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.
35 * Only types which are _not_ listed in I2C_CLIENT_INSMOD_*() need to be
36 * listed here. We start at 9 since I2C_CLIENT_INSMOD_*() currently allow
37 * definition of up to 8 chip types (plus zero).
40 enum lm75_type { /* keep sorted in alphabetical order */
43 /* lm75 -- in I2C_CLIENT_INSMOD_1() */
57 /* Addresses scanned */
58 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
59 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
61 /* Insmod parameters */
62 I2C_CLIENT_INSMOD_1(lm75);
65 /* The LM75 registers */
66 #define LM75_REG_CONF 0x01
67 static const u8 LM75_REG_TEMP[3] = {
73 /* Each client has this additional data */
75 struct device *hwmon_dev;
76 struct mutex update_lock;
78 char valid; /* !=0 if registers are valid */
79 unsigned long last_updated; /* In jiffies */
80 u16 temp[3]; /* Register values,
86 static int lm75_read_value(struct i2c_client *client, u8 reg);
87 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
88 static struct lm75_data *lm75_update_device(struct device *dev);
91 /*-----------------------------------------------------------------------*/
93 /* sysfs attributes for hwmon */
95 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
98 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
99 struct lm75_data *data = lm75_update_device(dev);
100 return sprintf(buf, "%d\n",
101 LM75_TEMP_FROM_REG(data->temp[attr->index]));
104 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
105 const char *buf, size_t count)
107 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
108 struct i2c_client *client = to_i2c_client(dev);
109 struct lm75_data *data = i2c_get_clientdata(client);
110 int nr = attr->index;
111 long temp = simple_strtol(buf, NULL, 10);
113 mutex_lock(&data->update_lock);
114 data->temp[nr] = LM75_TEMP_TO_REG(temp);
115 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
116 mutex_unlock(&data->update_lock);
120 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
121 show_temp, set_temp, 1);
122 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
123 show_temp, set_temp, 2);
124 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
126 static struct attribute *lm75_attributes[] = {
127 &sensor_dev_attr_temp1_input.dev_attr.attr,
128 &sensor_dev_attr_temp1_max.dev_attr.attr,
129 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
134 static const struct attribute_group lm75_group = {
135 .attrs = lm75_attributes,
138 /*-----------------------------------------------------------------------*/
140 /* device probe and removal */
143 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
145 struct lm75_data *data;
147 u8 set_mask, clr_mask;
150 if (!i2c_check_functionality(client->adapter,
151 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
154 data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
158 i2c_set_clientdata(client, data);
159 mutex_init(&data->update_lock);
161 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
162 * Then tweak to be more precise when appropriate.
165 clr_mask = (1 << 0) /* continuous conversions */
166 | (1 << 6) | (1 << 5); /* 9-bit mode */
168 /* configure as specified */
169 status = lm75_read_value(client, LM75_REG_CONF);
171 dev_dbg(&client->dev, "Can't read config? %d\n", status);
174 data->orig_conf = status;
175 new = status & ~clr_mask;
178 lm75_write_value(client, LM75_REG_CONF, new);
179 dev_dbg(&client->dev, "Config %02x\n", new);
181 /* Register sysfs hooks */
182 status = sysfs_create_group(&client->dev.kobj, &lm75_group);
186 data->hwmon_dev = hwmon_device_register(&client->dev);
187 if (IS_ERR(data->hwmon_dev)) {
188 status = PTR_ERR(data->hwmon_dev);
192 dev_info(&client->dev, "%s: sensor '%s'\n",
193 dev_name(data->hwmon_dev), client->name);
198 sysfs_remove_group(&client->dev.kobj, &lm75_group);
200 i2c_set_clientdata(client, NULL);
205 static int lm75_remove(struct i2c_client *client)
207 struct lm75_data *data = i2c_get_clientdata(client);
209 hwmon_device_unregister(data->hwmon_dev);
210 sysfs_remove_group(&client->dev.kobj, &lm75_group);
211 lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
212 i2c_set_clientdata(client, NULL);
217 static const struct i2c_device_id lm75_ids[] = {
218 { "ds1775", ds1775, },
222 { "max6625", max6625, },
223 { "max6626", max6626, },
224 { "mcp980x", mcp980x, },
225 { "stds75", stds75, },
227 { "tmp100", tmp100, },
228 { "tmp101", tmp101, },
229 { "tmp175", tmp175, },
230 { "tmp275", tmp275, },
234 MODULE_DEVICE_TABLE(i2c, lm75_ids);
236 /* Return 0 if detection is successful, -ENODEV otherwise */
237 static int lm75_detect(struct i2c_client *new_client, int kind,
238 struct i2c_board_info *info)
240 struct i2c_adapter *adapter = new_client->adapter;
243 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
244 I2C_FUNC_SMBUS_WORD_DATA))
247 /* Now, we do the remaining detection. There is no identification-
248 dedicated register so we have to rely on several tricks:
249 unused bits, registers cycling over 8-address boundaries,
250 addresses 0x04-0x07 returning the last read value.
