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 enum rx_model {
64 model_rx_unknown,
65 model_rx_8025,
66 model_rx_8035,
67 model_last
68 };
69
70 static const struct i2c_device_id rx8025_id[] = {
71 { "rx8025", model_rx_8025 },
72 { "rx8035", model_rx_8035 },
73 { }
74 };
75 MODULE_DEVICE_TABLE(i2c, rx8025_id);
76
77 struct rx8025_data {
78 struct rtc_device *rtc;
79 enum rx_model model;
80 u8 ctrl1;
81 };
82
rx8025_read_reg(const struct i2c_client * client,u8 number)83 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
84 {
85 return i2c_smbus_read_byte_data(client, number << 4);
86 }
87
rx8025_read_regs(const struct i2c_client * client,u8 number,u8 length,u8 * values)88 static int rx8025_read_regs(const struct i2c_client *client,
89 u8 number, u8 length, u8 *values)
90 {
91 int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
92 values);
93 if (ret != length)
94 return ret < 0 ? ret : -EIO;
95
96 return 0;
97 }
98
rx8025_write_reg(const struct i2c_client * client,u8 number,u8 value)99 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
100 u8 value)
101 {
102 return i2c_smbus_write_byte_data(client, number << 4, value);
103 }
104
rx8025_write_regs(const struct i2c_client * client,u8 number,u8 length,const u8 * values)105 static s32 rx8025_write_regs(const struct i2c_client *client,
106 u8 number, u8 length, const u8 *values)
107 {
108 return i2c_smbus_write_i2c_block_data(client, number << 4,
109 length, values);
110 }
111
rx8025_is_osc_stopped(enum rx_model model,int ctrl2)112 static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
113 {
114 int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
115 /* XSTP bit has different polarity on RX-8025 vs RX-8035.
116 * RX-8025: 0 == oscillator stopped
117 * RX-8035: 1 == oscillator stopped
118 */
119
120 if (model == model_rx_8025)
121 xstp = !xstp;
122
123 return xstp;
124 }
125
rx8025_check_validity(struct device * dev)126 static int rx8025_check_validity(struct device *dev)
127 {
128 struct i2c_client *client = to_i2c_client(dev);
129 struct rx8025_data *drvdata = dev_get_drvdata(dev);
130 int ctrl2;
131 int xstp;
132
133 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
134 if (ctrl2 < 0)
135 return ctrl2;
136
137 if (ctrl2 & RX8025_BIT_CTRL2_VDET)
138 dev_warn(dev, "power voltage drop detected\n");
139
140 if (ctrl2 & RX8025_BIT_CTRL2_PON) {
141 dev_warn(dev, "power-on reset detected, date is invalid\n");
142 return -EINVAL;
143 }
144
145 xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
146 if (xstp) {
147 dev_warn(dev, "crystal stopped, date is invalid\n");
148 return -EINVAL;
149 }
150
151 return 0;
152 }
153
rx8025_reset_validity(struct i2c_client * client)154 static int rx8025_reset_validity(struct i2c_client *client)
155 {
156 struct rx8025_data *drvdata = i2c_get_clientdata(client);
157 int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
158
159 if (ctrl2 < 0)
160 return ctrl2;
161
162 ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
163
164 if (drvdata->model == model_rx_8025)
165 ctrl2 |= RX8025_BIT_CTRL2_XST;
166 else
167 ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
168
169 return rx8025_write_reg(client, RX8025_REG_CTRL2,
170 ctrl2);
171 }
172
rx8025_handle_irq(int irq,void * dev_id)173 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
174 {
175 struct i2c_client *client = dev_id;
176 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
177 int status, xstp;
178
179 rtc_lock(rx8025->rtc);
180 status = rx8025_read_reg(client, RX8025_REG_CTRL2);
181 if (status < 0)
182 goto out;
183
184 xstp = rx8025_is_osc_stopped(rx8025->model, status);
185 if (xstp)
186 dev_warn(&client->dev, "Oscillation stop was detected,"
187 "you may have to readjust the clock\n");
188
189 if (status & RX8025_BIT_CTRL2_CTFG) {
190 /* periodic */
191 status &= ~RX8025_BIT_CTRL2_CTFG;
192 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
193 }
194
195 if (status & RX8025_BIT_CTRL2_DAFG) {
196 /* alarm */
197 status &= RX8025_BIT_CTRL2_DAFG;
198 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
199 rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
200 goto out;
201 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
202 }
203
204 out:
205 rtc_unlock(rx8025->rtc);
206
207 return IRQ_HANDLED;
208 }
209
rx8025_get_time(struct device * dev,struct rtc_time * dt)210 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
211 {
212 struct i2c_client *client = to_i2c_client(dev);
213 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
214 u8 date[7];
215 int err;
216
217 err = rx8025_check_validity(dev);
218 if (err)
219 return err;
220
221 err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
222 if (err)
223 return err;
224
225 dev_dbg(dev, "%s: read %7ph\n", __func__, date);
226
227 dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
228 dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
229 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
230 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
231 else
232 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
233 + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
234
235 dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
236 dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
237 dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
238
239 dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
240
241 return 0;
242 }
243
rx8025_set_time(struct device * dev,struct rtc_time * dt)244 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
245 {
246 struct i2c_client *client = to_i2c_client(dev);
247 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
248 u8 date[7];
249 int ret;
250
251 if ((dt->tm_year < 100) || (dt->tm_year > 199))
252 return -EINVAL;
253
254 /*
255 * Here the read-only bits are written as "0". I'm not sure if that
256 * is sound.
