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Commit | Line | Data |
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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 | ||
142 | in[0-*]_label Suggested voltage channel label. | |
143 | Text string | |
144 | Should only be created if the driver has hints about what | |
145 | this voltage channel is being used for, and user-space | |
146 | doesn't. In all other cases, the label is provided by | |
147 | user-space. | |
148 | RO | |
1da177e4 | 149 | |
057bc350 | 150 | cpu[0-*]_vid CPU core reference voltage. |
1da177e4 | 151 | Unit: millivolt |
057bc350 | 152 | RO |
1da177e4 LT |
153 | Not always correct. |
154 | ||
155 | vrm Voltage Regulator Module version number. | |
057bc350 RM |
156 | RW (but changing it should no more be necessary) |
157 | Originally the VRM standard version multiplied by 10, but now | |
158 | an arbitrary number, as not all standards have a version | |
159 | number. | |
1da177e4 LT |
160 | Affects the way the driver calculates the CPU core reference |
161 | voltage from the vid pins. | |
162 | ||
057bc350 RM |
163 | Also see the Alarms section for status flags associated with voltages. |
164 | ||
1da177e4 LT |
165 | |
166 | ******** | |
167 | * Fans * | |
168 | ******** | |
169 | ||
057bc350 | 170 | fan[1-*]_min Fan minimum value |
1da177e4 | 171 | Unit: revolution/min (RPM) |
057bc350 | 172 | RW |
1da177e4 | 173 | |
d54d4624 CE |
174 | fan[1-*]_max Fan maximum value |
175 | Unit: revolution/min (RPM) | |
176 | Only rarely supported by the hardware. | |
177 | RW | |
178 | ||
057bc350 | 179 | fan[1-*]_input Fan input value. |
1da177e4 | 180 | Unit: revolution/min (RPM) |
057bc350 | 181 | RO |
1da177e4 | 182 | |
057bc350 | 183 | fan[1-*]_div Fan divisor. |
1da177e4 | 184 | Integer value in powers of two (1, 2, 4, 8, 16, 32, 64, 128). |
057bc350 | 185 | RW |
1da177e4 LT |
186 | Some chips only support values 1, 2, 4 and 8. |
187 | Note that this is actually an internal clock divisor, which | |
188 | affects the measurable speed range, not the read value. | |
189 | ||
2d2e148a GR |
190 | fan[1-*]_pulses Number of tachometer pulses per fan revolution. |
191 | Integer value, typically between 1 and 4. | |
192 | RW | |
193 | This value is a characteristic of the fan connected to the | |
194 | device's input, so it has to be set in accordance with the fan | |
195 | model. | |
196 | Should only be created if the chip has a register to configure | |
197 | the number of pulses. In the absence of such a register (and | |
198 | thus attribute) the value assumed by all devices is 2 pulses | |
199 | per fan revolution. | |
200 | ||
2dbc514a JD |
201 | fan[1-*]_target |
202 | Desired fan speed | |
203 | Unit: revolution/min (RPM) | |
204 | RW | |
205 | Only makes sense if the chip supports closed-loop fan speed | |
206 | control based on the measured fan speed. | |
207 | ||
176544dc JD |
208 | fan[1-*]_label Suggested fan channel label. |
209 | Text string | |
210 | Should only be created if the driver has hints about what | |
211 | this fan channel is being used for, and user-space doesn't. | |
212 | In all other cases, the label is provided by user-space. | |
213 | RO | |
214 | ||
057bc350 RM |
215 | Also see the Alarms section for status flags associated with fans. |
216 | ||
217 | ||
1da177e4 LT |
218 | ******* |
219 | * PWM * | |
220 | ******* | |
221 | ||
057bc350 | 222 | pwm[1-*] Pulse width modulation fan control. |
1da177e4 | 223 | Integer value in the range 0 to 255 |
057bc350 | 224 | RW |
1da177e4 LT |
225 | 255 is max or 100%. |
226 | ||
057bc350 | 227 | pwm[1-*]_enable |
