aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-pcf8563.c
blob: b3317fcc16c378c62525ad8d29035ec24b7b04a1 (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
/*
 * 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>

#define DRV_VERSION "0.4.2"

/* Addresses to scan: none
 * This chip cannot be reliably autodetected. An empty eeprom
 * located at 0x51 will pass the validation routine due to
 * the way the registers are implemented.
 */
static const unsigned short normal_i2c[] = { I2C_CLIENT_END };

/* Module parameters */
I2C_CLIENT_INSMOD;

#define PCF8563_REG_ST1		0x00 /* status */
#define PCF8563_REG_ST2		0x01

#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_AHR		0x0A
#define PCF8563_REG_ADM		0x0B
#define PCF8563_REG_ADW		0x0C

#define PCF8563_REG_CLKO	0x0D /* clock out */
#define PCF8563_REG_TMRC	0x0E /* timer control */
#define PCF8563_REG_TMR		0x0F /* timer */

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

struct pcf8563 {
	struct i2c_client client;
	/*
	 * 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 */
};

static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind);
static int pcf8563_detach(struct i2c_client *client);

/*
 * 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 = container_of(client, struct pcf8563, client);
	unsigned char buf[13] = { PCF8563_REG_ST1 };

	struct i2c_msg msgs[] = {
		{ client->addr, 0, 1, buf },	/* setup read ptr */
		{ client->addr, I2C_M_RD, 13, buf },	/* read status + date */
	};

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

	if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
		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",
		__FUNCTION__,
		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",
		__FUNCTION__,
		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 = container_of(client, struct pcf8563, client);
	int i, err;
	unsigned char buf[9];

	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
		"mday=%d, mon=%d, year=%d, wday=%d\n",
		__FUNCTION__,
		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;

	/* write register's data */
	for (i = 0; i < 7; i++) {
		unsigned char data[2] = { PCF8563_REG_SC + i,
						buf[PCF8563_REG_SC + 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",
				__FUNCTION__, err, data[0], data[1]);
			return -EIO;
		}
	};

	return 0;
}

struct pcf8563_limit
{
	unsigned char reg;
	unsigned char mask;
	unsigned char min;
	unsigned char max;
};

static int pcf8563_validate_client(struct i2c_client *client)
{
	int i;

	static const struct pcf8563_limit pattern[] = {
		/* register, mask, min, max */
		{ PCF8563_REG_SC,	0x7F,	0,	59	},
		{ PCF8563_REG_MN,	0x7F,	0,	59	},
		{ PCF8563_REG_HR,	0x3F,	0,	23	},
		{ PCF8563_REG_DM,	0x3F,	0,	31	},
		{ PCF8563_REG_MO,	0x1F,	0,	12	},
	};

	/* check limits (only registers with bcd values) */
	for (i = 0; i < ARRAY_SIZE(pattern); i++) {
		int xfer;
		unsigned char value;
		unsigned char buf = pattern[i].reg;

		struct i2c_msg msgs[] = {
			{ client->addr, 0, 1, &buf },
			{ client->addr, I2C_M_RD, 1, &buf },
		};

		xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

		if (xfer != ARRAY_SIZE(msgs)) {
			dev_err(&client->dev,
				"%s: could not read register 0x%02X\n",
				__FUNCTION__, pattern[i].reg);

			return -EIO;
		}

		value = BCD2BIN(buf & pattern[i].mask);

		if (value > pattern[i].max ||
			value < pattern[i].min) {
			dev_dbg(&client->dev,
				"%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, "
				"max=%d, value=%d, raw=0x%02X\n",
				__FUNCTION__, i, pattern[i].reg, pattern[i].mask,
				pattern[i].min, pattern[i].max,
				value, buf);

			return -ENODEV;
		}
	}

	return 0;
}

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 const struct rtc_class_ops pcf8563_rtc_ops = {
	.read_time	= pcf8563_rtc_read_time,
	.set_time	= pcf8563_rtc_set_time,
};

static int pcf8563_attach(struct i2c_adapter *adapter)
{
	return i2c_probe(adapter, &addr_data, pcf8563_probe);
}

static struct i2c_driver pcf8563_driver = {
	.driver		= {
		.name	= "pcf8563",
	},
	.id		= I2C_DRIVERID_PCF8563,
	.attach_adapter = &pcf8563_attach,
	.detach_client	= &pcf8563_detach,
};

static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind)
{
	struct pcf8563 *pcf8563;
	struct i2c_client *client;
	struct rtc_device *rtc;

	int err = 0;

	dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);

	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
		err = -ENODEV;
		goto exit;
	}

	if (!(pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}

	client = &pcf8563->client;
	client->addr = address;
	client->driver = &pcf8563_driver;
	client->adapter	= adapter;

	strlcpy(client->name, pcf8563_driver.driver.name, I2C_NAME_SIZE);

	/* Verify the chip is really an PCF8563 */
	if (kind < 0) {
		if (pcf8563_validate_client(client) < 0) {
			err = -ENODEV;
			goto exit_kfree;
		}
	}

	/* Inform the i2c layer */
	if ((err = i2c_attach_client(client)))
		goto exit_kfree;

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

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

	if (IS_ERR(rtc)) {
		err = PTR_ERR(rtc);
		goto exit_detach;
	}

	i2c_set_clientdata(client, rtc);

	return 0;

exit_detach:
	i2c_detach_client(client);

exit_kfree:
	kfree(pcf8563);

exit:
	return err;
}

static int pcf8563_detach(struct i2c_client *client)
{
	struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);
	int err;
	struct rtc_device *rtc = i2c_get_clientdata(client);

	if (rtc)
		rtc_device_unregister(rtc);

	if ((err = i2c_detach_client(client)))
		return err;

	kfree(pcf8563);

	return 0;
}

static int __init pcf8563_init(void)
{
	return i2c_add_driver(&pcf8563_driver);
}

static void __exit pcf8563_exit(void)
{
	i2c_del_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);

module_init(pcf8563_init);
module_exit(pcf8563_exit);