Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | Naming and data format standards for sysfs files |
2 | ------------------------------------------------ | |
3 | ||
4 | The libsensors library offers an interface to the raw sensors data | |
125ff808 JD |
5 | through the sysfs interface. Since lm-sensors 3.0.0, libsensors is |
6 | completely chip-independent. It assumes that all the kernel drivers | |
7 | implement the standard sysfs interface described in this document. | |
8 | This makes adding or updating support for any given chip very easy, as | |
9 | libsensors, and applications using it, do not need to be modified. | |
10 | This is a major improvement compared to lm-sensors 2. | |
1da177e4 LT |
11 | |
12 | Note that motherboards vary widely in the connections to sensor chips. | |
13 | There is no standard that ensures, for example, that the second | |
14 | temperature sensor is connected to the CPU, or that the second fan is on | |
15 | the CPU. Also, some values reported by the chips need some computation | |
16 | before they make full sense. For example, most chips can only measure | |
17 | voltages between 0 and +4V. Other voltages are scaled back into that | |
18 | range using external resistors. Since the values of these resistors | |
19 | can change from motherboard to motherboard, the conversions cannot be | |
20 | hard coded into the driver and have to be done in user space. | |
21 | ||
740e06a8 | 22 | For this reason, even if we aim at a chip-independent libsensors, it will |
1da177e4 LT |
23 | still require a configuration file (e.g. /etc/sensors.conf) for proper |
24 | values conversion, labeling of inputs and hiding of unused inputs. | |
25 | ||
26 | An alternative method that some programs use is to access the sysfs | |
27 | files directly. This document briefly describes the standards that the | |
28 | drivers follow, so that an application program can scan for entries and | |
29 | access this data in a simple and consistent way. That said, such programs | |
30 | will have to implement conversion, labeling and hiding of inputs. For | |
31 | this reason, it is still not recommended to bypass the library. | |
32 | ||
1da177e4 | 33 | Each chip gets its own directory in the sysfs /sys/devices tree. To |
740e06a8 JD |
34 | find all sensor chips, it is easier to follow the device symlinks from |
35 | /sys/class/hwmon/hwmon*. | |
1da177e4 | 36 | |
125ff808 JD |
37 | Up to lm-sensors 3.0.0, libsensors looks for hardware monitoring attributes |
38 | in the "physical" device directory. Since lm-sensors 3.0.1, attributes found | |
39 | in the hwmon "class" device directory are also supported. Complex drivers | |
40 | (e.g. drivers for multifunction chips) may want to use this possibility to | |
41 | avoid namespace pollution. The only drawback will be that older versions of | |
42 | libsensors won't support the driver in question. | |
43 | ||
740e06a8 | 44 | All sysfs values are fixed point numbers. |
1da177e4 LT |
45 | |
46 | There is only one value per file, unlike the older /proc specification. | |
47 | The common scheme for files naming is: <type><number>_<item>. Usual | |
48 | types for sensor chips are "in" (voltage), "temp" (temperature) and | |
49 | "fan" (fan). Usual items are "input" (measured value), "max" (high | |
50 | threshold, "min" (low threshold). Numbering usually starts from 1, | |
51 | except for voltages which start from 0 (because most data sheets use | |
52 | this). A number is always used for elements that can be present more | |
53 | than once, even if there is a single element of the given type on the | |
54 | specific chip. Other files do not refer to a specific element, so | |
55 | they have a simple name, and no number. | |
56 | ||
