1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for Epson's RTC module RX-8025 SA/NB
4 *
5 * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
6 *
7 * Copyright (C) 2005 by Digi International Inc.
8 * All rights reserved.
9 *
10 * Modified by fengjh at rising.com.cn
11 * <lm-sensors@lm-sensors.org>
12 * 2006.11
13 *
14 * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
15 * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
16 * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
17 */
18 #include <linux/bcd.h>
19 #include <linux/bitops.h>
20 #include <linux/i2c.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/rtc.h>
24
25 /* Register definitions */
26 #define RX8025_REG_SEC 0x00
27 #define RX8025_REG_MIN 0x01
28 #define RX8025_REG_HOUR 0x02
29 #define RX8025_REG_WDAY 0x03
30 #define RX8025_REG_MDAY 0x04
31 #define RX8025_REG_MONTH 0x05
32 #define RX8025_REG_YEAR 0x06
33 #define RX8025_REG_DIGOFF 0x07
34 #define RX8025_REG_ALWMIN 0x08
35 #define RX8025_REG_ALWHOUR 0x09
36 #define RX8025_REG_ALWWDAY 0x0a
37 #define RX8025_REG_ALDMIN 0x0b
38 #define RX8025_REG_ALDHOUR 0x0c
39 /* 0x0d is reserved */
40 #define RX8025_REG_CTRL1 0x0e
41 #define RX8025_REG_CTRL2 0x0f
42
43 #define RX8025_BIT_CTRL1_CT (7 << 0)
44 /* 1 Hz periodic level irq */
45 #define RX8025_BIT_CTRL1_CT_1HZ 4
46 #define RX8025_BIT_CTRL1_TEST BIT(3)
47 #define RX8025_BIT_CTRL1_1224 BIT(5)
48 #define RX8025_BIT_CTRL1_DALE BIT(6)
49 #define RX8025_BIT_CTRL1_WALE BIT(7)
50
51 #define RX8025_BIT_CTRL2_DAFG BIT(0)
52 #define RX8025_BIT_CTRL2_WAFG BIT(1)
53 #define RX8025_BIT_CTRL2_CTFG BIT(2)
54 #define RX8025_BIT_CTRL2_PON BIT(4)
55 #define RX8025_BIT_CTRL2_XST BIT(5)
56 #define RX8025_BIT_CTRL2_VDET BIT(6)
57
58 /* Clock precision adjustment */
59 #define RX8025_ADJ_RESOLUTION 3050 /* in ppb */
60 #define RX8025_ADJ_DATA_MAX 62
61 #define RX8025_ADJ_DATA_MIN -62
62
63 static const struct i2c_device_id rx8025_id[] = {
64 { "rx8025", 0 },
65 { }
66 };
67 MODULE_DEVICE_TABLE(i2c, rx8025_id);
68
69 struct rx8025_data {
70 struct rtc_device *rtc;
71 u8 ctrl1;
72 };
73
rx8025_read_reg(const struct i2c_client * client,u8 number)74 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
75 {
76 return i2c_smbus_read_byte_data(client, number << 4);
77 }
78
rx8025_read_regs(const struct i2c_client * client,u8 number,u8 length,u8 * values)79 static int rx8025_read_regs(const struct i2c_client *client,
80 u8 number, u8 length, u8 *values)
81 {
82 int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
83 values);
84 if (ret != length)
85 return ret < 0 ? ret : -EIO;
86
87 return 0;
88 }
89
rx8025_write_reg(const struct i2c_client * client,u8 number,u8 value)90 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
91 u8 value)
92 {
93 return i2c_smbus_write_byte_data(client, number << 4, value);
94 }
95
rx8025_write_regs(const struct i2c_client * client,u8 number,u8 length,const u8 * values)96 static s32 rx8025_write_regs(const struct i2c_client *client,
97 u8 number, u8 length, const u8 *values)
98 {
99 return i2c_smbus_write_i2c_block_data(client, number << 4,
100 length, values);
101 }
102
rx8025_check_validity(struct device * dev)103 static int rx8025_check_validity(struct device *dev)
104 {
105 struct i2c_client *client = to_i2c_client(dev);
106 int ctrl2;
107
108 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
109 if (ctrl2 < 0)
110 return ctrl2;
111
