summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-rx8581.c
blob: 07f3037b18f4c640b69f67abdf8f5360d72fe403 (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
/*
 * An I2C driver for the Epson RX8581 RTC
 *
 * Author: Martyn Welch <martyn.welch@ge.com>
 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
 *
 * 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.
 *
 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
 * Copyright 2005-06 Tower Technologies
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/log2.h>

#define DRV_VERSION "0.1"

#define RX8581_REG_SC		0x00 /* Second in BCD */
#define RX8581_REG_MN		0x01 /* Minute in BCD */
#define RX8581_REG_HR		0x02 /* Hour in BCD */
#define RX8581_REG_DW		0x03 /* Day of Week */
#define RX8581_REG_DM		0x04 /* Day of Month in BCD */
#define RX8581_REG_MO		0x05 /* Month in BCD */
#define RX8581_REG_YR		0x06 /* Year in BCD */
#define RX8581_REG_RAM		0x07 /* RAM */
#define RX8581_REG_AMN		0x08 /* Alarm Min in BCD*/
#define RX8581_REG_AHR		0x09 /* Alarm Hour in BCD */
#define RX8581_REG_ADM		0x0A
#define RX8581_REG_ADW		0x0A
#define RX8581_REG_TMR0		0x0B
#define RX8581_REG_TMR1		0x0C
#define RX8581_REG_EXT		0x0D /* Extension Register */
#define RX8581_REG_FLAG		0x0E /* Flag Register */
#define RX8581_REG_CTRL		0x0F /* Control Register */


/* Flag Register bit definitions */
#define RX8581_FLAG_UF		0x20 /* Update */
#define RX8581_FLAG_TF		0x10 /* Timer */
#define RX8581_FLAG_AF		0x08 /* Alarm */
#define RX8581_FLAG_VLF		0x02 /* Voltage Low */

/* Control Register bit definitions */
#define RX8581_CTRL_UIE		0x20 /* Update Interrupt Enable */
#define RX8581_CTRL_TIE		0x10 /* Timer Interrupt Enable */
#define RX8581_CTRL_AIE		0x08 /* Alarm Interrupt Enable */
#define RX8581_CTRL_STOP	0x02 /* STOP bit */
#define RX8581_CTRL_RESET	0x01 /* RESET bit */

static struct i2c_driver rx8581_driver;

/*
 * In the routines that deal directly with the rx8581 hardware, we use
 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 */
static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	unsigned char date[7];
	int data, err;

	/* First we ensure that the "update flag" is not set, we read the
	 * time and date then re-read the "update flag". If the update flag
	 * has been set, we know that the time has changed during the read so
	 * we repeat the whole process again.
	 */
	data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
	if (data < 0) {
		dev_err(&client->dev, "Unable to read device flags\n");
		return -EIO;
	}

	do {
		/* If update flag set, clear it */
		if (data & RX8581_FLAG_UF) {
			err = i2c_smbus_write_byte_data(client,
				RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
			if (err != 0) {
				dev_err(&client->dev, "Unable to write device "
					"flags\n");
				return -EIO;
			}
		}

		/* Now read time and date */
		err = i2c_smbus_read_i2c_block_data(client, RX8581_REG_SC,
			7, date);
		if (err < 0) {
			dev_err(&client->dev, "Unable to read date\n");
			return -EIO;
		}

		/* Check flag register */
		data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
		if (data < 0) {
			dev_err(&client->dev, "Unable to read device flags\n");
			return -EIO;
		}
	} while (data & RX8581_FLAG_UF);

	if (data & RX8581_FLAG_VLF)
		dev_info(&client->dev,
			"low voltage detected, date/time is not reliable.\n");

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

	tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
	tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
	tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
	tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
	tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
	tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
	tm->tm_year = bcd2bin(date[RX8581_REG_YR]);
	if (tm->tm_year < 70)
		tm->tm_year += 100;	/* assume we are in 1970...2069 */


	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);

	err = rtc_valid_tm(tm);
	if (err < 0)
		dev_err(&client->dev, "retrieved date/time is not valid.\n");

	return err;
}

static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	int data, err;
	unsigned char buf[7];

	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[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
	buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
	buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);

	buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);

	/* month, 1 - 12 */
	buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);

	/* year and century */
	buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100);
	buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);

	/* Stop the clock */
	data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
	if (data < 0) {
		dev_err(&client->dev, "Unable to read control register\n");
		return -EIO;
	}

	err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
		(data | RX8581_CTRL_STOP));
	if (err < 0) {
		dev_err(&client->dev, "Unable to write control register\n");
		return -EIO;
	}

	/* write register's data */
	err = i2c_smbus_write_i2c_block_data(client, RX8581_REG_SC, 7, buf);
	if (err < 0) {
		dev_err(&client->dev, "Unable to write to date registers\n");
		return -EIO;
	}

	/* get VLF and clear it */
	data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
	if (data < 0) {
		dev_err(&client->dev, "Unable to read flag register\n");
		return -EIO;
	}

	err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
		(data & ~(RX8581_FLAG_VLF)));
	if (err != 0) {
		dev_err(&client->dev, "Unable to write flag register\n");
		return -EIO;
	}

	/* Restart the clock */
	data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
	if (data < 0) {
		dev_err(&client->dev, "Unable to read control register\n");
		return -EIO;
	}

	err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
		(data & ~(RX8581_CTRL_STOP)));
	if (err != 0) {
		dev_err(&client->dev, "Unable to write control register\n");
		return -EIO;
	}

	return 0;
}

static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return rx8581_get_datetime(to_i2c_client(dev), tm);
}

static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	return rx8581_set_datetime(to_i2c_client(dev), tm);
}

static const struct rtc_class_ops rx8581_rtc_ops = {
	.read_time	= rx8581_rtc_read_time,
	.set_time	= rx8581_rtc_set_time,
};

static int rx8581_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct rtc_device *rtc;

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

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

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

	rtc = devm_rtc_device_register(&client->dev, rx8581_driver.driver.name,
					&rx8581_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	i2c_set_clientdata(client, rtc);

	return 0;
}

static int rx8581_remove(struct i2c_client *client)
{
	return 0;
}

static const struct i2c_device_id rx8581_id[] = {
	{ "rx8581", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, rx8581_id);

static struct i2c_driver rx8581_driver = {
	.driver		= {
		.name	= "rtc-rx8581",
		.owner	= THIS_MODULE,
	},
	.probe		= rx8581_probe,
	.remove		= rx8581_remove,
	.id_table	= rx8581_id,
};

module_i2c_driver(rx8581_driver);

MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
MODULE_DESCRIPTION("Epson RX-8581 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
OpenPOWER on IntegriCloud