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1/*
2 * RTC driver for the Micro Crystal RV8803
3 *
4 * Copyright (C) 2015 Micro Crystal SA
5 *
6 * Alexandre Belloni <alexandre.belloni@free-electrons.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#include <linux/bcd.h>
15#include <linux/bitops.h>
16#include <linux/log2.h>
17#include <linux/i2c.h>
18#include <linux/interrupt.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/of_device.h>
22#include <linux/rtc.h>
23
24#define RV8803_I2C_TRY_COUNT 4
25
26#define RV8803_SEC 0x00
27#define RV8803_MIN 0x01
28#define RV8803_HOUR 0x02
29#define RV8803_WEEK 0x03
30#define RV8803_DAY 0x04
31#define RV8803_MONTH 0x05
32#define RV8803_YEAR 0x06
33#define RV8803_RAM 0x07
34#define RV8803_ALARM_MIN 0x08
35#define RV8803_ALARM_HOUR 0x09
36#define RV8803_ALARM_WEEK_OR_DAY 0x0A
37#define RV8803_EXT 0x0D
38#define RV8803_FLAG 0x0E
39#define RV8803_CTRL 0x0F
40
41#define RV8803_EXT_WADA BIT(6)
42
43#define RV8803_FLAG_V1F BIT(0)
44#define RV8803_FLAG_V2F BIT(1)
45#define RV8803_FLAG_AF BIT(3)
46#define RV8803_FLAG_TF BIT(4)
47#define RV8803_FLAG_UF BIT(5)
48
49#define RV8803_CTRL_RESET BIT(0)
50
51#define RV8803_CTRL_EIE BIT(2)
52#define RV8803_CTRL_AIE BIT(3)
53#define RV8803_CTRL_TIE BIT(4)
54#define RV8803_CTRL_UIE BIT(5)
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_8900
63};
64
65struct rv8803_data {
66 struct i2c_client *client;
67 struct rtc_device *rtc;
68 struct mutex flags_lock;
69 u8 ctrl;
70 enum rv8803_type type;
71};
72
73static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
74{
75 int try = RV8803_I2C_TRY_COUNT;
76 s32 ret;
77
78 /*
79 * There is a 61µs window during which the RTC does not acknowledge I2C
80 * transfers. In that case, ensure that there are multiple attempts.
81 */
82 do
83 ret = i2c_smbus_read_byte_data(client, reg);
84 while ((ret == -ENXIO || ret == -EIO) && --try);
85 if (ret < 0)
86 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
87
88 return ret;
89}
90
91static int rv8803_read_regs(const struct i2c_client *client,
92 u8 reg, u8 count, u8 *values)
93{
94 int try = RV8803_I2C_TRY_COUNT;
95 s32 ret;
96
97 do
98 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
99 while ((ret == -ENXIO || ret == -EIO) && --try);
100 if (ret != count) {
101 dev_err(&client->dev,
102 "Unable to read registers 0x%02x..0x%02x\n",
103 reg, reg + count - 1);
104 return ret < 0 ? ret : -EIO;
105 }
106
107 return 0;
108}
109
110static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
111{
112 int try = RV8803_I2C_TRY_COUNT;
113 s32 ret;
114
115 do
116 ret = i2c_smbus_write_byte_data(client, reg, value);
117 while ((ret == -ENXIO || ret == -EIO) && --try);
118 if (ret)
119 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
120
121 return ret;
122}
123
124static int rv8803_write_regs(const struct i2c_client *client,
125 u8 reg, u8 count, const u8 *values)
126{
127 int try = RV8803_I2C_TRY_COUNT;
128 s32 ret;
129
130 do
131 ret = i2c_smbus_write_i2c_block_data(client, reg, count,
132 values);
133 while ((ret == -ENXIO || ret == -EIO) && --try);
134 if (ret)
135 dev_err(&client->dev,
136 "Unable to write registers 0x%02x..0x%02x\n",
137 reg, reg + count - 1);
138
139 return ret;
140}
141
142static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
143{
144 struct i2c_client *client = dev_id;
145 struct rv8803_data *rv8803 = i2c_get_clientdata(client);
146 unsigned long events = 0;
147 int flags;
148
149 mutex_lock(&rv8803->flags_lock);
150
151 flags = rv8803_read_reg(client, RV8803_FLAG);
152 if (flags <= 0) {
153 mutex_unlock(&rv8803->flags_lock);
154 return IRQ_NONE;
155 }
156
157 if (flags & RV8803_FLAG_V1F)
158 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
159
160 if (flags & RV8803_FLAG_V2F)
161 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
162
163 if (flags & RV8803_FLAG_TF) {
164 flags &= ~RV8803_FLAG_TF;
165 rv8803->ctrl &= ~RV8803_CTRL_TIE;
166 events |= RTC_PF;
167 }
168
169 if (flags & RV8803_FLAG_AF) {
170 flags &= ~RV8803_FLAG_AF;
171 rv8803->ctrl &= ~RV8803_CTRL_AIE;
172 events |= RTC_AF;
173 }
174
175 if (flags & RV8803_FLAG_UF) {
