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
63static const struct i2c_device_id rx8025_id[] = {
64	{ "rx8025", 0 },
65	{ }
66};
67MODULE_DEVICE_TABLE(i2c, rx8025_id);
68
69struct rx8025_data {
70	struct rtc_device *rtc;
71	u8 ctrl1;
72};
73
74static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
75{
76	return i2c_smbus_read_byte_data(client, number << 4);
77}
78
79static 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
90static 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
96static 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
103static 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
128static 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
141static 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
172out:
173	mutex_unlock(lock);
174
175	return IRQ_HANDLED;
176}
177
178static 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
212static 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
248static 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	}
277out:
278	return err;
279}
280
281/* Alarm support */
282static 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
319static 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
371static 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
394static 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 */
419static 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
436static 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
462static 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
475static 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
489static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
490		   rx8025_sysfs_show_clock_adjust,
491		   rx8025_sysfs_store_clock_adjust);
492
493static int rx8025_sysfs_register(struct device *dev)
494{
495	return device_create_file(dev, &dev_attr_clock_adjust_ppb);
496}
497
498static void rx8025_sysfs_unregister(struct device *dev)
499{
500	device_remove_file(dev, &dev_attr_clock_adjust_ppb);
501}
502
503static 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
555static int rx8025_remove(struct i2c_client *client)
556{
557	rx8025_sysfs_unregister(&client->dev);
558	return 0;
559}
560
561static 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
570module_i2c_driver(rx8025_driver);
571
572MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
573MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
574MODULE_LICENSE("GPL");
575