57 | Alarms are direct indications read from the chips. The drivers do NOT | |
58 | make comparisons of readings to thresholds. This allows violations | |
59 | between readings to be caught and alarmed. The exact definition of an | |
60 | alarm (for example, whether a threshold must be met or must be exceeded | |
61 | to cause an alarm) is chip-dependent. | |
62 | ||
2ed42633 HG |
63 | When setting values of hwmon sysfs attributes, the string representation of |
64 | the desired value must be written, note that strings which are not a number | |
65 | are interpreted as 0! For more on how written strings are interpreted see the | |
66 | "sysfs attribute writes interpretation" section at the end of this file. | |
1da177e4 LT |
67 | |
68 | ------------------------------------------------------------------------- | |
69 | ||
057bc350 RM |
70 | [0-*] denotes any positive number starting from 0 |
71 | [1-*] denotes any positive number starting from 1 | |
72 | RO read only value | |
cd4e96c5 | 73 | WO write only value |
057bc350 RM |
74 | RW read/write value |
75 | ||
76 | Read/write values may be read-only for some chips, depending on the | |
77 | hardware implementation. | |
78 | ||
176544dc JD |
79 | All entries (except name) are optional, and should only be created in a |
80 | given driver if the chip has the feature. | |
81 | ||
82 | ||
d2b847d4 IS |
83 | ********************* |
84 | * Global attributes * | |
85 | ********************* | |
176544dc JD |
86 | |
87 | name The chip name. | |
88 | This should be a short, lowercase string, not containing | |
89 | spaces nor dashes, representing the chip name. This is | |
90 | the only mandatory attribute. | |
91 | I2C devices get this attribute created automatically. | |
92 | RO | |
93 | ||
a51b9944 | 94 | update_interval The interval at which the chip will update readings. |
d2b847d4 IS |
95 | Unit: millisecond |
96 | RW | |
a51b9944 GR |
97 | Some devices have a variable update rate or interval. |
98 | This attribute can be used to change it to the desired value. | |
d2b847d4 | 99 | |
740e06a8 | 100 | |
1da177e4 LT |
101 | ************ |
102 | * Voltages * | |
103 | ************ | |
104 | ||
057bc350 | 105 | in[0-*]_min Voltage min value. |
1da177e4 | 106 | Unit: millivolt |
057bc350 | 107 | RW |
1da177e4 | 108 | |
f46fc8cd GR |
109 | in[0-*]_lcrit Voltage critical min value. |
110 | Unit: millivolt | |
111 | RW | |
112 | If voltage drops to or below this limit, the system may | |
113 | take drastic action such as power down or reset. At the very | |
114 | least, it should report a fault. | |
115 | ||
057bc350 | 116 | in[0-*]_max Voltage max value. |
1da177e4 | 117 | Unit: millivolt |
057bc350 | 118 | RW |
1da177e4 | 119 | |
f46fc8cd GR |
120 | in[0-*]_crit Voltage critical max value. |
121 | Unit: millivolt | |
122 | RW | |
123 | If voltage reaches or exceeds this limit, the system may | |
124 | take drastic action such as power down or reset. At the very | |
125 | least, it should report a fault. | |
126 | ||
057bc350 | 127 | in[0-*]_input Voltage input value. |
1da177e4 | 128 | Unit: millivolt |
057bc350 RM |
129 | RO |
130 | Voltage measured on the chip pin. | |
1da177e4 LT |
131 | Actual voltage depends on the scaling resistors on the |
132 | motherboard, as recommended in the chip datasheet. | |
133 | This varies by chip and by motherboard. | |
134 | Because of this variation, values are generally NOT scaled | |
135 | by the chip driver, and must be done by the application. | |
136 | However, some drivers (notably lm87 and via686a) | |
057bc350 | 137 | do scale, because of internal resistors built into a chip. |
176544dc JD |
138 | These drivers will output the actual voltage. Rule of |
139 | thumb: drivers should report the voltage values at the | |
140 | "pins" of the chip. | |
