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1 | /* |
2 | * lm75.c - Part of lm_sensors, Linux kernel modules for hardware |
3 | * monitoring |
4 | * Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl> |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify |
7 | * it under the terms of the GNU General Public License as published by |
8 | * the Free Software Foundation; either version 2 of the License, or |
9 | * (at your option) any later version. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | * GNU General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public License |
17 | * along with this program; if not, write to the Free Software |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
19 | */ |
20 | |
21 | #include <linux/module.h> |
22 | #include <linux/init.h> |
23 | #include <linux/slab.h> |
24 | #include <linux/jiffies.h> |
25 | #include <linux/i2c.h> |
26 | #include <linux/hwmon.h> |
27 | #include <linux/hwmon-sysfs.h> |
28 | #include <linux/err.h> |
29 | #include <linux/mutex.h> |
30 | #include "lm75.h" |
31 | |
32 | |
33 | /* |
34 | * This driver handles the LM75 and compatible digital temperature sensors. |
35 | */ |
36 | |
37 | enum lm75_type { /* keep sorted in alphabetical order */ |
38 | adt75, |
39 | ds1775, |
40 | ds75, |
41 | lm75, |
42 | lm75a, |
43 | max6625, |
44 | max6626, |
45 | mcp980x, |
46 | stds75, |
47 | tcn75, |
48 | tmp100, |
49 | tmp101, |
50 | tmp105, |
51 | tmp175, |
52 | tmp275, |
53 | tmp75, |
54 | }; |
55 | |
56 | /* Addresses scanned */ |
57 | static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, |
58 | 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; |
59 | |
60 | |
61 | /* The LM75 registers */ |
62 | #define LM75_REG_CONF 0x01 |
63 | static const u8 LM75_REG_TEMP[3] = { |
64 | 0x00, /* input */ |
65 | 0x03, /* max */ |
66 | 0x02, /* hyst */ |
67 | }; |
68 | |
69 | /* Each client has this additional data */ |
70 | struct lm75_data { |
71 | struct device *hwmon_dev; |
72 | struct mutex update_lock; |
73 | u8 orig_conf; |
74 | char valid; /* !=0 if registers are valid */ |
75 | unsigned long last_updated; /* In jiffies */ |
76 | u16 temp[3]; /* Register values, |
77 | 0 = input |
78 | 1 = max |
79 | 2 = hyst */ |
80 | }; |
81 | |
82 | static int lm75_read_value(struct i2c_client *client, u8 reg); |
83 | static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); |
84 | static struct lm75_data *lm75_update_device(struct device *dev); |
85 | |
86 | |
87 | /*-----------------------------------------------------------------------*/ |
88 | |
89 | /* sysfs attributes for hwmon */ |
90 | |
91 | static ssize_t show_temp(struct device *dev, struct device_attribute *da, |
92 | char *buf) |
93 | { |
94 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
95 | struct lm75_data *data = lm75_update_device(dev); |
96 | |
97 | if (IS_ERR(data)) |
98 | return PTR_ERR(data); |
99 | |
100 | return sprintf(buf, "%d\n", |
101 | LM75_TEMP_FROM_REG(data->temp[attr->index])); |
102 | } |
103 | |
104 | static ssize_t set_temp(struct device *dev, struct device_attribute *da, |
105 | const char *buf, size_t count) |
106 | { |
107 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
108 | struct i2c_client *client = to_i2c_client(dev); |
109 | struct lm75_data *data = i2c_get_clientdata(client); |
110 | int nr = attr->index; |
111 | long temp; |
112 | int error; |
113 | |
114 | error = kstrtol(buf, 10, &temp); |
115 | if (error) |
116 | return error; |
117 | |
118 | mutex_lock(&data->update_lock); |
119 | data->temp[nr] = LM75_TEMP_TO_REG(temp); |
120 | lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); |
121 | mutex_unlock(&data->update_lock); |
122 | return count; |
123 | } |
124 | |
