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/kstrtox.h>
23#include <linux/module.h>
24#include <linux/rtc.h>
25
26/* Register definitions */
27#define RX8025_REG_SEC		0x00
28#define RX8025_REG_MIN		0x01
29#define RX8025_REG_HOUR		0x02
30#define RX8025_REG_WDAY		0x03
31#define RX8025_REG_MDAY		0x04
32#define RX8025_REG_MONTH	0x05
33#define RX8025_REG_YEAR		0x06
34#define RX8025_REG_DIGOFF	0x07
35#define RX8025_REG_ALWMIN	0x08
36#define RX8025_REG_ALWHOUR	0x09
37#define RX8025_REG_ALWWDAY	0x0a
38#define RX8025_REG_ALDMIN	0x0b
39#define RX8025_REG_ALDHOUR	0x0c
40/* 0x0d is reserved */
41#define RX8025_REG_CTRL1	0x0e
42#define RX8025_REG_CTRL2	0x0f
43
44#define RX8025_BIT_CTRL1_CT	(7 << 0)
45/* 1 Hz periodic level irq */
46#define RX8025_BIT_CTRL1_CT_1HZ	4
47#define RX8025_BIT_CTRL1_TEST	BIT(3)
48#define RX8025_BIT_CTRL1_1224	BIT(5)
49#define RX8025_BIT_CTRL1_DALE	BIT(6)
50#define RX8025_BIT_CTRL1_WALE	BIT(7)
51
52#define RX8025_BIT_CTRL2_DAFG	BIT(0)
53#define RX8025_BIT_CTRL2_WAFG	BIT(1)
54#define RX8025_BIT_CTRL2_CTFG	BIT(2)
55#define RX8025_BIT_CTRL2_PON	BIT(4)
56#define RX8025_BIT_CTRL2_XST	BIT(5)
57#define RX8025_BIT_CTRL2_VDET	BIT(6)
58
59#define RX8035_BIT_HOUR_1224	BIT(7)
60
61/* Clock precision adjustment */
62#define RX8025_ADJ_RESOLUTION	3050 /* in ppb */
63#define RX8025_ADJ_DATA_MAX	62
64#define RX8025_ADJ_DATA_MIN	-62
65
66enum rx_model {
67	model_rx_unknown,
68	model_rx_8025,
69	model_rx_8035,
70	model_last
71};
72
73static const struct i2c_device_id rx8025_id[] = {
74	{ "rx8025", model_rx_8025 },
75	{ "rx8035", model_rx_8035 },
76	{ }
77};
78MODULE_DEVICE_TABLE(i2c, rx8025_id);
79
80struct rx8025_data {
81	struct rtc_device *rtc;
82	enum rx_model model;
83	u8 ctrl1;
84	int is_24;
85};
86
87static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
88{
89	return i2c_smbus_read_byte_data(client, number << 4);
90}
91
92static int rx8025_read_regs(const struct i2c_client *client,
93			    u8 number, u8 length, u8 *values)
94{
95	int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
96						values);
97	if (ret != length)
98		return ret < 0 ? ret : -EIO;
99
100	return 0;
101}
102
103static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
104			    u8 value)
105{
106	return i2c_smbus_write_byte_data(client, number << 4, value);
107}
108
109static s32 rx8025_write_regs(const struct i2c_client *client,
110			     u8 number, u8 length, const u8 *values)
111{
112	return i2c_smbus_write_i2c_block_data(client, number << 4,
113					      length, values);
114}
115
116static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
117{
118	int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
119	/* XSTP bit has different polarity on RX-8025 vs RX-8035.
