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1 | /* |
2 | * lm77.c - Part of lm_sensors, Linux kernel modules for hardware |
3 | * monitoring |
4 | * |
5 | * Copyright (c) 2004 Andras BALI <drewie@freemail.hu> |
6 | * |
7 | * Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77 |
8 | * is a temperature sensor and thermal window comparator with 0.5 deg |
9 | * resolution made by National Semiconductor. Complete datasheet can be |
10 | * obtained at their site: |
11 | * http://www.national.com/pf/LM/LM77.html |
12 | * |
13 | * This program is free software; you can redistribute it and/or modify |
14 | * it under the terms of the GNU General Public License as published by |
15 | * the Free Software Foundation; either version 2 of the License, or |
16 | * (at your option) any later version. |
17 | * |
18 | * This program is distributed in the hope that it will be useful, |
19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
21 | * GNU General Public License for more details. |
22 | * |
23 | * You should have received a copy of the GNU General Public License |
24 | * along with this program; if not, write to the Free Software |
25 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
26 | */ |
27 | |
28 | #include <linux/module.h> |
29 | #include <linux/init.h> |
30 | #include <linux/slab.h> |
31 | #include <linux/jiffies.h> |
32 | #include <linux/i2c.h> |
33 | #include <linux/hwmon.h> |
34 | #include <linux/hwmon-sysfs.h> |
35 | #include <linux/err.h> |
36 | #include <linux/mutex.h> |
37 | |
38 | /* Addresses to scan */ |
39 | static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, |
40 | I2C_CLIENT_END }; |
41 | |
42 | /* The LM77 registers */ |
43 | #define LM77_REG_TEMP 0x00 |
44 | #define LM77_REG_CONF 0x01 |
45 | #define LM77_REG_TEMP_HYST 0x02 |
46 | #define LM77_REG_TEMP_CRIT 0x03 |
47 | #define LM77_REG_TEMP_MIN 0x04 |
48 | #define LM77_REG_TEMP_MAX 0x05 |
49 | |
50 | /* Each client has this additional data */ |
51 | struct lm77_data { |
52 | struct device *hwmon_dev; |
53 | struct mutex update_lock; |
54 | char valid; |
55 | unsigned long last_updated; /* In jiffies */ |
56 | int temp_input; /* Temperatures */ |
57 | int temp_crit; |
58 | int temp_min; |
59 | int temp_max; |
60 | int temp_hyst; |
61 | u8 alarms; |
62 | }; |
63 | |
64 | static int lm77_probe(struct i2c_client *client, |
65 | const struct i2c_device_id *id); |
66 | static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info); |
67 | static void lm77_init_client(struct i2c_client *client); |
68 | static int lm77_remove(struct i2c_client *client); |
69 | static u16 lm77_read_value(struct i2c_client *client, u8 reg); |
70 | static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value); |
71 | |
72 | static struct lm77_data *lm77_update_device(struct device *dev); |
73 | |
74 | |
75 | static const struct i2c_device_id lm77_id[] = { |
76 | { "lm77", 0 }, |
77 | { } |
78 | }; |
79 | MODULE_DEVICE_TABLE(i2c, lm77_id); |
80 | |
81 | /* This is the driver that will be inserted */ |
82 | static struct i2c_driver lm77_driver = { |
83 | .class = I2C_CLASS_HWMON, |
84 | .driver = { |
85 | .name = "lm77", |
86 | }, |
87 | .probe = lm77_probe, |
88 | .remove = lm77_remove, |
89 | .id_table = lm77_id, |
90 | .detect = lm77_detect, |
91 | .address_list = normal_i2c, |
92 | }; |
93 | |
94 | /* straight from the datasheet */ |
95 | #define LM77_TEMP_MIN (-55000) |
96 | #define LM77_TEMP_MAX 125000 |
97 | |
98 | /* |
99 | * In the temperature registers, the low 3 bits are not part of the |
100 | * temperature values; they are the status bits. |
101 | */ |
102 | static inline s16 LM77_TEMP_TO_REG(int temp) |
103 | { |
104 | int ntemp = clamp_val(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); |
105 | return (ntemp / 500) * 8; |
106 | } |
107 | |
108 | static inline int LM77_TEMP_FROM_REG(s16 reg) |
109 | { |
110 | return (reg / 8) * 500; |
111 | } |
112 | |
113 | /* sysfs stuff */ |
114 | |
115 | /* read routines for temperature limits */ |