141 | ||
0084e9fa GR |
142 | in[0-*]_average |
143 | Average voltage | |
144 | Unit: millivolt | |
145 | RO | |
146 | ||
147 | in[0-*]_lowest | |
148 | Historical minimum voltage | |
149 | Unit: millivolt | |
150 | RO | |
151 | ||
152 | in[0-*]_highest | |
153 | Historical maximum voltage | |
154 | Unit: millivolt | |
155 | RO | |
156 | ||
157 | in[0-*]_reset_history | |
158 | Reset inX_lowest and inX_highest | |
159 | WO | |
160 | ||
161 | in_reset_history | |
162 | Reset inX_lowest and inX_highest for all sensors | |
163 | WO | |
164 | ||
176544dc JD |
165 | in[0-*]_label Suggested voltage channel label. |
166 | Text string | |
167 | Should only be created if the driver has hints about what | |
168 | this voltage channel is being used for, and user-space | |
169 | doesn't. In all other cases, the label is provided by | |
170 | user-space. | |
171 | RO | |
1da177e4 | 172 | |
057bc350 | 173 | cpu[0-*]_vid CPU core reference voltage. |
1da177e4 | 174 | Unit: millivolt |
057bc350 | 175 | RO |
1da177e4 LT |
176 | Not always correct. |
177 | ||
178 | vrm Voltage Regulator Module version number. | |
057bc350 RM |
179 | RW (but changing it should no more be necessary) |
180 | Originally the VRM standard version multiplied by 10, but now | |
181 | an arbitrary number, as not all standards have a version | |
182 | number. | |
1da177e4 LT |
183 | Affects the way the driver calculates the CPU core reference |
184 | voltage from the vid pins. | |
185 | ||
057bc350 RM |
186 | Also see the Alarms section for status flags associated with voltages. |
187 | ||
1da177e4 LT |
188 | |
189 | ******** | |
190 | * Fans * | |
191 | ******** | |
192 | ||
057bc350 | 193 | fan[1-*]_min Fan minimum value |
1da177e4 | 194 | Unit: revolution/min (RPM) |
057bc350 | 195 | RW |
1da177e4 | 196 | |
d54d4624 CE |
197 | fan[1-*]_max Fan maximum value |
198 | Unit: revolution/min (RPM) | |
199 | Only rarely supported by the hardware. | |
200 | RW | |
201 | ||
057bc350 | 202 | fan[1-*]_input Fan input value. |
1da177e4 | 203 | Unit: revolution/min (RPM) |
057bc350 | 204 | RO |
1da177e4 | 205 | |
057bc350 | 206 | fan[1-*]_div Fan divisor. |
1da177e4 | 207 | Integer value in powers of two (1, 2, 4, 8, 16, 32, 64, 128). |
057bc350 | 208 | RW |
1da177e4 LT |
209 | Some chips only support values 1, 2, 4 and 8. |
210 | Note that this is actually an internal clock divisor, which | |
211 | affects the measurable speed range, not the read value. | |
212 | ||
2d2e148a GR |
213 | fan[1-*]_pulses Number of tachometer pulses per fan revolution. |
214 | Integer value, typically between 1 and 4. | |
215 | RW | |
216 | This value is a characteristic of the fan connected to the | |
217 | device's input, so it has to be set in accordance with the fan | |
218 | model. | |
219 | Should only be created if the chip has a register to configure | |
220 | the number of pulses. In the absence of such a register (and | |
221 | thus attribute) the value assumed by all devices is 2 pulses | |
222 | per fan revolution. | |
223 | ||
2dbc514a JD |
224 | fan[1-*]_target |
225 | Desired fan speed | |
226 | Unit: revolution/min (RPM) | |
227 | RW | |
228 | Only makes sense if the chip supports closed-loop fan speed | |
229 | control based on the measured fan speed. | |
230 | ||
176544dc JD |
231 | fan[1-*]_label Suggested fan channel label. |
232 | Text string | |
233 | Should only be created if the driver has hints about what | |
234 | this fan channel is being used for, and user-space doesn't. | |
235 | In all other cases, the label is provided by user-space. | |
236 | RO | |
237 | ||
057bc350 RM |
238 | Also see the Alarms section for status flags associated with fans. |
239 | ||
240 | ||
1da177e4 LT |
241 | ******* |
242 | * PWM * | |
243 | ******* | |
244 | ||