112 if (ctrl2 & RX8025_BIT_CTRL2_VDET)
113 dev_warn(dev, "power voltage drop detected\n");
114
115 if (ctrl2 & RX8025_BIT_CTRL2_PON) {
116 dev_warn(dev, "power-on reset detected, date is invalid\n");
117 return -EINVAL;
118 }
119
120 if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
121 dev_warn(dev, "crystal stopped, date is invalid\n");
122 return -EINVAL;
123 }
124
125 return 0;
126 }
127
rx8025_reset_validity(struct i2c_client * client)128 static int rx8025_reset_validity(struct i2c_client *client)
129 {
130 int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
131
132 if (ctrl2 < 0)
133 return ctrl2;
134
135 ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
136
137 return rx8025_write_reg(client, RX8025_REG_CTRL2,
138 ctrl2 | RX8025_BIT_CTRL2_XST);
139 }
140
rx8025_handle_irq(int irq,void * dev_id)141 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
142 {
143 struct i2c_client *client = dev_id;
144 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
145 struct mutex *lock = &rx8025->rtc->ops_lock;
146 int status;
147
148 mutex_lock(lock);
149 status = rx8025_read_reg(client, RX8025_REG_CTRL2);
150 if (status < 0)
151 goto out;
152
153 if (!(status & RX8025_BIT_CTRL2_XST))
154 dev_warn(&client->dev, "Oscillation stop was detected,"
155 "you may have to readjust the clock\n");
156
157 if (status & RX8025_BIT_CTRL2_CTFG) {
158 /* periodic */
159 status &= ~RX8025_BIT_CTRL2_CTFG;
160 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
161 }
162
163 if (status & RX8025_BIT_CTRL2_DAFG) {
164 /* alarm */
165 status &= RX8025_BIT_CTRL2_DAFG;
166 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
167 rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
168 goto out;
169 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
170 }
171
172 out:
173 mutex_unlock(lock);
174
175 return IRQ_HANDLED;
176 }
177
rx8025_get_time(struct device * dev,struct rtc_time * dt)178 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
179 {
180 struct i2c_client *client = to_i2c_client(dev);
181 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
182 u8 date[7];
183 int err;
184
185 err = rx8025_check_validity(dev);
186 if (err)
187 return err;
188
189 err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
190 if (err)
191 return err;
192
193 dev_dbg(dev, "%s: read %7ph\n", __func__, date);
194
195 dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
196 dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
197 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
198 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
199 else
200 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
201 + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
202
203 dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
204 dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
205 dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
206
207 dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
208
209 return 0;
210 }
211
rx8025_set_time(struct device * dev,struct rtc_time * dt)212 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
213 {
214 struct i2c_client *client = to_i2c_client(dev);
215 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
216 u8 date[7];
217 int ret;
218
219 if ((dt->tm_year < 100) || (dt->tm_year > 199))
220 return -EINVAL;
221
222 /*
223 * Here the read-only bits are written as "0". I'm not sure if that
224 * is sound.