176 flags &= ~RV8803_FLAG_UF;
177 rv8803->ctrl &= ~RV8803_CTRL_UIE;
178 events |= RTC_UF;
179 }
180
181 if (events) {
182 rtc_update_irq(rv8803->rtc, 1, events);
183 rv8803_write_reg(client, RV8803_FLAG, flags);
184 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
185 }
186
187 mutex_unlock(&rv8803->flags_lock);
188
189 return IRQ_HANDLED;
190}
191
192static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
193{
194 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
195 u8 date1[7];
196 u8 date2[7];
197 u8 *date = date1;
198 int ret, flags;
199
200 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
201 if (flags < 0)
202 return flags;
203
204 if (flags & RV8803_FLAG_V2F) {
205 dev_warn(dev, "Voltage low, data is invalid.\n");
206 return -EINVAL;
207 }
208
209 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
210 if (ret)
211 return ret;
212
213 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
214 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
215 if (ret)
216 return ret;
217
218 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
219 date = date2;
220 }
221
222 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
223 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
224 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
225 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
226 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
227 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
228 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
229
230 return 0;
231}
232
233static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
234{
235 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
236 u8 date[7];
237 int ctrl, flags, ret;
238
239 if ((tm->tm_year < 100) || (tm->tm_year > 199))
240 return -EINVAL;
241
242 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
243 if (ctrl < 0)
244 return ctrl;
245
246 /* Stop the clock */
247 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
248 ctrl | RV8803_CTRL_RESET);
249 if (ret)
250 return ret;
251
252 date[RV8803_SEC] = bin2bcd(tm->tm_sec);
253 date[RV8803_MIN] = bin2bcd(tm->tm_min);
254 date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
255 date[RV8803_WEEK] = 1 << (tm->tm_wday);
256 date[RV8803_DAY] = bin2bcd(tm->tm_mday);
257 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
258 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
259
260 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
261 if (ret)
262 return ret;
263
264 /* Restart the clock */
265 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
266 ctrl & ~RV8803_CTRL_RESET);
267 if (ret)
268 return ret;
269
270 mutex_lock(&rv8803->flags_lock);
271
272 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
273 if (flags < 0) {
274 mutex_unlock(&rv8803->flags_lock);
275 return flags;
276 }
277
278 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
279 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
280
281 mutex_unlock(&rv8803->flags_lock);
282
283 return ret;
284}
285
286static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
287{
288 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
289 struct i2c_client *client = rv8803->client;
290 u8 alarmvals[3];
291 int flags, ret;
292
293 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
294 if (ret)
295 return ret;
296
297 flags = rv8803_read_reg(client, RV8803_FLAG);
298 if (flags < 0)
299 return flags;
300
301 alrm->time.tm_sec = 0;
302 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
303 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
304 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
305
306 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
307 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
308
309 return 0;
310}
311
312static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
313{
314 struct i2c_client *client = to_i2c_client(dev);
315 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
316 u8 alarmvals[3];
317 u8 ctrl[2];
318 int ret, err;
319
320 /* The alarm has no seconds, round up to nearest minute */
321 if (alrm->time.tm_sec) {
322 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