875f25d5 JD |
228 | Fan speed control method: |
229 | 0: no fan speed control (i.e. fan at full speed) | |
230 | 1: manual fan speed control enabled (using pwm[1-*]) | |
231 | 2+: automatic fan speed control enabled | |
f8d0c19a JD |
232 | Check individual chip documentation files for automatic mode |
233 | details. | |
057bc350 RM |
234 | RW |
235 | ||
f8d0c19a JD |
236 | pwm[1-*]_mode 0: DC mode (direct current) |
237 | 1: PWM mode (pulse-width modulation) | |
238 | RW | |
239 | ||
240 | pwm[1-*]_freq Base PWM frequency in Hz. | |
241 | Only possibly available when pwmN_mode is PWM, but not always | |
242 | present even then. | |
057bc350 | 243 | RW |
1da177e4 LT |
244 | |
245 | pwm[1-*]_auto_channels_temp | |
246 | Select which temperature channels affect this PWM output in | |
247 | auto mode. Bitfield, 1 is temp1, 2 is temp2, 4 is temp3 etc... | |
248 | Which values are possible depend on the chip used. | |
057bc350 | 249 | RW |
1da177e4 LT |
250 | |
251 | pwm[1-*]_auto_point[1-*]_pwm | |
252 | pwm[1-*]_auto_point[1-*]_temp | |
253 | pwm[1-*]_auto_point[1-*]_temp_hyst | |
254 | Define the PWM vs temperature curve. Number of trip points is | |
255 | chip-dependent. Use this for chips which associate trip points | |
256 | to PWM output channels. | |
057bc350 | 257 | RW |
1da177e4 | 258 | |
1da177e4 LT |
259 | temp[1-*]_auto_point[1-*]_pwm |
260 | temp[1-*]_auto_point[1-*]_temp | |
261 | temp[1-*]_auto_point[1-*]_temp_hyst | |
262 | Define the PWM vs temperature curve. Number of trip points is | |
263 | chip-dependent. Use this for chips which associate trip points | |
264 | to temperature channels. | |
057bc350 | 265 | RW |
1da177e4 | 266 | |
f7290e24 JD |
267 | There is a third case where trip points are associated to both PWM output |
268 | channels and temperature channels: the PWM values are associated to PWM | |
269 | output channels while the temperature values are associated to temperature | |
270 | channels. In that case, the result is determined by the mapping between | |
271 | temperature inputs and PWM outputs. When several temperature inputs are | |
272 | mapped to a given PWM output, this leads to several candidate PWM values. | |
273 | The actual result is up to the chip, but in general the highest candidate | |
274 | value (fastest fan speed) wins. | |
275 | ||
1da177e4 LT |
276 | |
277 | **************** | |
278 | * Temperatures * | |
279 | **************** | |
280 | ||
057bc350 | 281 | temp[1-*]_type Sensor type selection. |
b26f9330 | 282 | Integers 1 to 6 |
057bc350 | 283 | RW |
1da177e4 LT |
284 | 1: PII/Celeron Diode |
285 | 2: 3904 transistor | |
286 | 3: thermal diode | |
b26f9330 | 287 | 4: thermistor |
61db011d RM |
288 | 5: AMD AMDSI |
289 | 6: Intel PECI | |
1da177e4 LT |
290 | Not all types are supported by all chips |
291 | ||
057bc350 | 292 | temp[1-*]_max Temperature max value. |
740e06a8 | 293 | Unit: millidegree Celsius (or millivolt, see below) |
057bc350 | 294 | RW |
1da177e4 | 295 | |
057bc350 | 296 | temp[1-*]_min Temperature min value. |
740e06a8 | 297 | Unit: millidegree Celsius |
057bc350 | 298 | RW |
1da177e4 | 299 | |
057bc350 | 300 | temp[1-*]_max_hyst |
1da177e4 | 301 | Temperature hysteresis value for max limit. |
740e06a8 | 302 | Unit: millidegree Celsius |
1da177e4 LT |
303 | Must be reported as an absolute temperature, NOT a delta |
304 | from the max value. | |
057bc350 | 305 | RW |
1da177e4 | 306 | |
057bc350 | 307 | temp[1-*]_input Temperature input value. |
740e06a8 | 308 | Unit: millidegree Celsius |
057bc350 | 309 | RO |
1da177e4 | 310 | |