125 | static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, |
126 | show_temp, set_temp, 1); |
127 | static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, |
128 | show_temp, set_temp, 2); |
129 | static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); |
130 | |
131 | static struct attribute *lm75_attributes[] = { |
132 | &sensor_dev_attr_temp1_input.dev_attr.attr, |
133 | &sensor_dev_attr_temp1_max.dev_attr.attr, |
134 | &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, |
135 | |
136 | NULL |
137 | }; |
138 | |
139 | static const struct attribute_group lm75_group = { |
140 | .attrs = lm75_attributes, |
141 | }; |
142 | |
143 | /*-----------------------------------------------------------------------*/ |
144 | |
145 | /* device probe and removal */ |
146 | |
147 | static int |
148 | lm75_probe(struct i2c_client *client, const struct i2c_device_id *id) |
149 | { |
150 | struct lm75_data *data; |
151 | int status; |
152 | u8 set_mask, clr_mask; |
153 | int new; |
154 | |
155 | if (!i2c_check_functionality(client->adapter, |
156 | I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) |
157 | return -EIO; |
158 | |
159 | data = devm_kzalloc(&client->dev, sizeof(struct lm75_data), GFP_KERNEL); |
160 | if (!data) |
161 | return -ENOMEM; |
162 | |
163 | i2c_set_clientdata(client, data); |
164 | mutex_init(&data->update_lock); |
165 | |
166 | /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. |
167 | * Then tweak to be more precise when appropriate. |
168 | */ |
169 | set_mask = 0; |
170 | clr_mask = (1 << 0) /* continuous conversions */ |
171 | | (1 << 6) | (1 << 5); /* 9-bit mode */ |
172 | |
173 | /* configure as specified */ |
174 | status = lm75_read_value(client, LM75_REG_CONF); |
175 | if (status < 0) { |
176 | dev_dbg(&client->dev, "Can't read config? %d\n", status); |
177 | return status; |
178 | } |
179 | data->orig_conf = status; |
180 | new = status & ~clr_mask; |
181 | new |= set_mask; |
182 | if (status != new) |
183 | lm75_write_value(client, LM75_REG_CONF, new); |
184 | dev_dbg(&client->dev, "Config %02x\n", new); |
185 | |
186 | /* Register sysfs hooks */ |
187 | status = sysfs_create_group(&client->dev.kobj, &lm75_group); |
188 | if (status) |
189 | return status; |
190 | |
191 | data->hwmon_dev = hwmon_device_register(&client->dev); |
192 | if (IS_ERR(data->hwmon_dev)) { |
193 | status = PTR_ERR(data->hwmon_dev); |
194 | goto exit_remove; |
195 | } |
196 | |
197 | dev_info(&client->dev, "%s: sensor '%s'\n", |
198 | dev_name(data->hwmon_dev), client->name); |
199 | |
200 | return 0; |
201 | |
202 | exit_remove: |
203 | sysfs_remove_group(&client->dev.kobj, &lm75_group); |
204 | return status; |
205 | } |
206 | |
207 | static int lm75_remove(struct i2c_client *client) |
208 | { |
209 | struct lm75_data *data = i2c_get_clientdata(client); |
210 | |
211 | hwmon_device_unregister(data->hwmon_dev); |
212 | sysfs_remove_group(&client->dev.kobj, &lm75_group); |
213 | lm75_write_value(client, LM75_REG_CONF, data->orig_conf); |
214 | return 0; |
215 | } |
216 | |
217 | static const struct i2c_device_id lm75_ids[] = { |
218 | { "adt75", adt75, }, |
219 | { "ds1775", ds1775, }, |
220 | { "ds75", ds75, }, |
221 | { "lm75", lm75, }, |
222 | { "lm75a", lm75a, }, |
223 | { "max6625", max6625, }, |
224 | { "max6626", max6626, }, |
225 | { "mcp980x", mcp980x, }, |
226 | { "stds75", stds75, }, |
227 | { "tcn75", tcn75, }, |
228 | { "tmp100", tmp100, }, |
229 | { "tmp101", tmp101, }, |
230 | { "tmp105", tmp105, }, |
231 | { "tmp175", tmp175, }, |
232 | { "tmp275", tmp275, }, |
233 | { "tmp75", tmp75, }, |
234 | { /* LIST END */ } |
235 | }; |
236 | MODULE_DEVICE_TABLE(i2c, lm75_ids); |
237 | |
238 | #define LM75A_ID 0xA1 |
239 | |
