hwmon: (lm90) Restore configuration on exit
[linux-2.6.git] / drivers / hwmon / lm73.c
1 /*
2  * LM73 Sensor driver
3  * Based on LM75
4  *
5  * Copyright (C) 2007, CenoSYS (www.cenosys.com).
6  * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
7  *
8  * Guillaume Ligneul <guillaume.ligneul@gmail.com>
9  * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
10  * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
11  *
12  * This software program is licensed subject to the GNU General Public License
13  * (GPL).Version 2,June 1991, available at
14  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
15  */
16
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/i2c.h>
21 #include <linux/hwmon.h>
22 #include <linux/hwmon-sysfs.h>
23 #include <linux/err.h>
24
25
26 /* Addresses scanned */
27 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
28                                         0x4d, 0x4e, I2C_CLIENT_END };
29
30 /* LM73 registers */
31 #define LM73_REG_INPUT          0x00
32 #define LM73_REG_CONF           0x01
33 #define LM73_REG_MAX            0x02
34 #define LM73_REG_MIN            0x03
35 #define LM73_REG_CTRL           0x04
36 #define LM73_REG_ID             0x07
37
38 #define LM73_ID                 0x9001 /* or 0x190 after a swab16() */
39 #define DRVNAME                 "lm73"
40 #define LM73_TEMP_MIN           (-40)
41 #define LM73_TEMP_MAX           150
42
43 /*-----------------------------------------------------------------------*/
44
45
46 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
47                         const char *buf, size_t count)
48 {
49         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
50         struct i2c_client *client = to_i2c_client(dev);
51         long temp;
52         short value;
53
54         int status = strict_strtol(buf, 10, &temp);
55         if (status < 0)
56                 return status;
57
58         /* Write value */
59         value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
60                 (LM73_TEMP_MAX*4)) << 5;
61         i2c_smbus_write_word_data(client, attr->index, swab16(value));
62         return count;
63 }
64
65 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
66                          char *buf)
67 {
68         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
69         struct i2c_client *client = to_i2c_client(dev);
70         /* use integer division instead of equivalent right shift to
71            guarantee arithmetic shift and preserve the sign */
72         int temp = ((s16) (swab16(i2c_smbus_read_word_data(client,
73                 attr->index)))*250) / 32;
74         return sprintf(buf, "%d\n", temp);
75 }
76
77
78 /*-----------------------------------------------------------------------*/
79
80 /* sysfs attributes for hwmon */
81
82 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
83                         show_temp, set_temp, LM73_REG_MAX);
84 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
85                         show_temp, set_temp, LM73_REG_MIN);
86 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
87                         show_temp, NULL, LM73_REG_INPUT);
88
89
90 static struct attribute *lm73_attributes[] = {
91         &sensor_dev_attr_temp1_input.dev_attr.attr,
92         &sensor_dev_attr_temp1_max.dev_attr.attr,
93         &sensor_dev_attr_temp1_min.dev_attr.attr,
94
95         NULL
96 };
97
98 static const struct attribute_group lm73_group = {
99         .attrs = lm73_attributes,
100 };
101
102 /*-----------------------------------------------------------------------*/
103
104 /* device probe and removal */
105
106 static int
107 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
108 {
109         struct device *hwmon_dev;
110         int status;
111
112         /* Register sysfs hooks */
113         status = sysfs_create_group(&client->dev.kobj, &lm73_group);
114         if (status)
115                 return status;
116
117         hwmon_dev = hwmon_device_register(&client->dev);
118         if (IS_ERR(hwmon_dev)) {
119                 status = PTR_ERR(hwmon_dev);
120                 goto exit_remove;
121         }
122         i2c_set_clientdata(client, hwmon_dev);
123
124         dev_info(&client->dev, "%s: sensor '%s'\n",
125                  dev_name(hwmon_dev), client->name);
126
127         return 0;
128
129 exit_remove:
130         sysfs_remove_group(&client->dev.kobj, &lm73_group);
131         return status;
132 }
133
134 static int lm73_remove(struct i2c_client *client)
135 {
136         struct device *hwmon_dev = i2c_get_clientdata(client);
137
138         hwmon_device_unregister(hwmon_dev);
139         sysfs_remove_group(&client->dev.kobj, &lm73_group);
140         i2c_set_clientdata(client, NULL);
141         return 0;
142 }
143
144 static const struct i2c_device_id lm73_ids[] = {
145         { "lm73", 0 },
146         { /* LIST END */ }
147 };
148 MODULE_DEVICE_TABLE(i2c, lm73_ids);
149
150 /* Return 0 if detection is successful, -ENODEV otherwise */
151 static int lm73_detect(struct i2c_client *new_client,
152                         struct i2c_board_info *info)
153 {
154         struct i2c_adapter *adapter = new_client->adapter;
155         u16 id;
156         u8 ctrl;
157
158         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
159                                         I2C_FUNC_SMBUS_WORD_DATA))
160                 return -ENODEV;
161
162         /* Check device ID */
163         id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
164         ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
165         if ((id != LM73_ID) || (ctrl & 0x10))
166                 return -ENODEV;
167
168         strlcpy(info->type, "lm73", I2C_NAME_SIZE);
169
170         return 0;
171 }
172
173 static struct i2c_driver lm73_driver = {
174         .class          = I2C_CLASS_HWMON,
175         .driver = {
176                 .name   = "lm73",
177         },
178         .probe          = lm73_probe,
179         .remove         = lm73_remove,
180         .id_table       = lm73_ids,
181         .detect         = lm73_detect,
182         .address_list   = normal_i2c,
183 };
184
185 /* module glue */
186
187 static int __init sensors_lm73_init(void)
188 {
189         return i2c_add_driver(&lm73_driver);
190 }
191
192 static void __exit sensors_lm73_exit(void)
193 {
194         i2c_del_driver(&lm73_driver);
195 }
196
197 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
198 MODULE_DESCRIPTION("LM73 driver");
199 MODULE_LICENSE("GPL");
200
201 module_init(sensors_lm73_init);
202 module_exit(sensors_lm73_exit);