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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC driver for the Micro Crystal RV8803
4 *
5 * Copyright (C) 2015 Micro Crystal SA
6 * Alexandre Belloni <alexandre.belloni@bootlin.com>
7 *
8 */
9
10#include <linux/bcd.h>
11#include <linux/bitops.h>
12#include <linux/bitfield.h>
13#include <linux/log2.h>
14#include <linux/i2c.h>
15#include <linux/interrupt.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/of_device.h>
19#include <linux/rtc.h>
20
21#define RV8803_I2C_TRY_COUNT 4
22
23#define RV8803_SEC 0x00
24#define RV8803_MIN 0x01
25#define RV8803_HOUR 0x02
26#define RV8803_WEEK 0x03
27#define RV8803_DAY 0x04
28#define RV8803_MONTH 0x05
29#define RV8803_YEAR 0x06
30#define RV8803_RAM 0x07
31#define RV8803_ALARM_MIN 0x08
32#define RV8803_ALARM_HOUR 0x09
33#define RV8803_ALARM_WEEK_OR_DAY 0x0A
34#define RV8803_EXT 0x0D
35#define RV8803_FLAG 0x0E
36#define RV8803_CTRL 0x0F
37#define RV8803_OSC_OFFSET 0x2C
38
39#define RV8803_EXT_WADA BIT(6)
40
41#define RV8803_FLAG_V1F BIT(0)
42#define RV8803_FLAG_V2F BIT(1)
43#define RV8803_FLAG_AF BIT(3)
44#define RV8803_FLAG_TF BIT(4)
45#define RV8803_FLAG_UF BIT(5)
46
47#define RV8803_CTRL_RESET BIT(0)
48
49#define RV8803_CTRL_EIE BIT(2)
50#define RV8803_CTRL_AIE BIT(3)
51#define RV8803_CTRL_TIE BIT(4)
52#define RV8803_CTRL_UIE BIT(5)
53
54#define RX8803_CTRL_CSEL GENMASK(7, 6)
55
56#define RX8900_BACKUP_CTRL 0x18
57#define RX8900_FLAG_SWOFF BIT(2)
58#define RX8900_FLAG_VDETOFF BIT(3)
59
60enum rv8803_type {
61 rv_8803,
62 rx_8803,
63 rx_8804,
64 rx_8900
65};
66
67struct rv8803_data {
68 struct i2c_client *client;
69 struct rtc_device *rtc;
70 struct mutex flags_lock;
71 u8 ctrl;
72 u8 backup;
73 enum rv8803_type type;
74};
75
76static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
77{
78 int try = RV8803_I2C_TRY_COUNT;
79 s32 ret;
80
81 /*
82 * There is a 61µs window during which the RTC does not acknowledge I2C
83 * transfers. In that case, ensure that there are multiple attempts.
84 */
85 do
86 ret = i2c_smbus_read_byte_data(client, reg);
87 while ((ret == -ENXIO || ret == -EIO) && --try);
88 if (ret < 0)
89 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
90
91 return ret;
92}
93
94static int rv8803_read_regs(const struct i2c_client *client,
95 u8 reg, u8 count, u8 *values)
96{
97 int try = RV8803_I2C_TRY_COUNT;
98 s32 ret;
99
100 do
101 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
102 while ((ret == -ENXIO || ret == -EIO) && --try);
103 if (ret != count) {
104 dev_err(&client->dev,
105 "Unable to read registers 0x%02x..0x%02x\n",
106 reg, reg + count - 1);
107 return ret < 0 ? ret : -EIO;
108 }
109
110 return 0;
111}
112
113static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
114{
115 int try = RV8803_I2C_TRY_COUNT;
116 s32 ret;
117
118 do
119 ret = i2c_smbus_write_byte_data(client, reg, value);
120 while ((ret == -ENXIO || ret == -EIO) && --try);
121 if (ret)
122 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
123
124 return ret;
125}
126
127static int rv8803_write_regs(const struct i2c_client *client,
128 u8 reg, u8 count, const u8 *values)
129{
130 int try = RV8803_I2C_TRY_COUNT;
131 s32 ret;
132
133 do
134 ret = i2c_smbus_write_i2c_block_data(client, reg, count,
135 values);
136 while ((ret == -ENXIO || ret == -EIO) && --try);
137 if (ret)
138 dev_err(&client->dev,
139 "Unable to write registers 0x%02x..0x%02x\n",
140 reg, reg + count - 1);
141
142 return ret;
143}
144
145static int rv8803_regs_init(struct rv8803_data *rv8803)
146{
147 int ret;
148
149 ret = rv8803_write_reg(rv8803->client, RV8803_OSC_OFFSET, 0x00);
150 if (ret)
151 return ret;
152
153 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
154 FIELD_PREP(RX8803_CTRL_CSEL, 1)); /* 2s */
155 if (ret)
156 return ret;
157
158 ret = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3,
159 (u8[]){ 0, 0, 0 });
160 if (ret)
161 return ret;
162
163 return rv8803_write_reg(rv8803->client, RV8803_RAM, 0x00);
164}
165
166static int rv8803_regs_configure(struct rv8803_data *rv8803);
167
168static int rv8803_regs_reset(struct rv8803_data *rv8803)
169{
170 /*
171 * The RV-8803 resets all registers to POR defaults after voltage-loss,
172 * the Epson RTCs don't, so we manually reset the remainder here.
