1 /*
2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005-2008 Jean Delvare <khali@linux-fr.org>
4 *
5 * Based on the lm90 driver, with some ideas taken from the lm_sensors
6 * lm92 driver as well.
7 *
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
13 *
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
19 *
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.
23 *
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.
27 *
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.
32 *
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.
37 *
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.
41 */
42
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>
51
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 };
56
57 /* Insmod parameters */
58 I2C_CLIENT_INSMOD_1(lm92);
59
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 */
68
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)
75 {
76 return reg / 8 * 625 / 10;
77 }
78
79 static inline s16 TEMP_TO_REG(int val)
80 {
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;
86 }
87
88 /* Alarm flags are stored in the 3 LSB of the temperature register */
89 static inline u8 ALARMS_FROM_REG(s16 reg)
90 {
91 return reg & 0x0007;
92 }
93
94 /* Driver data (common to all clients) */
95 static struct i2c_driver lm92_driver;
96
97 /* Client data (each client gets its own) */
98 struct lm92_data {
99 struct device *hwmon_dev;
100 struct mutex update_lock;
101 char valid; /* zero until following fields are valid */
102 unsigned long last_updated; /* in jiffies */
103
104 /* registers values */
105 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
106 };
107
108
109 /*
110 * Sysfs attributes and callback functions
111 */
112
113 static struct lm92_data *lm92_update_device(struct device *dev)
114 {
115 struct i2c_client *client = to_i2c_client(dev);
116 struct lm92_data *data = i2c_get_clientdata(client);
117
118 mutex_lock(&data->update_lock);
119
120 if (time_after(jiffies, data->last_updated + HZ)
121 || !data->valid) {
122 dev_dbg(&client->dev, "Updating lm92 data\n");
123 data->temp1_input = swab16(i2c_smbus_read_word_data(client,
124 LM92_REG_TEMP));
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,
130 LM92_REG_TEMP_LOW));
131 data->temp1_max = swab16(i2c_smbus_read_word_data(client,
132 LM92_REG_TEMP_HIGH));
133
134 data->last_updated = jiffies;
135 data->valid = 1;
136 }
137
138 mutex_unlock(&data->update_lock);
139
140 return data;
141 }
142
143 #define show_temp(value) \
144 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
145 { \
146 struct lm92_data *data = lm92_update_device(dev); \
147 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
148 }
149 show_temp(temp1_input);
150 show_temp(temp1_crit);
151 show_temp(temp1_min);
152 show_temp(temp1_max);
153
154 #define set_temp(value, reg) \
155 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
156 size_t count) \
157 { \
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); \
161 \
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); \
166 return count; \
167 }
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);
171
172 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
173 {
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));
177 }
178 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
179 {
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));
183 }
184 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
185 {
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));
189 }
190
191 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
192 size_t count)
193 {
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);
197
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);
203 return count;
204 }
205
206 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
207 {
208 struct lm92_data *data = lm92_update_device(dev);
209 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
210 }
211
212 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
213 char *buf)
214 {
215 int bitnr = to_sensor_dev_attr(attr)->index;
216 struct lm92_data *data = lm92_update_device(dev);
217 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
218 }
219
220 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
221 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
222 set_temp1_crit);
223 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
224 set_temp1_crit_hyst);
225 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
226 set_temp1_min);
227 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
228 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
229 set_temp1_max);
230 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
231 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
232 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
233 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
234 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
235
236
237 /*
238 * Detection and registration
239 */
240
241 static void lm92_init_client(struct i2c_client *client)
242 {
243 u8 config;
244
245 /* Start the conversions if needed */
246 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
247 if (config & 0x01)
248 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
249 config & 0xFE);
250 }
251
252 /* The MAX6635 has no identification register, so we have to use tricks
253 to identify it reliably. This is somewhat slow.
254 Note that we do NOT rely on the 2 MSB of the configuration register
255 always reading 0, as suggested by the datasheet, because it was once
256 reported not to be true. */
257 static int max6635_check(struct i2c_client *client)
258 {
259 u16 temp_low, temp_high, temp_hyst, temp_crit;
260 u8 conf;
261 int i;
262
263 /* No manufacturer ID register, so a read from this address will
264 always return the last read value. */
265 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
266 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
267 return 0;
268 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
269 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
270 return 0;
271
272 /* Limits are stored as integer values (signed, 9-bit). */
273 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
274 return 0;
275 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
276 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
277 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
278 return 0;
279
280 /* Registers addresses were found to cycle over 16-byte boundaries.
