summaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-rx8025.c
blob: aabe62c283a150f18810545a05827f54b8ed468f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Epson's RTC module RX-8025 SA/NB
 *
 * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
 *
 * Copyright (C) 2005 by Digi International Inc.
 * All rights reserved.
 *
 * Modified by fengjh at rising.com.cn
 * <lm-sensors@lm-sensors.org>
 * 2006.11
 *
 * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
 * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
 * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
 */
#include <linux/bcd.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/kstrtox.h>
#include <linux/module.h>
#include <linux/rtc.h>

/* Register definitions */
#define RX8025_REG_SEC		0x00
#define RX8025_REG_MIN		0x01
#define RX8025_REG_HOUR		0x02
#define RX8025_REG_WDAY		0x03
#define RX8025_REG_MDAY		0x04
#define RX8025_REG_MONTH	0x05
#define RX8025_REG_YEAR		0x06
#define RX8025_REG_DIGOFF	0x07
#define RX8025_REG_ALWMIN	0x08
#define RX8025_REG_ALWHOUR	0x09
#define RX8025_REG_ALWWDAY	0x0a
#define RX8025_REG_ALDMIN	0x0b
#define RX8025_REG_ALDHOUR	0x0c
/* 0x0d is reserved */
#define RX8025_REG_CTRL1	0x0e
#define RX8025_REG_CTRL2	0x0f

#define RX8025_BIT_CTRL1_CT	(7 << 0)
/* 1 Hz periodic level irq */
#define RX8025_BIT_CTRL1_CT_1HZ	4
#define RX8025_BIT_CTRL1_TEST	BIT(3)
#define RX8025_BIT_CTRL1_1224	BIT(5)
#define RX8025_BIT_CTRL1_DALE	BIT(6)
#define RX8025_BIT_CTRL1_WALE	BIT(7)

#define RX8025_BIT_CTRL2_DAFG	BIT(0)
#define RX8025_BIT_CTRL2_WAFG	BIT(1)
#define RX8025_BIT_CTRL2_CTFG	BIT(2)
#define RX8025_BIT_CTRL2_PON	BIT(4)
#define RX8025_BIT_CTRL2_XST	BIT(5)
#define RX8025_BIT_CTRL2_VDET	BIT(6)

#define RX8035_BIT_HOUR_1224	BIT(7)

/* Clock precision adjustment */
#define RX8025_ADJ_RESOLUTION	3050 /* in ppb */
#define RX8025_ADJ_DATA_MAX	62
#define RX8025_ADJ_DATA_MIN	-62

enum rx_model {
	model_rx_unknown,
	model_rx_8025,
	model_rx_8035,
	model_last
};

static const struct i2c_device_id rx8025_id[] = {
	{ "rx8025", model_rx_8025 },
	{ "rx8035", model_rx_8035 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, rx8025_id);

struct rx8025_data {
	struct rtc_device *rtc;
	enum rx_model model;
	u8 ctrl1;
	int is_24;
};

static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
{
	return i2c_smbus_read_byte_data(client, number << 4);
}

static int rx8025_read_regs(const struct i2c_client *client,
			    u8 number, u8 length, u8 *values)
{
	int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
						values);
	if (ret != length)
		return ret < 0 ? ret : -EIO;

	return 0;
}

static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
			    u8 value)
{
	return i2c_smbus_write_byte_data(client, number << 4, value);
}

static s32 rx8025_write_regs(const struct i2c_client *client,
			     u8 number, u8 length, const u8 *values)
{
	return i2c_smbus_write_i2c_block_data(client, number << 4,
					      length, values);
}

static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
{
	int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
	/* XSTP bit has different polarity on RX-8025 vs RX-8035.
	 * RX-8025: 0 == oscillator stopped
	 * RX-8035: 1 == oscillator stopped
	 */

	if (model == model_rx_8025)
		xstp = !xstp;

	return xstp;
}

static int rx8025_check_validity(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8025_data *drvdata = dev_get_drvdata(dev);
	int ctrl2;
	int xstp;

	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
	if (ctrl2 < 0)
		return ctrl2;

	if (ctrl2 & RX8025_BIT_CTRL2_VDET)
		dev_warn(dev, "power voltage drop detected\n");

	if (ctrl2 & RX8025_BIT_CTRL2_PON) {
		dev_warn(dev, "power-on reset detected, date is invalid\n");
		return -EINVAL;
	}

	xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
	if (xstp) {
		dev_warn(dev, "crystal stopped, date is invalid\n");
		return -EINVAL;
	}

	return 0;
}

static int rx8025_reset_validity(struct i2c_client *client)
{
	struct rx8025_data *drvdata = i2c_get_clientdata(client);
	int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);

	if (ctrl2 < 0)
		return ctrl2;

	ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);

	if (drvdata->model == model_rx_8025)
		ctrl2 |= RX8025_BIT_CTRL2_XST;
	else
		ctrl2 &= ~(RX8025_BIT_CTRL2_XST);

	return rx8025_write_reg(client, RX8025_REG_CTRL2,
				ctrl2);
}

static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
{
	struct i2c_client *client = dev_id;
	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
	int status, xstp;

	rtc_lock(rx8025->rtc);
	status = rx8025_read_reg(client, RX8025_REG_CTRL2);
	if (status < 0)
		goto out;

	xstp = rx8025_is_osc_stopped(rx8025->model, status);
	if (xstp)
		dev_warn(&client->dev, "Oscillation stop was detected,"
			 "you may have to readjust the clock\n");

	if (status & RX8025_BIT_CTRL2_CTFG) {
		/* periodic */
		status &= ~RX8025_BIT_CTRL2_CTFG;
		rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
	}

	if (status & RX8025_BIT_CTRL2_DAFG) {
		/* alarm */
		status &= RX8025_BIT_CTRL2_DAFG;
		if (rx8025_write_reg(client, RX8025_REG_CTRL1,
				     rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
			goto out;
		rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
	}

out:
	rtc_unlock(rx8025->rtc);

	return IRQ_HANDLED;
}

static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
	u8 date[7];
	int err;

	err = rx8025_check_validity(dev);
	if (err)
		return err;

	err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
	if (err)
		return err;

	dev_dbg(dev, "%s: read %7ph\n", __func__, date);

	dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
	dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
	if (rx8025->is_24)
		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
	else
		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
			+ (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);

	dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
	dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
	dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;

	dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);

	return 0;
}

static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
	u8 date[7];
	int ret;

	/*
	 * Here the read-only bits are written as "0".  I'm not sure if that
	 * is sound.
	 */
	date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
	date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
	if (rx8025->is_24)
		date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
	else
		date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
			| bin2bcd((dt->tm_hour + 11) % 12 + 1);

	date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
	date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
	date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
	date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);

	dev_dbg(dev, "%s: write %7ph\n", __func__, date);

	ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
	if (ret < 0)
		return ret;

	return rx8025_reset_validity(client);
}

static int rx8025_init_client(struct i2c_client *client)
{
	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
	u8 ctrl[2], ctrl2;
	int need_clear = 0;
	int hour_reg;
	int err;

	err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
	if (err)
		goto out;

	/* Keep test bit zero ! */
	rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;

	if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
		dev_warn(&client->dev, "Alarm was detected\n");
		need_clear = 1;
	}

	if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
		need_clear = 1;

	if (need_clear) {
		ctrl2 = ctrl[1];
		ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
			   RX8025_BIT_CTRL2_DAFG);

		err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
	}

	if (rx8025->model == model_rx_8035) {
		/* In RX-8035, 12/24 flag is in the hour register */
		hour_reg = rx8025_read_reg(client, RX8025_REG_HOUR);
		if (hour_reg < 0)
			return hour_reg;
		rx8025->is_24 = (hour_reg & RX8035_BIT_HOUR_1224);
	} else {
		rx8025->is_24 = (ctrl[1] & RX8025_BIT_CTRL1_1224);
	}
out:
	return err;
}

/* Alarm support */
static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
	u8 ald[2];
	int ctrl2, err;

	err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
	if (err)
		return err;

	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
	if (ctrl2 < 0)
		return ctrl2;

	dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
		__func__, ald[0], ald[1], ctrl2);

	/* Hardware alarms precision is 1 minute! */
	t->time.tm_sec = 0;
	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
	if (rx8025->is_24)
		t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
	else
		t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
			+ (ald[1] & 0x20 ? 12 : 0);

	dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
	t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
	t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;

	return err;
}

static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
	u8 ald[2];
	int err;

	ald[0] = bin2bcd(t->time.tm_min);
	if (rx8025->is_24)
		ald[1] = bin2bcd(t->time.tm_hour);
	else
		ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
			| bin2bcd((t->time.tm_hour + 11) % 12 + 1);

	dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);

	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
		rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
				       rx8025->ctrl1);
		if (err)
			return err;
	}
	err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
	if (err)
		return err;

	if (t->enabled) {
		rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
				       rx8025->ctrl1);
		if (err)
			return err;
	}

	return 0;
}

static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
	u8 ctrl1;
	int err;

	ctrl1 = rx8025->ctrl1;
	if (enabled)
		ctrl1 |= RX8025_BIT_CTRL1_DALE;
	else
		ctrl1 &= ~RX8025_BIT_CTRL1_DALE;

	if (ctrl1 != rx8025->ctrl1) {
		rx8025->ctrl1 = ctrl1;
		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
				       rx8025->ctrl1);
		if (err)
			return err;
	}
	return 0;
}

