Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6/linux-mips/linux-dm7025.git] / drivers / hwmon / lm92.c
blobc31942e08246a9ee3441258f7f7365c14784ba2b
1 /*
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
6 * lm92 driver as well.
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
11 * at:
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
17 * at:
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
26 * with the LM92.
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,
55 I2C_CLIENT_END };
57 /* Insmod parameters */
58 I2C_CLIENT_INSMOD_1(lm92);
60 /* The LM92 registers */
61 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
62 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
63 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
64 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
65 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
66 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
67 #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). */
74 static inline int TEMP_FROM_REG(s16 reg)
76 return reg / 8 * 625 / 10;
79 static inline s16 TEMP_TO_REG(int val)
81 if (val <= -60000)
82 return -60000 * 10 / 625 * 8;
83 if (val >= 160000)
84 return 160000 * 10 / 625 * 8;
85 return val * 10 / 625 * 8;
88 /* Alarm flags are stored in the 3 LSB of the temperature register */
89 static inline u8 ALARMS_FROM_REG(s16 reg)
91 return reg & 0x0007;
94 /* Driver data (common to all clients) */
95 static struct i2c_driver lm92_driver;
97 /* Client data (each client gets its own) */
98 struct lm92_data {
99 struct i2c_client client;
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)
122 || !data->valid) {
123 dev_dbg(&client->dev, "Updating lm92 data\n");
124 data->temp1_input = swab16(i2c_smbus_read_word_data(client,
125 LM92_REG_TEMP));
126 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
127 LM92_REG_TEMP_HYST));
128 data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
129 LM92_REG_TEMP_CRIT));
130 data->temp1_min = swab16(i2c_smbus_read_word_data(client,
131 LM92_REG_TEMP_LOW));
132 data->temp1_max = swab16(i2c_smbus_read_word_data(client,
133 LM92_REG_TEMP_HIGH));
135 data->last_updated = jiffies;
136 data->valid = 1;
139 mutex_unlock(&data->update_lock);
141 return data;
144 #define show_temp(value) \
145 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
147 struct lm92_data *data = lm92_update_device(dev); \
148 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
150 show_temp(temp1_input);
151 show_temp(temp1_crit);
152 show_temp(temp1_min);
153 show_temp(temp1_max);
155 #define set_temp(value, reg) \
156 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
157 size_t count) \
159 struct i2c_client *client = to_i2c_client(dev); \
160 struct lm92_data *data = i2c_get_clientdata(client); \
161 long val = simple_strtol(buf, NULL, 10); \
163 mutex_lock(&data->update_lock); \
164 data->value = TEMP_TO_REG(val); \
165 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
166 mutex_unlock(&data->update_lock); \
167 return count; \
169 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
170 set_temp(temp1_min, LM92_REG_TEMP_LOW);
171 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
173 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
175 struct lm92_data *data = lm92_update_device(dev);
176 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
177 - TEMP_FROM_REG(data->temp1_hyst));
179 static ssize_t show_temp1_max_hyst(struct device *dev, 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_max)
183 - TEMP_FROM_REG(data->temp1_hyst));
185 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
187 struct lm92_data *data = lm92_update_device(dev);
188 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
189 + TEMP_FROM_REG(data->temp1_hyst));
192 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
193 size_t count)
195 struct i2c_client *client = to_i2c_client(dev);
196 struct lm92_data *data = i2c_get_clientdata(client);
197 long val = simple_strtol(buf, NULL, 10);
199 mutex_lock(&data->update_lock);
200 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
201 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
202 swab16(TEMP_TO_REG(data->temp1_hyst)));
203 mutex_unlock(&data->update_lock);
204 return count;
207 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
209 struct lm92_data *data = lm92_update_device(dev);
210 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
213 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
214 char *buf)
216 int bitnr = to_sensor_dev_attr(attr)->index;
217 struct lm92_data *data = lm92_update_device(dev);
218 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
221 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
222 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
223 set_temp1_crit);
224 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
225 set_temp1_crit_hyst);
226 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
227 set_temp1_min);
228 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
229 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
230 set_temp1_max);
231 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
232 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
233 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
234 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
235 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
239 * Detection and registration
242 static void lm92_init_client(struct i2c_client *client)
244 u8 config;
246 /* Start the conversions if needed */
247 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
248 if (config & 0x01)
249 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
250 config & 0xFE);
253 /* The MAX6635 has no identification register, so we have to use tricks
254 to identify it reliably. This is somewhat slow.
255 Note that we do NOT rely on the 2 MSB of the configuration register
256 always reading 0, as suggested by the datasheet, because it was once
257 reported not to be true. */
258 static int max6635_check(struct i2c_client *client)
260 u16 temp_low, temp_high, temp_hyst, temp_crit;
261 u8 conf;
262 int i;
264 /* No manufacturer ID register, so a read from this address will
265 always return the last read value. */
266 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
267 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
268 return 0;
269 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
270 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
271 return 0;
273 /* Limits are stored as integer values (signed, 9-bit). */
274 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
275 return 0;
276 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
277 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
278 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
279 return 0;
281 /* Registers addresses were found to cycle over 16-byte boundaries.
