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1 /*
2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005 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/err.h>
49
50 /* The LM92 and MAX6635 have 2 two-state pins for address selection,
51 resulting in 4 possible addresses. */
52 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
53 I2C_CLIENT_END };
54
55 /* Insmod parameters */
56 I2C_CLIENT_INSMOD_1(lm92);
57
58 /* The LM92 registers */
59 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
60 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
61 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
62 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
63 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
64 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
65 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
66
67 /* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
68 left-justified in 16-bit registers. No rounding is done, with such
69 a resolution it's just not worth it. Note that the MAX6635 doesn't
70 make use of the 4 lower bits for limits (i.e. effective resolution
71 for limits is 1 degree Celsius). */
72 static inline int TEMP_FROM_REG(s16 reg)
73 {
74 return reg / 8 * 625 / 10;
75 }
76
77 static inline s16 TEMP_TO_REG(int val)
78 {
79 if (val <= -60000)
80 return -60000 * 10 / 625 * 8;
81 if (val >= 160000)
82 return 160000 * 10 / 625 * 8;
83 return val * 10 / 625 * 8;
84 }
85
86 /* Alarm flags are stored in the 3 LSB of the temperature register */
87 static inline u8 ALARMS_FROM_REG(s16 reg)
88 {
89 return reg & 0x0007;
90 }
91
92 /* Driver data (common to all clients) */
93 static struct i2c_driver lm92_driver;
94
95 /* Client data (each client gets its own) */
96 struct lm92_data {
97 struct i2c_client client;
98 struct class_device *class_dev;
99 struct semaphore update_lock;
100 char valid; /* zero until following fields are valid */
101 unsigned long last_updated; /* in jiffies */
102
103 /* registers values */
104 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
105 };
106
107
108 /*
109 * Sysfs attributes and callback functions
110 */
111
112 static struct lm92_data *lm92_update_device(struct device *dev)
113 {
114 struct i2c_client *client = to_i2c_client(dev);
115 struct lm92_data *data = i2c_get_clientdata(client);
116
117 down(&data->update_lock);
118
119 if (time_after(jiffies, data->last_updated + HZ)
120 || !data->valid) {
121 dev_dbg(&client->dev, "Updating lm92 data\n");
122 data->temp1_input = swab16(i2c_smbus_read_word_data(client,
123 LM92_REG_TEMP));
124 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
125 LM92_REG_TEMP_HYST));
126 data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
127 LM92_REG_TEMP_CRIT));
128 data->temp1_min = swab16(i2c_smbus_read_word_data(client,
129 LM92_REG_TEMP_LOW));
130 data->temp1_max = swab16(i2c_smbus_read_word_data(client,
131 LM92_REG_TEMP_HIGH));
132
133 data->last_updated = jiffies;
134 data->valid = 1;
135 }
136
137 up(&data->update_lock);
138
139 return data;
140 }
141
142 #define show_temp(value) \
143 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
144 { \
145 struct lm92_data *data = lm92_update_device(dev); \
146 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
147 }
148 show_temp(temp1_input);
149 show_temp(temp1_crit);
150 show_temp(temp1_min);
151 show_temp(temp1_max);
152
153 #define set_temp(value, reg) \
154 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
155 size_t count) \
156 { \
157 struct i2c_client *client = to_i2c_client(dev); \
158 struct lm92_data *data = i2c_get_clientdata(client); \
159 long val = simple_strtol(buf, NULL, 10); \
160 \
161 down(&data->update_lock); \
162 data->value = TEMP_TO_REG(val); \
163 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
164 up(&data->update_lock); \
165 return count; \
166 }
167 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
168 set_temp(temp1_min, LM92_REG_TEMP_LOW);
169 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
170
171 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
172 {
173 struct lm92_data *data = lm92_update_device(dev);
174 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
175 - TEMP_FROM_REG(data->temp1_hyst));
176 }
177 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
178 {
179 struct lm92_data *data = lm92_update_device(dev);
180 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
181 - TEMP_FROM_REG(data->temp1_hyst));
182 }
183 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
184 {
185 struct lm92_data *data = lm92_update_device(dev);
186 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
187 + TEMP_FROM_REG(data->temp1_hyst));
188 }
189
190 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
191 size_t count)
192 {
193 struct i2c_client *client = to_i2c_client(dev);
194 struct lm92_data *data = i2c_get_clientdata(client);
195 long val = simple_strtol(buf, NULL, 10);
196
197 down(&data->update_lock);
198 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
199 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
200 swab16(TEMP_TO_REG(data->temp1_hyst)));
201 up(&data->update_lock);
202 return count;
203 }
204
205 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
206 {
207 struct lm92_data *data = lm92_update_device(dev);
208 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
209 }
210
211 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
212 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
213 set_temp1_crit);
214 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
215 set_temp1_crit_hyst);
216 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
217 set_temp1_min);
218 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
219 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
220 set_temp1_max);
221 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
222 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
223
224
225 /*
226 * Detection and registration
227 */
228
229 static void lm92_init_client(struct i2c_client *client)
230 {
231 u8 config;
232
233 /* Start the conversions if needed */
234 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
235 if (config & 0x01)
236 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
237 config & 0xFE);
238 }
239
240 /* The MAX6635 has no identification register, so we have to use tricks
241 to identify it reliably. This is somewhat slow.