225 */
226 date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
227 date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
228 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
229 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
230 else
231 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
232 | bin2bcd((dt->tm_hour + 11) % 12 + 1);
233
234 date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
235 date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
236 date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
237 date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
238
239 dev_dbg(dev, "%s: write %7ph\n", __func__, date);
240
241 ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
242 if (ret < 0)
243 return ret;
244
245 return rx8025_reset_validity(client);
246 }
247
rx8025_init_client(struct i2c_client * client)248 static int rx8025_init_client(struct i2c_client *client)
249 {
250 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
251 u8 ctrl[2], ctrl2;
252 int need_clear = 0;
253 int err;
254
255 err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
256 if (err)
257 goto out;
258
259 /* Keep test bit zero ! */
260 rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
261
262 if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
263 dev_warn(&client->dev, "Alarm was detected\n");
264 need_clear = 1;
265 }
266
267 if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
268 need_clear = 1;
269
270 if (need_clear) {
271 ctrl2 = ctrl[1];
272 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
273 RX8025_BIT_CTRL2_DAFG);
274
275 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
276 }
277 out:
278 return err;
279 }
280
281 /* Alarm support */
rx8025_read_alarm(struct device * dev,struct rtc_wkalrm * t)282 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
283 {
284 struct i2c_client *client = to_i2c_client(dev);
285 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
286 u8 ald[2];
287 int ctrl2, err;
288
289 if (client->irq <= 0)
290 return -EINVAL;
291
292 err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
293 if (err)
294 return err;
295
296 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
297 if (ctrl2 < 0)
298 return ctrl2;
299
300 dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
301 __func__, ald[0], ald[1], ctrl2);
302
303 /* Hardware alarms precision is 1 minute! */
304 t->time.tm_sec = 0;
305 t->time.tm_min = bcd2bin(ald[0] & 0x7f);
306 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
307 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
308 else
309 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
310 + (ald[1] & 0x20 ? 12 : 0);
311
312 dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
313 t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
314 t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
315
316 return err;
317 }
318
rx8025_set_alarm(struct device * dev,struct rtc_wkalrm * t)319 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
320 {
321 struct i2c_client *client = to_i2c_client(dev);
322 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
323 u8 ald[2];
324 int err;
325
326 if (client->irq <= 0)
327 return -EINVAL;
328
329 /*
330 * Hardware alarm precision is 1 minute!
331 * round up to nearest minute
332 */
333 if (t->time.tm_sec) {
334 time64_t alarm_time = rtc_tm_to_time64(&t->time);
335
336 alarm_time += 60 - t->time.tm_sec;
337 rtc_time64_to_tm(alarm_time, &t->time);
338 }
339
340 ald[0] = bin2bcd(t->time.tm_min);
341 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
342 ald[1] = bin2bcd(t->time.tm_hour);
343 else
344 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
345 | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
346
347 dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
348
349 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
350 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
351 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
352 rx8025->ctrl1);
353 if (err)
354 return err;
355 }
356 err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
357 if (err)
358 return err;
359
360 if (t->enabled) {
361 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
362 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
363 rx8025->ctrl1);
364 if (err)
365 return err;
366 }
367
368 return 0;
369 }
370
rx8025_alarm_irq_enable(struct device * dev,unsigned int enabled)371 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
372 {
373 struct i2c_client *client = to_i2c_client(dev);
374 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
375 u8 ctrl1;
376 int err;
377
378 ctrl1 = rx8025->ctrl1;
379 if (enabled)
380 ctrl1 |= RX8025_BIT_CTRL1_DALE;
381 else
382 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
383
384 if (ctrl1 != rx8025->ctrl1) {
385 rx8025->ctrl1 = ctrl1;
386 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
387 rx8025->ctrl1);
388 if (err)
389 return err;
390 }
391 return 0;
392 }
393
394 static const struct rtc_class_ops rx8025_rtc_ops = {
395 .read_time = rx8025_get_time,
396 .set_time = rx8025_set_time,
397 .read_alarm = rx8025_read_alarm,
398 .set_alarm = rx8025_set_alarm,
399 .alarm_irq_enable = rx8025_alarm_irq_enable,
400 };
401
402 /*
403 * Clock precision adjustment support
404 *
405 * According to the RX8025 SA/NB application manual the frequency and
406 * temperature characteristics can be approximated using the following
407 * equation:
408 *
409 * df = a * (ut - t)**2
410 *
411 * df: Frequency deviation in any temperature
412 * a : Coefficient = (-35 +-5) * 10**-9
413 * ut: Ultimate temperature in degree = +25 +-5 degree
414 * t : Any temperature in degree
415 *
416 * Note that the clock adjustment in ppb must be entered (which is
417 * the negative value of the deviation).