173 */
174 if (rv8803->type == rx_8803 || rv8803->type == rx_8900) {
175 int ret = rv8803_regs_init(rv8803);
176 if (ret)
177 return ret;
178 }
179
180 return rv8803_regs_configure(rv8803);
181}
182
183static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
184{
185 struct i2c_client *client = dev_id;
186 struct rv8803_data *rv8803 = i2c_get_clientdata(client);
187 unsigned long events = 0;
188 int flags;
189
190 mutex_lock(&rv8803->flags_lock);
191
192 flags = rv8803_read_reg(client, RV8803_FLAG);
193 if (flags <= 0) {
194 mutex_unlock(&rv8803->flags_lock);
195 return IRQ_NONE;
196 }
197
198 if (flags & RV8803_FLAG_V1F)
199 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
200
201 if (flags & RV8803_FLAG_V2F)
202 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
203
204 if (flags & RV8803_FLAG_TF) {
205 flags &= ~RV8803_FLAG_TF;
206 rv8803->ctrl &= ~RV8803_CTRL_TIE;
207 events |= RTC_PF;
208 }
209
210 if (flags & RV8803_FLAG_AF) {
211 flags &= ~RV8803_FLAG_AF;
212 rv8803->ctrl &= ~RV8803_CTRL_AIE;
213 events |= RTC_AF;
214 }
215
216 if (flags & RV8803_FLAG_UF) {
217 flags &= ~RV8803_FLAG_UF;
218 rv8803->ctrl &= ~RV8803_CTRL_UIE;
219 events |= RTC_UF;
220 }
221
222 if (events) {
223 rtc_update_irq(rv8803->rtc, 1, events);
224 rv8803_write_reg(client, RV8803_FLAG, flags);
225 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
226 }
227
228 mutex_unlock(&rv8803->flags_lock);
229
230 return IRQ_HANDLED;
231}
232
233static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
234{
235 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
236 u8 date1[7];
237 u8 date2[7];
238 u8 *date = date1;
239 int ret, flags;
240
241 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
242 if (flags < 0)
243 return flags;
244
245 if (flags & RV8803_FLAG_V2F) {
246 dev_warn(dev, "Voltage low, data is invalid.\n");
247 return -EINVAL;
248 }
249
250 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
251 if (ret)
252 return ret;
253
254 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
255 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
256 if (ret)
257 return ret;
258
259 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
260 date = date2;
261 }
262
263 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
264 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
265 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
266 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
267 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
268 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
269 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
270
271 return 0;
272}
273
274static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
275{
276 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
277 u8 date[7];
278 int ctrl, flags, ret;
279
280 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
281 if (ctrl < 0)
282 return ctrl;
283
284 /* Stop the clock */
285 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
286 ctrl | RV8803_CTRL_RESET);
287 if (ret)
288 return ret;
289
290 date[RV8803_SEC] = bin2bcd(tm->tm_sec);
291 date[RV8803_MIN] = bin2bcd(tm->tm_min);
292 date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
293 date[RV8803_WEEK] = 1 << (tm->tm_wday);
294 date[RV8803_DAY] = bin2bcd(tm->tm_mday);
295 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
296 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
297
298 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
299 if (ret)
300 return ret;
301
302 /* Restart the clock */
303 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
304 ctrl & ~RV8803_CTRL_RESET);
305 if (ret)
306 return ret;
307
308 mutex_lock(&rv8803->flags_lock);
309
310 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
311 if (flags < 0) {
312 mutex_unlock(&rv8803->flags_lock);
313 return flags;
314 }
315
316 if (flags & RV8803_FLAG_V2F) {
317 ret = rv8803_regs_reset(rv8803);
318 if (ret) {
319 mutex_unlock(&rv8803->flags_lock);
320 return ret;
