2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005-2008 Jean Delvare <khali@linux-fr.org>
5 * Based on the lm90 driver, with some ideas taken from the lm_sensors
8 * The LM92 is a sensor chip made by National Semiconductor. It reports
9 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
10 * accuracy. Complete datasheet can be obtained from National's website
12 * http://www.national.com/pf/LM/LM92.html
14 * This driver also supports the MAX6635 sensor chip made by Maxim.
15 * This chip is compatible with the LM92, but has a lesser accuracy
16 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
18 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
20 * Since the LM92 was the first chipset supported by this driver, most
21 * comments will refer to this chipset, but are actually general and
22 * concern all supported chipsets, unless mentioned otherwise.
24 * Support could easily be added for the National Semiconductor LM76
25 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
28 * This program is free software; you can redistribute it and/or modify
29 * it under the terms of the GNU General Public License as published by
30 * the Free Software Foundation; either version 2 of the License, or
31 * (at your option) any later version.
33 * This program is distributed in the hope that it will be useful,
34 * but WITHOUT ANY WARRANTY; without even the implied warranty of
35 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
36 * GNU General Public License for more details.
38 * You should have received a copy of the GNU General Public License
39 * along with this program; if not, write to the Free Software
40 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
43 #include <linux/module.h>
44 #include <linux/init.h>
45 #include <linux/slab.h>
46 #include <linux/i2c.h>
47 #include <linux/hwmon.h>
48 #include <linux/hwmon-sysfs.h>
49 #include <linux/err.h>
50 #include <linux/mutex.h>
52 /* The LM92 and MAX6635 have 2 two-state pins for address selection,
53 resulting in 4 possible addresses. */
54 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
57 /* The LM92 registers */
58 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
59 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
60 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
61 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
62 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
63 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
64 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
66 /* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
67 left-justified in 16-bit registers. No rounding is done, with such
68 a resolution it's just not worth it. Note that the MAX6635 doesn't
69 make use of the 4 lower bits for limits (i.e. effective resolution
70 for limits is 1 degree Celsius). */
71 static inline int TEMP_FROM_REG(s16 reg)
73 return reg / 8 * 625 / 10;
76 static inline s16 TEMP_TO_REG(long val)
78 val = clamp_val(val, -60000, 160000);
79 return val * 10 / 625 * 8;
82 /* Alarm flags are stored in the 3 LSB of the temperature register */
83 static inline u8 ALARMS_FROM_REG(s16 reg)
88 /* Driver data (common to all clients) */
89 static struct i2c_driver lm92_driver;
91 /* Client data (each client gets its own) */
93 struct device *hwmon_dev;
94 struct mutex update_lock;
95 char valid; /* zero until following fields are valid */
96 unsigned long last_updated; /* in jiffies */
98 /* registers values */
99 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
104 * Sysfs attributes and callback functions
107 static struct lm92_data *lm92_update_device(struct device *dev)
109 struct i2c_client *client = to_i2c_client(dev);
110 struct lm92_data *data = i2c_get_clientdata(client);
112 mutex_lock(&data->update_lock);
114 if (time_after(jiffies, data->last_updated + HZ)
116 dev_dbg(&client->dev, "Updating lm92 data\n");
117 data->temp1_input = i2c_smbus_read_word_swapped(client,
119 data->temp1_hyst = i2c_smbus_read_word_swapped(client,
121 data->temp1_crit = i2c_smbus_read_word_swapped(client,
123 data->temp1_min = i2c_smbus_read_word_swapped(client,
125 data->temp1_max = i2c_smbus_read_word_swapped(client,
128 data->last_updated = jiffies;
132 mutex_unlock(&data->update_lock);
137 #define show_temp(value) \
138 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
140 struct lm92_data *data = lm92_update_device(dev); \
141 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
143 show_temp(temp1_input);
144 show_temp(temp1_crit);
145 show_temp(temp1_min);
146 show_temp(temp1_max);
148 #define set_temp(value, reg) \
149 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
152 struct i2c_client *client = to_i2c_client(dev); \
153 struct lm92_data *data = i2c_get_clientdata(client); \
154 long val = simple_strtol(buf, NULL, 10); \
156 mutex_lock(&data->update_lock); \
157 data->value = TEMP_TO_REG(val); \
158 i2c_smbus_write_word_swapped(client, reg, data->value); \
159 mutex_unlock(&data->update_lock); \
162 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
163 set_temp(temp1_min, LM92_REG_TEMP_LOW);
164 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
166 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
168 struct lm92_data *data = lm92_update_device(dev);
169 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
170 - TEMP_FROM_REG(data->temp1_hyst));
172 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
174 struct lm92_data *data = lm92_update_device(dev);
175 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
176 - TEMP_FROM_REG(data->temp1_hyst));
178 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
180 struct lm92_data *data = lm92_update_device(dev);
181 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
182 + TEMP_FROM_REG(data->temp1_hyst));
185 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
188 struct i2c_client *client = to_i2c_client(dev);
189 struct lm92_data *data = i2c_get_clientdata(client);
190 long val = simple_strtol(buf, NULL, 10);
192 val = clamp_val(val, -120000, 220000);
193 mutex_lock(&data->update_lock);
195 TEMP_TO_REG(TEMP_FROM_REG(data->temp1_crit) - val);
196 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
198 mutex_unlock(&data->update_lock);
202 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
204 struct lm92_data *data = lm92_update_device(dev);
205 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
208 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
211 int bitnr = to_sensor_dev_attr(attr)->index;
212 struct lm92_data *data = lm92_update_device(dev);
213 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
216 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
217 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
219 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
220 set_temp1_crit_hyst);
221 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
223 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
224 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
226 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
227 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
228 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
229 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
230 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
234 * Detection and registration
237 static void lm92_init_client(struct i2c_client *client)
241 /* Start the conversions if needed */
242 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
244 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
248 /* The MAX6635 has no identification register, so we have to use tricks
249 to identify it reliably. This is somewhat slow.
