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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 | #include <linux/jiffies.h> |
52 | |
53 | /* |
54 | * The LM92 and MAX6635 have 2 two-state pins for address selection, |
55 | * resulting in 4 possible addresses. |
56 | */ |
57 | static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, |
58 | I2C_CLIENT_END }; |
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 | /* |
70 | * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius, |
71 | * left-justified in 16-bit registers. No rounding is done, with such |
72 | * a resolution it's just not worth it. Note that the MAX6635 doesn't |
73 | * make use of the 4 lower bits for limits (i.e. effective resolution |
74 | * for limits is 1 degree Celsius). |
75 | */ |
76 | static inline int TEMP_FROM_REG(s16 reg) |
77 | { |
78 | return reg / 8 * 625 / 10; |
79 | } |
80 | |
81 | static inline s16 TEMP_TO_REG(int val) |
82 | { |
83 | if (val <= -60000) |
84 | return -60000 * 10 / 625 * 8; |
85 | if (val >= 160000) |
86 | return 160000 * 10 / 625 * 8; |
87 | return val * 10 / 625 * 8; |
88 | } |
89 | |
90 | /* Alarm flags are stored in the 3 LSB of the temperature register */ |
91 | static inline u8 ALARMS_FROM_REG(s16 reg) |
92 | { |
93 | return reg & 0x0007; |
94 | } |
95 | |
96 | /* Driver data (common to all clients) */ |
97 | static struct i2c_driver lm92_driver; |
98 | |
99 | /* Client data (each client gets its own) */ |
100 | struct lm92_data { |
101 | struct device *hwmon_dev; |
102 | struct mutex update_lock; |
103 | char valid; /* zero until following fields are valid */ |
104 | unsigned long last_updated; /* in jiffies */ |
105 | |
106 | /* registers values */ |
107 | s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst; |
108 | }; |
109 | |
110 | |
111 | /* |
112 | * Sysfs attributes and callback functions |
113 | */ |
114 | |
115 | static struct lm92_data *lm92_update_device(struct device *dev) |
116 | { |
117 | struct i2c_client *client = to_i2c_client(dev); |
118 | struct lm92_data *data = i2c_get_clientdata(client); |
119 | |
120 | mutex_lock(&data->update_lock); |
121 | |
122 | if (time_after(jiffies, data->last_updated + HZ) |
123 | || !data->valid) { |
124 | dev_dbg(&client->dev, "Updating lm92 data\n"); |
125 | data->temp1_input = i2c_smbus_read_word_swapped(client, |
126 | LM92_REG_TEMP); |
127 | data->temp1_hyst = i2c_smbus_read_word_swapped(client, |
128 | LM92_REG_TEMP_HYST); |
129 | data->temp1_crit = i2c_smbus_read_word_swapped(client, |
130 | LM92_REG_TEMP_CRIT); |
131 | data->temp1_min = i2c_smbus_read_word_swapped(client, |
132 | LM92_REG_TEMP_LOW); |
133 | data->temp1_max = i2c_smbus_read_word_swapped(client, |
134 | LM92_REG_TEMP_HIGH); |
135 | |
136 | data->last_updated = jiffies; |
137 | data->valid = 1; |
138 | } |
139 | |
140 | mutex_unlock(&data->update_lock); |
141 | |
142 | return data; |
143 | } |
144 | |
145 | #define show_temp(value) \ |
146 | static ssize_t show_##value(struct device *dev, struct device_attribute *attr, \ |
147 | char *buf) \ |
148 | { \ |
149 | struct lm92_data *data = lm92_update_device(dev); \ |
150 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ |
151 | } |
152 | show_temp(temp1_input); |
153 | show_temp(temp1_crit); |
154 | show_temp(temp1_min); |
155 | show_temp(temp1_max); |
156 | |
157 | #define set_temp(value, reg) \ |
158 | static ssize_t set_##value(struct device *dev, struct device_attribute *attr, \ |
159 | const char *buf, \ |
160 | size_t count) \ |
161 | { \ |
162 | struct i2c_client *client = to_i2c_client(dev); \ |
163 | struct lm92_data *data = i2c_get_clientdata(client); \ |
164 | long val; \ |
165 | int err = kstrtol(buf, 10, &val); \ |
166 | if (err) \ |
167 | return err; \ |
168 | \ |
169 | mutex_lock(&data->update_lock); \ |
170 | data->value = TEMP_TO_REG(val); \ |
171 | i2c_smbus_write_word_swapped(client, reg, data->value); \ |
172 | mutex_unlock(&data->update_lock); \ |
173 | return count; \ |
174 | } |
175 | set_temp(temp1_crit, LM92_REG_TEMP_CRIT); |
176 | set_temp(temp1_min, LM92_REG_TEMP_LOW); |
177 | set_temp(temp1_max, LM92_REG_TEMP_HIGH); |
178 | |
179 | static ssize_t show_temp1_crit_hyst(struct device *dev, |
180 | struct device_attribute *attr, char *buf) |
181 | { |
182 | struct lm92_data *data = lm92_update_device(dev); |
183 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit) |
184 | - TEMP_FROM_REG(data->temp1_hyst)); |
185 | } |
186 | static ssize_t show_temp1_max_hyst(struct device *dev, |