057bc350 | 245 | pwm[1-*] Pulse width modulation fan control. |
1da177e4 | 246 | Integer value in the range 0 to 255 |
057bc350 | 247 | RW |
1da177e4 LT |
248 | 255 is max or 100%. |
249 | ||
057bc350 | 250 | pwm[1-*]_enable |
875f25d5 JD |
251 | Fan speed control method: |
252 | 0: no fan speed control (i.e. fan at full speed) | |
253 | 1: manual fan speed control enabled (using pwm[1-*]) | |
254 | 2+: automatic fan speed control enabled | |
f8d0c19a JD |
255 | Check individual chip documentation files for automatic mode |
256 | details. | |
057bc350 RM |
257 | RW |
258 | ||
f8d0c19a JD |
259 | pwm[1-*]_mode 0: DC mode (direct current) |
260 | 1: PWM mode (pulse-width modulation) | |
261 | RW | |
262 | ||
263 | pwm[1-*]_freq Base PWM frequency in Hz. | |
264 | Only possibly available when pwmN_mode is PWM, but not always | |
265 | present even then. | |
057bc350 | 266 | RW |
1da177e4 LT |
267 | |
268 | pwm[1-*]_auto_channels_temp | |
269 | Select which temperature channels affect this PWM output in | |
270 | auto mode. Bitfield, 1 is temp1, 2 is temp2, 4 is temp3 etc... | |
271 | Which values are possible depend on the chip used. | |
057bc350 | 272 | RW |
1da177e4 LT |
273 | |
274 | pwm[1-*]_auto_point[1-*]_pwm | |
275 | pwm[1-*]_auto_point[1-*]_temp | |
276 | pwm[1-*]_auto_point[1-*]_temp_hyst | |
277 | Define the PWM vs temperature curve. Number of trip points is | |
278 | chip-dependent. Use this for chips which associate trip points | |
279 | to PWM output channels. | |
057bc350 | 280 | RW |
1da177e4 | 281 | |
1da177e4 LT |
282 | temp[1-*]_auto_point[1-*]_pwm |
283 | temp[1-*]_auto_point[1-*]_temp | |
284 | temp[1-*]_auto_point[1-*]_temp_hyst | |
285 | Define the PWM vs temperature curve. Number of trip points is | |
286 | chip-dependent. Use this for chips which associate trip points | |
287 | to temperature channels. | |
057bc350 | 288 | RW |
1da177e4 | 289 | |
f7290e24 JD |
290 | There is a third case where trip points are associated to both PWM output |
291 | channels and temperature channels: the PWM values are associated to PWM | |
292 | output channels while the temperature values are associated to temperature | |
293 | channels. In that case, the result is determined by the mapping between | |
294 | temperature inputs and PWM outputs. When several temperature inputs are | |
295 | mapped to a given PWM output, this leads to several candidate PWM values. | |
296 | The actual result is up to the chip, but in general the highest candidate | |
297 | value (fastest fan speed) wins. | |
298 | ||
1da177e4 LT |
299 | |
300 | **************** | |
301 | * Temperatures * | |
302 | **************** | |
303 | ||
057bc350 | 304 | temp[1-*]_type Sensor type selection. |
b26f9330 | 305 | Integers 1 to 6 |
057bc350 | 306 | RW |
5f8b1f87 | 307 | 1: CPU embedded diode |
1da177e4 LT |
308 | 2: 3904 transistor |
309 | 3: thermal diode | |
b26f9330 | 310 | 4: thermistor |
61db011d RM |
311 | 5: AMD AMDSI |
312 | 6: Intel PECI | |
1da177e4 LT |
313 | Not all types are supported by all chips |
314 | ||
057bc350 | 315 | temp[1-*]_max Temperature max value. |
740e06a8 | 316 | Unit: millidegree Celsius (or millivolt, see below) |
057bc350 | 317 | RW |
1da177e4 | 318 | |
057bc350 | 319 | temp[1-*]_min Temperature min value. |
740e06a8 | 320 | Unit: millidegree Celsius |
057bc350 | 321 | RW |
1da177e4 | 322 | |
057bc350 | 323 | temp[1-*]_max_hyst |
1da177e4 | 324 | Temperature hysteresis value for max limit. |
740e06a8 | 325 | Unit: millidegree Celsius |
1da177e4 LT |
326 | Must be reported as an absolute temperature, NOT a delta |
327 | from the max value. | |
057bc350 | 328 | RW |
1da177e4 | 329 | |
057bc350 | 330 | temp[1-*]_input Temperature input value. |
740e06a8 | 331 | Unit: millidegree Celsius |
057bc350 | 332 | RO |
