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 /*
252 * Here the read-only bits are written as "0". I'm not sure if that
253 * is sound.
254 */
255 date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
256 date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
257 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
258 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
259 else
260 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
261 | bin2bcd((dt->tm_hour + 11) % 12 + 1);
262
263 date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
264 date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
265 date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
266 date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
267
268 dev_dbg(dev, "%s: write %7ph\n", __func__, date);
269
270 ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
271 if (ret < 0)
272 return ret;
273
274 return rx8025_reset_validity(client);
275 }
276
rx8025_init_client(struct i2c_client * client)277 static int rx8025_init_client(struct i2c_client *client)
278 {
279 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
280 u8 ctrl[2], ctrl2;
281 int need_clear = 0;
282 int err;
283
284 err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
285 if (err)
286 goto out;
287
288 /* Keep test bit zero ! */
289 rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
290
291 if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
292 dev_warn(&client->dev, "Alarm was detected\n");
293 need_clear = 1;
294 }
295
296 if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
297 need_clear = 1;
298
299 if (need_clear) {
300 ctrl2 = ctrl[1];
301 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
302 RX8025_BIT_CTRL2_DAFG);
303
304 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
305 }
306 out:
307 return err;
308 }
309
310 /* Alarm support */
rx8025_read_alarm(struct device * dev,struct rtc_wkalrm * t)311 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
312 {
313 struct i2c_client *client = to_i2c_client(dev);
314 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
315 u8 ald[2];
316 int ctrl2, err;
317
318 err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
319 if (err)
320 return err;
321
322 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
323 if (ctrl2 < 0)
324 return ctrl2;
325
326 dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
327 __func__, ald[0], ald[1], ctrl2);
328
329 /* Hardware alarms precision is 1 minute! */
330 t->time.tm_sec = 0;
331 t->time.tm_min = bcd2bin(ald[0] & 0x7f);
332 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
333 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
334 else
335 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
336 + (ald[1] & 0x20 ? 12 : 0);
337
338 dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
339 t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
340 t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
341
342 return err;
343 }
344
rx8025_set_alarm(struct device * dev,struct rtc_wkalrm * t)345 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
346 {
347 struct i2c_client *client = to_i2c_client(dev);
348 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
349 u8 ald[2];
350 int err;
351
352 ald[0] = bin2bcd(t->time.tm_min);
353 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
354 ald[1] = bin2bcd(t->time.tm_hour);
355 else
356 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
357 | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
358
359 dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
360
361 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
362 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
363 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
364 rx8025->ctrl1);
365 if (err)
366 return err;
367 }
368 err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
369 if (err)
370 return err;
371
372 if (t->enabled) {
373 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
374 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
375 rx8025->ctrl1);
376 if (err)
377 return err;
378 }
379
380 return 0;
381 }
382
rx8025_alarm_irq_enable(struct device * dev,unsigned int enabled)383 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
384 {
385 struct i2c_client *client = to_i2c_client(dev);
386 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
387 u8 ctrl1;
388 int err;
389
390 ctrl1 = rx8025->ctrl1;
391 if (enabled)
392 ctrl1 |= RX8025_BIT_CTRL1_DALE;
393 else
394 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
395
396 if (ctrl1 != rx8025->ctrl1) {
397 rx8025->ctrl1 = ctrl1;
398 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
399 rx8025->ctrl1);
400 if (err)
401 return err;
402 }
403 return 0;
404 }
405
406 /*
407 * According to the RX8025 SA/NB application manual the frequency and
408 * temperature characteristics can be approximated using the following
