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.
68 -------------------------------------------------------------------------
71 `[0-*]`	denotes any positive number starting from 0
72 `[1-*]`	denotes any positive number starting from 1
78 Read/write values may be read-only for some chips, depending on the
82 given driver if the chip has the feature.
90 		The chip name.
93 		This attribute represents the chip name. It is the only
100 		The interval at which the chip will update readings.
113 `in[0-*]_min`
120 `in[0-*]_lcrit`
131 `in[0-*]_max`
138 `in[0-*]_crit`
149 `in[0-*]_input`
156 		Voltage measured on the chip pin.
159 		motherboard, as recommended in the chip datasheet.
161 		This varies by chip and by motherboard.
163 		by the chip driver, and must be done by the application.
165 		do scale, because of internal resistors built into a chip.
168 		"pins" of the chip.
170 `in[0-*]_average`
177 `in[0-*]_lowest`
184 `in[0-*]_highest`
191 `in[0-*]_reset_history`
201 `in[0-*]_label`
207 		this voltage channel is being used for, and user-space
209 		user-space.
213 `in[0-*]_enable`
216 		When disabled the sensor read will return -ENODATA.
218 		- 1: Enable
219 		- 0: Disable
223 `cpu[0-*]_vid`
244 `in[0-*]_rated_min`
251 `in[0-*]_rated_max`
265 `fan[1-*]_min`
272 `fan[1-*]_max`
280 `fan[1-*]_input`
287 `fan[1-*]_div`
298 `fan[1-*]_pulses`
309 		Should only be created if the chip has a register to configure
314 `fan[1-*]_target`
321 		Only makes sense if the chip supports closed-loop fan speed
324 `fan[1-*]_label`
330 		this fan channel is being used for, and user-space doesn't.
331 		In all other cases, the label is provided by user-space.
335 `fan[1-*]_enable`
338 		When disabled the sensor read will return -ENODATA.
340 		- 1: Enable
341 		- 0: Disable
352 `pwm[1-*]`
361 `pwm[1-*]_enable`
364 		- 0: no fan speed control (i.e. fan at full speed)
365 		- 1: manual fan speed control enabled (using `pwm[1-*]`)
366 		- 2+: automatic fan speed control enabled
368 		Check individual chip documentation files for automatic mode
373 `pwm[1-*]_mode`
374 		- 0: DC mode (direct current)
375 		- 1: PWM mode (pulse-width modulation)
379 `pwm[1-*]_freq`
387 `pwm[1-*]_auto_channels_temp`
388 		Select which temperature channels affect this PWM output in
392 		Which values are possible depend on the chip used.
396 `pwm[1-*]_auto_point[1-*]_pwm` / `pwm[1-*]_auto_point[1-*]_temp` / `pwm[1-*]_auto_point[1-*]_temp_h…
397 		Define the PWM vs temperature curve.
399 		Number of trip points is chip-dependent. Use this for chips
404 `temp[1-*]_auto_point[1-*]_pwm` / `temp[1-*]_auto_point[1-*]_temp` / `temp[1-*]_auto_point[1-*]_tem…
405 		Define the PWM vs temperature curve.
407 		Number of trip points is chip-dependent. Use this for chips
408 		which associate trip points to temperature channels.