282 We don't test all registers with all offsets so as to save some
283 reads and time, but this should still be sufficient to dismiss
284 non-MAX6635 chips. */
285 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
286 for (i=16; i<96; i*=2) {
287 if (temp_hyst != i2c_smbus_read_word_data(client,
288 LM92_REG_TEMP_HYST + i - 16)
289 || temp_crit != i2c_smbus_read_word_data(client,
290 LM92_REG_TEMP_CRIT + i)
291 || temp_low != i2c_smbus_read_word_data(client,
292 LM92_REG_TEMP_LOW + i + 16)
293 || temp_high != i2c_smbus_read_word_data(client,
294 LM92_REG_TEMP_HIGH + i + 32)
295 || conf != i2c_smbus_read_byte_data(client,
296 LM92_REG_CONFIG + i))
297 return 0;
300 return 1;
303 static struct attribute *lm92_attributes[] = {
304 &dev_attr_temp1_input.attr,
305 &dev_attr_temp1_crit.attr,
306 &dev_attr_temp1_crit_hyst.attr,
307 &dev_attr_temp1_min.attr,
308 &dev_attr_temp1_min_hyst.attr,
309 &dev_attr_temp1_max.attr,
310 &dev_attr_temp1_max_hyst.attr,
311 &dev_attr_alarms.attr,
312 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
313 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
314 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
315 NULL
318 static const struct attribute_group lm92_group = {
319 .attrs = lm92_attributes,
322 /* The following function does more than just detection. If detection
323 succeeds, it also registers the new chip. */
324 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
326 struct i2c_client *new_client;
327 struct lm92_data *data;
328 int err = 0;
329 char *name;
331 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
332 | I2C_FUNC_SMBUS_WORD_DATA))
333 goto exit;
335 if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
336 err = -ENOMEM;
337 goto exit;
340 /* Fill in enough client fields so that we can read from the chip,
341 which is required for identication */
342 new_client = &data->client;
343 i2c_set_clientdata(new_client, data);
344 new_client->addr = address;
345 new_client->adapter = adapter;
346 new_client->driver = &lm92_driver;
347 new_client->flags = 0;
349 /* A negative kind means that the driver was loaded with no force
350 parameter (default), so we must identify the chip. */
351 if (kind < 0) {
352 u8 config = i2c_smbus_read_byte_data(new_client,
353 LM92_REG_CONFIG);
354 u16 man_id = i2c_smbus_read_word_data(new_client,
355 LM92_REG_MAN_ID);
357 if ((config & 0xe0) == 0x00
358 && man_id == 0x0180) {
359 pr_info("lm92: Found National Semiconductor LM92 chip\n");
360 kind = lm92;
361 } else
362 if (max6635_check(new_client)) {
363 pr_info("lm92: Found Maxim MAX6635 chip\n");
364 kind = lm92; /* No separate prefix */
366 else
367 goto exit_free;
368 } else
369 if (kind == 0) /* Default to an LM92 if forced */
370 kind = lm92;
372 /* Give it the proper name */
373 if (kind == lm92) {
374 name = "lm92";
375 } else { /* Supposedly cannot happen */
376 dev_dbg(&new_client->dev, "Kind out of range?\n");
377 goto exit_free;
380 /* Fill in the remaining client fields */
381 strlcpy(new_client->name, name, I2C_NAME_SIZE);
382 data->valid = 0;
383 mutex_init(&data->update_lock);
385 /* Tell the i2c subsystem a new client has arrived */
386 if ((err = i2c_attach_client(new_client)))
387 goto exit_free;
389 /* Initialize the chipset */
390 lm92_init_client(new_client);
392 /* Register sysfs hooks */
393 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group)))
394 goto exit_detach;
396 data->hwmon_dev = hwmon_device_register(&new_client->dev);
397 if (IS_ERR(data->hwmon_dev)) {
398 err = PTR_ERR(data->hwmon_dev);
399 goto exit_remove;
402 return 0;
404 exit_remove:
405 sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
406 exit_detach:
407 i2c_detach_client(new_client);
408 exit_free:
409 kfree(data);
410 exit:
411 return err;
414 static int lm92_attach_adapter(struct i2c_adapter *adapter)
416 if (!(adapter->class & I2C_CLASS_HWMON))
417 return 0;
418 return i2c_probe(adapter, &addr_data, lm92_detect);
421 static int lm92_detach_client(struct i2c_client *client)
423 struct lm92_data *data = i2c_get_clientdata(client);
424 int err;
426 hwmon_device_unregister(data->hwmon_dev);
427 sysfs_remove_group(&client->dev.kobj, &lm92_group);
429 if ((err = i2c_detach_client(client)))
430 return err;
432 kfree(data);
433 return 0;
438 * Module and driver stuff
441 static struct i2c_driver lm92_driver = {
442 .driver = {
443 .name = "lm92",
445 .attach_adapter = lm92_attach_adapter,
446 .detach_client = lm92_detach_client,
449 static int __init sensors_lm92_init(void)
451 return i2c_add_driver(&lm92_driver);
454 static void __exit sensors_lm92_exit(void)
456 i2c_del_driver(&lm92_driver);
459 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
460 MODULE_DESCRIPTION("LM92/MAX6635 driver");
461 MODULE_LICENSE("GPL");
463 module_init(sensors_lm92_init);
464 module_exit(sensors_lm92_exit);