1da177e4 | 333 | |
f46fc8cd | 334 | temp[1-*]_crit Temperature critical max value, typically greater than |
1da177e4 | 335 | corresponding temp_max values. |
740e06a8 | 336 | Unit: millidegree Celsius |
057bc350 | 337 | RW |
1da177e4 | 338 | |
057bc350 | 339 | temp[1-*]_crit_hyst |
1da177e4 | 340 | Temperature hysteresis value for critical limit. |
740e06a8 | 341 | Unit: millidegree Celsius |
1da177e4 LT |
342 | Must be reported as an absolute temperature, NOT a delta |
343 | from the critical value. | |
057bc350 | 344 | RW |
1da177e4 | 345 | |
28e7438f GR |
346 | temp[1-*]_emergency |
347 | Temperature emergency max value, for chips supporting more than | |
348 | two upper temperature limits. Must be equal or greater than | |
349 | corresponding temp_crit values. | |
350 | Unit: millidegree Celsius | |
351 | RW | |
352 | ||
353 | temp[1-*]_emergency_hyst | |
354 | Temperature hysteresis value for emergency limit. | |
355 | Unit: millidegree Celsius | |
356 | Must be reported as an absolute temperature, NOT a delta | |
357 | from the emergency value. | |
358 | RW | |
359 | ||
f46fc8cd GR |
360 | temp[1-*]_lcrit Temperature critical min value, typically lower than |
361 | corresponding temp_min values. | |
362 | Unit: millidegree Celsius | |
363 | RW | |
364 | ||
176544dc | 365 | temp[1-*]_offset |
59ac8367 HR |
366 | Temperature offset which is added to the temperature reading |
367 | by the chip. | |
368 | Unit: millidegree Celsius | |
369 | Read/Write value. | |
370 | ||
176544dc JD |
371 | temp[1-*]_label Suggested temperature channel label. |
372 | Text string | |
373 | Should only be created if the driver has hints about what | |
374 | this temperature channel is being used for, and user-space | |
375 | doesn't. In all other cases, the label is provided by | |
376 | user-space. | |
377 | RO | |
1da177e4 | 378 | |
cd4e96c5 AP |
379 | temp[1-*]_lowest |
380 | Historical minimum temperature | |
381 | Unit: millidegree Celsius | |
382 | RO | |
383 | ||
384 | temp[1-*]_highest | |
385 | Historical maximum temperature | |
386 | Unit: millidegree Celsius | |
387 | RO | |
388 | ||
389 | temp[1-*]_reset_history | |
390 | Reset temp_lowest and temp_highest | |
391 | WO | |
392 | ||
393 | temp_reset_history | |
394 | Reset temp_lowest and temp_highest for all sensors | |
395 | WO | |
396 | ||
740e06a8 JD |
397 | Some chips measure temperature using external thermistors and an ADC, and |
398 | report the temperature measurement as a voltage. Converting this voltage | |
399 | back to a temperature (or the other way around for limits) requires | |
400 | mathematical functions not available in the kernel, so the conversion | |
401 | must occur in user space. For these chips, all temp* files described | |
402 | above should contain values expressed in millivolt instead of millidegree | |
403 | Celsius. In other words, such temperature channels are handled as voltage | |
404 | channels by the driver. | |
405 | ||
057bc350 RM |
406 | Also see the Alarms section for status flags associated with temperatures. |
407 | ||
1da177e4 LT |
408 | |
409 | ************ | |
410 | * Currents * | |
411 | ************ | |
412 | ||
057bc350 | 413 | curr[1-*]_max Current max value |
1da177e4 | 414 | Unit: milliampere |
057bc350 | 415 | RW |
1da177e4 | 416 | |
057bc350 | 417 | curr[1-*]_min Current min value. |
1da177e4 | 418 | Unit: milliampere |
057bc350 | 419 | RW |
1da177e4 | 420 | |
581693b5 GR |
421 | curr[1-*]_lcrit Current critical low value |
422 | Unit: milliampere | |
423 | RW | |
424 | ||
425 | curr[1-*]_crit Current critical high value. | |
426 | Unit: milliampere | |
427 | RW | |
428 | ||
057bc350 | 429 | curr[1-*]_input Current input value |
1da177e4 | 430 | Unit: milliampere |
057bc350 | 431 | RO |