120	 * RX-8025: 0 == oscillator stopped
121	 * RX-8035: 1 == oscillator stopped
122	 */
123
124	if (model == model_rx_8025)
125		xstp = !xstp;
126
127	return xstp;
128}
129
130static int rx8025_check_validity(struct device *dev)
131{
132	struct i2c_client *client = to_i2c_client(dev);
133	struct rx8025_data *drvdata = dev_get_drvdata(dev);
134	int ctrl2;
135	int xstp;
136
137	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
138	if (ctrl2 < 0)
139		return ctrl2;
140
141	if (ctrl2 & RX8025_BIT_CTRL2_VDET)
142		dev_warn(dev, "power voltage drop detected\n");
143
144	if (ctrl2 & RX8025_BIT_CTRL2_PON) {
145		dev_warn(dev, "power-on reset detected, date is invalid\n");
146		return -EINVAL;
147	}
148
149	xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
150	if (xstp) {
151		dev_warn(dev, "crystal stopped, date is invalid\n");
152		return -EINVAL;
153	}
154
155	return 0;
156}
157
158static int rx8025_reset_validity(struct i2c_client *client)
159{
160	struct rx8025_data *drvdata = i2c_get_clientdata(client);
161	int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
162
163	if (ctrl2 < 0)
164		return ctrl2;
165
166	ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
167
168	if (drvdata->model == model_rx_8025)
169		ctrl2 |= RX8025_BIT_CTRL2_XST;
170	else
171		ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
172
173	return rx8025_write_reg(client, RX8025_REG_CTRL2,
174				ctrl2);
175}
176
177static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
178{
179	struct i2c_client *client = dev_id;
180	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
181	int status, xstp;
182
183	rtc_lock(rx8025->rtc);
184	status = rx8025_read_reg(client, RX8025_REG_CTRL2);
185	if (status < 0)
186		goto out;
187
188	xstp = rx8025_is_osc_stopped(rx8025->model, status);
189	if (xstp)
190		dev_warn(&client->dev, "Oscillation stop was detected,"
191			 "you may have to readjust the clock\n");
192
193	if (status & RX8025_BIT_CTRL2_CTFG) {
194		/* periodic */
195		status &= ~RX8025_BIT_CTRL2_CTFG;
196		rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
197	}
198
199	if (status & RX8025_BIT_CTRL2_DAFG) {
200		/* alarm */
201		status &= RX8025_BIT_CTRL2_DAFG;
202		if (rx8025_write_reg(client, RX8025_REG_CTRL1,
203				     rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
204			goto out;
205		rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
206	}
207
208out:
209	rtc_unlock(rx8025->rtc);
210
211	return IRQ_HANDLED;
212}
213
214static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
215{
216	struct i2c_client *client = to_i2c_client(dev);
217	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
218	u8 date[7];
219	int err;
220
221	err = rx8025_check_validity(dev);
222	if (err)
223		return err;
224
225	err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
226	if (err)
227		return err;
228
229	dev_dbg(dev, "%s: read %7ph\n", __func__, date);
230
231	dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
232	dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
233	if (rx8025->is_24)
234		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
235	else
236		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
237			+ (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
238
239	dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
240	dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
241	dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
242
243	dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
244
245	return 0;
246}
247
248static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
249{
250	struct i2c_client *client = to_i2c_client(dev);
251	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
252	u8 date[7];
253	int ret;
254
255	/*
256	 * Here the read-only bits are written as "0".  I'm not sure if that
257	 * is sound.
