390a)
162 {
163 char buf[1];
164
165 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
166 return -EIO;
167
168 if (!(buf[0] & S35390A_FLAG_TEST))
169 return 0;
170
171 buf[0] &= ~S35390A_FLAG_TEST;
172 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
173 }
174
s35390a_hr2reg(struct s35390a * s35390a,int hour)175 static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
176 {
177 if (s35390a->twentyfourhour)
178 return bin2bcd(hour);
179
180 if (hour < 12)
181 return bin2bcd(hour);
182
183 return 0x40 | bin2bcd(hour - 12);
184 }
185
s35390a_reg2hr(struct s35390a * s35390a,char reg)186 static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
187 {
188 unsigned hour;
189
190 if (s35390a->twentyfourhour)
191 return bcd2bin(reg & 0x3f);
192
193 hour = bcd2bin(reg & 0x3f);
194 if (reg & 0x40)
195 hour += 12;
196
197 return hour;
198 }
199
s35390a_set_datetime(struct i2c_client * client,struct rtc_time * tm)200 static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
201 {
202 struct s35390a *s35390a = i2c_get_clientdata(client);
203 int i, err;
204 char buf[7];
205
206 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
207 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
208 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
209 tm->tm_wday);
210
211 buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
212 buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
213 buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
214 buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
215 buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
216 buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
217 buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
218
219 /* This chip expects the bits of each byte to be in reverse order */
220 for (i = 0; i < 7; ++i)
221 buf[i] = bitrev8(buf[i]);
222
223 err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
224
225 return err;
226 }
227
s35390a_get_datetime(struct i2c_client * client,struct rtc_time * tm)228 static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
229 {
230 struct s35390a *s35390a = i2c_get_clientdata(client);
231 char buf[7];
232 int i, err;
233
234 err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
235 if (err < 0)
236 return err;
237
238 /* This chip returns the bits of each byte in reverse order */
239 for (i = 0; i < 7; ++i)
240 buf[i] = bitrev8(buf[i]);
241
242 tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
243 tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
244 tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
245 tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
246 tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
247 tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
248 tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
249
250 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
251 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
252 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
253 tm->tm_wday);
254
255 return rtc_valid_tm(tm);
256 }
257
s35390a_set_alarm(struct i2c_client * client,struct rtc_wkalrm * alm)258 static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
259 {
260 struct s35390a *s35390a = i2c_get_clientdata(client);
261 char buf[3], sts = 0;
262 int err, i;
263
264 dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
265 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
266 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
267 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
268
269 /* disable interrupt */
270 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
271 if (err < 0)
272 return err;
273
274 /* clear pending interrupt, if any */
275 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
276 if (err < 0)
277 return err;
278
279 if (alm->enabled)
280 sts = S35390A_INT2_MODE_ALARM;
281 else
282 sts = S35390A_INT2_MODE_NOINTR;
283
284 /* This chip expects the bits of each byte to be in reverse order */
285 sts = bitrev8(sts);
286
287 /* set interupt mode*/
288 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
289 if (err < 0)
290 return err;
291
292 if (alm->time.tm_wday != -1)
293 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
294 else
295 buf[S35390A_ALRM_BYTE_WDAY] = 0;
296
297 buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
298 alm->time.tm_hour) | 0x80;
299 buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
300
301 if (alm->time.tm_hour >= 12)
302 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
303
304 for (i = 0; i < 3; ++i)
305 buf[i] = bitrev8(buf[i]);
306
307 err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
308 sizeof(buf));
309
310 return err;
311 }
312
s35390a_read_alarm(struct i2c_client * client,struct rtc_wkalrm * alm)313 static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
314 {
315 struct s35390a *s35390a = i2c_get_clientdata(client);
316 char buf[3], sts;
317 int i, err;
318
319 /*
320 * initialize all members to -1 to signal the core that they are not
321 * defined by the hardware.
322 */
323 alm->time.tm_sec = -1;
324 alm->time.tm_min = -1;
325 alm->time.tm_hour = -1;
326 alm->time.tm_mday = -1;
327 alm->time.tm_mon = -1;
328 alm->time.tm_year = -1;
329 alm->time.tm_wday = -1;
330 alm->time.tm_yday = -1;
331 alm->time.tm_isdst = -1;
332
333 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
334 if (err < 0)
335 return err;
336
337 if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
338 /*
339 * When the alarm isn't enabled, the register to configure
340 * the alarm time isn't accessible.
341 */
342 alm->enabled = 0;
343 return 0;
344 } else {
345 alm->enabled = 1;
346 }
347
348 err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
349 if (err < 0)
350 return err;
351
352 /* This chip returns the bits of each byte in reverse order */
353 for (i = 0; i < 3; ++i)
354 buf[i] = bitrev8(buf[i]);
355
356 /*
357 * B0 of the three matching registers is an enable flag. Iff it is set
358 * the configured value is used for matching.