187 | struct device_attribute *attr, char *buf) |
188 | { |
189 | struct lm92_data *data = lm92_update_device(dev); |
190 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) |
191 | - TEMP_FROM_REG(data->temp1_hyst)); |
192 | } |
193 | static ssize_t show_temp1_min_hyst(struct device *dev, |
194 | struct device_attribute *attr, char *buf) |
195 | { |
196 | struct lm92_data *data = lm92_update_device(dev); |
197 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) |
198 | + TEMP_FROM_REG(data->temp1_hyst)); |
199 | } |
200 | |
201 | static ssize_t set_temp1_crit_hyst(struct device *dev, |
202 | struct device_attribute *attr, |
203 | const char *buf, size_t count) |
204 | { |
205 | struct i2c_client *client = to_i2c_client(dev); |
206 | struct lm92_data *data = i2c_get_clientdata(client); |
207 | long val; |
208 | int err; |
209 | |
210 | err = kstrtol(buf, 10, &val); |
211 | if (err) |
212 | return err; |
213 | |
214 | mutex_lock(&data->update_lock); |
215 | data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; |
216 | i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST, |
217 | TEMP_TO_REG(data->temp1_hyst)); |
218 | mutex_unlock(&data->update_lock); |
219 | return count; |
220 | } |
221 | |
222 | static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, |
223 | char *buf) |
224 | { |
225 | struct lm92_data *data = lm92_update_device(dev); |
226 | return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); |
227 | } |
228 | |
229 | static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, |
230 | char *buf) |
231 | { |
232 | int bitnr = to_sensor_dev_attr(attr)->index; |
233 | struct lm92_data *data = lm92_update_device(dev); |
234 | return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1); |
235 | } |
236 | |
237 | static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); |
238 | static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, |
239 | set_temp1_crit); |
240 | static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, |
241 | set_temp1_crit_hyst); |
242 | static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, |
243 | set_temp1_min); |
244 | static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); |
245 | static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, |
246 | set_temp1_max); |
247 | static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); |
248 | static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); |
249 | static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); |
250 | static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); |
251 | static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); |
252 | |
253 | |
254 | /* |
255 | * Detection and registration |
256 | */ |
257 | |
258 | static void lm92_init_client(struct i2c_client *client) |
259 | { |
260 | u8 config; |
261 | |
262 | /* Start the conversions if needed */ |
263 | config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); |
264 | if (config & 0x01) |
265 | i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, |
266 | config & 0xFE); |
267 | } |
268 | |
269 | /* |
270 | * The MAX6635 has no identification register, so we have to use tricks |
271 | * to identify it reliably. This is somewhat slow. |
272 | * Note that we do NOT rely on the 2 MSB of the configuration register |
273 | * always reading 0, as suggested by the datasheet, because it was once |
274 | * reported not to be true. |
275 | */ |
276 | static int max6635_check(struct i2c_client *client) |
277 | { |
278 | u16 temp_low, temp_high, temp_hyst, temp_crit; |
279 | u8 conf; |
280 | int i; |
281 | |
282 | /* |
283 | * No manufacturer ID register, so a read from this address will |
284 | * always return the last read value. |
285 | */ |
286 | temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); |
287 | if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) |
288 | return 0; |
289 | temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); |
290 | if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) |
291 | return 0; |
292 | |
293 | /* Limits are stored as integer values (signed, 9-bit). */ |
294 | if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) |
295 | return 0; |
296 | temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); |
297 | temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); |
298 | if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) |
299 | return 0; |
300 | |
301 | /* |
302 | * Registers addresses were found to cycle over 16-byte boundaries. |