321 }
322 }
323
324 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
325 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
326
327 mutex_unlock(&rv8803->flags_lock);
328
329 return ret;
330}
331
332static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
333{
334 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
335 struct i2c_client *client = rv8803->client;
336 u8 alarmvals[3];
337 int flags, ret;
338
339 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
340 if (ret)
341 return ret;
342
343 flags = rv8803_read_reg(client, RV8803_FLAG);
344 if (flags < 0)
345 return flags;
346
347 alrm->time.tm_sec = 0;
348 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
349 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
350 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
351
352 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
353 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
354
355 return 0;
356}
357
358static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
359{
360 struct i2c_client *client = to_i2c_client(dev);
361 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
362 u8 alarmvals[3];
363 u8 ctrl[2];
364 int ret, err;
365
366 /* The alarm has no seconds, round up to nearest minute */
367 if (alrm->time.tm_sec) {
368 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
369
370 alarm_time += 60 - alrm->time.tm_sec;
371 rtc_time64_to_tm(alarm_time, &alrm->time);
372 }
373
374 mutex_lock(&rv8803->flags_lock);
375
376 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
377 if (ret) {
378 mutex_unlock(&rv8803->flags_lock);
379 return ret;
380 }
381
382 alarmvals[0] = bin2bcd(alrm->time.tm_min);
383 alarmvals[1] = bin2bcd(alrm->time.tm_hour);
384 alarmvals[2] = bin2bcd(alrm->time.tm_mday);
385
386 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
387 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
388 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
389 rv8803->ctrl);
390 if (err) {
391 mutex_unlock(&rv8803->flags_lock);
392 return err;
393 }
394 }
395
396 ctrl[0] &= ~RV8803_FLAG_AF;
397 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[0]);
398 mutex_unlock(&rv8803->flags_lock);
399 if (err)
400 return err;
401
402 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
403 if (err)
404 return err;
405
406 if (alrm->enabled) {
407 if (rv8803->rtc->uie_rtctimer.enabled)
408 rv8803->ctrl |= RV8803_CTRL_UIE;
409 if (rv8803->rtc->aie_timer.enabled)
410 rv8803->ctrl |= RV8803_CTRL_AIE;
411
412 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
413 rv8803->ctrl);
414 if (err)
415 return err;
416 }
417
418 return 0;
419}
420
421static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
422{
423 struct i2c_client *client = to_i2c_client(dev);
424 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
425 int ctrl, flags, err;
426
427 ctrl = rv8803->ctrl;
428
429 if (enabled) {
430 if (rv8803->rtc->uie_rtctimer.enabled)
431 ctrl |= RV8803_CTRL_UIE;
432 if (rv8803->rtc->aie_timer.enabled)
433 ctrl |= RV8803_CTRL_AIE;
434 } else {
435 if (!rv8803->rtc->uie_rtctimer.enabled)
436 ctrl &= ~RV8803_CTRL_UIE;
437 if (!rv8803->rtc->aie_timer.enabled)
438 ctrl &= ~RV8803_CTRL_AIE;
439 }
440
441 mutex_lock(&rv8803->flags_lock);
442 flags = rv8803_read_reg(client, RV8803_FLAG);
443 if (flags < 0) {
444 mutex_unlock(&rv8803->flags_lock);
445 return flags;
446 }
447 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
448 err = rv8803_write_reg(client, RV8803_FLAG, flags);
449 mutex_unlock(&rv8803->flags_lock);
450 if (err)
451 return err;
452
453 if (ctrl != rv8803->ctrl) {
454 rv8803->ctrl = ctrl;
455 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
456 if (err)
457 return err;
458 }
459
460 return 0;
461}
462
463static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
464{
465 struct i2c_client *client = to_i2c_client(dev);
466 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
467 unsigned int vl = 0;
468 int flags, ret = 0;
469
470 switch (cmd) {