413 channels and temperature channels: the PWM values are associated to PWM
414 output channels while the temperature values are associated to temperature
416 temperature inputs and PWM outputs. When several temperature inputs are
418 The actual result is up to the chip, but in general the highest candidate
426 `temp[1-*]_type`
433 		- 1: CPU embedded diode
434 		- 2: 3904 transistor
435 		- 3: thermal diode
436 		- 4: thermistor
437 		- 5: AMD AMDSI
438 		- 6: Intel PECI
442 `temp[1-*]_max`
443 		Temperature max value.
445 		Unit: millidegree Celsius (or millivolt, see below)
449 `temp[1-*]_min`
450 		Temperature min value.
452 		Unit: millidegree Celsius
456 `temp[1-*]_max_hyst`
457 		Temperature hysteresis value for max limit.
459 		Unit: millidegree Celsius
461 		Must be reported as an absolute temperature, NOT a delta
466 `temp[1-*]_min_hyst`
467 		Temperature hysteresis value for min limit.
468 		Unit: millidegree Celsius
470 		Must be reported as an absolute temperature, NOT a delta
475 `temp[1-*]_input`
476 	 Temperature input value.
478 		Unit: millidegree Celsius
482 `temp[1-*]_crit`
483 		Temperature critical max value, typically greater than
486 		Unit: millidegree Celsius
490 `temp[1-*]_crit_hyst`
491 		Temperature hysteresis value for critical limit.
493 		Unit: millidegree Celsius
495 		Must be reported as an absolute temperature, NOT a delta
500 `temp[1-*]_emergency`
501 		Temperature emergency max value, for chips supporting more than
502 		two upper temperature limits. Must be equal or greater than
505 		Unit: millidegree Celsius
509 `temp[1-*]_emergency_hyst`
510 		Temperature hysteresis value for emergency limit.
512 		Unit: millidegree Celsius
514 		Must be reported as an absolute temperature, NOT a delta
519 `temp[1-*]_lcrit`
520 		Temperature critical min value, typically lower than
523 		Unit: millidegree Celsius
527 `temp[1-*]_lcrit_hyst`
528 		Temperature hysteresis value for critical min limit.
530 		Unit: millidegree Celsius
532 		Must be reported as an absolute temperature, NOT a delta
537 `temp[1-*]_offset`
538 		Temperature offset which is added to the temperature reading
539 		by the chip.
541 		Unit: millidegree Celsius
545 `temp[1-*]_label`
546 		Suggested temperature channel label.
551 		this temperature channel is being used for, and user-space
553 		user-space.
557 `temp[1-*]_lowest`
558 		Historical minimum temperature
560 		Unit: millidegree Celsius
564 `temp[1-*]_highest`
565 		Historical maximum temperature
567 		Unit: millidegree Celsius
571 `temp[1-*]_reset_history`
581 `temp[1-*]_enable`
584 		When disabled the sensor read will return -ENODATA.
586 		- 1: Enable
587 		- 0: Disable
591 `temp[1-*]_rated_min`
592 		Minimum rated temperature.
594 		Unit: millidegree Celsius
598 `temp[1-*]_rated_max`
599 		Maximum rated temperature.
601 		Unit: millidegree Celsius
605 Some chips measure temperature using external thermistors and an ADC, and
606 report the temperature measurement as a voltage. Converting this voltage
607 back to a temperature (or the other way around for limits) requires
611 Celsius. In other words, such temperature channels are handled as voltage
621 `curr[1-*]_max`
628 `curr[1-*]_min`
635 `curr[1-*]_lcrit`
642 `curr[1-*]_crit`
649 `curr[1-*]_input`
656 `curr[1-*]_average`
663 `curr[1-*]_lowest`
670 `curr[1-*]_highest`
675 `curr[1-*]_reset_history`
685 `curr[1-*]_enable`
688 		When disabled the sensor read will return -ENODATA.
690 		- 1: Enable
691 		- 0: Disable
695 `curr[1-*]_rated_min`
702 `curr[1-*]_rated_max`
715 `power[1-*]_average`
722 `power[1-*]_average_interval`
731 `power[1-*]_average_interval_max`
738 `power[1-*]_average_interval_min`
745 `power[1-*]_average_highest`
752 `power[1-*]_average_lowest`
759 `power[1-*]_average_max`
761 				`power[1-*]_average` when power use
768 `power[1-*]_average_min`
770 				`power[1-*]_average` when power use
777 `power[1-*]_input`
784 `power[1-*]_input_highest`
791 `power[1-*]_input_lowest`
798 `power[1-*]_reset_history`
804 `power[1-*]_accuracy`
811 `power[1-*]_cap`
823 `power[1-*]_cap_hyst`
831 `power[1-*]_cap_max`
838 `power[1-*]_cap_min`
845 `power[1-*]_max`
852 `power[1-*]_crit`
864 `power[1-*]_enable`
868 				-ENODATA.