1da177e4 | 432 | |
0084e9fa GR |
433 | curr[1-*]_average |
434 | Average current use | |
435 | Unit: milliampere | |
436 | RO | |
437 | ||
438 | curr[1-*]_lowest | |
439 | Historical minimum current | |
440 | Unit: milliampere | |
441 | RO | |
442 | ||
443 | curr[1-*]_highest | |
444 | Historical maximum current | |
445 | Unit: milliampere | |
446 | RO | |
447 | ||
448 | curr[1-*]_reset_history | |
449 | Reset currX_lowest and currX_highest | |
450 | WO | |
451 | ||
452 | curr_reset_history | |
453 | Reset currX_lowest and currX_highest for all sensors | |
454 | WO | |
455 | ||
581693b5 GR |
456 | Also see the Alarms section for status flags associated with currents. |
457 | ||
38fb56a2 DW |
458 | ********* |
459 | * Power * | |
460 | ********* | |
461 | ||
462 | power[1-*]_average Average power use | |
463 | Unit: microWatt | |
464 | RO | |
465 | ||
115a57c5 DW |
466 | power[1-*]_average_interval Power use averaging interval. A poll |
467 | notification is sent to this file if the | |
468 | hardware changes the averaging interval. | |
ddedc658 DW |
469 | Unit: milliseconds |
470 | RW | |
471 | ||
115a57c5 DW |
472 | power[1-*]_average_interval_max Maximum power use averaging interval |
473 | Unit: milliseconds | |
474 | RO | |
475 | ||
476 | power[1-*]_average_interval_min Minimum power use averaging interval | |
477 | Unit: milliseconds | |
478 | RO | |
479 | ||
38fb56a2 DW |
480 | power[1-*]_average_highest Historical average maximum power use |
481 | Unit: microWatt | |
482 | RO | |
483 | ||
484 | power[1-*]_average_lowest Historical average minimum power use | |
485 | Unit: microWatt | |
486 | RO | |
487 | ||
115a57c5 DW |
488 | power[1-*]_average_max A poll notification is sent to |
489 | power[1-*]_average when power use | |
490 | rises above this value. | |
491 | Unit: microWatt | |
492 | RW | |
493 | ||
494 | power[1-*]_average_min A poll notification is sent to | |
495 | power[1-*]_average when power use | |
496 | sinks below this value. | |
497 | Unit: microWatt | |
498 | RW | |
499 | ||
38fb56a2 DW |
500 | power[1-*]_input Instantaneous power use |
501 | Unit: microWatt | |
502 | RO | |
503 | ||
504 | power[1-*]_input_highest Historical maximum power use | |
505 | Unit: microWatt | |
506 | RO | |
507 | ||
508 | power[1-*]_input_lowest Historical minimum power use | |
509 | Unit: microWatt | |
510 | RO | |
511 | ||
512 | power[1-*]_reset_history Reset input_highest, input_lowest, | |
513 | average_highest and average_lowest. | |
514 | WO | |
1da177e4 | 515 | |
115a57c5 DW |
516 | power[1-*]_accuracy Accuracy of the power meter. |
517 | Unit: Percent | |
518 | RO | |
519 | ||
115a57c5 DW |
520 | power[1-*]_cap If power use rises above this limit, the |
521 | system should take action to reduce power use. | |
522 | A poll notification is sent to this file if the | |
523 | cap is changed by the hardware. The *_cap | |
524 | files only appear if the cap is known to be | |
525 | enforced by hardware. | |
526 | Unit: microWatt | |
527 | RW | |
528 | ||
529 | power[1-*]_cap_hyst Margin of hysteresis built around capping and | |
530 | notification. | |
531 | Unit: microWatt | |
532 | RW | |
533 | ||
534 | power[1-*]_cap_max Maximum cap that can be set. | |
535 | Unit: microWatt | |
536 | RO | |
537 | ||
538 | power[1-*]_cap_min Minimum cap that can be set. | |
539 | Unit: microWatt | |
540 | RO | |
541 | ||
581693b5 GR |
542 | power[1-*]_max Maximum power. |
543 | Unit: microWatt | |
544 | RW | |
545 | ||
546 | power[1-*]_crit Critical maximum power. | |
547 | If power rises to or above this limit, the | |
548 | system is expected take drastic action to reduce | |
549 | power consumption, such as a system shutdown or | |
550 | a forced powerdown of some devices. | |
551 | Unit: microWatt | |
552 | RW | |