116 | #define show(value) \ |
117 | static ssize_t show_##value(struct device *dev, \ |
118 | struct device_attribute *attr, \ |
119 | char *buf) \ |
120 | { \ |
121 | struct lm77_data *data = lm77_update_device(dev); \ |
122 | return sprintf(buf, "%d\n", data->value); \ |
123 | } |
124 | |
125 | show(temp_input); |
126 | show(temp_crit); |
127 | show(temp_min); |
128 | show(temp_max); |
129 | |
130 | /* read routines for hysteresis values */ |
131 | static ssize_t show_temp_crit_hyst(struct device *dev, |
132 | struct device_attribute *attr, char *buf) |
133 | { |
134 | struct lm77_data *data = lm77_update_device(dev); |
135 | return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); |
136 | } |
137 | static ssize_t show_temp_min_hyst(struct device *dev, |
138 | struct device_attribute *attr, char *buf) |
139 | { |
140 | struct lm77_data *data = lm77_update_device(dev); |
141 | return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); |
142 | } |
143 | static ssize_t show_temp_max_hyst(struct device *dev, |
144 | struct device_attribute *attr, char *buf) |
145 | { |
146 | struct lm77_data *data = lm77_update_device(dev); |
147 | return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); |
148 | } |
149 | |
150 | /* write routines */ |
151 | #define set(value, reg) \ |
152 | static ssize_t set_##value(struct device *dev, struct device_attribute *attr, \ |
153 | const char *buf, size_t count) \ |
154 | { \ |
155 | struct i2c_client *client = to_i2c_client(dev); \ |
156 | struct lm77_data *data = i2c_get_clientdata(client); \ |
157 | long val; \ |
158 | int err = kstrtol(buf, 10, &val); \ |
159 | if (err) \ |
160 | return err; \ |
161 | \ |
162 | mutex_lock(&data->update_lock); \ |
163 | data->value = val; \ |
164 | lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ |
165 | mutex_unlock(&data->update_lock); \ |
166 | return count; \ |
167 | } |
168 | |
169 | set(temp_min, LM77_REG_TEMP_MIN); |
170 | set(temp_max, LM77_REG_TEMP_MAX); |
171 | |
172 | /* |
173 | * hysteresis is stored as a relative value on the chip, so it has to be |
174 | * converted first |
175 | */ |
176 | static ssize_t set_temp_crit_hyst(struct device *dev, |
177 | struct device_attribute *attr, |
178 | const char *buf, size_t count) |
179 | { |
180 | struct i2c_client *client = to_i2c_client(dev); |
181 | struct lm77_data *data = i2c_get_clientdata(client); |
182 | unsigned long val; |
183 | int err; |
184 | |
185 | err = kstrtoul(buf, 10, &val); |
186 | if (err) |
187 | return err; |
188 | |
189 | mutex_lock(&data->update_lock); |
190 | data->temp_hyst = data->temp_crit - val; |
191 | lm77_write_value(client, LM77_REG_TEMP_HYST, |
192 | LM77_TEMP_TO_REG(data->temp_hyst)); |
193 | mutex_unlock(&data->update_lock); |
194 | return count; |
195 | } |
196 | |
197 | /* preserve hysteresis when setting T_crit */ |
198 | static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, |
199 | const char *buf, size_t count) |
200 | { |
201 | struct i2c_client *client = to_i2c_client(dev); |
202 | struct lm77_data *data = i2c_get_clientdata(client); |
203 | int oldcrithyst; |
204 | unsigned long val; |
205 | int err; |
206 | |
207 | err = kstrtoul(buf, 10, &val); |
208 | if (err) |
209 | return err; |
210 | |
211 | mutex_lock(&data->update_lock); |
212 | oldcrithyst = data->temp_crit - data->temp_hyst; |
213 | data->temp_crit = val; |
214 | data->temp_hyst = data->temp_crit - oldcrithyst; |
215 | lm77_write_value(client, LM77_REG_TEMP_CRIT, |
216 | LM77_TEMP_TO_REG(data->temp_crit)); |
217 | lm77_write_value(client, LM77_REG_TEMP_HYST, |
218 | LM77_TEMP_TO_REG(data->temp_hyst)); |
219 | mutex_unlock(&data->update_lock); |
220 | return count; |
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 lm77_data *data = lm77_update_device(dev); |
228 | return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); |
229 | } |
230 | |
231 | static DEVICE_ATTR(temp1_input, S_IRUGO, |
232 | show_temp_input, NULL); |
233 | static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, |
