aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/ds1621.c
blob: 2a4c6a05b14f594b5760f3d62c98b07d7dbc0bcc (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
/*
    ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
             monitoring
    Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
    based on lm75.c by Frodo Looijaard <frodol@dds.nl>
    Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with 
    the help of Jean Delvare <khali@linux-fr.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include "lm75.h"

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
					0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

/* Insmod parameters */
I2C_CLIENT_INSMOD_1(ds1621);
static int polarity = -1;
module_param(polarity, int, 0);
MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");

/* Many DS1621 constants specified below */
/* Config register used for detection         */
/*  7    6    5    4    3    2    1    0      */
/* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
#define DS1621_REG_CONFIG_NVB		0x10
#define DS1621_REG_CONFIG_POLARITY	0x02
#define DS1621_REG_CONFIG_1SHOT		0x01
#define DS1621_REG_CONFIG_DONE		0x80

/* The DS1621 registers */
static const u8 DS1621_REG_TEMP[3] = {
	0xAA,		/* input, word, RO */
	0xA2,		/* min, word, RW */
	0xA1,		/* max, word, RW */
};
#define DS1621_REG_CONF			0xAC /* byte, RW */
#define DS1621_COM_START		0xEE /* no data */
#define DS1621_COM_STOP			0x22 /* no data */

/* The DS1621 configuration register */
#define DS1621_ALARM_TEMP_HIGH		0x40
#define DS1621_ALARM_TEMP_LOW		0x20

/* Conversions */
#define ALARMS_FROM_REG(val) ((val) & \
                              (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))

/* Each client has this additional data */
struct ds1621_data {
	struct device *hwmon_dev;
	struct mutex update_lock;
	char valid;			/* !=0 if following fields are valid */
	unsigned long last_updated;	/* In jiffies */

	u16 temp[3];			/* Register values, word */
	u8 conf;			/* Register encoding, combined */
};

/* Temperature registers are word-sized.
   DS1621 uses a high-byte first convention, which is exactly opposite to
   the SMBus standard. */
static int ds1621_read_temp(struct i2c_client *client, u8 reg)
{
	int ret;

	ret = i2c_smbus_read_word_data(client, reg);
	if (ret < 0)
		return ret;
	return swab16(ret);
}

static int ds1621_write_temp(struct i2c_client *client, u8 reg, u16 value)
{
	return i2c_smbus_write_word_data(client, reg, swab16(value));
}

static void ds1621_init_client(struct i2c_client *client)
{
	u8 conf, new_conf;

	new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
	/* switch to continuous conversion mode */
	new_conf &= ~DS1621_REG_CONFIG_1SHOT;

	/* setup output polarity */
	if (polarity == 0)
		new_conf &= ~DS1621_REG_CONFIG_POLARITY;
	else if (polarity == 1)
		new_conf |= DS1621_REG_CONFIG_POLARITY;
	
	if (conf != new_conf)
		i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
	
	/* start conversion */
	i2c_smbus_write_byte(client, DS1621_COM_START);
}

static struct ds1621_data *ds1621_update_client(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1621_data *data = i2c_get_clientdata(client);
	u8 new_conf;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	    || !data->valid) {
		int i;

		dev_dbg(&client->dev, "Starting ds1621 update\n");

		data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);

		for (i = 0; i < ARRAY_SIZE(data->temp); i++)
			data->temp[i] = ds1621_read_temp(client,
							 DS1621_REG_TEMP[i]);

		/* reset alarms if necessary */
		new_conf = data->conf;
		if (data->temp[0] > data->temp[1])	/* input > min */
			new_conf &= ~DS1621_ALARM_TEMP_LOW;
		if (data->temp[0] < data->temp[2])	/* input < max */
			new_conf &= ~DS1621_ALARM_TEMP_HIGH;
		if (data->conf != new_conf)
			i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
						  new_conf);

		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

static ssize_t show_temp(struct device *dev, struct device_attribute *da,
			 char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n",
		       LM75_TEMP_FROM_REG(data->temp[attr->index]));
}

static ssize_t set_temp(struct device *dev, struct device_attribute *da,
			const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1621_data *data = i2c_get_clientdata(client);
	u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));

	mutex_lock(&data->update_lock);
	data->temp[attr->index] = val;
	ds1621_write_temp(client, DS1621_REG_TEMP[attr->index],
			  data->temp[attr->index]);
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
			   char *buf)
{
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
			  char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n", !!(data->conf & attr->index));
}

static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
		DS1621_ALARM_TEMP_LOW);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
		DS1621_ALARM_TEMP_HIGH);

static struct attribute *ds1621_attributes[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	&dev_attr_alarms.attr,
	NULL
};

static const struct attribute_group ds1621_group = {
	.attrs = ds1621_attributes,
};


/* Return 0 if detection is successful, -ENODEV otherwise */
static int ds1621_detect(struct i2c_client *client, int kind,
			 struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = client->adapter;
	int conf, temp;
	int i;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 
				     | I2C_FUNC_SMBUS_WORD_DATA 
				     | I2C_FUNC_SMBUS_WRITE_BYTE))
		return -ENODEV;

	/* Now, we do the remaining detection. It is lousy. */
	/* The NVB bit should be low if no EEPROM write has been  requested
	   during the latest 10ms, which is highly improbable in our case. */
	conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
	if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
		return -ENODEV;
	/* The 7 lowest bits of a temperature should always be 0. */
	for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
		temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
		if (temp < 0 || (temp & 0x7f00))
			return -ENODEV;
	}

	strlcpy(info->type, "ds1621", I2C_NAME_SIZE);

	return 0;
}

static int ds1621_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct ds1621_data *data;
	int err;

	data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);

	/* Initialize the DS1621 chip */
	ds1621_init_client(client);

	/* Register sysfs hooks */
	if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
		goto exit_free;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove_files;
	}

	return 0;

      exit_remove_files:
	sysfs_remove_group(&client->dev.kobj, &ds1621_group);
      exit_free:
	kfree(data);
      exit:
	return err;
}

static int ds1621_remove(struct i2c_client *client)
{
	struct ds1621_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &ds1621_group);

	kfree(data);

	return 0;
}

static const struct i2c_device_id ds1621_id[] = {
	{ "ds1621", ds1621 },
	{ "ds1625", ds1621 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ds1621_id);

/* This is the driver that will be inserted */
static struct i2c_driver ds1621_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "ds1621",
	},
	.probe		= ds1621_probe,
	.remove		= ds1621_remove,
	.id_table	= ds1621_id,
	.detect		= ds1621_detect,
	.address_data	= &addr_data,
};

static int __init ds1621_init(void)
{
	return i2c_add_driver(&ds1621_driver);
}

static void __exit ds1621_exit(void)
{
	i2c_del_driver(&ds1621_driver);
}


MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
MODULE_DESCRIPTION("DS1621 driver");
MODULE_LICENSE("GPL");

module_init(ds1621_init);
module_exit(ds1621_exit);