250 Note that we do NOT rely on the 2 MSB of the configuration register
251 always reading 0, as suggested by the datasheet, because it was once
252 reported not to be true. */
253 static int max6635_check(struct i2c_client *client)
255 u16 temp_low, temp_high, temp_hyst, temp_crit;
259 /* No manufacturer ID register, so a read from this address will
260 always return the last read value. */
261 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
262 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
264 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
265 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
268 /* Limits are stored as integer values (signed, 9-bit). */
269 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
271 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
272 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
273 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
276 /* Registers addresses were found to cycle over 16-byte boundaries.
277 We don't test all registers with all offsets so as to save some
278 reads and time, but this should still be sufficient to dismiss
279 non-MAX6635 chips. */
280 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
281 for (i=16; i<96; i*=2) {
282 if (temp_hyst != i2c_smbus_read_word_data(client,
283 LM92_REG_TEMP_HYST + i - 16)
284 || temp_crit != i2c_smbus_read_word_data(client,
285 LM92_REG_TEMP_CRIT + i)
286 || temp_low != i2c_smbus_read_word_data(client,
287 LM92_REG_TEMP_LOW + i + 16)
288 || temp_high != i2c_smbus_read_word_data(client,
289 LM92_REG_TEMP_HIGH + i + 32)
290 || conf != i2c_smbus_read_byte_data(client,
291 LM92_REG_CONFIG + i))
298 static struct attribute *lm92_attributes[] = {
299 &dev_attr_temp1_input.attr,
300 &dev_attr_temp1_crit.attr,
301 &dev_attr_temp1_crit_hyst.attr,
302 &dev_attr_temp1_min.attr,
303 &dev_attr_temp1_min_hyst.attr,
304 &dev_attr_temp1_max.attr,
305 &dev_attr_temp1_max_hyst.attr,
306 &dev_attr_alarms.attr,
307 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
308 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
309 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
313 static const struct attribute_group lm92_group = {
314 .attrs = lm92_attributes,
317 /* Return 0 if detection is successful, -ENODEV otherwise */
318 static int lm92_detect(struct i2c_client *new_client,
319 struct i2c_board_info *info)
321 struct i2c_adapter *adapter = new_client->adapter;
325 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
326 | I2C_FUNC_SMBUS_WORD_DATA))
329 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
330 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
332 if ((config & 0xe0) == 0x00 && man_id == 0x0180)
333 pr_info("lm92: Found National Semiconductor LM92 chip\n");
334 else if (max6635_check(new_client))
335 pr_info("lm92: Found Maxim MAX6635 chip\n");
339 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
344 static int lm92_probe(struct i2c_client *new_client,
345 const struct i2c_device_id *id)
347 struct lm92_data *data;
350 data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL);
356 i2c_set_clientdata(new_client, data);
358 mutex_init(&data->update_lock);
360 /* Initialize the chipset */
361 lm92_init_client(new_client);
363 /* Register sysfs hooks */
364 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group)))
367 data->hwmon_dev = hwmon_device_register(&new_client->dev);
368 if (IS_ERR(data->hwmon_dev)) {
369 err = PTR_ERR(data->hwmon_dev);
376 sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
383 static int lm92_remove(struct i2c_client *client)
385 struct lm92_data *data = i2c_get_clientdata(client);
387 hwmon_device_unregister(data->hwmon_dev);
388 sysfs_remove_group(&client->dev.kobj, &lm92_group);
396 * Module and driver stuff
399 static const struct i2c_device_id lm92_id[] = {
401 /* max6635 could be added here */
404 MODULE_DEVICE_TABLE(i2c, lm92_id);
406 static struct i2c_driver lm92_driver = {
407 .class = I2C_CLASS_HWMON,
412 .remove = lm92_remove,
414 .detect = lm92_detect,
415 .address_list = normal_i2c,
418 static int __init sensors_lm92_init(void)
420 return i2c_add_driver(&lm92_driver);
423 static void __exit sensors_lm92_exit(void)
425 i2c_del_driver(&lm92_driver);
428 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
429 MODULE_DESCRIPTION("LM92/MAX6635 driver");
430 MODULE_LICENSE("GPL");
432 module_init(sensors_lm92_init);
433 module_exit(sensors_lm92_exit);