409 * equation:
410 *
411 * df = a * (ut - t)**2
412 *
413 * df: Frequency deviation in any temperature
414 * a : Coefficient = (-35 +-5) * 10**-9
415 * ut: Ultimate temperature in degree = +25 +-5 degree
416 * t : Any temperature in degree
417 */
rx8025_read_offset(struct device * dev,long * offset)418 static int rx8025_read_offset(struct device *dev, long *offset)
419 {
420 struct i2c_client *client = to_i2c_client(dev);
421 int digoff;
422
423 digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
424 if (digoff < 0)
425 return digoff;
426
427 *offset = digoff >= 64 ? digoff - 128 : digoff;
428 if (*offset > 0)
429 (*offset)--;
430 *offset *= RX8025_ADJ_RESOLUTION;
431
432 return 0;
433 }
434
rx8025_set_offset(struct device * dev,long offset)435 static int rx8025_set_offset(struct device *dev, long offset)
436 {
437 struct i2c_client *client = to_i2c_client(dev);
438 u8 digoff;
439 int err;
440
441 offset /= RX8025_ADJ_RESOLUTION;
442 if (offset > RX8025_ADJ_DATA_MAX)
443 offset = RX8025_ADJ_DATA_MAX;
444 else if (offset < RX8025_ADJ_DATA_MIN)
445 offset = RX8025_ADJ_DATA_MIN;
446 else if (offset > 0)
447 offset++;
448 else if (offset < 0)
449 offset += 128;
450 digoff = offset;
451
452 err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
453 if (err)
454 return err;
455
456 return 0;
457 }
458
459 static const struct rtc_class_ops rx8025_rtc_ops = {
460 .read_time = rx8025_get_time,
461 .set_time = rx8025_set_time,
462 .read_alarm = rx8025_read_alarm,
463 .set_alarm = rx8025_set_alarm,
464 .alarm_irq_enable = rx8025_alarm_irq_enable,
465 .read_offset = rx8025_read_offset,
466 .set_offset = rx8025_set_offset,
467 };
468
rx8025_sysfs_show_clock_adjust(struct device * dev,struct device_attribute * attr,char * buf)469 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
470 struct device_attribute *attr,
471 char *buf)
472 {
473 long adj;
474 int err;
475
476 dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
477 err = rx8025_read_offset(dev, &adj);
478 if (err)
479 return err;
480
481 return sprintf(buf, "%ld\n", -adj);
482 }
483
rx8025_sysfs_store_clock_adjust(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)484 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
485 struct device_attribute *attr,
486 const char *buf, size_t count)
487 {
488 long adj;
489 int err;
490
491 dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
492 if (kstrtol(buf, 10, &adj) != 0)
493 return -EINVAL;
494
495 err = rx8025_set_offset(dev, -adj);
496
497 return err ? err : count;
498 }
499
500 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
501 rx8025_sysfs_show_clock_adjust,
502 rx8025_sysfs_store_clock_adjust);
503
504 static struct attribute *rx8025_attrs[] = {
505 &dev_attr_clock_adjust_ppb.attr,
506 NULL
507 };
508
509 static const struct attribute_group rx8025_attr_group = {
510 .attrs = rx8025_attrs,
511 };
512
rx8025_probe(struct i2c_client * client,const struct i2c_device_id * id)513 static int rx8025_probe(struct i2c_client *client,
514 const struct i2c_device_id *id)
515 {
516 struct i2c_adapter *adapter = client->adapter;
517 struct rx8025_data *rx8025;
518 int err = 0;
519
520 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
521 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
522 dev_err(&adapter->dev,
523 "doesn't support required functionality\n");
524 return -EIO;
525 }
526
527 rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
528 if (!rx8025)
529 return -ENOMEM;
530
531 i2c_set_clientdata(client, rx8025);
532
533 if (id)
534 rx8025->model = id->driver_data;
535
536 err = rx8025_init_client(client);
537 if (err)
538 return err;
539
540 rx8025->rtc = devm_rtc_allocate_device(&client->dev);
541 if (IS_ERR(rx8025->rtc))
542 return PTR_ERR(rx8025->rtc);
543
544 rx8025->rtc->ops = &rx8025_rtc_ops;
545 rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
546 rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;
547
548 if (client->irq > 0) {
549 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
550 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
551 rx8025_handle_irq,
552 IRQF_ONESHOT,
553 "rx8025", client);
554 if (err)
555 clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
556 }
557
558 rx8025->rtc->max_user_freq = 1;
559
560 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
561 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);
562
563 err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
564 if (err)
565 return err;
566
567 return devm_rtc_register_device(rx8025->rtc);
568 }
569
570 static struct i2c_driver rx8025_driver = {
571 .driver = {
572 .name = "rtc-rx8025",
573 },
574 .probe = rx8025_probe,
575 .id_table = rx8025_id,
576 };
577
578 module_i2c_driver(rx8025_driver);
579
580 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
581 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
582 MODULE_LICENSE("GPL");
583