471 case RTC_VL_READ:
472 flags = rv8803_read_reg(client, RV8803_FLAG);
473 if (flags < 0)
474 return flags;
475
476 if (flags & RV8803_FLAG_V1F) {
477 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
478 vl = RTC_VL_ACCURACY_LOW;
479 }
480
481 if (flags & RV8803_FLAG_V2F)
482 vl |= RTC_VL_DATA_INVALID;
483
484 return put_user(vl, (unsigned int __user *)arg);
485
486 case RTC_VL_CLR:
487 mutex_lock(&rv8803->flags_lock);
488 flags = rv8803_read_reg(client, RV8803_FLAG);
489 if (flags < 0) {
490 mutex_unlock(&rv8803->flags_lock);
491 return flags;
492 }
493
494 flags &= ~RV8803_FLAG_V1F;
495 ret = rv8803_write_reg(client, RV8803_FLAG, flags);
496 mutex_unlock(&rv8803->flags_lock);
497 if (ret)
498 return ret;
499
500 return 0;
501
502 default:
503 return -ENOIOCTLCMD;
504 }
505}
506
507static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
508 size_t bytes)
509{
510 return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
511}
512
513static int rv8803_nvram_read(void *priv, unsigned int offset,
514 void *val, size_t bytes)
515{
516 int ret;
517
518 ret = rv8803_read_reg(priv, RV8803_RAM);
519 if (ret < 0)
520 return ret;
521
522 *(u8 *)val = ret;
523
524 return 0;
525}
526
527static const struct rtc_class_ops rv8803_rtc_ops = {
528 .read_time = rv8803_get_time,
529 .set_time = rv8803_set_time,
530 .ioctl = rv8803_ioctl,
531 .read_alarm = rv8803_get_alarm,
532 .set_alarm = rv8803_set_alarm,
533 .alarm_irq_enable = rv8803_alarm_irq_enable,
534};
535
536static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
537{
538 struct i2c_client *client = rv8803->client;
539 struct device_node *node = client->dev.of_node;
540 int err;
541 u8 flags;
542
543 if (!node)
544 return 0;
545
546 if (rv8803->type != rx_8900)
547 return 0;
548
549 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
550 if (err < 0)
551 return err;
552
553 flags = (u8)err;
554 flags &= ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF);
555 flags |= rv8803->backup;
556
557 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
558 flags);
559}
560
561/* configure registers with values different than the Power-On reset defaults */
562static int rv8803_regs_configure(struct rv8803_data *rv8803)
563{
564 int err;
565
566 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
567 if (err)
568 return err;
569
570 err = rx8900_trickle_charger_init(rv8803);
571 if (err) {
572 dev_err(&rv8803->client->dev, "failed to init charger\n");
573 return err;
574 }
575
576 return 0;
577}
578
579static const struct i2c_device_id rv8803_id[] = {
580 { "rv8803", rv_8803 },
581 { "rv8804", rx_8804 },
582 { "rx8803", rx_8803 },
583 { "rx8900", rx_8900 },
584 { }
585};
586MODULE_DEVICE_TABLE(i2c, rv8803_id);
587
588static int rv8803_probe(struct i2c_client *client)
589{
590 struct i2c_adapter *adapter = client->adapter;
591 struct rv8803_data *rv8803;
592 int err, flags;
593 struct nvmem_config nvmem_cfg = {
594 .name = "rv8803_nvram",
595 .word_size = 1,
596 .stride = 1,
597 .size = 1,
598 .reg_read = rv8803_nvram_read,
599 .reg_write = rv8803_nvram_write,
600 .priv = client,
601 };
602
603 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
604 I2C_FUNC_SMBUS_I2C_BLOCK)) {
605 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
606 return -EIO;
607 }
608
609 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
610 GFP_KERNEL);
611 if (!rv8803)
612 return -ENOMEM;
613
614 mutex_init(&rv8803->flags_lock);
615 rv8803->client = client;
616 if (client->dev.of_node) {
617 rv8803->type = (enum rv8803_type)
618 of_device_get_match_data(&client->dev);
619 } else {
620 const struct i2c_device_id *id = i2c_match_id(rv8803_id, client);
621
622 rv8803->type = id->driver_data;
623 }
624 i2c_set_clientdata(client, rv8803);
625
626 flags = rv8803_read_reg(client, RV8803_FLAG);
627 if (flags < 0)
628 return flags;
629
630 if (flags & RV8803_FLAG_V1F)
631 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
632
633 if (flags & RV8803_FLAG_V2F)
