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 /* 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 */
65
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). */
TEMP_FROM_REG(s16 reg)71 static inline int TEMP_FROM_REG(s16 reg)
72 {
73 return reg / 8 * 625 / 10;
74 }
75
TEMP_TO_REG(int val)76 static inline s16 TEMP_TO_REG(int val)
77 {
78 if (val <= -60000)
79 return -60000 * 10 / 625 * 8;
80 if (val >= 160000)
81 return 160000 * 10 / 625 * 8;
82 return val * 10 / 625 * 8;
83 }
84
85 /* Alarm flags are stored in the 3 LSB of the temperature register */
ALARMS_FROM_REG(s16 reg)86 static inline u8 ALARMS_FROM_REG(s16 reg)
87 {
88 return reg & 0x0007;
89 }
90
91 /* Driver data (common to all clients) */
92 static struct i2c_driver lm92_driver;
93
94 /* Client data (each client gets its own) */
95 struct lm92_data {
96 struct device *hwmon_dev;
97 struct mutex update_lock;
98 char valid; /* zero until following fields are valid */
99 unsigned long last_updated; /* in jiffies */
100
101 /* registers values */
102 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
103 };
104
105
106 /*
107 * Sysfs attributes and callback functions
108 */
109
lm92_update_device(struct device * dev)110 static struct lm92_data *lm92_update_device(struct device *dev)
111 {
112 struct i2c_client *client = to_i2c_client(dev);
113 struct lm92_data *data = i2c_get_clientdata(client);
114
115 mutex_lock(&data->update_lock);
116
117 if (time_after(jiffies, data->last_updated + HZ)
118 || !data->valid) {
119 dev_dbg(&client->dev, "Updating lm92 data\n");
120 data->temp1_input = swab16(i2c_smbus_read_word_data(client,
121 LM92_REG_TEMP));
122 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
123 LM92_REG_TEMP_HYST));
124 data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
125 LM92_REG_TEMP_CRIT));
126 data->temp1_min = swab16(i2c_smbus_read_word_data(client,
127 LM92_REG_TEMP_LOW));
128 data->temp1_max = swab16(i2c_smbus_read_word_data(client,
129 LM92_REG_TEMP_HIGH));
130
131 data->last_updated = jiffies;
132 data->valid = 1;
133 }
134
135 mutex_unlock(&data->update_lock);
136
137 return data;
138 }
139
140 #define show_temp(value) \
141 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
142 { \
143 struct lm92_data *data = lm92_update_device(dev); \
144 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
145 }
146 show_temp(temp1_input);
147 show_temp(temp1_crit);
148 show_temp(temp1_min);
149 show_temp(temp1_max);
150
151 #define set_temp(value, reg) \
152 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
153 size_t count) \
154 { \
155 struct i2c_client *client = to_i2c_client(dev); \
156 struct lm92_data *data = i2c_get_clientdata(client); \
157 long val = simple_strtol(buf, NULL, 10); \
158 \
159 mutex_lock(&data->update_lock); \
160 data->value = TEMP_TO_REG(val); \
161 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
162 mutex_unlock(&data->update_lock); \
163 return count; \
164 }
165 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
166 set_temp(temp1_min, LM92_REG_TEMP_LOW);
167 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
168
show_temp1_crit_hyst(struct device * dev,struct device_attribute * attr,char * buf)169 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
170 {
171 struct lm92_data *data = lm92_update_device(dev);
172 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
173 - TEMP_FROM_REG(data->temp1_hyst));
174 }
show_temp1_max_hyst(struct device * dev,struct device_attribute * attr,char * buf)175 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
176 {
177 struct lm92_data *data = lm92_update_device(dev);
178 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
179 - TEMP_FROM_REG(data->temp1_hyst));
180 }
show_temp1_min_hyst(struct device * dev,struct device_attribute * attr,char * buf)181 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
182 {
183 struct lm92_data *data = lm92_update_device(dev);
184 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
185 + TEMP_FROM_REG(data->temp1_hyst));
186 }
187
set_temp1_crit_hyst(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)188 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
189 size_t count)
190 {
191 struct i2c_client *client = to_i2c_client(dev);
192 struct lm92_data *data = i2c_get_clientdata(client);
193 long val = simple_strtol(buf, NULL, 10);
194
195 mutex_lock(&data->update_lock);
196 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
197 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
198 swab16(TEMP_TO_REG(data->temp1_hyst)));
199 mutex_unlock(&data->update_lock);
200 return count;
201 }
202
show_alarms(struct device * dev,struct device_attribute * attr,char * buf)203 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
204 {
205 struct lm92_data *data = lm92_update_device(dev);
206 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
207 }
208
show_alarm(struct device * dev,struct device_attribute * attr,char * buf)209 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
210 char *buf)
211 {
212 int bitnr = to_sensor_dev_attr(attr)->index;
213 struct lm92_data *data = lm92_update_device(dev);
214 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
215 }
216
217 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
218 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
219 set_temp1_crit);
220 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
221 set_temp1_crit_hyst);
222 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
223 set_temp1_min);
224 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
225 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
226 set_temp1_max);
227 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
228 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
229 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
230 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
231 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
232
233
234 /*
235 * Detection and registration
236 */
237
lm92_init_client(struct i2c_client * client)238 static void lm92_init_client(struct i2c_client *client)
239 {
240 u8 config;
241
242 /* Start the conversions if needed */
243 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
244 if (config & 0x01)
245 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
246 config & 0xFE);
247 }
248
249 /* The MAX6635 has no identification register, so we have to use tricks
250 to identify it reliably. This is somewhat slow.
