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 */
TEMP_FROM_REG(s16 reg)72 static inline int TEMP_FROM_REG(s16 reg)
73 {
74 return reg / 8 * 625 / 10;
75 }
76
TEMP_TO_REG(long val)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 */
ALARMS_FROM_REG(s16 reg)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
lm92_update_device(struct device * dev)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
show_temp(struct device * dev,struct device_attribute * devattr,char * buf)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
set_temp(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)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
show_temp_hyst(struct device * dev,struct device_attribute * devattr,char * buf)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
show_temp_min_hyst(struct device * dev,struct device_attribute * attr,char * buf)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
set_temp_hyst(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)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
show_alarms(struct device * dev,struct device_attribute * attr,char * buf)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
show_alarm(struct device * dev,struct device_attribute * attr,char * buf)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
lm92_init_client(struct i2c_client * client)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 */
max6635_check(struct i2c_client * client)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 */
lm92_detect(struct i2c_client * new_client,struct i2c_board_info * info)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
lm92_probe(struct i2c_client * new_client,const struct i2c_device_id * id)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");
412