258	 */
259	date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
260	date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
261	if (rx8025->is_24)
262		date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
263	else
264		date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
265			| bin2bcd((dt->tm_hour + 11) % 12 + 1);
266
267	date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
268	date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
269	date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
270	date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
271
272	dev_dbg(dev, "%s: write %7ph\n", __func__, date);
273
274	ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
275	if (ret < 0)
276		return ret;
277
278	return rx8025_reset_validity(client);
279}
280
281static int rx8025_init_client(struct i2c_client *client)
282{
283	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
284	u8 ctrl[2], ctrl2;
285	int need_clear = 0;
286	int hour_reg;
287	int err;
288
289	err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
290	if (err)
291		goto out;
292
293	/* Keep test bit zero ! */
294	rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
295
296	if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
297		dev_warn(&client->dev, "Alarm was detected\n");
298		need_clear = 1;
299	}
300
301	if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
302		need_clear = 1;
303
304	if (need_clear) {
305		ctrl2 = ctrl[1];
306		ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
307			   RX8025_BIT_CTRL2_DAFG);
308
309		err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
310	}
311
312	if (rx8025->model == model_rx_8035) {
313		/* In RX-8035, 12/24 flag is in the hour register */
314		hour_reg = rx8025_read_reg(client, RX8025_REG_HOUR);
315		if (hour_reg < 0)
316			return hour_reg;
317		rx8025->is_24 = (hour_reg & RX8035_BIT_HOUR_1224);
318	} else {
319		rx8025->is_24 = (ctrl[1] & RX8025_BIT_CTRL1_1224);
320	}
321out:
322	return err;
323}
324
325/* Alarm support */
326static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
327{
328	struct i2c_client *client = to_i2c_client(dev);
329	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
330	u8 ald[2];
331	int ctrl2, err;
332
333	err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
334	if (err)
335		return err;
336
337	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
338	if (ctrl2 < 0)
339		return ctrl2;
340
341	dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
342		__func__, ald[0], ald[1], ctrl2);
343
344	/* Hardware alarms precision is 1 minute! */
345	t->time.tm_sec = 0;
346	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
347	if (rx8025->is_24)
348		t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
349	else
350		t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
351			+ (ald[1] & 0x20 ? 12 : 0);
352
353	dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
354	t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
355	t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
356
357	return err;
358}
359
360static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
361{
362	struct i2c_client *client = to_i2c_client(dev);
363	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
364	u8 ald[2];
365	int err;
366
367	ald[0] = bin2bcd(t->time.tm_min);
368	if (rx8025->is_24)
369		ald[1] = bin2bcd(t->time.tm_hour);
370	else
371		ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
372			| bin2bcd((t->time.tm_hour + 11) % 12 + 1);
373
374	dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
375
376	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
377		rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
378		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
379				       rx8025->ctrl1);
380		if (err)
381			return err;
382	}
383	err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
384	if (err)
385		return err;
386
387	if (t->enabled) {
388		rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
389		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
390				       rx8025->ctrl1);
391		if (err)
392			return err;
393	}
394
395	return 0;
396}
397
398static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
399{
400	struct i2c_client *client = to_i2c_client(dev);
401	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
402	u8 ctrl1;
403	int err;
404
405	ctrl1 = rx8025->ctrl1;
406	if (enabled)
407		ctrl1 |= RX8025_BIT_CTRL1_DALE;
408	else
409		ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
410
411	if (ctrl1 != rx8025->ctrl1) {
412		rx8025->ctrl1 = ctrl1;
413		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
414				       rx8025->ctrl1);
415		if (err)
416			return err;
417	}
418	return 0;
419}
420
421/*