257 */
258 date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
259 date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
260 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
261 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
262 else
263 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
264 | bin2bcd((dt->tm_hour + 11) % 12 + 1);
265
266 date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
267 date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
268 date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
269 date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
270
271 dev_dbg(dev, "%s: write %7ph\n", __func__, date);
272
273 ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
274 if (ret < 0)
275 return ret;
276
277 return rx8025_reset_validity(client);
278 }
279
rx8025_init_client(struct i2c_client * client)280 static int rx8025_init_client(struct i2c_client *client)
281 {
282 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
283 u8 ctrl[2], ctrl2;
284 int need_clear = 0;
285 int err;
286
287 err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
288 if (err)
289 goto out;
290
291 /* Keep test bit zero ! */
292 rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
293
294 if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
295 dev_warn(&client->dev, "Alarm was detected\n");
296 need_clear = 1;
297 }
298
299 if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
300 need_clear = 1;
301
302 if (need_clear) {
303 ctrl2 = ctrl[1];
304 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
305 RX8025_BIT_CTRL2_DAFG);
306
307 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
308 }
309 out:
310 return err;
311 }
312
313 /* Alarm support */
rx8025_read_alarm(struct device * dev,struct rtc_wkalrm * t)314 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
315 {
316 struct i2c_client *client = to_i2c_client(dev);
317 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
318 u8 ald[2];
319 int ctrl2, err;
320
321 if (client->irq <= 0)
322 return -EINVAL;
323
324 err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
325 if (err)
326 return err;
327
328 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
329 if (ctrl2 < 0)
330 return ctrl2;
331
332 dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
333 __func__, ald[0], ald[1], ctrl2);
334
335 /* Hardware alarms precision is 1 minute! */
336 t->time.tm_sec = 0;
337 t->time.tm_min = bcd2bin(ald[0] & 0x7f);
338 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
339 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
340 else
341 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
342 + (ald[1] & 0x20 ? 12 : 0);
343
344 dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
345 t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
346 t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
347
348 return err;
349 }
350
rx8025_set_alarm(struct device * dev,struct rtc_wkalrm * t)351 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
352 {
353 struct i2c_client *client = to_i2c_client(dev);
354 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
355 u8 ald[2];
356 int err;
357
358 if (client->irq <= 0)
359 return -EINVAL;
360
361 /*
362 * Hardware alarm precision is 1 minute!
363 * round up to nearest minute
364 */
365 if (t->time.tm_sec) {
366 time64_t alarm_time = rtc_tm_to_time64(&t->time);
367
368 alarm_time += 60 - t->time.tm_sec;
369 rtc_time64_to_tm(alarm_time, &t->time);
370 }
371
372 ald[0] = bin2bcd(t->time.tm_min);
373 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
374 ald[1] = bin2bcd(t->time.tm_hour);
375 else
376 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
377 | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
378
379 dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
380
381 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
382 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
383 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
384 rx8025->ctrl1);
385 if (err)
386 return err;
387 }
388 err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
389 if (err)
390 return err;
391
392 if (t->enabled) {
393 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
394 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
395 rx8025->ctrl1);
396 if (err)
397 return err;
398 }
399
400 return 0;
401 }
402
rx8025_alarm_irq_enable(struct device * dev,unsigned int enabled)403 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
404 {
405 struct i2c_client *client = to_i2c_client(dev);
406 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
407 u8 ctrl1;
408 int err;
409
410 ctrl1 = rx8025->ctrl1;
411 if (enabled)
412 ctrl1 |= RX8025_BIT_CTRL1_DALE;
413 else
414 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
415
416 if (ctrl1 != rx8025->ctrl1) {
417 rx8025->ctrl1 = ctrl1;
418 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
419 rx8025->ctrl1);
420 if (err)
421 return err;
422 }
423 return 0;
424 }
425
426 static const struct rtc_class_ops rx8025_rtc_ops = {
427 .read_time = rx8025_get_time,
428 .set_time = rx8025_set_time,
429 .read_alarm = rx8025_read_alarm,
430 .set_alarm = rx8025_set_alarm,
431 .alarm_irq_enable = rx8025_alarm_irq_enable,
432 };
433
434 /*
435 * Clock precision adjustment support
436 *
437 * According to the RX8025 SA/NB application manual the frequency and
438 * temperature characteristics can be approximated using the following
439 * equation:
440 *
441 * df = a * (ut - t)**2
442 *
443 * df: Frequency deviation in any temperature
444 * a : Coefficient = (-35 +-5) * 10**-9
445 * ut: Ultimate temperature in degree = +25 +-5 degree
446 * t : Any temperature in degree
447 *
448 * Note that the clock adjustment in ppb must be entered (which is
449 * the negative value of the deviation).