634 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
635
636 if (flags & RV8803_FLAG_AF)
637 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
638
639 rv8803->rtc = devm_rtc_allocate_device(&client->dev);
640 if (IS_ERR(rv8803->rtc))
641 return PTR_ERR(rv8803->rtc);
642
643 if (client->irq > 0) {
644 err = devm_request_threaded_irq(&client->dev, client->irq,
645 NULL, rv8803_handle_irq,
646 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
647 "rv8803", client);
648 if (err) {
649 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
650 client->irq = 0;
651 }
652 }
653 if (!client->irq)
654 clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
655
656 if (of_property_read_bool(client->dev.of_node, "epson,vdet-disable"))
657 rv8803->backup |= RX8900_FLAG_VDETOFF;
658
659 if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
660 rv8803->backup |= RX8900_FLAG_SWOFF;
661
662 err = rv8803_regs_configure(rv8803);
663 if (err)
664 return err;
665
666 rv8803->rtc->ops = &rv8803_rtc_ops;
667 rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
668 rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
669 err = devm_rtc_register_device(rv8803->rtc);
670 if (err)
671 return err;
672
673 devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
674
675 rv8803->rtc->max_user_freq = 1;
676
677 return 0;
678}
679
680static const __maybe_unused struct of_device_id rv8803_of_match[] = {
681 {
682 .compatible = "microcrystal,rv8803",
683 .data = (void *)rv_8803
684 },
685 {
686 .compatible = "epson,rx8803",
687 .data = (void *)rx_8803
688 },
689 {
690 .compatible = "epson,rx8804",
691 .data = (void *)rx_8804
692 },
693 {
694 .compatible = "epson,rx8900",
695 .data = (void *)rx_8900
696 },
697 { }
698};
699MODULE_DEVICE_TABLE(of, rv8803_of_match);
700
701static struct i2c_driver rv8803_driver = {
702 .driver = {
703 .name = "rtc-rv8803",
704 .of_match_table = of_match_ptr(rv8803_of_match),
705 },
706 .probe_new = rv8803_probe,
707 .id_table = rv8803_id,
708};
709module_i2c_driver(rv8803_driver);
710
711MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
712MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
713MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC driver for the Micro Crystal RV8803
4 *
5 * Copyright (C) 2015 Micro Crystal SA
6 * Alexandre Belloni <alexandre.belloni@bootlin.com>
7 *
8 */
9
10#include <linux/bcd.h>
11#include <linux/bitops.h>
12#include <linux/log2.h>
13#include <linux/i2c.h>
14#include <linux/interrupt.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/of_device.h>
18#include <linux/rtc.h>
19
20#define RV8803_I2C_TRY_COUNT 4
21
22#define RV8803_SEC 0x00
23#define RV8803_MIN 0x01
24#define RV8803_HOUR 0x02
25#define RV8803_WEEK 0x03
26#define RV8803_DAY 0x04
27#define RV8803_MONTH 0x05
28#define RV8803_YEAR 0x06
29#define RV8803_RAM 0x07
30#define RV8803_ALARM_MIN 0x08
31#define RV8803_ALARM_HOUR 0x09
32#define RV8803_ALARM_WEEK_OR_DAY 0x0A
33#define RV8803_EXT 0x0D
34#define RV8803_FLAG 0x0E
35#define RV8803_CTRL 0x0F
36
37#define RV8803_EXT_WADA BIT(6)
38
39#define RV8803_FLAG_V1F BIT(0)
40#define RV8803_FLAG_V2F BIT(1)
41#define RV8803_FLAG_AF BIT(3)
42#define RV8803_FLAG_TF BIT(4)
43#define RV8803_FLAG_UF BIT(5)
44
45#define RV8803_CTRL_RESET BIT(0)
46
47#define RV8803_CTRL_EIE BIT(2)
48#define RV8803_CTRL_AIE BIT(3)
49#define RV8803_CTRL_TIE BIT(4)
50#define RV8803_CTRL_UIE BIT(5)
51
52#define RX8900_BACKUP_CTRL 0x18
53#define RX8900_FLAG_SWOFF BIT(2)
54#define RX8900_FLAG_VDETOFF BIT(3)
55
56enum rv8803_type {
57 rv_8803,
58 rx_8900
59};
60
61struct rv8803_data {
62 struct i2c_client *client;
63 struct rtc_device *rtc;
64 struct mutex flags_lock;
65 u8 ctrl;
66 enum rv8803_type type;
67};
68
69static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
70{
71 int try = RV8803_I2C_TRY_COUNT;
72 s32 ret;
73
74 /*
75 * There is a 61µs window during which the RTC does not acknowledge I2C
76 * transfers. In that case, ensure that there are multiple attempts.