f46fc8cd | 311 | temp[1-*]_crit Temperature critical max value, typically greater than |
1da177e4 | 312 | corresponding temp_max values. |
740e06a8 | 313 | Unit: millidegree Celsius |
057bc350 | 314 | RW |
1da177e4 | 315 | |
057bc350 | 316 | temp[1-*]_crit_hyst |
1da177e4 | 317 | Temperature hysteresis value for critical limit. |
740e06a8 | 318 | Unit: millidegree Celsius |
1da177e4 LT |
319 | Must be reported as an absolute temperature, NOT a delta |
320 | from the critical value. | |
057bc350 | 321 | RW |
1da177e4 | 322 | |
28e7438f GR |
323 | temp[1-*]_emergency |
324 | Temperature emergency max value, for chips supporting more than | |
325 | two upper temperature limits. Must be equal or greater than | |
326 | corresponding temp_crit values. | |
327 | Unit: millidegree Celsius | |
328 | RW | |
329 | ||
330 | temp[1-*]_emergency_hyst | |
331 | Temperature hysteresis value for emergency limit. | |
332 | Unit: millidegree Celsius | |
333 | Must be reported as an absolute temperature, NOT a delta | |
334 | from the emergency value. | |
335 | RW | |
336 | ||
f46fc8cd GR |
337 | temp[1-*]_lcrit Temperature critical min value, typically lower than |
338 | corresponding temp_min values. | |
339 | Unit: millidegree Celsius | |
340 | RW | |
341 | ||
176544dc | 342 | temp[1-*]_offset |
59ac8367 HR |
343 | Temperature offset which is added to the temperature reading |
344 | by the chip. | |
345 | Unit: millidegree Celsius | |
346 | Read/Write value. | |
347 | ||
176544dc JD |
348 | temp[1-*]_label Suggested temperature channel label. |
349 | Text string | |
350 | Should only be created if the driver has hints about what | |
351 | this temperature channel is being used for, and user-space | |
352 | doesn't. In all other cases, the label is provided by | |
353 | user-space. | |
354 | RO | |
1da177e4 | 355 | |
cd4e96c5 AP |
356 | temp[1-*]_lowest |
357 | Historical minimum temperature | |
358 | Unit: millidegree Celsius | |
359 | RO | |
360 | ||
361 | temp[1-*]_highest | |
362 | Historical maximum temperature | |
363 | Unit: millidegree Celsius | |
364 | RO | |
365 | ||
366 | temp[1-*]_reset_history | |
367 | Reset temp_lowest and temp_highest | |
368 | WO | |
369 | ||
370 | temp_reset_history | |
371 | Reset temp_lowest and temp_highest for all sensors | |
372 | WO | |
373 | ||
740e06a8 JD |
374 | Some chips measure temperature using external thermistors and an ADC, and |
375 | report the temperature measurement as a voltage. Converting this voltage | |
376 | back to a temperature (or the other way around for limits) requires | |
377 | mathematical functions not available in the kernel, so the conversion | |
378 | must occur in user space. For these chips, all temp* files described | |
379 | above should contain values expressed in millivolt instead of millidegree | |
380 | Celsius. In other words, such temperature channels are handled as voltage | |
381 | channels by the driver. | |
382 | ||
057bc350 RM |
383 | Also see the Alarms section for status flags associated with temperatures. |
384 | ||
1da177e4 LT |
385 | |
386 | ************ | |
387 | * Currents * | |
388 | ************ | |
389 | ||
057bc350 | 390 | curr[1-*]_max Current max value |
1da177e4 | 391 | Unit: milliampere |
057bc350 | 392 | RW |
1da177e4 | 393 | |
057bc350 | 394 | curr[1-*]_min Current min value. |
1da177e4 | 395 | Unit: milliampere |
057bc350 | 396 | RW |
1da177e4 | 397 | |
581693b5 GR |
398 | curr[1-*]_lcrit Current critical low value |
399 | Unit: milliampere | |
400 | RW | |
401 | ||
402 | curr[1-*]_crit Current critical high value. | |
403 | Unit: milliampere | |
404 | RW | |
405 | ||
057bc350 | 406 | curr[1-*]_input Current input value |