234 | show_temp_crit, set_temp_crit); |
235 | static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, |
236 | show_temp_min, set_temp_min); |
237 | static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, |
238 | show_temp_max, set_temp_max); |
239 | |
240 | static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, |
241 | show_temp_crit_hyst, set_temp_crit_hyst); |
242 | static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, |
243 | show_temp_min_hyst, NULL); |
244 | static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, |
245 | show_temp_max_hyst, NULL); |
246 | |
247 | static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); |
248 | static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); |
249 | static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); |
250 | |
251 | static struct attribute *lm77_attributes[] = { |
252 | &dev_attr_temp1_input.attr, |
253 | &dev_attr_temp1_crit.attr, |
254 | &dev_attr_temp1_min.attr, |
255 | &dev_attr_temp1_max.attr, |
256 | &dev_attr_temp1_crit_hyst.attr, |
257 | &dev_attr_temp1_min_hyst.attr, |
258 | &dev_attr_temp1_max_hyst.attr, |
259 | &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, |
260 | &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, |
261 | &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, |
262 | NULL |
263 | }; |
264 | |
265 | static const struct attribute_group lm77_group = { |
266 | .attrs = lm77_attributes, |
267 | }; |
268 | |
269 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
270 | static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info) |
271 | { |
272 | struct i2c_adapter *adapter = client->adapter; |
273 | int i, cur, conf, hyst, crit, min, max; |
274 | |
275 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | |
276 | I2C_FUNC_SMBUS_WORD_DATA)) |
277 | return -ENODEV; |
278 | |
279 | /* |
280 | * Here comes the remaining detection. Since the LM77 has no |
281 | * register dedicated to identification, we have to rely on the |
282 | * following tricks: |
283 | * |
284 | * 1. the high 4 bits represent the sign and thus they should |
285 | * always be the same |
286 | * 2. the high 3 bits are unused in the configuration register |
287 | * 3. addresses 0x06 and 0x07 return the last read value |
288 | * 4. registers cycling over 8-address boundaries |
289 | * |
290 | * Word-sized registers are high-byte first. |
291 | */ |
292 | |
293 | /* addresses cycling */ |
294 | cur = i2c_smbus_read_word_data(client, 0); |
295 | conf = i2c_smbus_read_byte_data(client, 1); |
296 | hyst = i2c_smbus_read_word_data(client, 2); |
297 | crit = i2c_smbus_read_word_data(client, 3); |
298 | min = i2c_smbus_read_word_data(client, 4); |
299 | max = i2c_smbus_read_word_data(client, 5); |
300 | for (i = 8; i <= 0xff; i += 8) { |
301 | if (i2c_smbus_read_byte_data(client, i + 1) != conf |
302 | || i2c_smbus_read_word_data(client, i + 2) != hyst |
303 | || i2c_smbus_read_word_data(client, i + 3) != crit |
304 | || i2c_smbus_read_word_data(client, i + 4) != min |
305 | || i2c_smbus_read_word_data(client, i + 5) != max) |
306 | return -ENODEV; |
307 | } |
308 | |
309 | /* sign bits */ |
310 | if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) |
311 | || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) |
312 | || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) |
313 | || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) |
314 | || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) |
315 | return -ENODEV; |
316 | |
317 | /* unused bits */ |
318 | if (conf & 0xe0) |
319 | return -ENODEV; |
320 | |
321 | /* 0x06 and 0x07 return the last read value */ |
322 | cur = i2c_smbus_read_word_data(client, 0); |
323 | if (i2c_smbus_read_word_data(client, 6) != cur |
324 | || i2c_smbus_read_word_data(client, 7) != cur) |
325 | return -ENODEV; |
326 | hyst = i2c_smbus_read_word_data(client, 2); |
327 | if (i2c_smbus_read_word_data(client, 6) != hyst |
328 | || i2c_smbus_read_word_data(client, 7) != hyst) |
