2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005 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/err.h>
49 #include <linux/mutex.h>
51 /* The LM92 and MAX6635 have 2 two-state pins for address selection,
52 resulting in 4 possible addresses. */
53 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
56 /* Insmod parameters */
57 I2C_CLIENT_INSMOD_1(lm92);
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 */
68 /* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
69 left-justified in 16-bit registers. No rounding is done, with such
70 a resolution it's just not worth it. Note that the MAX6635 doesn't
71 make use of the 4 lower bits for limits (i.e. effective resolution
72 for limits is 1 degree Celsius). */
73 static inline int TEMP_FROM_REG(s16 reg)
75 return reg / 8 * 625 / 10;
78 static inline s16 TEMP_TO_REG(int val)
81 return -60000 * 10 / 625 * 8;
83 return 160000 * 10 / 625 * 8;
84 return val * 10 / 625 * 8;
87 /* Alarm flags are stored in the 3 LSB of the temperature register */
88 static inline u8 ALARMS_FROM_REG(s16 reg)
93 /* Driver data (common to all clients) */
94 static struct i2c_driver lm92_driver;
96 /* Client data (each client gets its own) */
98 struct i2c_client client;
99 struct class_device *class_dev;
100 struct mutex update_lock;
101 char valid; /* zero until following fields are valid */
102 unsigned long last_updated; /* in jiffies */
104 /* registers values */
105 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
110 * Sysfs attributes and callback functions
113 static struct lm92_data *lm92_update_device(struct device *dev)
115 struct i2c_client *client = to_i2c_client(dev);
116 struct lm92_data *data = i2c_get_clientdata(client);
118 mutex_lock(&data->update_lock);
120 if (time_after(jiffies, data->last_updated + HZ)
122 dev_dbg(&client->dev, "Updating lm92 data\n");
123 data->temp1_input = swab16(i2c_smbus_read_word_data(client,
125 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
126 LM92_REG_TEMP_HYST));
127 data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
128 LM92_REG_TEMP_CRIT));
129 data->temp1_min = swab16(i2c_smbus_read_word_data(client,
131 data->temp1_max = swab16(i2c_smbus_read_word_data(client,
132 LM92_REG_TEMP_HIGH));
134 data->last_updated = jiffies;
138 mutex_unlock(&data->update_lock);
143 #define show_temp(value) \
144 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
146 struct lm92_data *data = lm92_update_device(dev); \
147 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
149 show_temp(temp1_input);
150 show_temp(temp1_crit);
151 show_temp(temp1_min);
152 show_temp(temp1_max);
154 #define set_temp(value, reg) \
155 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
158 struct i2c_client *client = to_i2c_client(dev); \
159 struct lm92_data *data = i2c_get_clientdata(client); \
160 long val = simple_strtol(buf, NULL, 10); \
162 mutex_lock(&data->update_lock); \
163 data->value = TEMP_TO_REG(val); \
164 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
165 mutex_unlock(&data->update_lock); \
168 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
169 set_temp(temp1_min, LM92_REG_TEMP_LOW);
170 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
172 static ssize_t show_temp1_crit_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_crit)
176 - TEMP_FROM_REG(data->temp1_hyst));
178 static ssize_t show_temp1_max_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_max)
182 - TEMP_FROM_REG(data->temp1_hyst));
184 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
186 struct lm92_data *data = lm92_update_device(dev);
187 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
188 + TEMP_FROM_REG(data->temp1_hyst));
191 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
194 struct i2c_client *client = to_i2c_client(dev);
195 struct lm92_data *data = i2c_get_clientdata(client);
196 long val = simple_strtol(buf, NULL, 10);
198 mutex_lock(&data->update_lock);
199 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
200 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
201 swab16(TEMP_TO_REG(data->temp1_hyst)));
202 mutex_unlock(&data->update_lock);
206 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
208 struct lm92_data *data = lm92_update_device(dev);
209 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
212 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
213 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
215 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
216 set_temp1_crit_hyst);
217 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
219 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
220 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
222 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
223 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
227 * Detection and registration
230 static void lm92_init_client(struct i2c_client *client)
234 /* Start the conversions if needed */
235 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
237 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
241 /* The MAX6635 has no identification register, so we have to use tricks
242 to identify it reliably. This is somewhat slow.