1da177e4 | 407 | Unit: milliampere |
057bc350 | 408 | RO |
1da177e4 | 409 | |
581693b5 GR |
410 | Also see the Alarms section for status flags associated with currents. |
411 | ||
38fb56a2 DW |
412 | ********* |
413 | * Power * | |
414 | ********* | |
415 | ||
416 | power[1-*]_average Average power use | |
417 | Unit: microWatt | |
418 | RO | |
419 | ||
115a57c5 DW |
420 | power[1-*]_average_interval Power use averaging interval. A poll |
421 | notification is sent to this file if the | |
422 | hardware changes the averaging interval. | |
ddedc658 DW |
423 | Unit: milliseconds |
424 | RW | |
425 | ||
115a57c5 DW |
426 | power[1-*]_average_interval_max Maximum power use averaging interval |
427 | Unit: milliseconds | |
428 | RO | |
429 | ||
430 | power[1-*]_average_interval_min Minimum power use averaging interval | |
431 | Unit: milliseconds | |
432 | RO | |
433 | ||
38fb56a2 DW |
434 | power[1-*]_average_highest Historical average maximum power use |
435 | Unit: microWatt | |
436 | RO | |
437 | ||
438 | power[1-*]_average_lowest Historical average minimum power use | |
439 | Unit: microWatt | |
440 | RO | |
441 | ||
115a57c5 DW |
442 | power[1-*]_average_max A poll notification is sent to |
443 | power[1-*]_average when power use | |
444 | rises above this value. | |
445 | Unit: microWatt | |
446 | RW | |
447 | ||
448 | power[1-*]_average_min A poll notification is sent to | |
449 | power[1-*]_average when power use | |
450 | sinks below this value. | |
451 | Unit: microWatt | |
452 | RW | |
453 | ||
38fb56a2 DW |
454 | power[1-*]_input Instantaneous power use |
455 | Unit: microWatt | |
456 | RO | |
457 | ||
458 | power[1-*]_input_highest Historical maximum power use | |
459 | Unit: microWatt | |
460 | RO | |
461 | ||
462 | power[1-*]_input_lowest Historical minimum power use | |
463 | Unit: microWatt | |
464 | RO | |
465 | ||
466 | power[1-*]_reset_history Reset input_highest, input_lowest, | |
467 | average_highest and average_lowest. | |
468 | WO | |
1da177e4 | 469 | |
115a57c5 DW |
470 | power[1-*]_accuracy Accuracy of the power meter. |
471 | Unit: Percent | |
472 | RO | |
473 | ||
115a57c5 DW |
474 | power[1-*]_cap If power use rises above this limit, the |
475 | system should take action to reduce power use. | |
476 | A poll notification is sent to this file if the | |
477 | cap is changed by the hardware. The *_cap | |
478 | files only appear if the cap is known to be | |
479 | enforced by hardware. | |
480 | Unit: microWatt | |
481 | RW | |
482 | ||
483 | power[1-*]_cap_hyst Margin of hysteresis built around capping and | |
484 | notification. | |
485 | Unit: microWatt | |
486 | RW | |
487 | ||
488 | power[1-*]_cap_max Maximum cap that can be set. | |
489 | Unit: microWatt | |
490 | RO | |
491 | ||
492 | power[1-*]_cap_min Minimum cap that can be set. | |
493 | Unit: microWatt | |
494 | RO | |
495 | ||
581693b5 GR |
496 | power[1-*]_max Maximum power. |
497 | Unit: microWatt | |
498 | RW | |
499 | ||
500 | power[1-*]_crit Critical maximum power. | |
501 | If power rises to or above this limit, the | |
502 | system is expected take drastic action to reduce | |
503 | power consumption, such as a system shutdown or | |
504 | a forced powerdown of some devices. | |
505 | Unit: microWatt | |
506 | RW | |
507 | ||
508 | Also see the Alarms section for status flags associated with power readings. | |
509 | ||
ddedc658 DW |
510 | ********** |
511 | * Energy * | |
512 | ********** | |
513 | ||
514 | energy[1-*]_input Cumulative energy use | |
515 | Unit: microJoule | |
516 | RO | |
517 | ||
ec199209 | 518 | |
c6c2c163 GR |
