2 lm75.c - Part of lm_sensors, Linux kernel modules for hardware
4 Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/jiffies.h>
25 #include <linux/i2c.h>
26 #include <linux/hwmon.h>
27 #include <linux/hwmon-sysfs.h>
28 #include <linux/err.h>
29 #include <linux/mutex.h>
34 * This driver handles the LM75 and compatible digital temperature sensors.
37 enum lm75_type { /* keep sorted in alphabetical order */
55 /* Addresses scanned */
56 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
57 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
60 /* The LM75 registers */
61 #define LM75_REG_CONF 0x01
62 static const u8 LM75_REG_TEMP[3] = {
68 /* Each client has this additional data */
70 struct device *hwmon_dev;
71 struct mutex update_lock;
73 char valid; /* !=0 if registers are valid */
74 unsigned long last_updated; /* In jiffies */
75 u16 temp[3]; /* Register values,
81 static int lm75_read_value(struct i2c_client *client, u8 reg);
82 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
83 static struct lm75_data *lm75_update_device(struct device *dev);
86 /*-----------------------------------------------------------------------*/
88 /* sysfs attributes for hwmon */
90 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
93 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
94 struct lm75_data *data = lm75_update_device(dev);
95 return sprintf(buf, "%d\n",
96 LM75_TEMP_FROM_REG(data->temp[attr->index]));
99 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
100 const char *buf, size_t count)
102 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
103 struct i2c_client *client = to_i2c_client(dev);
104 struct lm75_data *data = i2c_get_clientdata(client);
105 int nr = attr->index;
106 long temp = simple_strtol(buf, NULL, 10);
108 mutex_lock(&data->update_lock);
109 data->temp[nr] = LM75_TEMP_TO_REG(temp);
110 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
111 mutex_unlock(&data->update_lock);
115 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
116 show_temp, set_temp, 1);
117 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
118 show_temp, set_temp, 2);
119 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
121 static struct attribute *lm75_attributes[] = {
122 &sensor_dev_attr_temp1_input.dev_attr.attr,
123 &sensor_dev_attr_temp1_max.dev_attr.attr,
124 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
129 static const struct attribute_group lm75_group = {
130 .attrs = lm75_attributes,
133 /*-----------------------------------------------------------------------*/
135 /* device probe and removal */
138 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
140 struct lm75_data *data;
142 u8 set_mask, clr_mask;
145 if (!i2c_check_functionality(client->adapter,
146 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
149 data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
153 i2c_set_clientdata(client, data);
154 mutex_init(&data->update_lock);
156 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
157 * Then tweak to be more precise when appropriate.
160 clr_mask = (1 << 0) /* continuous conversions */
161 | (1 << 6) | (1 << 5); /* 9-bit mode */
163 /* configure as specified */
164 status = lm75_read_value(client, LM75_REG_CONF);
166 dev_dbg(&client->dev, "Can't read config? %d\n", status);
169 data->orig_conf = status;
170 new = status & ~clr_mask;
173 lm75_write_value(client, LM75_REG_CONF, new);
174 dev_dbg(&client->dev, "Config %02x\n", new);
176 /* Register sysfs hooks */
177 status = sysfs_create_group(&client->dev.kobj, &lm75_group);
181 data->hwmon_dev = hwmon_device_register(&client->dev);
182 if (IS_ERR(data->hwmon_dev)) {
183 status = PTR_ERR(data->hwmon_dev);
187 dev_info(&client->dev, "%s: sensor '%s'\n",
188 dev_name(data->hwmon_dev), client->name);
193 sysfs_remove_group(&client->dev.kobj, &lm75_group);
195 i2c_set_clientdata(client, NULL);
200 static int lm75_remove(struct i2c_client *client)
202 struct lm75_data *data = i2c_get_clientdata(client);
204 hwmon_device_unregister(data->hwmon_dev);
205 sysfs_remove_group(&client->dev.kobj, &lm75_group);
206 lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
207 i2c_set_clientdata(client, NULL);
212 static const struct i2c_device_id lm75_ids[] = {
213 { "ds1775", ds1775, },
217 { "max6625", max6625, },
218 { "max6626", max6626, },
219 { "mcp980x", mcp980x, },
220 { "stds75", stds75, },
222 { "tmp100", tmp100, },
223 { "tmp101", tmp101, },
224 { "tmp105", tmp105, },
225 { "tmp175", tmp175, },
226 { "tmp275", tmp275, },
230 MODULE_DEVICE_TABLE(i2c, lm75_ids);
232 /* Return 0 if detection is successful, -ENODEV otherwise */
233 static int lm75_detect(struct i2c_client *new_client,
234 struct i2c_board_info *info)
236 struct i2c_adapter *adapter = new_client->adapter;
238 int cur, conf, hyst, os;
240 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
241 I2C_FUNC_SMBUS_WORD_DATA))
244 /* Now, we do the remaining detection. There is no identification-
245 dedicated register so we have to rely on several tricks:
246 unused bits, registers cycling over 8-address boundaries,
247 addresses 0x04-0x07 returning the last read value.
