summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/rtc/rtc-pcf8563.c
blob: 0ba7e59929beab93b53c2a0d35a9c49b4cf562c5 (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
/*
 * An I2C driver for the Philips PCF8563 RTC
 * Copyright 2005-06 Tower Technologies
 *
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 * Maintainers: http://www.nslu2-linux.org/
 *
 * based on the other drivers in this same directory.
 *
 * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/err.h>

#define DRV_VERSION "0.4.3"

#define PCF8563_REG_ST1		0x00 /* status */
#define PCF8563_REG_ST2		0x01
#define PCF8563_BIT_AIE		(1 << 1)
#define PCF8563_BIT_AF		(1 << 3)
#define PCF8563_BITS_ST2_N	(7 << 5)

#define PCF8563_REG_SC		0x02 /* datetime */
#define PCF8563_REG_MN		0x03
#define PCF8563_REG_HR		0x04
#define PCF8563_REG_DM		0x05
#define PCF8563_REG_DW		0x06
#define PCF8563_REG_MO		0x07
#define PCF8563_REG_YR		0x08

#define PCF8563_REG_AMN		0x09 /* alarm */

#define PCF8563_REG_CLKO	0x0D /* clock out */
#define PCF8563_REG_TMRC	0x0E /* timer control */
#define PCF8563_TMRC_ENABLE	BIT(7)
#define PCF8563_TMRC_4096	0
#define PCF8563_TMRC_64		1
#define PCF8563_TMRC_1		2
#define PCF8563_TMRC_1_60	3
#define PCF8563_TMRC_MASK	3

#define PCF8563_REG_TMR		0x0F /* timer */

#define PCF8563_SC_LV		0x80 /* low voltage */
#define PCF8563_MO_C		0x80 /* century */

static struct i2c_driver pcf8563_driver;

struct pcf8563 {
	struct rtc_device *rtc;
	/*
	 * The meaning of MO_C bit varies by the chip type.
	 * From PCF8563 datasheet: this bit is toggled when the years
	 * register overflows from 99 to 00
	 *   0 indicates the century is 20xx
	 *   1 indicates the century is 19xx
	 * From RTC8564 datasheet: this bit indicates change of
	 * century. When the year digit data overflows from 99 to 00,
	 * this bit is set. By presetting it to 0 while still in the
	 * 20th century, it will be set in year 2000, ...
	 * There seems no reliable way to know how the system use this
	 * bit.  So let's do it heuristically, assuming we are live in
	 * 1970...2069.
	 */
	int c_polarity;	/* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
	int voltage_low; /* incicates if a low_voltage was detected */

	struct i2c_client *client;
};

static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
				   unsigned char length, unsigned char *buf)
{
	struct i2c_msg msgs[] = {
		{/* setup read ptr */
			.addr = client->addr,
			.len = 1,
			.buf = &reg,
		},
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = length,
			.buf = buf
		},
	};

	if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
		dev_err(&client->dev, "%s: read error\n", __func__);
		return -EIO;
	}

	return 0;
}

static int pcf8563_write_block_data(struct i2c_client *client,
				   unsigned char reg, unsigned char length,
				   unsigned char *buf)
{
	int i, err;

	for (i = 0; i < length; i++) {
		unsigned char data[2] = { reg + i, buf[i] };

		err = i2c_master_send(client, data, sizeof(data));
		if (err != sizeof(data)) {
			dev_err(&client->dev,
				"%s: err=%d addr=%02x, data=%02x\n",
				__func__, err, data[0], data[1]);
			return -EIO;
		}
	}

	return 0;
}

static int pcf8563_set_alarm_mode(struct i2c_client *client, bool on)
{
	unsigned char buf;
	int err;

	err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
	if (err < 0)
		return err;

	if (on)
		buf |= PCF8563_BIT_AIE;
	else
		buf &= ~PCF8563_BIT_AIE;

	buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);

	err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
	if (err < 0) {
		dev_err(&client->dev, "%s: write error\n", __func__);
		return -EIO;
	}

	return 0;
}

static int pcf8563_get_alarm_mode(struct i2c_client *client, unsigned char *en,
				  unsigned char *pen)
{
	unsigned char buf;
	int err;

	err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
	if (err)
		return err;

	if (en)
		*en = !!(buf & PCF8563_BIT_AIE);
	if (pen)
		*pen = !!(buf & PCF8563_BIT_AF);

	return 0;
}

static irqreturn_t pcf8563_irq(int irq, void *dev_id)
{
	struct pcf8563 *pcf8563 = i2c_get_clientdata(dev_id);
	int err;
	char pending;

	err = pcf8563_get_alarm_mode(pcf8563->client, NULL, &pending);
	if (err)
		return IRQ_NONE;

	if (pending) {
		rtc_update_irq(pcf8563->rtc, 1, RTC_IRQF | RTC_AF);
		pcf8563_set_alarm_mode(pcf8563->client, 1);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