251 Note that we do NOT rely on the 2 MSB of the configuration register
252 always reading 0, as suggested by the datasheet, because it was once
253 reported not to be true. */
max6635_check(struct i2c_client * client)254 static int max6635_check(struct i2c_client *client)
255 {
256 u16 temp_low, temp_high, temp_hyst, temp_crit;
257 u8 conf;
258 int i;
259
260 /* No manufacturer ID register, so a read from this address will
261 always return the last read value. */
262 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
263 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
264 return 0;
265 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
266 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
267 return 0;
268
269 /* Limits are stored as integer values (signed, 9-bit). */
270 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
271 return 0;
272 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
273 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
274 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
275 return 0;
276
277 /* Registers addresses were found to cycle over 16-byte boundaries.
278 We don't test all registers with all offsets so as to save some
279 reads and time, but this should still be sufficient to dismiss
280 non-MAX6635 chips. */
281 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
282 for (i=16; i<96; i*=2) {
283 if (temp_hyst != i2c_smbus_read_word_data(client,
284 LM92_REG_TEMP_HYST + i - 16)
285 || temp_crit != i2c_smbus_read_word_data(client,
286 LM92_REG_TEMP_CRIT + i)
287 || temp_low != i2c_smbus_read_word_data(client,
288 LM92_REG_TEMP_LOW + i + 16)
289 || temp_high != i2c_smbus_read_word_data(client,
290 LM92_REG_TEMP_HIGH + i + 32)
291 || conf != i2c_smbus_read_byte_data(client,
292 LM92_REG_CONFIG + i))
293 return 0;
294 }
295
296 return 1;
297 }
298
299 static struct attribute *lm92_attributes[] = {
300 &dev_attr_temp1_input.attr,
301 &dev_attr_temp1_crit.attr,
302 &dev_attr_temp1_crit_hyst.attr,
303 &dev_attr_temp1_min.attr,
304 &dev_attr_temp1_min_hyst.attr,
305 &dev_attr_temp1_max.attr,
306 &dev_attr_temp1_max_hyst.attr,
307 &dev_attr_alarms.attr,
308 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
309 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
310 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
311 NULL
312 };
313
314 static const struct attribute_group lm92_group = {
315 .attrs = lm92_attributes,
316 };
317
318 /* Return 0 if detection is successful, -ENODEV otherwise */
lm92_detect(struct i2c_client * new_client,struct i2c_board_info * info)319 static int lm92_detect(struct i2c_client *new_client,
320 struct i2c_board_info *info)
321 {
322 struct i2c_adapter *adapter = new_client->adapter;
323 u8 config;
324 u16 man_id;
325
326 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
327 | I2C_FUNC_SMBUS_WORD_DATA))
328 return -ENODEV;
329
330 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
331 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
332
333 if ((config & 0xe0) == 0x00 && man_id == 0x0180)
334 pr_info("lm92: Found National Semiconductor LM92 chip\n");
335 else if (max6635_check(new_client))
336 pr_info("lm92: Found Maxim MAX6635 chip\n");
337 else
338 return -ENODEV;
339
340 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
341
342 return 0;
343 }
344
lm92_probe(struct i2c_client * new_client,const struct i2c_device_id * id)345 static int lm92_probe(struct i2c_client *new_client,
346 const struct i2c_device_id *id)
347 {
348 struct lm92_data *data;
349 int err;
350
351 data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL);
352 if (!data) {
353 err = -ENOMEM;
354 goto exit;
355 }
356
357 i2c_set_clientdata(new_client, data);
358 data->valid = 0;
359 mutex_init(&data->update_lock);
360
361 /* Initialize the chipset */
362 lm92_init_client(new_client);
363
364 /* Register sysfs hooks */
365 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group)))
366 goto exit_free;
367
368 data->hwmon_dev = hwmon_device_register(&new_client->dev);
369 if (IS_ERR(data->hwmon_dev)) {
370 err = PTR_ERR(data->hwmon_dev);
371 goto exit_remove;
372 }
373
374 return 0;
375
376 exit_remove:
377 sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
378 exit_free:
379 kfree(data);
380 exit:
381 return err;
382 }
383
lm92_remove(struct i2c_client * client)384 static int lm92_remove(struct i2c_client *client)
385 {
386 struct lm92_data *data = i2c_get_clientdata(client);
387
388 hwmon_device_unregister(data->hwmon_dev);
389 sysfs_remove_group(&client->dev.kobj, &lm92_group);
390
391 kfree(data);
392 return 0;
393 }
394
395
396 /*
397 * Module and driver stuff
398 */
399
400 static const struct i2c_device_id lm92_id[] = {
401 { "lm92", 0 },
402 /* max6635 could be added here */
403 { }
404 };
405 MODULE_DEVICE_TABLE(i2c, lm92_id);
406
407 static struct i2c_driver lm92_driver = {
408 .class = I2C_CLASS_HWMON,
409 .driver = {
410 .name = "lm92",
411 },
412 .probe = lm92_probe,
413 .remove = lm92_remove,
414 .id_table = lm92_id,
415 .detect = lm92_detect,
416 .address_list = normal_i2c,
417 };
418
sensors_lm92_init(void)419 static int __init sensors_lm92_init(void)
420 {
421 return i2c_add_driver(&lm92_driver);
422 }
423
sensors_lm92_exit(void)424 static void __exit sensors_lm92_exit(void)
425 {
426 i2c_del_driver(&lm92_driver);
427 }
428
429 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
430 MODULE_DESCRIPTION("LM92/MAX6635 driver");
431 MODULE_LICENSE("GPL");
432
433 module_init(sensors_lm92_init);
434 module_exit(sensors_lm92_exit);
435