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>
53 * The LM92 and MAX6635 have 2 two-state pins for address selection,
54 * resulting in 4 possible addresses.
56 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
59 /* The LM92 registers */
60 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
61 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
62 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
63 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
64 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
65 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
66 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
69 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
70 * left-justified in 16-bit registers. No rounding is done, with such
71 * a resolution it's just not worth it. Note that the MAX6635 doesn't
72 * make use of the 4 lower bits for limits (i.e. effective resolution
73 * for limits is 1 degree Celsius).
75 static inline int TEMP_FROM_REG(s16 reg)
77 return reg / 8 * 625 / 10;
80 static inline s16 TEMP_TO_REG(int val)
83 return -60000 * 10 / 625 * 8;
85 return 160000 * 10 / 625 * 8;
86 return val * 10 / 625 * 8;
89 /* Alarm flags are stored in the 3 LSB of the temperature register */
90 static inline u8 ALARMS_FROM_REG(s16 reg)
95 /* Driver data (common to all clients) */
96 static struct i2c_driver lm92_driver;
98 /* Client data (each client gets its own) */
100 struct device *hwmon_dev;
101 struct mutex update_lock;
102 char valid; /* zero until following fields are valid */
103 unsigned long last_updated; /* in jiffies */
105 /* registers values */
106 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
111 * Sysfs attributes and callback functions
114 static struct lm92_data *lm92_update_device(struct device *dev)
116 struct i2c_client *client = to_i2c_client(dev);
117 struct lm92_data *data = i2c_get_clientdata(client);
119 mutex_lock(&data->update_lock);
121 if (time_after(jiffies, data->last_updated + HZ)
123 dev_dbg(&client->dev, "Updating lm92 data\n");
124 data->temp1_input = i2c_smbus_read_word_swapped(client,
126 data->temp1_hyst = i2c_smbus_read_word_swapped(client,
128 data->temp1_crit = i2c_smbus_read_word_swapped(client,
130 data->temp1_min = i2c_smbus_read_word_swapped(client,
132 data->temp1_max = i2c_smbus_read_word_swapped(client,
135 data->last_updated = jiffies;
139 mutex_unlock(&data->update_lock);
144 #define show_temp(value) \
145 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, \
148 struct lm92_data *data = lm92_update_device(dev); \
149 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
151 show_temp(temp1_input);
152 show_temp(temp1_crit);
153 show_temp(temp1_min);
154 show_temp(temp1_max);
156 #define set_temp(value, reg) \
157 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, \
161 struct i2c_client *client = to_i2c_client(dev); \
162 struct lm92_data *data = i2c_get_clientdata(client); \
164 int err = kstrtol(buf, 10, &val); \
168 mutex_lock(&data->update_lock); \
169 data->value = TEMP_TO_REG(val); \
170 i2c_smbus_write_word_swapped(client, reg, data->value); \
171 mutex_unlock(&data->update_lock); \
174 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
175 set_temp(temp1_min, LM92_REG_TEMP_LOW);
176 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
178 static ssize_t show_temp1_crit_hyst(struct device *dev,
179 struct device_attribute *attr, char *buf)
181 struct lm92_data *data = lm92_update_device(dev);
182 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
183 - TEMP_FROM_REG(data->temp1_hyst));
185 static ssize_t show_temp1_max_hyst(struct device *dev,
186 struct device_attribute *attr, char *buf)
188 struct lm92_data *data = lm92_update_device(dev);
189 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
190 - TEMP_FROM_REG(data->temp1_hyst));
192 static ssize_t show_temp1_min_hyst(struct device *dev,
193 struct device_attribute *attr, char *buf)
195 struct lm92_data *data = lm92_update_device(dev);
196 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
197 + TEMP_FROM_REG(data->temp1_hyst));
200 static ssize_t set_temp1_crit_hyst(struct device *dev,
201 struct device_attribute *attr,
202 const char *buf, size_t count)
204 struct i2c_client *client = to_i2c_client(dev);
205 struct lm92_data *data = i2c_get_clientdata(client);
209 err = kstrtol(buf, 10, &val);
213 mutex_lock(&data->update_lock);
214 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
215 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
216 TEMP_TO_REG(data->temp1_hyst));
217 mutex_unlock(&data->update_lock);
221 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
224 struct lm92_data *data = lm92_update_device(dev);
225 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
228 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
231 int bitnr = to_sensor_dev_attr(attr)->index;
232 struct lm92_data *data = lm92_update_device(dev);
233 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
236 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
237 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
239 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
240 set_temp1_crit_hyst);
241 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
243 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
244 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
246 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
247 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
248 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
249 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
250 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
254 * Detection and registration
257 static void lm92_init_client(struct i2c_client *client)
261 /* Start the conversions if needed */
262 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
264 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
269 * The MAX6635 has no identification register, so we have to use tricks
270 * to identify it reliably. This is somewhat slow.
