Documentation/hwmon/sysfs-interface.rst

5 through the sysfs interface. Since lm-sensors 3.0.0, libsensors is
6 completely chip-independent. It assumes that all the kernel drivers
8 This makes adding or updating support for any given chip very easy, as
10 This is a major improvement compared to lm-sensors 2.
14 temperature sensor is connected to the CPU, or that the second fan is on
22 For this reason, even if we aim at a chip-independent libsensors, it will
33 Each chip gets its own directory in the sysfs /sys/devices tree.  To
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
48 types for sensor chips are "in" (voltage), "temp" (temperature) and
50 threshold, "min" (low threshold). Numbering usually starts from 1,
54 specific chip. Other files do not refer to a specific element, so
60 alarm (for example, whether a threshold must be met or must be exceeded
61 to cause an alarm) is chip-dependent.
69 ----------------
76 -------------------------------------------------------------------------
79 `[0-*]`	denotes any positive number starting from 0
80 `[1-*]`	denotes any positive number starting from 1
86 Read/write values may be read-only for some chips, depending on the
90 given driver if the chip has the feature.
92 See Documentation/ABI/testing/sysfs-class-hwmon for a complete description
100 		The chip name.
107 		The interval at which the chip will update readings.
114 `in[0-*]_min`
117 `in[0-*]_lcrit`
120 `in[0-*]_max`
123 `in[0-*]_crit`
126 `in[0-*]_input`
129 `in[0-*]_average`
132 `in[0-*]_lowest`
135 `in[0-*]_highest`
138 `in[0-*]_reset_history`
144 `in[0-*]_label`
147 `in[0-*]_enable`
150 `cpu[0-*]_vid`
156 `in[0-*]_rated_min`
159 `in[0-*]_rated_max`
169 `fan[1-*]_min`
172 `fan[1-*]_max`
175 `fan[1-*]_input`
178 `fan[1-*]_div`
181 `fan[1-*]_pulses`
184 `fan[1-*]_target`
187 `fan[1-*]_label`
190 `fan[1-*]_enable`
200 `pwm[1-*]`
203 `pwm[1-*]_enable`
206 `pwm[1-*]_mode`
207 		direct current or pulse-width modulation.
209 `pwm[1-*]_freq`
212 `pwm[1-*]_auto_channels_temp`
213 		Select which temperature channels affect this PWM output in
216 `pwm[1-*]_auto_point[1-*]_pwm` / `pwm[1-*]_auto_point[1-*]_temp` / `pwm[1-*]_auto_point[1-*]_temp_h…
217 		Define the PWM vs temperature curve.
219 `temp[1-*]_auto_point[1-*]_pwm` / `temp[1-*]_auto_point[1-*]_temp` / `temp[1-*]_auto_point[1-*]_tem…
220 		Define the PWM vs temperature curve.
223 channels and temperature channels: the PWM values are associated to PWM
224 output channels while the temperature values are associated to temperature
226 temperature inputs and PWM outputs. When several temperature inputs are
228 The actual result is up to the chip, but in general the highest candidate
236 `temp[1-*]_type`
239 `temp[1-*]_max`
240 		Temperature max value.
242 `temp[1-*]_min`
243 		Temperature min value.
245 `temp[1-*]_max_hyst`
246 		Temperature hysteresis value for max limit.
248 `temp[1-*]_min_hyst`
249 		Temperature hysteresis value for min limit.
251 `temp[1-*]_input`
252 		Temperature input value.
254 `temp[1-*]_crit`
255 		Temperature critical max value, typically greater than
258 `temp[1-*]_crit_hyst`
259 		Temperature hysteresis value for critical limit.
261 `temp[1-*]_emergency`
262 		Temperature emergency max value, for chips supporting more than
263 		two upper temperature limits.
265 `temp[1-*]_emergency_hyst`
266 		Temperature hysteresis value for emergency limit.
268 `temp[1-*]_lcrit`
269 		Temperature critical min value, typically lower than
272 `temp[1-*]_lcrit_hyst`
273 		Temperature hysteresis value for critical min limit.
275 `temp[1-*]_offset`
276 		Temperature offset which is added to the temperature reading
277 		by the chip.