281 We don't test all registers with all offsets so as to save some
282 reads and time, but this should still be sufficient to dismiss
283 non-MAX6635 chips. */
284 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
285 for (i=16; i<96; i*=2) {
286 if (temp_hyst != i2c_smbus_read_word_data(client,
287 LM92_REG_TEMP_HYST + i - 16)
288 || temp_crit != i2c_smbus_read_word_data(client,
289 LM92_REG_TEMP_CRIT + i)
290 || temp_low != i2c_smbus_read_word_data(client,
291 LM92_REG_TEMP_LOW + i + 16)
292 || temp_high != i2c_smbus_read_word_data(client,
293 LM92_REG_TEMP_HIGH + i + 32)
294 || conf != i2c_smbus_read_byte_data(client,
295 LM92_REG_CONFIG + i))
296 return 0;
297 }
298
299 return 1;
300 }
301
302 static struct attribute *lm92_attributes[] = {
303 &dev_attr_temp1_input.attr,
304 &dev_attr_temp1_crit.attr,
305 &dev_attr_temp1_crit_hyst.attr,
306 &dev_attr_temp1_min.attr,
307 &dev_attr_temp1_min_hyst.attr,
308 &dev_attr_temp1_max.attr,
309 &dev_attr_temp1_max_hyst.attr,
310 &dev_attr_alarms.attr,
311 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
312 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
313 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
314 NULL
315 };
316
317 static const struct attribute_group lm92_group = {
318 .attrs = lm92_attributes,
319 };
320
321 /* Return 0 if detection is successful, -ENODEV otherwise */
322 static int lm92_detect(struct i2c_client *new_client, int kind,
323 struct i2c_board_info *info)
324 {
325 struct i2c_adapter *adapter = new_client->adapter;
326
327 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
328 | I2C_FUNC_SMBUS_WORD_DATA))
329 return -ENODEV;
330
331 /* A negative kind means that the driver was loaded with no force
332 parameter (default), so we must identify the chip. */
333 if (kind < 0) {
334 u8 config = i2c_smbus_read_byte_data(new_client,
335 LM92_REG_CONFIG);
336 u16 man_id = i2c_smbus_read_word_data(new_client,
337 LM92_REG_MAN_ID);
338
339 if ((config & 0xe0) == 0x00
340 && man_id == 0x0180) {
341 pr_info("lm92: Found National Semiconductor LM92 chip\n");
342 kind = lm92;
343 } else
344 if (max6635_check(new_client)) {
345 pr_info("lm92: Found Maxim MAX6635 chip\n");
346 kind = lm92; /* No separate prefix */
347 }
348 else
349 return -ENODEV;
350 }
351
352 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
353
354 return 0;
355 }
356
357 static int lm92_probe(struct i2c_client *new_client,
358 const struct i2c_device_id *id)
359 {
360 struct lm92_data *data;
361 int err;
362
363 data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL);
364 if (!data) {
365 err = -ENOMEM;
366 goto exit;
367 }
368
369 i2c_set_clientdata(new_client, data);
370 data->valid = 0;
371 mutex_init(&data->update_lock);
372
373 /* Initialize the chipset */
374 lm92_init_client(new_client);
375
376 /* Register sysfs hooks */
377 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group)))
378 goto exit_free;
379
380 data->hwmon_dev = hwmon_device_register(&new_client->dev);
381 if (IS_ERR(data->hwmon_dev)) {
382 err = PTR_ERR(data->hwmon_dev);
383 goto exit_remove;
384 }
385
386 return 0;
387
388 exit_remove:
389 sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
390 exit_free:
391 kfree(data);
392 exit:
393 return err;
394 }
395
396 static int lm92_remove(struct i2c_client *client)
397 {
398 struct lm92_data *data = i2c_get_clientdata(client);
399
400 hwmon_device_unregister(data->hwmon_dev);
401 sysfs_remove_group(&client->dev.kobj, &lm92_group);
402
403 kfree(data);
404 return 0;
405 }
406
407
408 /*
409 * Module and driver stuff
410 */
411
412 static const struct i2c_device_id lm92_id[] = {
413 { "lm92", lm92 },
414 /* max6635 could be added here */
415 { }
416 };
417 MODULE_DEVICE_TABLE(i2c, lm92_id);
418
419 static struct i2c_driver lm92_driver = {
420 .class = I2C_CLASS_HWMON,
421 .driver = {
422 .name = "lm92",
423 },
424 .probe = lm92_probe,
425 .remove = lm92_remove,
426 .id_table = lm92_id,
427 .detect = lm92_detect,
428 .address_data = &addr_data,
429 };
430
431 static int __init sensors_lm92_init(void)
432 {
433 return i2c_add_driver(&lm92_driver);
434 }
435
436 static void __exit sensors_lm92_exit(void)
437 {
438 i2c_del_driver(&lm92_driver);
439 }
440
441 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
442 MODULE_DESCRIPTION("LM92/MAX6635 driver");
443 MODULE_LICENSE("GPL");
444
445 module_init(sensors_lm92_init);
446 module_exit(sensors_lm92_exit);
447
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