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1 | /* | |
2 | * lm92 - Hardware monitoring driver | |
3 | * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de> | |
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 | ||
39 | #include <linux/module.h> | |
40 | #include <linux/init.h> | |
41 | #include <linux/slab.h> | |
42 | #include <linux/i2c.h> | |
43 | #include <linux/hwmon.h> | |
44 | #include <linux/hwmon-sysfs.h> | |
45 | #include <linux/err.h> | |
46 | #include <linux/mutex.h> | |
47 | #include <linux/jiffies.h> | |
48 | ||
49 | /* | |
50 | * The LM92 and MAX6635 have 2 two-state pins for address selection, | |
51 | * resulting in 4 possible addresses. | |
52 | */ | |
53 | static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, | |
54 | I2C_CLIENT_END }; | |
55 | ||
56 | /* The LM92 registers */ | |
57 | #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */ | |
58 | #define LM92_REG_TEMP 0x00 /* 16-bit, RO */ | |
59 | #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */ | |
60 | #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */ | |
61 | #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */ | |
62 | #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */ | |
63 | #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */ | |
64 | ||
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). | |
71 | */ | |
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(long val) | |
78 | { | |
79 | val = clamp_val(val, -60000, 160000); | |
80 | return val * 10 / 625 * 8; | |
81 | } | |
82 | ||
83 | /* Alarm flags are stored in the 3 LSB of the temperature register */ | |
84 | static inline u8 ALARMS_FROM_REG(s16 reg) | |
85 | { | |
86 | return reg & 0x0007; | |
87 | } | |
88 | ||
89 | enum temp_index { | |
90 | t_input, | |
91 | t_crit, | |
92 | t_min, | |
93 | t_max, | |
94 | t_hyst, | |
95 | t_num_regs | |
96 | }; | |
97 | ||
98 | static const u8 regs[t_num_regs] = { | |
99 | [t_input] = LM92_REG_TEMP, | |
100 | [t_crit] = LM92_REG_TEMP_CRIT, | |
101 | [t_min] = LM92_REG_TEMP_LOW, | |
102 | [t_max] = LM92_REG_TEMP_HIGH, | |
103 | [t_hyst] = LM92_REG_TEMP_HYST, | |
104 | }; | |
105 | ||
106 | /* Client data (each client gets its own) */ | |
107 | struct lm92_data { | |
108 | struct i2c_client *client; | |
109 | struct mutex update_lock; | |
110 | char valid; /* zero until following fields are valid */ | |
111 | unsigned long last_updated; /* in jiffies */ | |
112 | ||
113 | /* registers values */ | |
114 | s16 temp[t_num_regs]; /* index with enum temp_index */ | |
115 | }; | |
116 | ||
117 | /* | |
118 | * Sysfs attributes and callback functions | |
119 | */ | |
120 | ||
121 | static struct lm92_data *lm92_update_device(struct device *dev) | |
122 | { | |
123 | struct lm92_data *data = dev_get_drvdata(dev); | |
124 | struct i2c_client *client = data->client; | |
125 | int i; | |
126 | ||
127 | mutex_lock(&data->update_lock); | |
128 | ||
129 | if (time_after(jiffies, data->last_updated + HZ) | |
130 | || !data->valid) { | |
131 | dev_dbg(&client->dev, "Updating lm92 data\n"); | |
132 | for (i = 0; i < t_num_regs; i++) { | |
133 | data->temp[i] = | |
134 | i2c_smbus_read_word_swapped(client, regs[i]); | |
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 | static ssize_t show_temp(struct device *dev, struct device_attribute *devattr, | |
146 | char *buf) | |
147 | { | |
148 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); | |
149 | struct lm92_data *data = lm92_update_device(dev); | |
150 | ||
151 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])); | |
152 | } | |
153 | ||
154 | static ssize_t set_temp(struct device *dev, struct device_attribute *devattr, | |
155 | const char *buf, size_t count) | |
156 | { | |
157 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); | |
158 | struct lm92_data *data = dev_get_drvdata(dev); | |
159 | struct i2c_client *client = data->client; | |
160 | int nr = attr->index; | |
161 | long val; | |
162 | int err; | |
163 | ||
164 | err = kstrtol(buf, 10, &val); | |
165 | if (err) | |
166 | return err; | |
167 | ||
168 | mutex_lock(&data->update_lock); | |
169 | data->temp[nr] = TEMP_TO_REG(val); | |
170 | i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]); | |
171 | mutex_unlock(&data->update_lock); | |
172 | return count; | |
173 | } | |
174 | ||
175 | static ssize_t show_temp_hyst(struct device *dev, | |
176 | struct device_attribute *devattr, char *buf) | |
177 | { | |