359 */
360 if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
361 alm->time.tm_wday =
362 bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
363
364 if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
365 alm->time.tm_hour =
366 s35390a_reg2hr(s35390a,
367 buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
368
369 if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
370 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
371
372 /* alarm triggers always at s=0 */
373 alm->time.tm_sec = 0;
374
375 dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
376 __func__, alm->time.tm_min, alm->time.tm_hour,
377 alm->time.tm_wday);
378
379 return 0;
380 }
381
s35390a_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alm)382 static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
383 {
384 return s35390a_read_alarm(to_i2c_client(dev), alm);
385 }
386
s35390a_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alm)387 static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
388 {
389 return s35390a_set_alarm(to_i2c_client(dev), alm);
390 }
391
s35390a_rtc_read_time(struct device * dev,struct rtc_time * tm)392 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
393 {
394 return s35390a_get_datetime(to_i2c_client(dev), tm);
395 }
396
s35390a_rtc_set_time(struct device * dev,struct rtc_time * tm)397 static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
398 {
399 return s35390a_set_datetime(to_i2c_client(dev), tm);
400 }
401
402 static const struct rtc_class_ops s35390a_rtc_ops = {
403 .read_time = s35390a_rtc_read_time,
404 .set_time = s35390a_rtc_set_time,
405 .set_alarm = s35390a_rtc_set_alarm,
406 .read_alarm = s35390a_rtc_read_alarm,
407
408 };
409
410 static struct i2c_driver s35390a_driver;
411
s35390a_probe(struct i2c_client * client,const struct i2c_device_id * id)412 static int s35390a_probe(struct i2c_client *client,
413 const struct i2c_device_id *id)
414 {
415 int err, err_reset;
416 unsigned int i;
417 struct s35390a *s35390a;
418 struct rtc_time tm;
419 char buf, status1;
420
421 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
422 err = -ENODEV;
423 goto exit;
424 }
425
426 s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a),
427 GFP_KERNEL);
428 if (!s35390a) {
429 err = -ENOMEM;
430 goto exit;
431 }
432
433 s35390a->client[0] = client;
434 i2c_set_clientdata(client, s35390a);
435
436 /* This chip uses multiple addresses, use dummy devices for them */
437 for (i = 1; i < 8; ++i) {
438 s35390a->client[i] = i2c_new_dummy(client->adapter,
439 client->addr + i);
440 if (!s35390a->client[i]) {
441 dev_err(&client->dev, "Address %02x unavailable\n",
442 client->addr + i);
443 err = -EBUSY;
444 goto exit_dummy;
445 }
446 }
447
448 err_reset = s35390a_reset(s35390a, &status1);
449 if (err_reset < 0) {
450 err = err_reset;
451 dev_err(&client->dev, "error resetting chip\n");
452 goto exit_dummy;
453 }
454
455 if (status1 & S35390A_FLAG_24H)
456 s35390a->twentyfourhour = 1;
457 else
458 s35390a->twentyfourhour = 0;
459
460 if (status1 & S35390A_FLAG_INT2) {
461 /* disable alarm (and maybe test mode) */
462 buf = 0;
463 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
464 if (err < 0) {
465 dev_err(&client->dev, "error disabling alarm");
466 goto exit_dummy;
467 }
468 } else {
469 err = s35390a_disable_test_mode(s35390a);
470 if (err < 0) {
471 dev_err(&client->dev, "error disabling test mode\n");
472 goto exit_dummy;
473 }
474 }
475
476 if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0)
477 dev_warn(&client->dev, "clock needs to be set\n");
478
479 device_set_wakeup_capable(&client->dev, 1);
480
481 s35390a->rtc = devm_rtc_device_register(&client->dev,
482 s35390a_driver.driver.name,
483 &s35390a_rtc_ops, THIS_MODULE);
484
485 if (IS_ERR(s35390a->rtc)) {
486 err = PTR_ERR(s35390a->rtc);
487 goto exit_dummy;
488 }
489
490 if (status1 & S35390A_FLAG_INT2)
491 rtc_update_irq(s35390a->rtc, 1, RTC_AF);
492
493 return 0;
494
495 exit_dummy:
496 for (i = 1; i < 8; ++i)
497 if (s35390a->client[i])
498 i2c_unregister_device(s35390a->client[i]);
499
500 exit:
501 return err;
502 }
503
s35390a_remove(struct i2c_client * client)504 static int s35390a_remove(struct i2c_client *client)
505 {
506 unsigned int i;
507 struct s35390a *s35390a = i2c_get_clientdata(client);
508
509 for (i = 1; i < 8; ++i)
510 if (s35390a->client[i])
511 i2c_unregister_device(s35390a->client[i]);
512
513 return 0;
514 }
515
516 static struct i2c_driver s35390a_driver = {
517 .driver = {
518 .name = "rtc-s35390a",
519 },
520 .probe = s35390a_probe,
521 .remove = s35390a_remove,
522 .id_table = s35390a_id,
523 };
524
525 module_i2c_driver(s35390a_driver);
526
527 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
528 MODULE_DESCRIPTION("S35390A RTC driver");
529 MODULE_LICENSE("GPL");
530