summaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-ds1672.c
blob: 9c68ec99afa5776ad23d039efd693b02ef2d4890 (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
/*
 * An rtc/i2c driver for the Dallas DS1672
 * Copyright 2005-06 Tower Technologies
 *
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * 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/module.h>
#include <linux/i2c.h>
#include <linux/rtc.h>

#define DRV_VERSION "0.3"

/* Addresses to scan: none. This chip cannot be detected. */
static unsigned short normal_i2c[] = { I2C_CLIENT_END };

/* Insmod parameters */
I2C_CLIENT_INSMOD;

/* Registers */

#define DS1672_REG_CNT_BASE	0
#define DS1672_REG_CONTROL	4
#define DS1672_REG_TRICKLE	5

#define DS1672_REG_CONTROL_EOSC	0x80

/* Prototypes */
static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind);

/*
 * In the routines that deal directly with the ds1672 hardware, we use
 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
 * Epoch is initialized as 2000. Time is set to UTC.
 */
static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	unsigned long time;
	unsigned char addr = DS1672_REG_CNT_BASE;
	unsigned char buf[4];

	struct i2c_msg msgs[] = {
		{ client->addr, 0, 1, &addr },		/* setup read ptr */
		{ client->addr, I2C_M_RD, 4, buf },	/* read date */
	};

	/* read date registers */
	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
		return -EIO;
	}

	dev_dbg(&client->dev,
		"%s: raw read data - counters=%02x,%02x,%02x,%02x\n"
		__FUNCTION__, buf[0], buf[1], buf[2], buf[3]);

	time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];

	rtc_time_to_tm(time, tm);

	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);

	return 0;
}

static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
{
	int xfer;
	unsigned char buf[6];

	buf[0] = DS1672_REG_CNT_BASE;
	buf[1] = secs & 0x000000FF;
	buf[2] = (secs & 0x0000FF00) >> 8;
	buf[3] = (secs & 0x00FF0000) >> 16;
	buf[4] = (secs & 0xFF000000) >> 24;
	buf[5] = 0;	/* set control reg to enable counting */

	xfer = i2c_master_send(client, buf, 6);
	if (xfer != 6) {
		dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer);
		return -EIO;
	}

	return 0;
}

static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	unsigned long secs;

	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);

	rtc_tm_to_time(tm, &secs);

	return ds1672_set_mmss(client, secs);
}

static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return ds1672_get_datetime(to_i2c_client(dev), tm);
}

static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	return ds1672_set_datetime(to_i2c_client(dev), tm);
}

static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
{
	return ds1672_set_mmss(to_i2c_client(dev), secs);
}

static int ds1672_get_control(struct i2c_client *client, u8 *status)
{
	unsigned char addr = DS1672_REG_CONTROL;

	struct i2c_msg msgs[] = {
		{ client->addr, 0, 1, &addr },		/* setup read ptr */
		{ client->addr, I2C_M_RD, 1, status },	/* read control */
	};

	/* read control register */
	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
		return -EIO;
	}

	return 0;
}

/* following are the sysfs callback functions */
static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	u8 control;
	int err;

	err = ds1672_get_control(client, &control);
	if (err)
		return err;

	return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
					? "disabled" : "enabled");
}
static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);

static const struct rtc_class_ops ds1672_rtc_ops = {
	.read_time	= ds1672_rtc_read_time,
	.set_time	= ds1672_rtc_set_time,
	.set_mmss	= ds1672_rtc_set_mmss,
};

static int ds1672_attach(struct i2c_adapter *adapter)
{
	return i2c_probe(adapter, &addr_data, ds1672_probe);
}

static int ds1672_detach(struct i2c_client *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(client);

	return 0;
}

static struct i2c_driver ds1672_driver = {
	.driver		= {
		.name	= "ds1672",
	},
	.id		= I2C_DRIVERID_DS1672,
	.attach_adapter = &ds1672_attach,
	.detach_client	= &ds1672_detach,
};

static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)
{
	int err = 0;
	u8 control;
	struct i2c_client *client;
	struct rtc_device *rtc;

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

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

	if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}

	/* I2C client */
	client->addr = address;
	client->driver = &ds1672_driver;
	client->adapter	= adapter;

	strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE);

	/* 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(ds1672_driver.driver.name, &client->dev,
				&ds1672_rtc_ops, THIS_MODULE);

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

	i2c_set_clientdata(client, rtc);

	/* read control register */
	err = ds1672_get_control(client, &control);
	if (err)
		goto exit_detach;

	if (control & DS1672_REG_CONTROL_EOSC)
		dev_warn(&client->dev, "Oscillator not enabled. "
					"Set time to enable.\n");

	/* Register sysfs hooks */
	device_create_file(&client->dev, &dev_attr_control);

	return 0;

exit_detach:
	i2c_detach_client(client);

exit_kfree:
	kfree(client);

exit:
	return err;
}

static int __init ds1672_init(void)
{
	return i2c_add_driver(&ds1672_driver);
}

static void __exit ds1672_exit(void)
{
	i2c_del_driver(&ds1672_driver);
}

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);

module_init(ds1672_init);
module_exit(ds1672_exit);