323
324 alarm_time += 60 - alrm->time.tm_sec;
325 rtc_time64_to_tm(alarm_time, &alrm->time);
326 }
327
328 mutex_lock(&rv8803->flags_lock);
329
330 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
331 if (ret) {
332 mutex_unlock(&rv8803->flags_lock);
333 return ret;
334 }
335
336 alarmvals[0] = bin2bcd(alrm->time.tm_min);
337 alarmvals[1] = bin2bcd(alrm->time.tm_hour);
338 alarmvals[2] = bin2bcd(alrm->time.tm_mday);
339
340 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
341 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
342 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
343 rv8803->ctrl);
344 if (err) {
345 mutex_unlock(&rv8803->flags_lock);
346 return err;
347 }
348 }
349
350 ctrl[1] &= ~RV8803_FLAG_AF;
351 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]);
352 mutex_unlock(&rv8803->flags_lock);
353 if (err)
354 return err;
355
356 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
357 if (err)
358 return err;
359
360 if (alrm->enabled) {
361 if (rv8803->rtc->uie_rtctimer.enabled)
362 rv8803->ctrl |= RV8803_CTRL_UIE;
363 if (rv8803->rtc->aie_timer.enabled)
364 rv8803->ctrl |= RV8803_CTRL_AIE;
365
366 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
367 rv8803->ctrl);
368 if (err)
369 return err;
370 }
371
372 return 0;
373}
374
375static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
376{
377 struct i2c_client *client = to_i2c_client(dev);
378 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
379 int ctrl, flags, err;
380
381 ctrl = rv8803->ctrl;
382
383 if (enabled) {
384 if (rv8803->rtc->uie_rtctimer.enabled)
385 ctrl |= RV8803_CTRL_UIE;
386 if (rv8803->rtc->aie_timer.enabled)
387 ctrl |= RV8803_CTRL_AIE;
388 } else {
389 if (!rv8803->rtc->uie_rtctimer.enabled)
390 ctrl &= ~RV8803_CTRL_UIE;
391 if (!rv8803->rtc->aie_timer.enabled)
392 ctrl &= ~RV8803_CTRL_AIE;
393 }
394
395 mutex_lock(&rv8803->flags_lock);
396 flags = rv8803_read_reg(client, RV8803_FLAG);
397 if (flags < 0) {
398 mutex_unlock(&rv8803->flags_lock);
399 return flags;
400 }
401 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
402 err = rv8803_write_reg(client, RV8803_FLAG, flags);
403 mutex_unlock(&rv8803->flags_lock);
404 if (err)
405 return err;
406
407 if (ctrl != rv8803->ctrl) {
408 rv8803->ctrl = ctrl;
409 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
410 if (err)
411 return err;
412 }
413
414 return 0;
415}
416
417static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
418{
419 struct i2c_client *client = to_i2c_client(dev);
420 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
421 int flags, ret = 0;
422
423 switch (cmd) {
424 case RTC_VL_READ:
425 flags = rv8803_read_reg(client, RV8803_FLAG);
426 if (flags < 0)
427 return flags;
428
429 if (flags & RV8803_FLAG_V1F)
430 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
431
432 if (flags & RV8803_FLAG_V2F)
433 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
434
435 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
436
437 if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
438 return -EFAULT;
439
440 return 0;
441
442 case RTC_VL_CLR:
443 mutex_lock(&rv8803->flags_lock);
444 flags = rv8803_read_reg(client, RV8803_FLAG);
445 if (flags < 0) {
446 mutex_unlock(&rv8803->flags_lock);
447 return flags;
448 }
449
450 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
451 ret = rv8803_write_reg(client, RV8803_FLAG, flags);
452 mutex_unlock(&rv8803->flags_lock);
453 if (ret)
454 return ret;
455
456 return 0;
457
458 default:
459 return -ENOIOCTLCMD;
460 }
461}
462
463static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
464 size_t bytes)
465{
466 int ret;
467
468 ret = rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
469 if (ret)
470 return ret;
471
472 return 0;
473}
474
475static int rv8803_nvram_read(void *priv, unsigned int offset,
476 void *val, size_t bytes)
477{
478 int ret;
479
480 ret = rv8803_read_reg(priv, RV8803_RAM);
481 if (ret < 0)
482 return ret;
483
484 *(u8 *)val = ret;
485
486 return 0;
487}
488
489static struct rtc_class_ops rv8803_rtc_ops = {
490 .read_time = rv8803_get_time,
491 .set_time = rv8803_set_time,