329 | return -ENODEV; |
330 | min = i2c_smbus_read_word_data(client, 4); |
331 | if (i2c_smbus_read_word_data(client, 6) != min |
332 | || i2c_smbus_read_word_data(client, 7) != min) |
333 | return -ENODEV; |
334 | |
335 | strlcpy(info->type, "lm77", I2C_NAME_SIZE); |
336 | |
337 | return 0; |
338 | } |
339 | |
340 | static int lm77_probe(struct i2c_client *client, const struct i2c_device_id *id) |
341 | { |
342 | struct device *dev = &client->dev; |
343 | struct lm77_data *data; |
344 | int err; |
345 | |
346 | data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL); |
347 | if (!data) |
348 | return -ENOMEM; |
349 | |
350 | i2c_set_clientdata(client, data); |
351 | data->valid = 0; |
352 | mutex_init(&data->update_lock); |
353 | |
354 | /* Initialize the LM77 chip */ |
355 | lm77_init_client(client); |
356 | |
357 | /* Register sysfs hooks */ |
358 | err = sysfs_create_group(&dev->kobj, &lm77_group); |
359 | if (err) |
360 | return err; |
361 | |
362 | data->hwmon_dev = hwmon_device_register(dev); |
363 | if (IS_ERR(data->hwmon_dev)) { |
364 | err = PTR_ERR(data->hwmon_dev); |
365 | goto exit_remove; |
366 | } |
367 | |
368 | return 0; |
369 | |
370 | exit_remove: |
371 | sysfs_remove_group(&dev->kobj, &lm77_group); |
372 | return err; |
373 | } |
374 | |
375 | static int lm77_remove(struct i2c_client *client) |
376 | { |
377 | struct lm77_data *data = i2c_get_clientdata(client); |
378 | hwmon_device_unregister(data->hwmon_dev); |
379 | sysfs_remove_group(&client->dev.kobj, &lm77_group); |
380 | return 0; |
381 | } |
382 | |
383 | /* |
384 | * All registers are word-sized, except for the configuration register. |
385 | * The LM77 uses the high-byte first convention. |
386 | */ |
387 | static u16 lm77_read_value(struct i2c_client *client, u8 reg) |
388 | { |
389 | if (reg == LM77_REG_CONF) |
390 | return i2c_smbus_read_byte_data(client, reg); |
391 | else |
392 | return i2c_smbus_read_word_swapped(client, reg); |
393 | } |
394 | |
395 | static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) |
396 | { |
397 | if (reg == LM77_REG_CONF) |
398 | return i2c_smbus_write_byte_data(client, reg, value); |
399 | else |
400 | return i2c_smbus_write_word_swapped(client, reg, value); |
401 | } |
402 | |
403 | static void lm77_init_client(struct i2c_client *client) |
404 | { |
405 | /* Initialize the LM77 chip - turn off shutdown mode */ |
406 | int conf = lm77_read_value(client, LM77_REG_CONF); |
407 | if (conf & 1) |
408 | lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); |
409 | } |
410 | |
411 | static struct lm77_data *lm77_update_device(struct device *dev) |
412 | { |
413 | struct i2c_client *client = to_i2c_client(dev); |
414 | struct lm77_data *data = i2c_get_clientdata(client); |
415 | |
416 | mutex_lock(&data->update_lock); |
417 | |
418 | if (time_after(jiffies, data->last_updated + HZ + HZ / 2) |
419 | || !data->valid) { |
420 | dev_dbg(&client->dev, "Starting lm77 update\n"); |
421 | data->temp_input = |
422 | LM77_TEMP_FROM_REG(lm77_read_value(client, |
423 | LM77_REG_TEMP)); |
424 | data->temp_hyst = |
425 | LM77_TEMP_FROM_REG(lm77_read_value(client, |
426 | LM77_REG_TEMP_HYST)); |
427 | data->temp_crit = |
428 | LM77_TEMP_FROM_REG(lm77_read_value(client, |
429 | LM77_REG_TEMP_CRIT)); |
430 | data->temp_min = |
431 | LM77_TEMP_FROM_REG(lm77_read_value(client, |
432 | LM77_REG_TEMP_MIN)); |
433 | data->temp_max = |
434 | LM77_TEMP_FROM_REG(lm77_read_value(client, |
435 | LM77_REG_TEMP_MAX)); |
436 | data->alarms = |
437 | lm77_read_value(client, LM77_REG_TEMP) & 0x0007; |
438 | data->last_updated = jiffies; |
439 | data->valid = 1; |
440 | } |
441 | |
442 | mutex_unlock(&data->update_lock); |
443 | |
444 | return data; |
445 | } |
446 | |
447 | module_i2c_driver(lm77_driver); |
448 | |
449 | MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); |
450 | MODULE_DESCRIPTION("LM77 driver"); |
451 | MODULE_LICENSE("GPL"); |
452 |
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