279 `temp[1-*]_label`
280 		Suggested temperature channel label.
282 `temp[1-*]_lowest`
283 		Historical minimum temperature
285 `temp[1-*]_highest`
286 		Historical maximum temperature
288 `temp[1-*]_reset_history`
294 `temp[1-*]_enable`
297 `temp[1-*]_rated_min`
298 		Minimum rated temperature.
300 `temp[1-*]_rated_max`
301 		Maximum rated temperature.
303 Some chips measure temperature using external thermistors and an ADC, and
304 report the temperature measurement as a voltage. Converting this voltage
305 back to a temperature (or the other way around for limits) requires
309 Celsius. In other words, such temperature channels are handled as voltage
319 `curr[1-*]_max`
322 `curr[1-*]_min`
325 `curr[1-*]_lcrit`
328 `curr[1-*]_crit`
331 `curr[1-*]_input`
334 `curr[1-*]_average`
337 `curr[1-*]_lowest`
340 `curr[1-*]_highest`
343 `curr[1-*]_reset_history`
351 `curr[1-*]_enable`
354 `curr[1-*]_rated_min`
357 `curr[1-*]_rated_max`
366 `power[1-*]_average`
369 `power[1-*]_average_interval`
372 `power[1-*]_average_interval_max`
375 `power[1-*]_average_interval_min`
378 `power[1-*]_average_highest`
381 `power[1-*]_average_lowest`
384 `power[1-*]_average_max`
385 		A poll notification is sent to `power[1-*]_average` when
388 `power[1-*]_average_min`
389 		A poll notification is sent to `power[1-*]_average` when
392 `power[1-*]_input`
395 `power[1-*]_input_highest`
398 `power[1-*]_input_lowest`
401 `power[1-*]_reset_history`
405 `power[1-*]_accuracy`
408 `power[1-*]_cap`
412 `power[1-*]_cap_hyst`
415 `power[1-*]_cap_max`
418 `power[1-*]_cap_min`
421 `power[1-*]_max`
424 `power[1-*]_crit`
436 `power[1-*]_enable`
440 				-ENODATA.
442 				- 1: Enable
443 				- 0: Disable
447 `power[1-*]_rated_min`
454 `power[1-*]_rated_max`
467 `energy[1-*]_input`
474 `energy[1-*]_enable`
478 				-ENODATA.
480 				- 1: Enable
481 				- 0: Disable
489 `humidity[1-*]_input`
492 `humidity[1-*]_enable`
495 `humidity[1-*]_rated_min`
498 `humidity[1-*]_rated_max`
508 Usually a given chip will either use channel-related alarms, or
509 limit-related alarms, not both. The driver should just reflect the hardware
512 +-------------------------------+-----------------------+
513 | **`in[0-*]_alarm`,		| Channel alarm		|
514 | `curr[1-*]_alarm`,		|			|
515 | `power[1-*]_alarm`,		|   - 0: no alarm	|
516 | `fan[1-*]_alarm`,		|   - 1: alarm		|
517 | `temp[1-*]_alarm`**		|			|
519 +-------------------------------+-----------------------+
523 +-------------------------------+-----------------------+
524 | **`in[0-*]_min_alarm`,	| Limit alarm		|
525 | `in[0-*]_max_alarm`,		|			|
526 | `in[0-*]_lcrit_alarm`,	|   - 0: no alarm	|
527 | `in[0-*]_crit_alarm`,		|   - 1: alarm		|
528 | `curr[1-*]_min_alarm`,	|			|
529 | `curr[1-*]_max_alarm`,	| RO			|
530 | `curr[1-*]_lcrit_alarm`,	|			|
531 | `curr[1-*]_crit_alarm`,	|			|
532 | `power[1-*]_cap_alarm`,	|			|
533 | `power[1-*]_max_alarm`,	|			|
534 | `power[1-*]_crit_alarm`,	|			|
535 | `fan[1-*]_min_alarm`,		|			|
536 | `fan[1-*]_max_alarm`,		|			|
537 | `temp[1-*]_min_alarm`,	|			|
538 | `temp[1-*]_max_alarm`,	|			|
539 | `temp[1-*]_lcrit_alarm`,	|			|
540 | `temp[1-*]_crit_alarm`,	|			|
541 | `temp[1-*]_emergency_alarm`**	|			|
542 +-------------------------------+-----------------------+
549 `fan[1-*]_fault` / `temp[1-*]_fault`
557 `in[0-*]_beep`, `curr[1-*]_beep`, `fan[1-*]_beep`, `temp[1-*]_beep`,
560 In theory, a chip could provide per-limit beep masking, but no such chip
563 Old drivers provided a different, non-standard interface to alarms and
578 `intrusion[0-*]_alarm`
581 `intrusion[0-*]_beep`
591 +--------------+---------------------------------------------------------------+
595 +--------------+---------------------------------------------------------------+
604 +--------------+---------------------------------------------------------------+
607 -------------------------------------
637 -EINVAL should be returned.
639 Example1, temp1_max, register is a signed 8 bit value (-128 - 127 degrees)::
642 	v = clamp_val(v, -128, 127);
654 		return -EINVAL;