242 Note that we do NOT rely on the 2 MSB of the configuration register
243 always reading 0, as suggested by the datasheet, because it was once
244 reported not to be true. */
245 static int max6635_check(struct i2c_client *client)
246 {
247 u16 temp_low, temp_high, temp_hyst, temp_crit;
248 u8 conf;
249 int i;
250
251 /* No manufacturer ID register, so a read from this address will
252 always return the last read value. */
253 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
254 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
255 return 0;
256 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
257 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
258 return 0;
259
260 /* Limits are stored as integer values (signed, 9-bit). */
261 if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
262 return 0;
263 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
264 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
265 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
266 return 0;
267
268 /* Registers addresses were found to cycle over 16-byte boundaries.
269 We don't test all registers with all offsets so as to save some
270 reads and time, but this should still be sufficient to dismiss
271 non-MAX6635 chips. */
272 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
273 for (i=16; i<96; i*=2) {
274 if (temp_hyst != i2c_smbus_read_word_data(client,
275 LM92_REG_TEMP_HYST + i - 16)
276 || temp_crit != i2c_smbus_read_word_data(client,
277 LM92_REG_TEMP_CRIT + i)
278 || temp_low != i2c_smbus_read_word_data(client,
279 LM92_REG_TEMP_LOW + i + 16)
280 || temp_high != i2c_smbus_read_word_data(client,
281 LM92_REG_TEMP_HIGH + i + 32)
282 || conf != i2c_smbus_read_byte_data(client,
283 LM92_REG_CONFIG + i))
284 return 0;
285 }
286
287 return 1;
288 }
289
290 /* The following function does more than just detection. If detection
291 succeeds, it also registers the new chip. */
292 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
293 {
294 struct i2c_client *new_client;
295 struct lm92_data *data;
296 int err = 0;
297 char *name;
298
299 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
300 | I2C_FUNC_SMBUS_WORD_DATA))
301 goto exit;
302
303 if (!(data = kmalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
304 err = -ENOMEM;
305 goto exit;
306 }
307 memset(data, 0, sizeof(struct lm92_data));
308
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;
317
318 /* A negative kind means that the driver was loaded with no force
319 parameter (default), so we must identify the chip. */
320 if (kind < 0) {
321 u8 config = i2c_smbus_read_byte_data(new_client,
322 LM92_REG_CONFIG);
323 u16 man_id = i2c_smbus_read_word_data(new_client,
324 LM92_REG_MAN_ID);
325
326 if ((config & 0xe0) == 0x00
327 && man_id == 0x0180) {
328 pr_info("lm92: Found National Semiconductor LM92 chip\n");
329 kind = lm92;
330 } else
331 if (max6635_check(new_client)) {
332 pr_info("lm92: Found Maxim MAX6635 chip\n");
333 kind = lm92; /* No separate prefix */
334 }
335 else
336 goto exit_free;
337 } else
338 if (kind == 0) /* Default to an LM92 if forced */
339 kind = lm92;
340
341 /* Give it the proper name */
342 if (kind == lm92) {
343 name = "lm92";
344 } else { /* Supposedly cannot happen */
345 dev_dbg(&new_client->dev, "Kind out of range?\n");
346 goto exit_free;
347 }
348
349 /* Fill in the remaining client fields */
350 strlcpy(new_client->name, name, I2C_NAME_SIZE);
351 data->valid = 0;
352 init_MUTEX(&data->update_lock);
353
354 /* Tell the i2c subsystem a new client has arrived */
355 if ((err = i2c_attach_client(new_client)))
356 goto exit_free;
357
358 /* Initialize the chipset */
359 lm92_init_client(new_client);
360
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);
365 goto exit_detach;
366 }
367
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);
376
377 return 0;
378
379 exit_detach:
380 i2c_detach_client(new_client);
381 exit_free:
382 kfree(data);
383 exit:
384 return err;
385 }
386
387 static int lm92_attach_adapter(struct i2c_adapter *adapter)
388 {
389 if (!(adapter->class & I2C_CLASS_HWMON))
390 return 0;
391 return i2c_probe(adapter, &addr_data, lm92_detect);
392 }
393
394 static int lm92_detach_client(struct i2c_client *client)
395 {
396 struct lm92_data *data = i2c_get_clientdata(client);
397 int err;
398
399 hwmon_device_unregister(data->class_dev);
400
401 if ((err = i2c_detach_client(client)))
402 return err;
403
404 kfree(data);
405 return 0;
406 }
407
408
409 /*
410 * Module and driver stuff
411 */
412
413 static struct i2c_driver lm92_driver = {
414 .owner = THIS_MODULE,
415 .name = "lm92",
416 .id = I2C_DRIVERID_LM92,
417 .flags = I2C_DF_NOTIFY,
418 .attach_adapter = lm92_attach_adapter,
419 .detach_client = lm92_detach_client,
420 };
421
422 static int __init sensors_lm92_init(void)
423 {
424 return i2c_add_driver(&lm92_driver);
425 }
426
427 static void __exit sensors_lm92_exit(void)
428 {
429 i2c_del_driver(&lm92_driver);
430 }
431
432 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
433 MODULE_DESCRIPTION("LM92/MAX6635 driver");
434 MODULE_LICENSE("GPL");
435
436 module_init(sensors_lm92_init);
437 module_exit(sensors_lm92_exit);