240 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
241 | static int lm75_detect(struct i2c_client *new_client, |
242 | struct i2c_board_info *info) |
243 | { |
244 | struct i2c_adapter *adapter = new_client->adapter; |
245 | int i; |
246 | int conf, hyst, os; |
247 | bool is_lm75a = 0; |
248 | |
249 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | |
250 | I2C_FUNC_SMBUS_WORD_DATA)) |
251 | return -ENODEV; |
252 | |
253 | /* |
254 | * Now, we do the remaining detection. There is no identification- |
255 | * dedicated register so we have to rely on several tricks: |
256 | * unused bits, registers cycling over 8-address boundaries, |
257 | * addresses 0x04-0x07 returning the last read value. |
258 | * The cycling+unused addresses combination is not tested, |
259 | * since it would significantly slow the detection down and would |
260 | * hardly add any value. |
261 | * |
262 | * The National Semiconductor LM75A is different than earlier |
263 | * LM75s. It has an ID byte of 0xaX (where X is the chip |
264 | * revision, with 1 being the only revision in existence) in |
265 | * register 7, and unused registers return 0xff rather than the |
266 | * last read value. |
267 | * |
268 | * Note that this function only detects the original National |
269 | * Semiconductor LM75 and the LM75A. Clones from other vendors |
270 | * aren't detected, on purpose, because they are typically never |
271 | * found on PC hardware. They are found on embedded designs where |
272 | * they can be instantiated explicitly so detection is not needed. |
273 | * The absence of identification registers on all these clones |
274 | * would make their exhaustive detection very difficult and weak, |
275 | * and odds are that the driver would bind to unsupported devices. |
276 | */ |
277 | |
278 | /* Unused bits */ |
279 | conf = i2c_smbus_read_byte_data(new_client, 1); |
280 | if (conf & 0xe0) |
281 | return -ENODEV; |
282 | |
283 | /* First check for LM75A */ |
284 | if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { |
285 | /* LM75A returns 0xff on unused registers so |
286 | just to be sure we check for that too. */ |
287 | if (i2c_smbus_read_byte_data(new_client, 4) != 0xff |
288 | || i2c_smbus_read_byte_data(new_client, 5) != 0xff |
289 | || i2c_smbus_read_byte_data(new_client, 6) != 0xff) |
290 | return -ENODEV; |
291 | is_lm75a = 1; |
292 | hyst = i2c_smbus_read_byte_data(new_client, 2); |
293 | os = i2c_smbus_read_byte_data(new_client, 3); |
294 | } else { /* Traditional style LM75 detection */ |
295 | /* Unused addresses */ |
296 | hyst = i2c_smbus_read_byte_data(new_client, 2); |
297 | if (i2c_smbus_read_byte_data(new_client, 4) != hyst |
298 | || i2c_smbus_read_byte_data(new_client, 5) != hyst |
299 | || i2c_smbus_read_byte_data(new_client, 6) != hyst |
300 | || i2c_smbus_read_byte_data(new_client, 7) != hyst) |
301 | return -ENODEV; |
302 | os = i2c_smbus_read_byte_data(new_client, 3); |
303 | if (i2c_smbus_read_byte_data(new_client, 4) != os |
304 | || i2c_smbus_read_byte_data(new_client, 5) != os |
305 | || i2c_smbus_read_byte_data(new_client, 6) != os |
306 | || i2c_smbus_read_byte_data(new_client, 7) != os) |
307 | return -ENODEV; |
308 | } |
309 | |
310 | /* Addresses cycling */ |
311 | for (i = 8; i <= 248; i += 40) { |
312 | if (i2c_smbus_read_byte_data(new_client, i + 1) != conf |
313 | || i2c_smbus_read_byte_data(new_client, i + 2) != hyst |
314 | || i2c_smbus_read_byte_data(new_client, i + 3) != os) |
315 | return -ENODEV; |
316 | if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) |
317 | != LM75A_ID) |
318 | return -ENODEV; |
319 | } |
320 | |
321 | strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); |
322 | |
323 | return 0; |
324 | } |
325 | |
326 | #ifdef CONFIG_PM |