178 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); | |
179 | struct lm92_data *data = lm92_update_device(dev); | |
180 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]) | |
181 | - TEMP_FROM_REG(data->temp[t_hyst])); | |
182 | } | |
183 | ||
184 | static ssize_t show_temp_min_hyst(struct device *dev, | |
185 | struct device_attribute *attr, char *buf) | |
186 | { | |
187 | struct lm92_data *data = lm92_update_device(dev); | |
188 | return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min]) | |
189 | + TEMP_FROM_REG(data->temp[t_hyst])); | |
190 | } | |
191 | ||
192 | static ssize_t set_temp_hyst(struct device *dev, | |
193 | struct device_attribute *devattr, | |
194 | const char *buf, size_t count) | |
195 | { | |
196 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); | |
197 | struct lm92_data *data = dev_get_drvdata(dev); | |
198 | struct i2c_client *client = data->client; | |
199 | long val; | |
200 | int err; | |
201 | ||
202 | err = kstrtol(buf, 10, &val); | |
203 | if (err) | |
204 | return err; | |
205 | ||
206 | val = clamp_val(val, -120000, 220000); | |
207 | mutex_lock(&data->update_lock); | |
208 | data->temp[t_hyst] = | |
209 | TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val); | |
210 | i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST, | |
211 | data->temp[t_hyst]); | |
212 | mutex_unlock(&data->update_lock); | |
213 | return count; | |
214 | } | |
215 | ||
216 | static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, | |
217 | char *buf) | |
218 | { | |
219 | struct lm92_data *data = lm92_update_device(dev); | |
220 | return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input])); | |
221 | } | |
222 | ||
223 | static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, | |
224 | char *buf) | |
225 | { | |
226 | int bitnr = to_sensor_dev_attr(attr)->index; | |
227 | struct lm92_data *data = lm92_update_device(dev); | |
228 | return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1); | |
229 | } | |
230 | ||
231 | static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input); | |
232 | static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp, | |
233 | t_crit); | |
234 | static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, | |
235 | set_temp_hyst, t_crit); | |
236 | static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, | |
237 | t_min); | |
238 | static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_min_hyst, NULL); | |
239 | static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, | |
240 | t_max); | |
241 | static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max); | |
242 | static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); | |
243 | static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); | |
244 | static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); | |
245 | static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); | |
246 | ||
247 | /* | |
248 | * Detection and registration | |
249 | */ | |
250 | ||
251 | static void lm92_init_client(struct i2c_client *client) | |
252 | { | |
253 | u8 config; | |
254 | ||
255 | /* Start the conversions if needed */ | |
256 | config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); | |
257 | if (config & 0x01) | |
258 | i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, | |
259 | config & 0xFE); | |
260 | } | |
261 | ||
262 | /* | |
263 | * The MAX6635 has no identification register, so we have to use tricks | |
264 | * to identify it reliably. This is somewhat slow. | |
265 | * Note that we do NOT rely on the 2 MSB of the configuration register | |
266 | * always reading 0, as suggested by the datasheet, because it was once | |
267 | * reported not to be true. | |
268 | */ | |
269 | static int max6635_check(struct i2c_client *client) | |
270 | { | |
271 | u16 temp_low, temp_high, temp_hyst, temp_crit; | |
272 | u8 conf; | |
273 | int i; | |
274 | ||
275 | /* | |
276 | * No manufacturer ID register, so a read from this address will | |
277 | * always return the last read value. | |
278 | */ | |
279 | temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); | |
280 | if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) | |
281 | return 0; | |
282 | temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); | |
283 | if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) | |
284 | return 0; | |
285 | ||
286 | /* Limits are stored as integer values (signed, 9-bit). */ | |
287 | if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) | |