248 The cycling+unused addresses combination is not tested,
249 since it would significantly slow the detection down and would
250 hardly add any value. */
252 /* Unused addresses */
253 cur = i2c_smbus_read_word_data(new_client, 0);
254 conf = i2c_smbus_read_byte_data(new_client, 1);
255 hyst = i2c_smbus_read_word_data(new_client, 2);
256 if (i2c_smbus_read_word_data(new_client, 4) != hyst
257 || i2c_smbus_read_word_data(new_client, 5) != hyst
258 || i2c_smbus_read_word_data(new_client, 6) != hyst
259 || i2c_smbus_read_word_data(new_client, 7) != hyst)
261 os = i2c_smbus_read_word_data(new_client, 3);
262 if (i2c_smbus_read_word_data(new_client, 4) != os
263 || i2c_smbus_read_word_data(new_client, 5) != os
264 || i2c_smbus_read_word_data(new_client, 6) != os
265 || i2c_smbus_read_word_data(new_client, 7) != os)
272 /* Addresses cycling */
273 for (i = 8; i < 0xff; i += 8) {
274 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
275 || i2c_smbus_read_word_data(new_client, i + 2) != hyst
276 || i2c_smbus_read_word_data(new_client, i + 3) != os)
280 strlcpy(info->type, "lm75", I2C_NAME_SIZE);
285 static struct i2c_driver lm75_driver = {
286 .class = I2C_CLASS_HWMON,
291 .remove = lm75_remove,
292 .id_table = lm75_ids,
293 .detect = lm75_detect,
294 .address_list = normal_i2c,
297 /*-----------------------------------------------------------------------*/
299 /* register access */
301 /* All registers are word-sized, except for the configuration register.
302 LM75 uses a high-byte first convention, which is exactly opposite to
303 the SMBus standard. */
304 static int lm75_read_value(struct i2c_client *client, u8 reg)
308 if (reg == LM75_REG_CONF)
309 return i2c_smbus_read_byte_data(client, reg);
311 value = i2c_smbus_read_word_data(client, reg);
312 return (value < 0) ? value : swab16(value);
315 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
317 if (reg == LM75_REG_CONF)
318 return i2c_smbus_write_byte_data(client, reg, value);
320 return i2c_smbus_write_word_data(client, reg, swab16(value));
323 static struct lm75_data *lm75_update_device(struct device *dev)
325 struct i2c_client *client = to_i2c_client(dev);
326 struct lm75_data *data = i2c_get_clientdata(client);
328 mutex_lock(&data->update_lock);
330 if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
333 dev_dbg(&client->dev, "Starting lm75 update\n");
335 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
338 status = lm75_read_value(client, LM75_REG_TEMP[i]);
340 dev_dbg(&client->dev, "reg %d, err %d\n",
341 LM75_REG_TEMP[i], status);
343 data->temp[i] = status;
345 data->last_updated = jiffies;
349 mutex_unlock(&data->update_lock);
354 /*-----------------------------------------------------------------------*/
358 static int __init sensors_lm75_init(void)
360 return i2c_add_driver(&lm75_driver);
363 static void __exit sensors_lm75_exit(void)
365 i2c_del_driver(&lm75_driver);
368 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
369 MODULE_DESCRIPTION("LM75 driver");
370 MODULE_LICENSE("GPL");
372 module_init(sensors_lm75_init);
373 module_exit(sensors_lm75_exit);