870 				- 1: Enable
871 				- 0: Disable
875 `power[1-*]_rated_min`
882 `power[1-*]_rated_max`
895 `energy[1-*]_input`
902 `energy[1-*]_enable`
906 				-ENODATA.
908 				- 1: Enable
909 				- 0: Disable
917 `humidity[1-*]_input`
920 				Unit: milli-percent (per cent mille, pcm)
925 `humidity[1-*]_enable`
929 				-ENODATA.
931 				- 1: Enable
932 				- 0: Disable
936 `humidity[1-*]_rated_min`
939 				Unit: milli-percent (per cent mille, pcm)
943 `humidity[1-*]_rated_max`
946 				Unit: milli-percent (per cent mille, pcm)
957 Usually a given chip will either use channel-related alarms, or
958 limit-related alarms, not both. The driver should just reflect the hardware
961 +-------------------------------+-----------------------+
962 | **`in[0-*]_alarm`,		| Channel alarm		|
963 | `curr[1-*]_alarm`,		|			|
964 | `power[1-*]_alarm`,		|   - 0: no alarm	|
965 | `fan[1-*]_alarm`,		|   - 1: alarm		|
966 | `temp[1-*]_alarm`**		|			|
968 +-------------------------------+-----------------------+
972 +-------------------------------+-----------------------+
973 | **`in[0-*]_min_alarm`,	| Limit alarm		|
974 | `in[0-*]_max_alarm`,		|			|
975 | `in[0-*]_lcrit_alarm`,	|   - 0: no alarm	|
976 | `in[0-*]_crit_alarm`,		|   - 1: alarm		|
977 | `curr[1-*]_min_alarm`,	|			|
978 | `curr[1-*]_max_alarm`,	| RO			|
979 | `curr[1-*]_lcrit_alarm`,	|			|
980 | `curr[1-*]_crit_alarm`,	|			|
981 | `power[1-*]_cap_alarm`,	|			|
982 | `power[1-*]_max_alarm`,	|			|
983 | `power[1-*]_crit_alarm`,	|			|
984 | `fan[1-*]_min_alarm`,		|			|
985 | `fan[1-*]_max_alarm`,		|			|
986 | `temp[1-*]_min_alarm`,	|			|
987 | `temp[1-*]_max_alarm`,	|			|
988 | `temp[1-*]_lcrit_alarm`,	|			|
989 | `temp[1-*]_crit_alarm`,	|			|
990 | `temp[1-*]_emergency_alarm`**	|			|
991 +-------------------------------+-----------------------+
998 `fan[1-*]_fault` / `temp[1-*]_fault`
1001 		- 0: no fault occurred
1002 		- 1: fault condition
1011 		- 0: no beeps
1012 		- 1: beeps
1016 `in[0-*]_beep`, `curr[1-*]_beep`, `fan[1-*]_beep`, `temp[1-*]_beep`,
1019 		- 0: disable
1020 		- 1: enable
1024 In theory, a chip could provide per-limit beep masking, but no such chip
1027 Old drivers provided a different, non-standard interface to alarms and
1044 		Generally a direct representation of a chip's internal
1063 `intrusion[0-*]_alarm`
1066 		- 0: OK
1067 		- 1: intrusion detected
1076 `intrusion[0-*]_beep`
1091 +--------------+---------------------------------------------------------------+
1095 +--------------+---------------------------------------------------------------+
1104 +--------------+---------------------------------------------------------------+
1107 -------------------------------------
1137 -EINVAL should be returned.
1139 Example1, temp1_max, register is a signed 8 bit value (-128 - 127 degrees)::
1142 	v = clamp_val(v, -128, 127);
1154 		return -EINVAL;