288 | return 0; | |
289 | temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); | |
290 | temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); | |
291 | if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) | |
292 | return 0; | |
293 | ||
294 | /* | |
295 | * Registers addresses were found to cycle over 16-byte boundaries. | |
296 | * We don't test all registers with all offsets so as to save some | |
297 | * reads and time, but this should still be sufficient to dismiss | |
298 | * non-MAX6635 chips. | |
299 | */ | |
300 | conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); | |
301 | for (i = 16; i < 96; i *= 2) { | |
302 | if (temp_hyst != i2c_smbus_read_word_data(client, | |
303 | LM92_REG_TEMP_HYST + i - 16) | |
304 | || temp_crit != i2c_smbus_read_word_data(client, | |
305 | LM92_REG_TEMP_CRIT + i) | |
306 | || temp_low != i2c_smbus_read_word_data(client, | |
307 | LM92_REG_TEMP_LOW + i + 16) | |
308 | || temp_high != i2c_smbus_read_word_data(client, | |
309 | LM92_REG_TEMP_HIGH + i + 32) | |
310 | || conf != i2c_smbus_read_byte_data(client, | |
311 | LM92_REG_CONFIG + i)) | |
312 | return 0; | |
313 | } | |
314 | ||
315 | return 1; | |
316 | } | |
317 | ||
318 | static struct attribute *lm92_attrs[] = { | |
319 | &sensor_dev_attr_temp1_input.dev_attr.attr, | |
320 | &sensor_dev_attr_temp1_crit.dev_attr.attr, | |
321 | &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, | |
322 | &sensor_dev_attr_temp1_min.dev_attr.attr, | |
323 | &dev_attr_temp1_min_hyst.attr, | |
324 | &sensor_dev_attr_temp1_max.dev_attr.attr, | |
325 | &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, | |
326 | &dev_attr_alarms.attr, | |
327 | &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, | |
328 | &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, | |
329 | &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, | |
330 | NULL | |
331 | }; | |
332 | ATTRIBUTE_GROUPS(lm92); | |
333 | ||
334 | /* Return 0 if detection is successful, -ENODEV otherwise */ | |
335 | static int lm92_detect(struct i2c_client *new_client, | |
336 | struct i2c_board_info *info) | |
337 | { | |
338 | struct i2c_adapter *adapter = new_client->adapter; | |
339 | u8 config; | |
340 | u16 man_id; | |
341 | ||
342 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | |
343 | | I2C_FUNC_SMBUS_WORD_DATA)) | |
344 | return -ENODEV; | |
345 | ||
346 | config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG); | |
347 | man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID); | |
348 | ||
349 | if ((config & 0xe0) == 0x00 && man_id == 0x0180) | |
350 | pr_info("lm92: Found National Semiconductor LM92 chip\n"); | |
351 | else if (max6635_check(new_client)) | |
352 | pr_info("lm92: Found Maxim MAX6635 chip\n"); | |
353 | else | |
354 | return -ENODEV; | |
355 | ||
356 | strlcpy(info->type, "lm92", I2C_NAME_SIZE); | |
357 | ||
358 | return 0; | |
359 | } | |
360 | ||
361 | static int lm92_probe(struct i2c_client *new_client, | |
362 | const struct i2c_device_id *id) | |
363 | { | |
364 | struct device *hwmon_dev; | |
365 | struct lm92_data *data; | |
366 | ||
367 | data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data), | |
368 | GFP_KERNEL); | |
369 | if (!data) | |
370 | return -ENOMEM; | |
371 | ||
372 | data->client = new_client; | |
373 | mutex_init(&data->update_lock); | |
374 | ||
375 | /* Initialize the chipset */ | |
376 | lm92_init_client(new_client); | |
377 | ||
378 | hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev, | |
379 | new_client->name, | |
380 | data, lm92_groups); | |
381 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
382 | } | |
383 | ||
384 | ||
385 | /* | |
386 | * Module and driver stuff | |
387 | */ | |
388 | ||
389 | static const struct i2c_device_id lm92_id[] = { | |
390 | { "lm92", 0 }, | |
391 | /* max6635 could be added here */ | |
392 | { } | |
393 | }; | |
394 | MODULE_DEVICE_TABLE(i2c, lm92_id); | |
395 | ||
396 | static struct i2c_driver lm92_driver = { | |
397 | .class = I2C_CLASS_HWMON, | |
398 | .driver = { | |
399 | .name = "lm92", | |
400 | }, | |
401 | .probe = lm92_probe, | |
402 | .id_table = lm92_id, | |
403 | .detect = lm92_detect, | |
404 | .address_list = normal_i2c, | |
405 | }; | |
406 | ||
407 | module_i2c_driver(lm92_driver); | |
408 | ||
409 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); | |
410 | MODULE_DESCRIPTION("LM92/MAX6635 driver"); | |
411 | MODULE_LICENSE("GPL"); |