/*
 * In the routines that deal directly with the pcf8563 hardware, we use
 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 */
static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
	unsigned char buf[9];
	int err;

	err = pcf8563_read_block_data(client, PCF8563_REG_ST1, 9, buf);
	if (err)
		return err;

	if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
		pcf8563->voltage_low = 1;
		dev_info(&client->dev,
			"low voltage detected, date/time is not reliable.\n");
	}

	dev_dbg(&client->dev,
		"%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
		"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
		__func__,
		buf[0], buf[1], buf[2], buf[3],
		buf[4], buf[5], buf[6], buf[7],
		buf[8]);


	tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
	tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
	tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
	tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
	tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
	tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
	tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
	if (tm->tm_year < 70)
		tm->tm_year += 100;	/* assume we are in 1970...2069 */
	/* detect the polarity heuristically. see note above. */
	pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
		(tm->tm_year >= 100) : (tm->tm_year < 100);

	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
		"mday=%d, mon=%d, year=%d, wday=%d\n",
		__func__,
		tm->tm_sec, tm->tm_min, tm->tm_hour,
		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

	/* the clock can give out invalid datetime, but we cannot return
	 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
	 */
	if (rtc_valid_tm(tm) < 0)
		dev_err(&client->dev, "retrieved date/time is not valid.\n");

	return 0;
}

static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
	unsigned char buf[9];

	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
		"mday=%d, mon=%d, year=%d, wday=%d\n",
		__func__,
		tm->tm_sec, tm->tm_min, tm->tm_hour,
		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

	/* hours, minutes and seconds */
	buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
	buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
	buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);

	buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);

	/* month, 1 - 12 */
	buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);

	/* year and century */
	buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
	if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
		buf[PCF8563_REG_MO] |= PCF8563_MO_C;

	buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;

	return pcf8563_write_block_data(client, PCF8563_REG_SC,
				9 - PCF8563_REG_SC, buf + PCF8563_REG_SC);
}

#ifdef CONFIG_RTC_INTF_DEV
static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
	struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
	struct rtc_time tm;

	switch (cmd) {
	case RTC_VL_READ:
		if (pcf8563->voltage_low)
			dev_info(dev, "low voltage detected, date/time is not reliable.\n");

		if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
					sizeof(int)))
			return -EFAULT;
		return 0;
	case RTC_VL_CLR:
		/*
		 * Clear the VL bit in the seconds register in case
		 * the time has not been set already (which would
		 * have cleared it). This does not really matter
		 * because of the cached voltage_low value but do it
		 * anyway for consistency.
		 */
		if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
			pcf8563_set_datetime(to_i2c_client(dev), &tm);

		/* Clear the cached value. */
		pcf8563->voltage_low = 0;

		return 0;
	default:
		return -ENOIOCTLCMD;
	}
}
#else
#define pcf8563_rtc_ioctl NULL
#endif

static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return pcf8563_get_datetime(to_i2c_client(dev), tm);
}

static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	return pcf8563_set_datetime(to_i2c_client(dev), tm);
}

static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char buf[4];
	int err;

	err = pcf8563_read_block_data(client, PCF8563_REG_AMN, 4, buf);
	if (err)
		return err;

	dev_dbg(&client->dev,
		"%s: raw data is min=%02x, hr=%02x, mday=%02x, wday=%02x\n",
		__func__, buf[0], buf[1], buf[2], buf[3]);

	tm->time.tm_min = bcd2bin(buf[0] & 0x7F);
	tm->time.tm_hour = bcd2bin(buf[1] & 0x3F);
	tm->time.tm_mday = bcd2bin(buf[2] & 0x3F);
	tm->time.tm_wday = bcd2bin(buf[3] & 0x7);
	tm->time.tm_mon = -1;
	tm->time.tm_year = -1;
	tm->time.tm_yday = -1;
	tm->time.tm_isdst = -1;

	err = pcf8563_get_alarm_mode(client, &tm->enabled, &tm->pending);
	if (err < 0)
		return err;

	dev_dbg(&client->dev, "%s: tm is mins=%d, hours=%d, mday=%d, wday=%d,"
		" enabled=%d, pending=%d\n", __func__, tm->time.tm_min,
		tm->time.tm_hour, tm->time.tm_mday, tm->time.tm_wday,
		tm->enabled, tm->pending);

	return 0;
}

static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char buf[4];
	int err;
	unsigned long alarm_time;