327 | static int lm75_suspend(struct device *dev) |
328 | { |
329 | int status; |
330 | struct i2c_client *client = to_i2c_client(dev); |
331 | status = lm75_read_value(client, LM75_REG_CONF); |
332 | if (status < 0) { |
333 | dev_dbg(&client->dev, "Can't read config? %d\n", status); |
334 | return status; |
335 | } |
336 | status = status | LM75_SHUTDOWN; |
337 | lm75_write_value(client, LM75_REG_CONF, status); |
338 | return 0; |
339 | } |
340 | |
341 | static int lm75_resume(struct device *dev) |
342 | { |
343 | int status; |
344 | struct i2c_client *client = to_i2c_client(dev); |
345 | status = lm75_read_value(client, LM75_REG_CONF); |
346 | if (status < 0) { |
347 | dev_dbg(&client->dev, "Can't read config? %d\n", status); |
348 | return status; |
349 | } |
350 | status = status & ~LM75_SHUTDOWN; |
351 | lm75_write_value(client, LM75_REG_CONF, status); |
352 | return 0; |
353 | } |
354 | |
355 | static const struct dev_pm_ops lm75_dev_pm_ops = { |
356 | .suspend = lm75_suspend, |
357 | .resume = lm75_resume, |
358 | }; |
359 | #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) |
360 | #else |
361 | #define LM75_DEV_PM_OPS NULL |
362 | #endif /* CONFIG_PM */ |
363 | |
364 | static struct i2c_driver lm75_driver = { |
365 | .class = I2C_CLASS_HWMON, |
366 | .driver = { |
367 | .name = "lm75", |
368 | .pm = LM75_DEV_PM_OPS, |
369 | }, |
370 | .probe = lm75_probe, |
371 | .remove = lm75_remove, |
372 | .id_table = lm75_ids, |
373 | .detect = lm75_detect, |
374 | .address_list = normal_i2c, |
375 | }; |
376 | |
377 | /*-----------------------------------------------------------------------*/ |
378 | |
379 | /* register access */ |
380 | |
381 | /* |
382 | * All registers are word-sized, except for the configuration register. |
383 | * LM75 uses a high-byte first convention, which is exactly opposite to |
384 | * the SMBus standard. |
385 | */ |
386 | static int lm75_read_value(struct i2c_client *client, u8 reg) |
387 | { |
388 | if (reg == LM75_REG_CONF) |
389 | return i2c_smbus_read_byte_data(client, reg); |
390 | else |
391 | return i2c_smbus_read_word_swapped(client, reg); |
392 | } |
393 | |
394 | static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) |
395 | { |
396 | if (reg == LM75_REG_CONF) |
397 | return i2c_smbus_write_byte_data(client, reg, value); |
398 | else |
399 | return i2c_smbus_write_word_swapped(client, reg, value); |
400 | } |
401 | |
402 | static struct lm75_data *lm75_update_device(struct device *dev) |
403 | { |
404 | struct i2c_client *client = to_i2c_client(dev); |
405 | struct lm75_data *data = i2c_get_clientdata(client); |
406 | struct lm75_data *ret = data; |
407 | |
408 | mutex_lock(&data->update_lock); |
409 | |
410 | if (time_after(jiffies, data->last_updated + HZ + HZ / 2) |
411 | || !data->valid) { |
412 | int i; |
413 | dev_dbg(&client->dev, "Starting lm75 update\n"); |
414 | |
415 | for (i = 0; i < ARRAY_SIZE(data->temp); i++) { |
416 | int status; |
417 | |
418 | status = lm75_read_value(client, LM75_REG_TEMP[i]); |
419 | if (unlikely(status < 0)) { |
420 | dev_dbg(dev, |
421 | "LM75: Failed to read value: reg %d, error %d\n", |
422 | LM75_REG_TEMP[i], status); |
423 | ret = ERR_PTR(status); |
424 | data->valid = 0; |
425 | goto abort; |
426 | } |
427 | data->temp[i] = status; |
428 | } |
429 | data->last_updated = jiffies; |
430 | data->valid = 1; |
431 | } |
432 | |
433 | abort: |
434 | mutex_unlock(&data->update_lock); |
435 | return ret; |
436 | } |
437 | |
438 | module_i2c_driver(lm75_driver); |
439 | |
440 | MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); |
441 | MODULE_DESCRIPTION("LM75 driver"); |
442 | MODULE_LICENSE("GPL"); |
443 |
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