492 .ioctl = rv8803_ioctl,
493};
494
495static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
496{
497 struct i2c_client *client = rv8803->client;
498 struct device_node *node = client->dev.of_node;
499 int err;
500 u8 flags;
501
502 if (!node)
503 return 0;
504
505 if (rv8803->type != rx_8900)
506 return 0;
507
508 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
509 if (err < 0)
510 return err;
511
512 flags = ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF) & (u8)err;
513
514 if (of_property_read_bool(node, "epson,vdet-disable"))
515 flags |= RX8900_FLAG_VDETOFF;
516
517 if (of_property_read_bool(node, "trickle-diode-disable"))
518 flags |= RX8900_FLAG_SWOFF;
519
520 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
521 flags);
522}
523
524static int rv8803_probe(struct i2c_client *client,
525 const struct i2c_device_id *id)
526{
527 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
528 struct rv8803_data *rv8803;
529 int err, flags;
530 struct nvmem_config nvmem_cfg = {
531 .name = "rv8803_nvram",
532 .word_size = 1,
533 .stride = 1,
534 .size = 1,
535 .reg_read = rv8803_nvram_read,
536 .reg_write = rv8803_nvram_write,
537 .priv = client,
538 };
539
540 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
541 I2C_FUNC_SMBUS_I2C_BLOCK)) {
542 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
543 return -EIO;
544 }
545
546 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
547 GFP_KERNEL);
548 if (!rv8803)
549 return -ENOMEM;
550
551 mutex_init(&rv8803->flags_lock);
552 rv8803->client = client;
553 if (client->dev.of_node)
554 rv8803->type = (enum rv8803_type)
555 of_device_get_match_data(&client->dev);
556 else
557 rv8803->type = id->driver_data;
558 i2c_set_clientdata(client, rv8803);
559
560 flags = rv8803_read_reg(client, RV8803_FLAG);
561 if (flags < 0)
562 return flags;
563
564 if (flags & RV8803_FLAG_V1F)
565 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
566
567 if (flags & RV8803_FLAG_V2F)
568 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
569
570 if (flags & RV8803_FLAG_AF)
571 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
572
573 rv8803->rtc = devm_rtc_allocate_device(&client->dev);
574 if (IS_ERR(rv8803->rtc)) {
575 return PTR_ERR(rv8803->rtc);
576 }
577
578 if (client->irq > 0) {
579 err = devm_request_threaded_irq(&client->dev, client->irq,
580 NULL, rv8803_handle_irq,
581 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
582 "rv8803", client);
583 if (err) {
584 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
585 client->irq = 0;
586 } else {
587 rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
588 rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
589 rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
590 }
591 }
592
593 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
594 if (err)
595 return err;
596
597 err = rx8900_trickle_charger_init(rv8803);
598 if (err) {
599 dev_err(&client->dev, "failed to init charger\n");
600 return err;
601 }
602
603 rv8803->rtc->ops = &rv8803_rtc_ops;
604 rv8803->rtc->nvram_old_abi = true;
605 err = rtc_register_device(rv8803->rtc);
606 if (err)
607 return err;
608
609 rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
610
611 rv8803->rtc->max_user_freq = 1;
612
613 return 0;
614}
615
616static const struct i2c_device_id rv8803_id[] = {
617 { "rv8803", rv_8803 },
618 { "rx8900", rx_8900 },
619 { }
620};
621MODULE_DEVICE_TABLE(i2c, rv8803_id);
622
623static const struct of_device_id rv8803_of_match[] = {
624 {
625 .compatible = "microcrystal,rv8803",
626 .data = (void *)rx_8900
627 },
628 {
629 .compatible = "epson,rx8900",
630 .data = (void *)rx_8900
631 },
632 { }
633};
634MODULE_DEVICE_TABLE(of, rv8803_of_match);
635
636static struct i2c_driver rv8803_driver = {
637 .driver = {
638 .name = "rtc-rv8803",
639 .of_match_table = of_match_ptr(rv8803_of_match),
640 },
641 .probe = rv8803_probe,
642 .id_table = rv8803_id,
643};
644module_i2c_driver(rv8803_driver);
645
646MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
647MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
648MODULE_LICENSE("GPL v2");