77 */
78 do
79 ret = i2c_smbus_read_byte_data(client, reg);
80 while ((ret == -ENXIO || ret == -EIO) && --try);
81 if (ret < 0)
82 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
83
84 return ret;
85}
86
87static int rv8803_read_regs(const struct i2c_client *client,
88 u8 reg, u8 count, u8 *values)
89{
90 int try = RV8803_I2C_TRY_COUNT;
91 s32 ret;
92
93 do
94 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
95 while ((ret == -ENXIO || ret == -EIO) && --try);
96 if (ret != count) {
97 dev_err(&client->dev,
98 "Unable to read registers 0x%02x..0x%02x\n",
99 reg, reg + count - 1);
100 return ret < 0 ? ret : -EIO;
101 }
102
103 return 0;
104}
105
106static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
107{
108 int try = RV8803_I2C_TRY_COUNT;
109 s32 ret;
110
111 do
112 ret = i2c_smbus_write_byte_data(client, reg, value);
113 while ((ret == -ENXIO || ret == -EIO) && --try);
114 if (ret)
115 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
116
117 return ret;
118}
119
120static int rv8803_write_regs(const struct i2c_client *client,
121 u8 reg, u8 count, const u8 *values)
122{
123 int try = RV8803_I2C_TRY_COUNT;
124 s32 ret;
125
126 do
127 ret = i2c_smbus_write_i2c_block_data(client, reg, count,
128 values);
129 while ((ret == -ENXIO || ret == -EIO) && --try);
130 if (ret)
131 dev_err(&client->dev,
132 "Unable to write registers 0x%02x..0x%02x\n",
133 reg, reg + count - 1);
134
135 return ret;
136}
137
138static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
139{
140 struct i2c_client *client = dev_id;
141 struct rv8803_data *rv8803 = i2c_get_clientdata(client);
142 unsigned long events = 0;
143 int flags;
144
145 mutex_lock(&rv8803->flags_lock);
146
147 flags = rv8803_read_reg(client, RV8803_FLAG);
148 if (flags <= 0) {
149 mutex_unlock(&rv8803->flags_lock);
150 return IRQ_NONE;
151 }
152
153 if (flags & RV8803_FLAG_V1F)
154 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
155
156 if (flags & RV8803_FLAG_V2F)
157 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
158
159 if (flags & RV8803_FLAG_TF) {
160 flags &= ~RV8803_FLAG_TF;
161 rv8803->ctrl &= ~RV8803_CTRL_TIE;
162 events |= RTC_PF;
163 }
164
165 if (flags & RV8803_FLAG_AF) {
166 flags &= ~RV8803_FLAG_AF;
167 rv8803->ctrl &= ~RV8803_CTRL_AIE;
168 events |= RTC_AF;
169 }
170
171 if (flags & RV8803_FLAG_UF) {
172 flags &= ~RV8803_FLAG_UF;
173 rv8803->ctrl &= ~RV8803_CTRL_UIE;
174 events |= RTC_UF;
175 }
176
177 if (events) {
178 rtc_update_irq(rv8803->rtc, 1, events);
179 rv8803_write_reg(client, RV8803_FLAG, flags);
180 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
181 }
182
183 mutex_unlock(&rv8803->flags_lock);
184
185 return IRQ_HANDLED;
186}
187
188static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
189{
190 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
191 u8 date1[7];
192 u8 date2[7];
193 u8 *date = date1;
194 int ret, flags;
195
196 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
197 if (flags < 0)
198 return flags;
199
200 if (flags & RV8803_FLAG_V2F) {
201 dev_warn(dev, "Voltage low, data is invalid.\n");
202 return -EINVAL;
203 }
204
205 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
206 if (ret)
207 return ret;
208
209 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
210 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
211 if (ret)
212 return ret;
213
214 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
215 date = date2;
216 }
217
218 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
219 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
220 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
221 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
222 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
223 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
224 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
225
226 return 0;
227}
228
229static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
230{
231 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
232 u8 date[7];
233 int ctrl, flags, ret;
234
235 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
236 if (ctrl < 0)
237 return ctrl;
238
239 /* Stop the clock */
240 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
241 ctrl | RV8803_CTRL_RESET);
242 if (ret)
243 return ret;
244
245 date[RV8803_SEC] = bin2bcd(tm->tm_sec);
246 date[RV8803_MIN] = bin2bcd(tm->tm_min);
247 date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
248 date[RV8803_WEEK] = 1 << (tm->tm_wday);
249 date[RV8803_DAY] = bin2bcd(tm->tm_mday);
250 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
251 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
252
253 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
254 if (ret)
255 return ret;
256
257 /* Restart the clock */
258 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
259 ctrl & ~RV8803_CTRL_RESET);
260 if (ret)
261 return ret;
262