422 * According to the RX8025 SA/NB application manual the frequency and
423 * temperature characteristics can be approximated using the following
424 * equation:
425 *
426 *   df = a * (ut - t)**2
427 *
428 *   df: Frequency deviation in any temperature
429 *   a : Coefficient = (-35 +-5) * 10**-9
430 *   ut: Ultimate temperature in degree = +25 +-5 degree
431 *   t : Any temperature in degree
432 */
433static int rx8025_read_offset(struct device *dev, long *offset)
434{
435	struct i2c_client *client = to_i2c_client(dev);
436	int digoff;
437
438	digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
439	if (digoff < 0)
440		return digoff;
441
442	*offset = digoff >= 64 ? digoff - 128 : digoff;
443	if (*offset > 0)
444		(*offset)--;
445	*offset *= RX8025_ADJ_RESOLUTION;
446
447	return 0;
448}
449
450static int rx8025_set_offset(struct device *dev, long offset)
451{
452	struct i2c_client *client = to_i2c_client(dev);
453	u8 digoff;
454
455	offset /= RX8025_ADJ_RESOLUTION;
456	if (offset > RX8025_ADJ_DATA_MAX)
457		offset = RX8025_ADJ_DATA_MAX;
458	else if (offset < RX8025_ADJ_DATA_MIN)
459		offset = RX8025_ADJ_DATA_MIN;
460	else if (offset > 0)
461		offset++;
462	else if (offset < 0)
463		offset += 128;
464	digoff = offset;
465
466	return rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
467}
468
469static const struct rtc_class_ops rx8025_rtc_ops = {
470	.read_time = rx8025_get_time,
471	.set_time = rx8025_set_time,
472	.read_alarm = rx8025_read_alarm,
473	.set_alarm = rx8025_set_alarm,
474	.alarm_irq_enable = rx8025_alarm_irq_enable,
475	.read_offset = rx8025_read_offset,
476	.set_offset = rx8025_set_offset,
477};
478
479static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
480					      struct device_attribute *attr,
481					      char *buf)
482{
483	long adj;
484	int err;
485
486	dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
487	err = rx8025_read_offset(dev, &adj);
488	if (err)
489		return err;
490
491	return sprintf(buf, "%ld\n", -adj);
492}
493
494static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
495					       struct device_attribute *attr,
496					       const char *buf, size_t count)
497{
498	long adj;
499	int err;
500
501	dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
502	if (kstrtol(buf, 10, &adj) != 0)
503		return -EINVAL;
504
505	err = rx8025_set_offset(dev, -adj);
506
507	return err ? err : count;
508}
509
510static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
511		   rx8025_sysfs_show_clock_adjust,
512		   rx8025_sysfs_store_clock_adjust);
513
514static struct attribute *rx8025_attrs[] = {
515	&dev_attr_clock_adjust_ppb.attr,
516	NULL
517};
518
519static const struct attribute_group rx8025_attr_group = {
520	.attrs	= rx8025_attrs,
521};
522
523static int rx8025_probe(struct i2c_client *client)
524{
525	const struct i2c_device_id *id = i2c_match_id(rx8025_id, client);
526	struct i2c_adapter *adapter = client->adapter;
527	struct rx8025_data *rx8025;
528	int err = 0;
529
530	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
531				     | I2C_FUNC_SMBUS_I2C_BLOCK)) {
532		dev_err(&adapter->dev,
533			"doesn't support required functionality\n");
534		return -EIO;
535	}
536
537	rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
538	if (!rx8025)
539		return -ENOMEM;
540
541	i2c_set_clientdata(client, rx8025);
542
543	if (id)
544		rx8025->model = id->driver_data;
545
546	err = rx8025_init_client(client);
547	if (err)
548		return err;
549
550	rx8025->rtc = devm_rtc_allocate_device(&client->dev);
551	if (IS_ERR(rx8025->rtc))
552		return PTR_ERR(rx8025->rtc);
553
554	rx8025->rtc->ops = &rx8025_rtc_ops;
555	rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
556	rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;
557
558	if (client->irq > 0) {
559		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
560		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
561						rx8025_handle_irq,
562						IRQF_ONESHOT,
563						"rx8025", client);
564		if (err)
565			clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
566	}
567
568	rx8025->rtc->max_user_freq = 1;
569
570	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
571	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);
572
573	err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
574	if (err)
575		return err;
576
577	return devm_rtc_register_device(rx8025->rtc);
578}
579
580static struct i2c_driver rx8025_driver = {
581	.driver = {
582		.name = "rtc-rx8025",
583	},
584	.probe		= rx8025_probe,
585	.id_table	= rx8025_id,
586};
587
588module_i2c_driver(rx8025_driver);
589
590MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
591MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
592MODULE_LICENSE("GPL");
593