243 Note that we do NOT rely on the 2 MSB of the configuration register
244 always reading 0, as suggested by the datasheet, because it was once
245 reported not to be true. */
246 static int max6635_check(struct i2c_client *client)
248 u16 temp_low, temp_high, temp_hyst, temp_crit;
252 /* No manufacturer ID register, so a read from this address will
253 always return the last read value. */
254 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
255 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
257 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
258 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
261 /* Limits are stored as integer values (signed, 9-bit). */
262 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
264 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
265 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
266 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
269 /* Registers addresses were found to cycle over 16-byte boundaries.
270 We don't test all registers with all offsets so as to save some
271 reads and time, but this should still be sufficient to dismiss
272 non-MAX6635 chips. */
273 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
274 for (i=16; i<96; i*=2) {
275 if (temp_hyst != i2c_smbus_read_word_data(client,
276 LM92_REG_TEMP_HYST + i - 16)
277 || temp_crit != i2c_smbus_read_word_data(client,
278 LM92_REG_TEMP_CRIT + i)
279 || temp_low != i2c_smbus_read_word_data(client,
280 LM92_REG_TEMP_LOW + i + 16)
281 || temp_high != i2c_smbus_read_word_data(client,
282 LM92_REG_TEMP_HIGH + i + 32)
283 || conf != i2c_smbus_read_byte_data(client,
284 LM92_REG_CONFIG + i))
291 /* The following function does more than just detection. If detection
292 succeeds, it also registers the new chip. */
293 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
295 struct i2c_client *new_client;
296 struct lm92_data *data;
300 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
301 | I2C_FUNC_SMBUS_WORD_DATA))
304 if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
309 /* Fill in enough client fields so that we can read from the chip,
310 which is required for identication */
311 new_client = &data->client;
312 i2c_set_clientdata(new_client, data);
313 new_client->addr = address;
314 new_client->adapter = adapter;
315 new_client->driver = &lm92_driver;
316 new_client->flags = 0;
318 /* A negative kind means that the driver was loaded with no force
319 parameter (default), so we must identify the chip. */
321 u8 config = i2c_smbus_read_byte_data(new_client,
323 u16 man_id = i2c_smbus_read_word_data(new_client,
326 if ((config & 0xe0) == 0x00
327 && man_id == 0x0180) {
328 pr_info("lm92: Found National Semiconductor LM92 chip\n");
331 if (max6635_check(new_client)) {
332 pr_info("lm92: Found Maxim MAX6635 chip\n");
333 kind = lm92; /* No separate prefix */
338 if (kind == 0) /* Default to an LM92 if forced */
341 /* Give it the proper name */
344 } else { /* Supposedly cannot happen */
345 dev_dbg(&new_client->dev, "Kind out of range?\n");
349 /* Fill in the remaining client fields */
350 strlcpy(new_client->name, name, I2C_NAME_SIZE);
352 mutex_init(&data->update_lock);
354 /* Tell the i2c subsystem a new client has arrived */
355 if ((err = i2c_attach_client(new_client)))
358 /* Initialize the chipset */
359 lm92_init_client(new_client);
361 /* Register sysfs hooks */
362 data->class_dev = hwmon_device_register(&new_client->dev);
363 if (IS_ERR(data->class_dev)) {
364 err = PTR_ERR(data->class_dev);
368 device_create_file(&new_client->dev, &dev_attr_temp1_input);
369 device_create_file(&new_client->dev, &dev_attr_temp1_crit);
370 device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
371 device_create_file(&new_client->dev, &dev_attr_temp1_min);
372 device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
373 device_create_file(&new_client->dev, &dev_attr_temp1_max);
374 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
375 device_create_file(&new_client->dev, &dev_attr_alarms);
380 i2c_detach_client(new_client);
387 static int lm92_attach_adapter(struct i2c_adapter *adapter)
389 if (!(adapter->class & I2C_CLASS_HWMON))
391 return i2c_probe(adapter, &addr_data, lm92_detect);
394 static int lm92_detach_client(struct i2c_client *client)
396 struct lm92_data *data = i2c_get_clientdata(client);
399 hwmon_device_unregister(data->class_dev);
401 if ((err = i2c_detach_client(client)))
410 * Module and driver stuff
413 static struct i2c_driver lm92_driver = {
417 .id = I2C_DRIVERID_LM92,
418 .attach_adapter = lm92_attach_adapter,
419 .detach_client = lm92_detach_client,
422 static int __init sensors_lm92_init(void)
424 return i2c_add_driver(&lm92_driver);
427 static void __exit sensors_lm92_exit(void)
429 i2c_del_driver(&lm92_driver);
432 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
433 MODULE_DESCRIPTION("LM92/MAX6635 driver");
434 MODULE_LICENSE("GPL");
436 module_init(sensors_lm92_init);
437 module_exit(sensors_lm92_exit);