263 mutex_lock(&rv8803->flags_lock);
264
265 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
266 if (flags < 0) {
267 mutex_unlock(&rv8803->flags_lock);
268 return flags;
269 }
270
271 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
272 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
273
274 mutex_unlock(&rv8803->flags_lock);
275
276 return ret;
277}
278
279static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
280{
281 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
282 struct i2c_client *client = rv8803->client;
283 u8 alarmvals[3];
284 int flags, ret;
285
286 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
287 if (ret)
288 return ret;
289
290 flags = rv8803_read_reg(client, RV8803_FLAG);
291 if (flags < 0)
292 return flags;
293
294 alrm->time.tm_sec = 0;
295 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
296 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
297 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
298
299 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
300 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
301
302 return 0;
303}
304
305static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
306{
307 struct i2c_client *client = to_i2c_client(dev);
308 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
309 u8 alarmvals[3];
310 u8 ctrl[2];
311 int ret, err;
312
313 /* The alarm has no seconds, round up to nearest minute */
314 if (alrm->time.tm_sec) {
315 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
316
317 alarm_time += 60 - alrm->time.tm_sec;
318 rtc_time64_to_tm(alarm_time, &alrm->time);
319 }
320
321 mutex_lock(&rv8803->flags_lock);
322
323 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
324 if (ret) {
325 mutex_unlock(&rv8803->flags_lock);
326 return ret;
327 }
328
329 alarmvals[0] = bin2bcd(alrm->time.tm_min);
330 alarmvals[1] = bin2bcd(alrm->time.tm_hour);
331 alarmvals[2] = bin2bcd(alrm->time.tm_mday);
332
333 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
334 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
335 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
336 rv8803->ctrl);
337 if (err) {
338 mutex_unlock(&rv8803->flags_lock);
339 return err;
340 }
341 }
342
343 ctrl[1] &= ~RV8803_FLAG_AF;
344 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]);
345 mutex_unlock(&rv8803->flags_lock);
346 if (err)
347 return err;
348
349 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
350 if (err)
351 return err;
352
353 if (alrm->enabled) {
354 if (rv8803->rtc->uie_rtctimer.enabled)
355 rv8803->ctrl |= RV8803_CTRL_UIE;
356 if (rv8803->rtc->aie_timer.enabled)
357 rv8803->ctrl |= RV8803_CTRL_AIE;
358
359 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
360 rv8803->ctrl);
361 if (err)
362 return err;
363 }
364
365 return 0;
366}
367
368static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
369{
370 struct i2c_client *client = to_i2c_client(dev);
371 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
372 int ctrl, flags, err;
373
374 ctrl = rv8803->ctrl;
375
376 if (enabled) {
377 if (rv8803->rtc->uie_rtctimer.enabled)
378 ctrl |= RV8803_CTRL_UIE;
379 if (rv8803->rtc->aie_timer.enabled)
380 ctrl |= RV8803_CTRL_AIE;
381 } else {
382 if (!rv8803->rtc->uie_rtctimer.enabled)
383 ctrl &= ~RV8803_CTRL_UIE;
384 if (!rv8803->rtc->aie_timer.enabled)
385 ctrl &= ~RV8803_CTRL_AIE;
386 }
387
388 mutex_lock(&rv8803->flags_lock);
389 flags = rv8803_read_reg(client, RV8803_FLAG);
390 if (flags < 0) {
391 mutex_unlock(&rv8803->flags_lock);
392 return flags;
393 }
394 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
395 err = rv8803_write_reg(client, RV8803_FLAG, flags);
396 mutex_unlock(&rv8803->flags_lock);
397 if (err)
398 return err;
399
400 if (ctrl != rv8803->ctrl) {
401 rv8803->ctrl = ctrl;
402 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
403 if (err)
404 return err;
405 }
406
407 return 0;
408}
409
410static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
411{
412 struct i2c_client *client = to_i2c_client(dev);
413 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
414 unsigned int vl = 0;
415 int flags, ret = 0;
416
417 switch (cmd) {
418 case RTC_VL_READ:
419 flags = rv8803_read_reg(client, RV8803_FLAG);
420 if (flags < 0)
421 return flags;
422
423 if (flags & RV8803_FLAG_V1F) {
424 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
425 vl = RTC_VL_ACCURACY_LOW;
426 }
427
428 if (flags & RV8803_FLAG_V2F)
429 vl |= RTC_VL_DATA_INVALID;
430
431 return put_user(vl, (unsigned int __user *)arg);
432
433 case RTC_VL_CLR:
434 mutex_lock(&rv8803->flags_lock);
435 flags = rv8803_read_reg(client, RV8803_FLAG);
436 if (flags < 0) {
437 mutex_unlock(&rv8803->flags_lock);
438 return flags;
439 }
440
441 flags &= ~RV8803_FLAG_V1F;
442 ret = rv8803_write_reg(client, RV8803_FLAG, flags);
443 mutex_unlock(&rv8803->flags_lock);
444 if (ret)
445 return ret;
446
447 return 0;
448