519 | ************ |
520 | * Humidity * | |
521 | ************ | |
522 | ||
523 | humidity[1-*]_input Humidity | |
524 | Unit: milli-percent (per cent mille, pcm) | |
525 | RO | |
526 | ||
527 | ||
400b48ec JD |
528 | ********** |
529 | * Alarms * | |
530 | ********** | |
531 | ||
532 | Each channel or limit may have an associated alarm file, containing a | |
533 | boolean value. 1 means than an alarm condition exists, 0 means no alarm. | |
534 | ||
535 | Usually a given chip will either use channel-related alarms, or | |
536 | limit-related alarms, not both. The driver should just reflect the hardware | |
537 | implementation. | |
538 | ||
057bc350 | 539 | in[0-*]_alarm |
e04a715e | 540 | curr[1-*]_alarm |
581693b5 | 541 | power[1-*]_alarm |
057bc350 RM |
542 | fan[1-*]_alarm |
543 | temp[1-*]_alarm | |
400b48ec | 544 | Channel alarm |
057bc350 RM |
545 | 0: no alarm |
546 | 1: alarm | |
547 | RO | |
400b48ec JD |
548 | |
549 | OR | |
550 | ||
057bc350 RM |
551 | in[0-*]_min_alarm |
552 | in[0-*]_max_alarm | |
581693b5 GR |
553 | in[0-*]_lcrit_alarm |
554 | in[0-*]_crit_alarm | |
e04a715e GR |
555 | curr[1-*]_min_alarm |
556 | curr[1-*]_max_alarm | |
581693b5 GR |
557 | curr[1-*]_lcrit_alarm |
558 | curr[1-*]_crit_alarm | |
559 | power[1-*]_cap_alarm | |
560 | power[1-*]_max_alarm | |
561 | power[1-*]_crit_alarm | |
057bc350 | 562 | fan[1-*]_min_alarm |
d54d4624 | 563 | fan[1-*]_max_alarm |
057bc350 RM |
564 | temp[1-*]_min_alarm |
565 | temp[1-*]_max_alarm | |
581693b5 | 566 | temp[1-*]_lcrit_alarm |
057bc350 | 567 | temp[1-*]_crit_alarm |
28e7438f | 568 | temp[1-*]_emergency_alarm |
400b48ec | 569 | Limit alarm |
057bc350 RM |
570 | 0: no alarm |
571 | 1: alarm | |
572 | RO | |
400b48ec JD |
573 | |
574 | Each input channel may have an associated fault file. This can be used | |
575 | to notify open diodes, unconnected fans etc. where the hardware | |
576 | supports it. When this boolean has value 1, the measurement for that | |
577 | channel should not be trusted. | |
578 | ||
7817a39e JD |
579 | fan[1-*]_fault |
580 | temp[1-*]_fault | |
400b48ec | 581 | Input fault condition |
25985edc | 582 | 0: no fault occurred |
057bc350 RM |
583 | 1: fault condition |
584 | RO | |
400b48ec JD |
585 | |
586 | Some chips also offer the possibility to get beeped when an alarm occurs: | |
587 | ||
588 | beep_enable Master beep enable | |
057bc350 RM |
589 | 0: no beeps |
590 | 1: beeps | |
591 | RW | |
400b48ec | 592 | |
057bc350 | 593 | in[0-*]_beep |
e04a715e | 594 | curr[1-*]_beep |
057bc350 RM |
595 | fan[1-*]_beep |
596 | temp[1-*]_beep | |
400b48ec | 597 | Channel beep |
057bc350 RM |
598 | 0: disable |
599 | 1: enable | |
600 | RW | |
400b48ec JD |
601 | |
602 | In theory, a chip could provide per-limit beep masking, but no such chip | |
603 | was seen so far. | |
604 | ||
605 | Old drivers provided a different, non-standard interface to alarms and | |
606 | beeps. These interface files are deprecated, but will be kept around | |
607 | for compatibility reasons: | |
1da177e4 LT |
608 | |
609 | alarms Alarm bitmask. | |
057bc350 | 610 | RO |
1da177e4 LT |
611 | Integer representation of one to four bytes. |
612 | A '1' bit means an alarm. | |
613 | Chips should be programmed for 'comparator' mode so that | |
614 | the alarm will 'come back' after you read the register | |
615 | if it is still valid. | |
616 | Generally a direct representation of a chip's internal | |
617 | alarm registers; there is no standard for the position | |
400b48ec JD |
618 | of individual bits. For this reason, the use of this |
619 | interface file for new drivers is discouraged. Use | |