271 * Note that we do NOT rely on the 2 MSB of the configuration register
272 * always reading 0, as suggested by the datasheet, because it was once
273 * reported not to be true.
275 static int max6635_check(struct i2c_client *client)
277 u16 temp_low, temp_high, temp_hyst, temp_crit;
282 * No manufacturer ID register, so a read from this address will
283 * always return the last read value.
285 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
286 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
288 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
289 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
292 /* Limits are stored as integer values (signed, 9-bit). */
293 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
295 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
296 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
297 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
301 * Registers addresses were found to cycle over 16-byte boundaries.
302 * We don't test all registers with all offsets so as to save some
303 * reads and time, but this should still be sufficient to dismiss
306 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
307 for (i = 16; i < 96; i *= 2) {
308 if (temp_hyst != i2c_smbus_read_word_data(client,
309 LM92_REG_TEMP_HYST + i - 16)
310 || temp_crit != i2c_smbus_read_word_data(client,
311 LM92_REG_TEMP_CRIT + i)
312 || temp_low != i2c_smbus_read_word_data(client,
313 LM92_REG_TEMP_LOW + i + 16)
314 || temp_high != i2c_smbus_read_word_data(client,
315 LM92_REG_TEMP_HIGH + i + 32)
316 || conf != i2c_smbus_read_byte_data(client,
317 LM92_REG_CONFIG + i))
324 static struct attribute *lm92_attributes[] = {
325 &dev_attr_temp1_input.attr,
326 &dev_attr_temp1_crit.attr,
327 &dev_attr_temp1_crit_hyst.attr,
328 &dev_attr_temp1_min.attr,
329 &dev_attr_temp1_min_hyst.attr,
330 &dev_attr_temp1_max.attr,
331 &dev_attr_temp1_max_hyst.attr,
332 &dev_attr_alarms.attr,
333 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
334 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
335 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
339 static const struct attribute_group lm92_group = {
340 .attrs = lm92_attributes,
343 /* Return 0 if detection is successful, -ENODEV otherwise */
344 static int lm92_detect(struct i2c_client *new_client,
345 struct i2c_board_info *info)
347 struct i2c_adapter *adapter = new_client->adapter;
351 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
352 | I2C_FUNC_SMBUS_WORD_DATA))
355 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
356 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
358 if ((config & 0xe0) == 0x00 && man_id == 0x0180)
359 pr_info("lm92: Found National Semiconductor LM92 chip\n");
360 else if (max6635_check(new_client))
361 pr_info("lm92: Found Maxim MAX6635 chip\n");
365 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
370 static int lm92_probe(struct i2c_client *new_client,
371 const struct i2c_device_id *id)
373 struct lm92_data *data;
376 data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
381 i2c_set_clientdata(new_client, data);
383 mutex_init(&data->update_lock);
385 /* Initialize the chipset */
386 lm92_init_client(new_client);
388 /* Register sysfs hooks */
389 err = sysfs_create_group(&new_client->dev.kobj, &lm92_group);
393 data->hwmon_dev = hwmon_device_register(&new_client->dev);
394 if (IS_ERR(data->hwmon_dev)) {
395 err = PTR_ERR(data->hwmon_dev);
402 sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
406 static int lm92_remove(struct i2c_client *client)
408 struct lm92_data *data = i2c_get_clientdata(client);
410 hwmon_device_unregister(data->hwmon_dev);
411 sysfs_remove_group(&client->dev.kobj, &lm92_group);
418 * Module and driver stuff
421 static const struct i2c_device_id lm92_id[] = {
423 /* max6635 could be added here */
426 MODULE_DEVICE_TABLE(i2c, lm92_id);
428 static struct i2c_driver lm92_driver = {
429 .class = I2C_CLASS_HWMON,
434 .remove = lm92_remove,
436 .detect = lm92_detect,
437 .address_list = normal_i2c,
440 module_i2c_driver(lm92_driver);
442 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
443 MODULE_DESCRIPTION("LM92/MAX6635 driver");
444 MODULE_LICENSE("GPL");