449 default:
450 return -ENOIOCTLCMD;
451 }
452}
453
454static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
455 size_t bytes)
456{
457 return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
458}
459
460static int rv8803_nvram_read(void *priv, unsigned int offset,
461 void *val, size_t bytes)
462{
463 int ret;
464
465 ret = rv8803_read_reg(priv, RV8803_RAM);
466 if (ret < 0)
467 return ret;
468
469 *(u8 *)val = ret;
470
471 return 0;
472}
473
474static const struct rtc_class_ops rv8803_rtc_ops = {
475 .read_time = rv8803_get_time,
476 .set_time = rv8803_set_time,
477 .ioctl = rv8803_ioctl,
478 .read_alarm = rv8803_get_alarm,
479 .set_alarm = rv8803_set_alarm,
480 .alarm_irq_enable = rv8803_alarm_irq_enable,
481};
482
483static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
484{
485 struct i2c_client *client = rv8803->client;
486 struct device_node *node = client->dev.of_node;
487 int err;
488 u8 flags;
489
490 if (!node)
491 return 0;
492
493 if (rv8803->type != rx_8900)
494 return 0;
495
496 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
497 if (err < 0)
498 return err;
499
500 flags = ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF) & (u8)err;
501
502 if (of_property_read_bool(node, "epson,vdet-disable"))
503 flags |= RX8900_FLAG_VDETOFF;
504
505 if (of_property_read_bool(node, "trickle-diode-disable"))
506 flags |= RX8900_FLAG_SWOFF;
507
508 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
509 flags);
510}
511
512static int rv8803_probe(struct i2c_client *client,
513 const struct i2c_device_id *id)
514{
515 struct i2c_adapter *adapter = client->adapter;
516 struct rv8803_data *rv8803;
517 int err, flags;
518 struct nvmem_config nvmem_cfg = {
519 .name = "rv8803_nvram",
520 .word_size = 1,
521 .stride = 1,
522 .size = 1,
523 .reg_read = rv8803_nvram_read,
524 .reg_write = rv8803_nvram_write,
525 .priv = client,
526 };
527
528 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
529 I2C_FUNC_SMBUS_I2C_BLOCK)) {
530 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
531 return -EIO;
532 }
533
534 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
535 GFP_KERNEL);
536 if (!rv8803)
537 return -ENOMEM;
538
539 mutex_init(&rv8803->flags_lock);
540 rv8803->client = client;
541 if (client->dev.of_node)
542 rv8803->type = (enum rv8803_type)
543 of_device_get_match_data(&client->dev);
544 else
545 rv8803->type = id->driver_data;
546 i2c_set_clientdata(client, rv8803);
547
548 flags = rv8803_read_reg(client, RV8803_FLAG);
549 if (flags < 0)
550 return flags;
551
552 if (flags & RV8803_FLAG_V1F)
553 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
554
555 if (flags & RV8803_FLAG_V2F)
556 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
557
558 if (flags & RV8803_FLAG_AF)
559 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
560
561 rv8803->rtc = devm_rtc_allocate_device(&client->dev);
562 if (IS_ERR(rv8803->rtc))
563 return PTR_ERR(rv8803->rtc);
564
565 if (client->irq > 0) {
566 err = devm_request_threaded_irq(&client->dev, client->irq,
567 NULL, rv8803_handle_irq,
568 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
569 "rv8803", client);
570 if (err) {
571 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
572 client->irq = 0;
573 }
574 }
575 if (!client->irq)
576 clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
577
578 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
579 if (err)
580 return err;
581
582 err = rx8900_trickle_charger_init(rv8803);
583 if (err) {
584 dev_err(&client->dev, "failed to init charger\n");
585 return err;
586 }
587
588 rv8803->rtc->ops = &rv8803_rtc_ops;
589 rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
590 rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
591 err = devm_rtc_register_device(rv8803->rtc);
592 if (err)
593 return err;
594
595 devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
596
597 rv8803->rtc->max_user_freq = 1;
598
599 return 0;
600}
601
602static const struct i2c_device_id rv8803_id[] = {
603 { "rv8803", rv_8803 },
604 { "rx8803", rv_8803 },
605 { "rx8900", rx_8900 },
606 { }
607};
608MODULE_DEVICE_TABLE(i2c, rv8803_id);
609
610static const __maybe_unused struct of_device_id rv8803_of_match[] = {
611 {
612 .compatible = "microcrystal,rv8803",
613 .data = (void *)rv_8803
614 },
615 {
616 .compatible = "epson,rx8803",
617 .data = (void *)rv_8803
618 },
619 {
620 .compatible = "epson,rx8900",
621 .data = (void *)rx_8900
622 },
623 { }
624};
625MODULE_DEVICE_TABLE(of, rv8803_of_match);
626
627static struct i2c_driver rv8803_driver = {
628 .driver = {
629 .name = "rtc-rv8803",
630 .of_match_table = of_match_ptr(rv8803_of_match),
631 },
632 .probe = rv8803_probe,
633 .id_table = rv8803_id,
634};
635module_i2c_driver(rv8803_driver);
636
637MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
638MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
639MODULE_LICENSE("GPL v2");