620 | individual *_alarm and *_fault files instead. | |
1da177e4 LT |
621 | Bits are defined in kernel/include/sensors.h. |
622 | ||
1da177e4 | 623 | beep_mask Bitmask for beep. |
400b48ec JD |
624 | Same format as 'alarms' with the same bit locations, |
625 | use discouraged for the same reason. Use individual | |
626 | *_beep files instead. | |
057bc350 | 627 | RW |
2ed42633 HG |
628 | |
629 | ||
ec199209 JD |
630 | *********************** |
631 | * Intrusion detection * | |
632 | *********************** | |
633 | ||
634 | intrusion[0-*]_alarm | |
635 | Chassis intrusion detection | |
636 | 0: OK | |
637 | 1: intrusion detected | |
638 | RW | |
639 | Contrary to regular alarm flags which clear themselves | |
640 | automatically when read, this one sticks until cleared by | |
641 | the user. This is done by writing 0 to the file. Writing | |
642 | other values is unsupported. | |
643 | ||
644 | intrusion[0-*]_beep | |
645 | Chassis intrusion beep | |
646 | 0: disable | |
647 | 1: enable | |
648 | RW | |
649 | ||
650 | ||
2ed42633 HG |
651 | sysfs attribute writes interpretation |
652 | ------------------------------------- | |
653 | ||
654 | hwmon sysfs attributes always contain numbers, so the first thing to do is to | |
655 | convert the input to a number, there are 2 ways todo this depending whether | |
656 | the number can be negative or not: | |
657 | unsigned long u = simple_strtoul(buf, NULL, 10); | |
658 | long s = simple_strtol(buf, NULL, 10); | |
659 | ||
660 | With buf being the buffer with the user input being passed by the kernel. | |
661 | Notice that we do not use the second argument of strto[u]l, and thus cannot | |
662 | tell when 0 is returned, if this was really 0 or is caused by invalid input. | |
663 | This is done deliberately as checking this everywhere would add a lot of | |
664 | code to the kernel. | |
665 | ||
666 | Notice that it is important to always store the converted value in an | |
667 | unsigned long or long, so that no wrap around can happen before any further | |
668 | checking. | |
669 | ||
670 | After the input string is converted to an (unsigned) long, the value should be | |
671 | checked if its acceptable. Be careful with further conversions on the value | |
672 | before checking it for validity, as these conversions could still cause a wrap | |
673 | around before the check. For example do not multiply the result, and only | |
674 | add/subtract if it has been divided before the add/subtract. | |
675 | ||
676 | What to do if a value is found to be invalid, depends on the type of the | |
677 | sysfs attribute that is being set. If it is a continuous setting like a | |
678 | tempX_max or inX_max attribute, then the value should be clamped to its | |
679 | limits using SENSORS_LIMIT(value, min_limit, max_limit). If it is not | |
680 | continuous like for example a tempX_type, then when an invalid value is | |
681 | written, -EINVAL should be returned. | |
682 | ||
683 | Example1, temp1_max, register is a signed 8 bit value (-128 - 127 degrees): | |
5fbea518 JD |
684 | |
685 | long v = simple_strtol(buf, NULL, 10) / 1000; | |
686 | v = SENSORS_LIMIT(v, -128, 127); | |
687 | /* write v to register */ | |
2ed42633 HG |
688 | |
689 | Example2, fan divider setting, valid values 2, 4 and 8: | |
5fbea518 JD |
690 | |
691 | unsigned long v = simple_strtoul(buf, NULL, 10); | |
692 | ||
693 | switch (v) { | |
694 | case 2: v = 1; break; | |
695 | case 4: v = 2; break; | |
696 | case 8: v = 3; break; | |
697 | default: | |
698 | return -EINVAL; | |
699 | } | |
700 | /* write v to register */ |