553 | ||
554 | Also see the Alarms section for status flags associated with power readings. | |
555 | ||
ddedc658 DW |
556 | ********** |
557 | * Energy * | |
558 | ********** | |
559 | ||
560 | energy[1-*]_input Cumulative energy use | |
561 | Unit: microJoule | |
562 | RO | |
563 | ||
ec199209 | 564 | |
c6c2c163 GR |
565 | ************ |
566 | * Humidity * | |
567 | ************ | |
568 | ||
569 | humidity[1-*]_input Humidity | |
570 | Unit: milli-percent (per cent mille, pcm) | |
571 | RO | |
572 | ||
573 | ||
400b48ec JD |
574 | ********** |
575 | * Alarms * | |
576 | ********** | |
577 | ||
578 | Each channel or limit may have an associated alarm file, containing a | |
579 | boolean value. 1 means than an alarm condition exists, 0 means no alarm. | |
580 | ||
581 | Usually a given chip will either use channel-related alarms, or | |
582 | limit-related alarms, not both. The driver should just reflect the hardware | |
583 | implementation. | |
584 | ||
057bc350 | 585 | in[0-*]_alarm |
e04a715e | 586 | curr[1-*]_alarm |
581693b5 | 587 | power[1-*]_alarm |
057bc350 RM |
588 | fan[1-*]_alarm |
589 | temp[1-*]_alarm | |
400b48ec | 590 | Channel alarm |
057bc350 RM |
591 | 0: no alarm |
592 | 1: alarm | |
593 | RO | |
400b48ec JD |
594 | |
595 | OR | |
596 | ||
057bc350 RM |
597 | in[0-*]_min_alarm |
598 | in[0-*]_max_alarm | |
581693b5 GR |
599 | in[0-*]_lcrit_alarm |
600 | in[0-*]_crit_alarm | |
e04a715e GR |
601 | curr[1-*]_min_alarm |
602 | curr[1-*]_max_alarm | |
581693b5 GR |
603 | curr[1-*]_lcrit_alarm |
604 | curr[1-*]_crit_alarm | |
605 | power[1-*]_cap_alarm | |
606 | power[1-*]_max_alarm | |
607 | power[1-*]_crit_alarm | |
057bc350 | 608 | fan[1-*]_min_alarm |
d54d4624 | 609 | fan[1-*]_max_alarm |
057bc350 RM |
610 | temp[1-*]_min_alarm |
611 | temp[1-*]_max_alarm | |
581693b5 | 612 | temp[1-*]_lcrit_alarm |
057bc350 | 613 | temp[1-*]_crit_alarm |
28e7438f | 614 | temp[1-*]_emergency_alarm |
400b48ec | 615 | Limit alarm |
057bc350 RM |
616 | 0: no alarm |
617 | 1: alarm | |
618 | RO | |
400b48ec JD |
619 | |
620 | Each input channel may have an associated fault file. This can be used | |
621 | to notify open diodes, unconnected fans etc. where the hardware | |
622 | supports it. When this boolean has value 1, the measurement for that | |
623 | channel should not be trusted. | |
624 | ||
7817a39e JD |
625 | fan[1-*]_fault |
626 | temp[1-*]_fault | |
400b48ec | 627 | Input fault condition |
25985edc | 628 | 0: no fault occurred |
057bc350 RM |
629 | 1: fault condition |
630 | RO | |
400b48ec JD |
631 | |
632 | Some chips also offer the possibility to get beeped when an alarm occurs: | |
633 | ||
634 | beep_enable Master beep enable | |
057bc350 RM |
635 | 0: no beeps |
636 | 1: beeps | |
637 | RW | |
400b48ec | 638 | |
057bc350 | 639 | in[0-*]_beep |
e04a715e | 640 | curr[1-*]_beep |
057bc350 RM |
641 | fan[1-*]_beep |
642 | temp[1-*]_beep | |
400b48ec | 643 | Channel beep |
057bc350 RM |
644 | 0: disable |
645 | 1: enable | |
646 | RW | |
400b48ec JD |
647 | |
648 | In theory, a chip could provide per-limit beep masking, but no such chip | |
649 | was seen so far. | |
650 | ||
651 | Old drivers provided a different, non-standard interface to alarms and | |
652 | beeps. These interface files are deprecated, but will be kept around | |
653 | for compatibility reasons: | |
1da177e4 LT |
654 | |
655 | alarms Alarm bitmask. | |
057bc350 | 656 | RO |
1da177e4 LT |
657 | Integer representation of one to four bytes. |
658 | A '1' bit means an alarm. | |
659 | Chips should be programmed for 'comparator' mode so that | |
660 | the alarm will 'come back' after you read the register | |
661 | if it is still valid. | |
662 | Generally a direct representation of a chip's internal | |