303 | * We don't test all registers with all offsets so as to save some |
304 | * reads and time, but this should still be sufficient to dismiss |
305 | * non-MAX6635 chips. |
306 | */ |
307 | conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); |
308 | for (i = 16; i < 96; i *= 2) { |
309 | if (temp_hyst != i2c_smbus_read_word_data(client, |
310 | LM92_REG_TEMP_HYST + i - 16) |
311 | || temp_crit != i2c_smbus_read_word_data(client, |
312 | LM92_REG_TEMP_CRIT + i) |
313 | || temp_low != i2c_smbus_read_word_data(client, |
314 | LM92_REG_TEMP_LOW + i + 16) |
315 | || temp_high != i2c_smbus_read_word_data(client, |
316 | LM92_REG_TEMP_HIGH + i + 32) |
317 | || conf != i2c_smbus_read_byte_data(client, |
318 | LM92_REG_CONFIG + i)) |
319 | return 0; |
320 | } |
321 | |
322 | return 1; |
323 | } |
324 | |
325 | static struct attribute *lm92_attributes[] = { |
326 | &dev_attr_temp1_input.attr, |
327 | &dev_attr_temp1_crit.attr, |
328 | &dev_attr_temp1_crit_hyst.attr, |
329 | &dev_attr_temp1_min.attr, |
330 | &dev_attr_temp1_min_hyst.attr, |
331 | &dev_attr_temp1_max.attr, |
332 | &dev_attr_temp1_max_hyst.attr, |
333 | &dev_attr_alarms.attr, |
334 | &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, |
335 | &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, |
336 | &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, |
337 | NULL |
338 | }; |
339 | |
340 | static const struct attribute_group lm92_group = { |
341 | .attrs = lm92_attributes, |
342 | }; |
343 | |
344 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
345 | static int lm92_detect(struct i2c_client *new_client, |
346 | struct i2c_board_info *info) |
347 | { |
348 | struct i2c_adapter *adapter = new_client->adapter; |
349 | u8 config; |
350 | u16 man_id; |
351 | |
352 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
353 | | I2C_FUNC_SMBUS_WORD_DATA)) |
354 | return -ENODEV; |
355 | |
356 | config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG); |
357 | man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID); |
358 | |
359 | if ((config & 0xe0) == 0x00 && man_id == 0x0180) |
360 | pr_info("lm92: Found National Semiconductor LM92 chip\n"); |
361 | else if (max6635_check(new_client)) |
362 | pr_info("lm92: Found Maxim MAX6635 chip\n"); |
363 | else |
364 | return -ENODEV; |
365 | |
366 | strlcpy(info->type, "lm92", I2C_NAME_SIZE); |
367 | |
368 | return 0; |
369 | } |
370 | |
371 | static int lm92_probe(struct i2c_client *new_client, |
372 | const struct i2c_device_id *id) |
373 | { |
374 | struct lm92_data *data; |
375 | int err; |
376 | |
377 | data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data), |
378 | GFP_KERNEL); |
379 | if (!data) |
380 | return -ENOMEM; |
381 | |
382 | i2c_set_clientdata(new_client, data); |
383 | data->valid = 0; |
384 | mutex_init(&data->update_lock); |
385 | |
386 | /* Initialize the chipset */ |
387 | lm92_init_client(new_client); |
388 | |
389 | /* Register sysfs hooks */ |
390 | err = sysfs_create_group(&new_client->dev.kobj, &lm92_group); |
391 | if (err) |
392 | return err; |
393 | |
394 | data->hwmon_dev = hwmon_device_register(&new_client->dev); |
395 | if (IS_ERR(data->hwmon_dev)) { |
396 | err = PTR_ERR(data->hwmon_dev); |
397 | goto exit_remove; |
398 | } |
399 | |
400 | return 0; |
401 | |
402 | exit_remove: |
403 | sysfs_remove_group(&new_client->dev.kobj, &lm92_group); |
404 | return err; |
405 | } |
406 | |
407 | static int lm92_remove(struct i2c_client *client) |
408 | { |
409 | struct lm92_data *data = i2c_get_clientdata(client); |
410 | |
411 | hwmon_device_unregister(data->hwmon_dev); |
412 | sysfs_remove_group(&client->dev.kobj, &lm92_group); |
413 | |
414 | return 0; |
415 | } |
416 | |
417 | |
418 | /* |
419 | * Module and driver stuff |
420 | */ |
421 | |
422 | static const struct i2c_device_id lm92_id[] = { |
423 | { "lm92", 0 }, |
424 | /* max6635 could be added here */ |
425 | { } |
426 | }; |
427 | MODULE_DEVICE_TABLE(i2c, lm92_id); |
428 | |
429 | static struct i2c_driver lm92_driver = { |
430 | .class = I2C_CLASS_HWMON, |
431 | .driver = { |
432 | .name = "lm92", |
433 | }, |
434 | .probe = lm92_probe, |
435 | .remove = lm92_remove, |
436 | .id_table = lm92_id, |
437 | .detect = lm92_detect, |
438 | .address_list = normal_i2c, |
439 | }; |
440 | |
441 | module_i2c_driver(lm92_driver); |
442 | |
443 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); |
444 | MODULE_DESCRIPTION("LM92/MAX6635 driver"); |
445 | MODULE_LICENSE("GPL"); |
446 |
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