418 */
rx8025_get_clock_adjust(struct device * dev,int * adj)419 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
420 {
421 struct i2c_client *client = to_i2c_client(dev);
422 int digoff;
423
424 digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
425 if (digoff < 0)
426 return digoff;
427
428 *adj = digoff >= 64 ? digoff - 128 : digoff;
429 if (*adj > 0)
430 (*adj)--;
431 *adj *= -RX8025_ADJ_RESOLUTION;
432
433 return 0;
434 }
435
rx8025_set_clock_adjust(struct device * dev,int adj)436 static int rx8025_set_clock_adjust(struct device *dev, int adj)
437 {
438 struct i2c_client *client = to_i2c_client(dev);
439 u8 digoff;
440 int err;
441
442 adj /= -RX8025_ADJ_RESOLUTION;
443 if (adj > RX8025_ADJ_DATA_MAX)
444 adj = RX8025_ADJ_DATA_MAX;
445 else if (adj < RX8025_ADJ_DATA_MIN)
446 adj = RX8025_ADJ_DATA_MIN;
447 else if (adj > 0)
448 adj++;
449 else if (adj < 0)
450 adj += 128;
451 digoff = adj;
452
453 err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
454 if (err)
455 return err;
456
457 dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
458
459 return 0;
460 }
461
rx8025_sysfs_show_clock_adjust(struct device * dev,struct device_attribute * attr,char * buf)462 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
463 struct device_attribute *attr,
464 char *buf)
465 {
466 int err, adj;
467
468 err = rx8025_get_clock_adjust(dev, &adj);
469 if (err)
470 return err;
471
472 return sprintf(buf, "%d\n", adj);
473 }
474
rx8025_sysfs_store_clock_adjust(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)475 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
476 struct device_attribute *attr,
477 const char *buf, size_t count)
478 {
479 int adj, err;
480
481 if (sscanf(buf, "%i", &adj) != 1)
482 return -EINVAL;
483
484 err = rx8025_set_clock_adjust(dev, adj);
485
486 return err ? err : count;
487 }
488
489 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
490 rx8025_sysfs_show_clock_adjust,
491 rx8025_sysfs_store_clock_adjust);
492
rx8025_sysfs_register(struct device * dev)493 static int rx8025_sysfs_register(struct device *dev)
494 {
495 return device_create_file(dev, &dev_attr_clock_adjust_ppb);
496 }
497
rx8025_sysfs_unregister(struct device * dev)498 static void rx8025_sysfs_unregister(struct device *dev)
499 {
500 device_remove_file(dev, &dev_attr_clock_adjust_ppb);
501 }
502
rx8025_probe(struct i2c_client * client,const struct i2c_device_id * id)503 static int rx8025_probe(struct i2c_client *client,
504 const struct i2c_device_id *id)
505 {
506 struct i2c_adapter *adapter = client->adapter;
507 struct rx8025_data *rx8025;
508 int err = 0;
509
510 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
511 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
512 dev_err(&adapter->dev,
513 "doesn't support required functionality\n");
514 return -EIO;
515 }
516
517 rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
518 if (!rx8025)
519 return -ENOMEM;
520
521 i2c_set_clientdata(client, rx8025);
522
523 err = rx8025_init_client(client);
524 if (err)
525 return err;
526
527 rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
528 &rx8025_rtc_ops, THIS_MODULE);
529 if (IS_ERR(rx8025->rtc)) {
530 dev_err(&client->dev, "unable to register the class device\n");
531 return PTR_ERR(rx8025->rtc);
532 }
533
534 if (client->irq > 0) {
535 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
536 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
537 rx8025_handle_irq,
538 IRQF_ONESHOT,
539 "rx8025", client);
540 if (err) {
541 dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
542 client->irq = 0;
543 }
544 }
545
546 rx8025->rtc->max_user_freq = 1;
547
548 /* the rx8025 alarm only supports a minute accuracy */
549 rx8025->rtc->uie_unsupported = 1;
550
551 err = rx8025_sysfs_register(&client->dev);
552 return err;
553 }
554
rx8025_remove(struct i2c_client * client)555 static int rx8025_remove(struct i2c_client *client)
556 {
557 rx8025_sysfs_unregister(&client->dev);
558 return 0;
559 }
560
561 static struct i2c_driver rx8025_driver = {
562 .driver = {
563 .name = "rtc-rx8025",
564 },
565 .probe = rx8025_probe,
566 .remove = rx8025_remove,
567 .id_table = rx8025_id,
568 };
569
570 module_i2c_driver(rx8025_driver);
571
572 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
573 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
574 MODULE_LICENSE("GPL");
575