/*
 * According to the RX8025 SA/NB application manual the frequency and
 * temperature characteristics can be approximated using the following
 * equation:
 *
 *   df = a * (ut - t)**2
 *
 *   df: Frequency deviation in any temperature
 *   a : Coefficient = (-35 +-5) * 10**-9
 *   ut: Ultimate temperature in degree = +25 +-5 degree
 *   t : Any temperature in degree
 */
static int rx8025_read_offset(struct device *dev, long *offset)
{
	struct i2c_client *client = to_i2c_client(dev);
	int digoff;

	digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
	if (digoff < 0)
		return digoff;

	*offset = digoff >= 64 ? digoff - 128 : digoff;
	if (*offset > 0)
		(*offset)--;
	*offset *= RX8025_ADJ_RESOLUTION;

	return 0;
}

static int rx8025_set_offset(struct device *dev, long offset)
{
	struct i2c_client *client = to_i2c_client(dev);
	u8 digoff;

	offset /= RX8025_ADJ_RESOLUTION;
	if (offset > RX8025_ADJ_DATA_MAX)
		offset = RX8025_ADJ_DATA_MAX;
	else if (offset < RX8025_ADJ_DATA_MIN)
		offset = RX8025_ADJ_DATA_MIN;
	else if (offset > 0)
		offset++;
	else if (offset < 0)
		offset += 128;
	digoff = offset;

	return rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
}

static const struct rtc_class_ops rx8025_rtc_ops = {
	.read_time = rx8025_get_time,
	.set_time = rx8025_set_time,
	.read_alarm = rx8025_read_alarm,
	.set_alarm = rx8025_set_alarm,
	.alarm_irq_enable = rx8025_alarm_irq_enable,
	.read_offset = rx8025_read_offset,
	.set_offset = rx8025_set_offset,
};

static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
					      struct device_attribute *attr,
					      char *buf)
{
	long adj;
	int err;

	dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
	err = rx8025_read_offset(dev, &adj);
	if (err)
		return err;

	return sprintf(buf, "%ld\n", -adj);
}

static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
					       struct device_attribute *attr,
					       const char *buf, size_t count)
{
	long adj;
	int err;

	dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
	if (kstrtol(buf, 10, &adj) != 0)
		return -EINVAL;

	err = rx8025_set_offset(dev, -adj);

	return err ? err : count;
}

static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
		   rx8025_sysfs_show_clock_adjust,
		   rx8025_sysfs_store_clock_adjust);

static struct attribute *rx8025_attrs[] = {
	&dev_attr_clock_adjust_ppb.attr,
	NULL
};

static const struct attribute_group rx8025_attr_group = {
	.attrs	= rx8025_attrs,
};

static int rx8025_probe(struct i2c_client *client)
{
	const struct i2c_device_id *id = i2c_match_id(rx8025_id, client);
	struct i2c_adapter *adapter = client->adapter;
	struct rx8025_data *rx8025;
	int err = 0;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
				     | I2C_FUNC_SMBUS_I2C_BLOCK)) {
		dev_err(&adapter->dev,
			"doesn't support required functionality\n");
		return -EIO;
	}

	rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
	if (!rx8025)
		return -ENOMEM;

	i2c_set_clientdata(client, rx8025);

	if (id)
		rx8025->model = id->driver_data;

	err = rx8025_init_client(client);
	if (err)
		return err;

	rx8025->rtc = devm_rtc_allocate_device(&client->dev);
	if (IS_ERR(rx8025->rtc))
		return PTR_ERR(rx8025->rtc);

	rx8025->rtc->ops = &rx8025_rtc_ops;
	rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
	rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;

	if (client->irq > 0) {
		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
						rx8025_handle_irq,
						IRQF_ONESHOT,
						"rx8025", client);
		if (err)
			clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
	}

	rx8025->rtc->max_user_freq = 1;

	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);

	err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
	if (err)
		return err;

	return devm_rtc_register_device(rx8025->rtc);
}

static struct i2c_driver rx8025_driver = {
	.driver = {
		.name = "rtc-rx8025",
	},
	.probe		= rx8025_probe,
	.id_table	= rx8025_id,
};

module_i2c_driver(rx8025_driver);

MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
MODULE_LICENSE("GPL");