450 */
rx8025_get_clock_adjust(struct device * dev,int * adj)451 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
452 {
453 struct i2c_client *client = to_i2c_client(dev);
454 int digoff;
455
456 digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
457 if (digoff < 0)
458 return digoff;
459
460 *adj = digoff >= 64 ? digoff - 128 : digoff;
461 if (*adj > 0)
462 (*adj)--;
463 *adj *= -RX8025_ADJ_RESOLUTION;
464
465 return 0;
466 }
467
rx8025_set_clock_adjust(struct device * dev,int adj)468 static int rx8025_set_clock_adjust(struct device *dev, int adj)
469 {
470 struct i2c_client *client = to_i2c_client(dev);
471 u8 digoff;
472 int err;
473
474 adj /= -RX8025_ADJ_RESOLUTION;
475 if (adj > RX8025_ADJ_DATA_MAX)
476 adj = RX8025_ADJ_DATA_MAX;
477 else if (adj < RX8025_ADJ_DATA_MIN)
478 adj = RX8025_ADJ_DATA_MIN;
479 else if (adj > 0)
480 adj++;
481 else if (adj < 0)
482 adj += 128;
483 digoff = adj;
484
485 err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
486 if (err)
487 return err;
488
489 dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
490
491 return 0;
492 }
493
rx8025_sysfs_show_clock_adjust(struct device * dev,struct device_attribute * attr,char * buf)494 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
495 struct device_attribute *attr,
496 char *buf)
497 {
498 int err, adj;
499
500 err = rx8025_get_clock_adjust(dev, &adj);
501 if (err)
502 return err;
503
504 return sprintf(buf, "%d\n", adj);
505 }
506
rx8025_sysfs_store_clock_adjust(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)507 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
508 struct device_attribute *attr,
509 const char *buf, size_t count)
510 {
511 int adj, err;
512
513 if (sscanf(buf, "%i", &adj) != 1)
514 return -EINVAL;
515
516 err = rx8025_set_clock_adjust(dev, adj);
517
518 return err ? err : count;
519 }
520
521 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
522 rx8025_sysfs_show_clock_adjust,
523 rx8025_sysfs_store_clock_adjust);
524
rx8025_sysfs_register(struct device * dev)525 static int rx8025_sysfs_register(struct device *dev)
526 {
527 return device_create_file(dev, &dev_attr_clock_adjust_ppb);
528 }
529
rx8025_sysfs_unregister(struct device * dev)530 static void rx8025_sysfs_unregister(struct device *dev)
531 {
532 device_remove_file(dev, &dev_attr_clock_adjust_ppb);
533 }
534
rx8025_probe(struct i2c_client * client,const struct i2c_device_id * id)535 static int rx8025_probe(struct i2c_client *client,
536 const struct i2c_device_id *id)
537 {
538 struct i2c_adapter *adapter = client->adapter;
539 struct rx8025_data *rx8025;
540 int err = 0;
541
542 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
543 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
544 dev_err(&adapter->dev,
545 "doesn't support required functionality\n");
546 return -EIO;
547 }
548
549 rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
550 if (!rx8025)
551 return -ENOMEM;
552
553 i2c_set_clientdata(client, rx8025);
554
555 if (id)
556 rx8025->model = id->driver_data;
557
558 err = rx8025_init_client(client);
559 if (err)
560 return err;
561
562 rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
563 &rx8025_rtc_ops, THIS_MODULE);
564 if (IS_ERR(rx8025->rtc)) {
565 dev_err(&client->dev, "unable to register the class device\n");
566 return PTR_ERR(rx8025->rtc);
567 }
568
569 if (client->irq > 0) {
570 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
571 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
572 rx8025_handle_irq,
573 IRQF_ONESHOT,
574 "rx8025", client);
575 if (err) {
576 dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
577 client->irq = 0;
578 }
579 }
580
581 rx8025->rtc->max_user_freq = 1;
582
583 /* the rx8025 alarm only supports a minute accuracy */
584 rx8025->rtc->uie_unsupported = 1;
585
586 err = rx8025_sysfs_register(&client->dev);
587 return err;
588 }
589
rx8025_remove(struct i2c_client * client)590 static int rx8025_remove(struct i2c_client *client)
591 {
592 rx8025_sysfs_unregister(&client->dev);
593 return 0;
594 }
595
596 static struct i2c_driver rx8025_driver = {
597 .driver = {
598 .name = "rtc-rx8025",
599 },
600 .probe = rx8025_probe,
601 .remove = rx8025_remove,
602 .id_table = rx8025_id,
603 };
604
605 module_i2c_driver(rx8025_driver);
606
607 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
608 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
609 MODULE_LICENSE("GPL");
610