663 | alarm registers; there is no standard for the position | |
400b48ec JD |
664 | of individual bits. For this reason, the use of this |
665 | interface file for new drivers is discouraged. Use | |
666 | individual *_alarm and *_fault files instead. | |
1da177e4 LT |
667 | Bits are defined in kernel/include/sensors.h. |
668 | ||
1da177e4 | 669 | beep_mask Bitmask for beep. |
400b48ec JD |
670 | Same format as 'alarms' with the same bit locations, |
671 | use discouraged for the same reason. Use individual | |
672 | *_beep files instead. | |
057bc350 | 673 | RW |
2ed42633 HG |
674 | |
675 | ||
ec199209 JD |
676 | *********************** |
677 | * Intrusion detection * | |
678 | *********************** | |
679 | ||
680 | intrusion[0-*]_alarm | |
681 | Chassis intrusion detection | |
682 | 0: OK | |
683 | 1: intrusion detected | |
684 | RW | |
685 | Contrary to regular alarm flags which clear themselves | |
686 | automatically when read, this one sticks until cleared by | |
687 | the user. This is done by writing 0 to the file. Writing | |
688 | other values is unsupported. | |
689 | ||
690 | intrusion[0-*]_beep | |
691 | Chassis intrusion beep | |
692 | 0: disable | |
693 | 1: enable | |
694 | RW | |
695 | ||
696 | ||
2ed42633 HG |
697 | sysfs attribute writes interpretation |
698 | ------------------------------------- | |
699 | ||
700 | hwmon sysfs attributes always contain numbers, so the first thing to do is to | |
701 | convert the input to a number, there are 2 ways todo this depending whether | |
702 | the number can be negative or not: | |
703 | unsigned long u = simple_strtoul(buf, NULL, 10); | |
704 | long s = simple_strtol(buf, NULL, 10); | |
705 | ||
706 | With buf being the buffer with the user input being passed by the kernel. | |
707 | Notice that we do not use the second argument of strto[u]l, and thus cannot | |
708 | tell when 0 is returned, if this was really 0 or is caused by invalid input. | |
709 | This is done deliberately as checking this everywhere would add a lot of | |
710 | code to the kernel. | |
711 | ||
712 | Notice that it is important to always store the converted value in an | |
713 | unsigned long or long, so that no wrap around can happen before any further | |
714 | checking. | |
715 | ||
716 | After the input string is converted to an (unsigned) long, the value should be | |
717 | checked if its acceptable. Be careful with further conversions on the value | |
718 | before checking it for validity, as these conversions could still cause a wrap | |
719 | around before the check. For example do not multiply the result, and only | |
720 | add/subtract if it has been divided before the add/subtract. | |
721 | ||
722 | What to do if a value is found to be invalid, depends on the type of the | |
723 | sysfs attribute that is being set. If it is a continuous setting like a | |
724 | tempX_max or inX_max attribute, then the value should be clamped to its | |
725 | limits using SENSORS_LIMIT(value, min_limit, max_limit). If it is not | |
726 | continuous like for example a tempX_type, then when an invalid value is | |
727 | written, -EINVAL should be returned. | |
728 | ||
729 | Example1, temp1_max, register is a signed 8 bit value (-128 - 127 degrees): | |
5fbea518 JD |
730 | |
731 | long v = simple_strtol(buf, NULL, 10) / 1000; | |
732 | v = SENSORS_LIMIT(v, -128, 127); | |
733 | /* write v to register */ | |
2ed42633 HG |
734 | |
735 | Example2, fan divider setting, valid values 2, 4 and 8: | |
5fbea518 JD |
736 | |
737 | unsigned long v = simple_strtoul(buf, NULL, 10); | |
738 | ||
739 | switch (v) { | |
740 | case 2: v = 1; break; | |
741 | case 4: v = 2; break; | |
742 | case 8: v = 3; break; | |
743 | default: | |
744 | return -EINVAL; | |
745 | } | |
746 | /* write v to register */ |