	/* The alarm has no seconds, round up to nearest minute */
	if (tm->time.tm_sec) {
		rtc_tm_to_time(&tm->time, &alarm_time);
		alarm_time += 60-tm->time.tm_sec;
		rtc_time_to_tm(alarm_time, &tm->time);
	}

	dev_dbg(dev, "%s, min=%d hour=%d wday=%d mday=%d "
		"enabled=%d pending=%d\n", __func__,
		tm->time.tm_min, tm->time.tm_hour, tm->time.tm_wday,
		tm->time.tm_mday, tm->enabled, tm->pending);

	buf[0] = bin2bcd(tm->time.tm_min);
	buf[1] = bin2bcd(tm->time.tm_hour);
	buf[2] = bin2bcd(tm->time.tm_mday);
	buf[3] = tm->time.tm_wday & 0x07;

	err = pcf8563_write_block_data(client, PCF8563_REG_AMN, 4, buf);
	if (err)
		return err;

	return pcf8563_set_alarm_mode(client, 1);
}

static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
{
	dev_dbg(dev, "%s: en=%d\n", __func__, enabled);
	return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
}

static const struct rtc_class_ops pcf8563_rtc_ops = {
	.ioctl		= pcf8563_rtc_ioctl,
	.read_time	= pcf8563_rtc_read_time,
	.set_time	= pcf8563_rtc_set_time,
	.read_alarm	= pcf8563_rtc_read_alarm,
	.set_alarm	= pcf8563_rtc_set_alarm,
	.alarm_irq_enable = pcf8563_irq_enable,
};

static int pcf8563_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	struct pcf8563 *pcf8563;
	int err;
	unsigned char buf;
	unsigned char alm_pending;

	dev_dbg(&client->dev, "%s\n", __func__);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
				GFP_KERNEL);
	if (!pcf8563)
		return -ENOMEM;

	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");

	i2c_set_clientdata(client, pcf8563);
	pcf8563->client = client;
	device_set_wakeup_capable(&client->dev, 1);

	/* Set timer to lowest frequency to save power (ref Haoyu datasheet) */
	buf = PCF8563_TMRC_1_60;
	err = pcf8563_write_block_data(client, PCF8563_REG_TMRC, 1, &buf);
	if (err < 0) {
		dev_err(&client->dev, "%s: write error\n", __func__);
		return err;
	}

	err = pcf8563_get_alarm_mode(client, NULL, &alm_pending);
	if (err < 0) {
		dev_err(&client->dev, "%s: read error\n", __func__);
		return err;
	}
	if (alm_pending)
		pcf8563_set_alarm_mode(client, 0);

	pcf8563->rtc = devm_rtc_device_register(&client->dev,
				pcf8563_driver.driver.name,
				&pcf8563_rtc_ops, THIS_MODULE);

	if (IS_ERR(pcf8563->rtc))
		return PTR_ERR(pcf8563->rtc);

	if (client->irq > 0) {
		err = devm_request_threaded_irq(&client->dev, client->irq,
				NULL, pcf8563_irq,
				IRQF_SHARED|IRQF_ONESHOT|IRQF_TRIGGER_FALLING,
				pcf8563->rtc->name, client);
		if (err) {
			dev_err(&client->dev, "unable to request IRQ %d\n",
								client->irq);
			return err;
		}

	}

	/* the pcf8563 alarm only supports a minute accuracy */
	pcf8563->rtc->uie_unsupported = 1;

	return 0;
}

static const struct i2c_device_id pcf8563_id[] = {
	{ "pcf8563", 0 },
	{ "rtc8564", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8563_id);

#ifdef CONFIG_OF
static const struct of_device_id pcf8563_of_match[] = {
	{ .compatible = "nxp,pcf8563" },
	{}
};
MODULE_DEVICE_TABLE(of, pcf8563_of_match);
#endif

static struct i2c_driver pcf8563_driver = {
	.driver		= {
		.name	= "rtc-pcf8563",
		.owner	= THIS_MODULE,
		.of_match_table = of_match_ptr(pcf8563_of_match),
	},
	.probe		= pcf8563_probe,
	.id_table	= pcf8563_id,
};

module_i2c_driver(pcf8563_driver);

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);