251 The cycling+unused addresses combination is not tested,
252 since it would significantly slow the detection down and would
253 hardly add any value. */
255 int cur, conf, hyst, os;
257 /* Unused addresses */
258 cur = i2c_smbus_read_word_data(new_client, 0);
259 conf = i2c_smbus_read_byte_data(new_client, 1);
260 hyst = i2c_smbus_read_word_data(new_client, 2);
261 if (i2c_smbus_read_word_data(new_client, 4) != hyst
262 || i2c_smbus_read_word_data(new_client, 5) != hyst
263 || i2c_smbus_read_word_data(new_client, 6) != hyst
264 || i2c_smbus_read_word_data(new_client, 7) != hyst)
266 os = i2c_smbus_read_word_data(new_client, 3);
267 if (i2c_smbus_read_word_data(new_client, 4) != os
268 || i2c_smbus_read_word_data(new_client, 5) != os
269 || i2c_smbus_read_word_data(new_client, 6) != os
270 || i2c_smbus_read_word_data(new_client, 7) != os)
277 /* Addresses cycling */
278 for (i = 8; i < 0xff; i += 8)
279 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
280 || i2c_smbus_read_word_data(new_client, i + 2) != hyst
281 || i2c_smbus_read_word_data(new_client, i + 3) != os)
285 /* NOTE: we treat "force=..." and "force_lm75=..." the same.
286 * Only new-style driver binding distinguishes chip types.
288 strlcpy(info->type, "lm75", I2C_NAME_SIZE);
293 static struct i2c_driver lm75_driver = {
294 .class = I2C_CLASS_HWMON,
299 .remove = lm75_remove,
300 .id_table = lm75_ids,
301 .detect = lm75_detect,
302 .address_data = &addr_data,
305 /*-----------------------------------------------------------------------*/
307 /* register access */
309 /* All registers are word-sized, except for the configuration register.
310 LM75 uses a high-byte first convention, which is exactly opposite to
311 the SMBus standard. */
312 static int lm75_read_value(struct i2c_client *client, u8 reg)
316 if (reg == LM75_REG_CONF)
317 return i2c_smbus_read_byte_data(client, reg);
319 value = i2c_smbus_read_word_data(client, reg);
320 return (value < 0) ? value : swab16(value);
323 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
325 if (reg == LM75_REG_CONF)
326 return i2c_smbus_write_byte_data(client, reg, value);
328 return i2c_smbus_write_word_data(client, reg, swab16(value));
331 static struct lm75_data *lm75_update_device(struct device *dev)
333 struct i2c_client *client = to_i2c_client(dev);
334 struct lm75_data *data = i2c_get_clientdata(client);
336 mutex_lock(&data->update_lock);
338 if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
341 dev_dbg(&client->dev, "Starting lm75 update\n");
343 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
346 status = lm75_read_value(client, LM75_REG_TEMP[i]);
348 dev_dbg(&client->dev, "reg %d, err %d\n",
349 LM75_REG_TEMP[i], status);
351 data->temp[i] = status;
353 data->last_updated = jiffies;
357 mutex_unlock(&data->update_lock);
362 /*-----------------------------------------------------------------------*/
366 static int __init sensors_lm75_init(void)
368 return i2c_add_driver(&lm75_driver);
371 static void __exit sensors_lm75_exit(void)
373 i2c_del_driver(&lm75_driver);
376 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
377 MODULE_DESCRIPTION("LM75 driver");
378 MODULE_LICENSE("GPL");
380 module_init(sensors_lm75_init);
381 module_exit(sensors_lm75_exit);