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Diffstat (limited to 'Documentation/hwmon/sysfs-interface')
| -rw-r--r-- | Documentation/hwmon/sysfs-interface | 332 |
1 files changed, 296 insertions, 36 deletions
diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface index f4a8ebc1ef1..2cc95ad4660 100644 --- a/Documentation/hwmon/sysfs-interface +++ b/Documentation/hwmon/sysfs-interface @@ -2,17 +2,12 @@ Naming and data format standards for sysfs files ------------------------------------------------ The libsensors library offers an interface to the raw sensors data -through the sysfs interface. See libsensors documentation and source for -further information. As of writing this document, libsensors -(from lm_sensors 2.8.3) is heavily chip-dependent. Adding or updating -support for any given chip requires modifying the library's code. -This is because libsensors was written for the procfs interface -older kernel modules were using, which wasn't standardized enough. -Recent versions of libsensors (from lm_sensors 2.8.2 and later) have -support for the sysfs interface, though. - -The new sysfs interface was designed to be as chip-independent as -possible. +through the sysfs interface. Since lm-sensors 3.0.0, libsensors is +completely chip-independent. It assumes that all the kernel drivers +implement the standard sysfs interface described in this document. +This makes adding or updating support for any given chip very easy, as +libsensors, and applications using it, do not need to be modified. +This is a major improvement compared to lm-sensors 2. Note that motherboards vary widely in the connections to sensor chips. There is no standard that ensures, for example, that the second @@ -35,19 +30,17 @@ access this data in a simple and consistent way. That said, such programs will have to implement conversion, labeling and hiding of inputs. For this reason, it is still not recommended to bypass the library. -If you are developing a userspace application please send us feedback on -this standard. - -Note that this standard isn't completely established yet, so it is subject -to changes. If you are writing a new hardware monitoring driver those -features can't seem to fit in this interface, please contact us with your -extension proposal. Keep in mind that backward compatibility must be -preserved. - Each chip gets its own directory in the sysfs /sys/devices tree. To find all sensor chips, it is easier to follow the device symlinks from /sys/class/hwmon/hwmon*. +Up to lm-sensors 3.0.0, libsensors looks for hardware monitoring attributes +in the "physical" device directory. Since lm-sensors 3.0.1, attributes found +in the hwmon "class" device directory are also supported. Complex drivers +(e.g. drivers for multifunction chips) may want to use this possibility to +avoid namespace pollution. The only drawback will be that older versions of +libsensors won't support the driver in question. + All sysfs values are fixed point numbers. There is only one value per file, unlike the older /proc specification. @@ -77,6 +70,7 @@ are interpreted as 0! For more on how written strings are interpreted see the [0-*] denotes any positive number starting from 0 [1-*] denotes any positive number starting from 1 RO read only value +WO write only value RW read/write value Read/write values may be read-only for some chips, depending on the @@ -86,9 +80,9 @@ All entries (except name) are optional, and should only be created in a given driver if the chip has the feature. -******** -* Name * -******** +********************* +* Global attributes * +********************* name The chip name. This should be a short, lowercase string, not containing @@ -97,6 +91,12 @@ name The chip name. I2C devices get this attribute created automatically. RO +update_interval The interval at which the chip will update readings. + Unit: millisecond + RW + Some devices have a variable update rate or interval. + This attribute can be used to change it to the desired value. + ************ * Voltages * @@ -106,10 +106,24 @@ in[0-*]_min Voltage min value. Unit: millivolt RW +in[0-*]_lcrit Voltage critical min value. + Unit: millivolt + RW + If voltage drops to or below this limit, the system may + take drastic action such as power down or reset. At the very + least, it should report a fault. + in[0-*]_max Voltage max value. Unit: millivolt RW +in[0-*]_crit Voltage critical max value. + Unit: millivolt + RW + If voltage reaches or exceeds this limit, the system may + take drastic action such as power down or reset. At the very + least, it should report a fault. + in[0-*]_input Voltage input value. Unit: millivolt RO @@ -125,6 +139,29 @@ in[0-*]_input Voltage input value. thumb: drivers should report the voltage values at the "pins" of the chip. +in[0-*]_average + Average voltage + Unit: millivolt + RO + +in[0-*]_lowest + Historical minimum voltage + Unit: millivolt + RO + +in[0-*]_highest + Historical maximum voltage + Unit: millivolt + RO + +in[0-*]_reset_history + Reset inX_lowest and inX_highest + WO + +in_reset_history + Reset inX_lowest and inX_highest for all sensors + WO + in[0-*]_label Suggested voltage channel label. Text string Should only be created if the driver has hints about what @@ -157,6 +194,11 @@ fan[1-*]_min Fan minimum value Unit: revolution/min (RPM) RW +fan[1-*]_max Fan maximum value + Unit: revolution/min (RPM) + Only rarely supported by the hardware. + RW + fan[1-*]_input Fan input value. Unit: revolution/min (RPM) RO @@ -168,6 +210,17 @@ fan[1-*]_div Fan divisor. Note that this is actually an internal clock divisor, which affects the measurable speed range, not the read value. +fan[1-*]_pulses Number of tachometer pulses per fan revolution. + Integer value, typically between 1 and 4. + RW + This value is a characteristic of the fan connected to the + device's input, so it has to be set in accordance with the fan + model. + Should only be created if the chip has a register to configure + the number of pulses. In the absence of such a register (and + thus attribute) the value assumed by all devices is 2 pulses + per fan revolution. + fan[1-*]_target Desired fan speed Unit: revolution/min (RPM) @@ -226,8 +279,6 @@ pwm[1-*]_auto_point[1-*]_temp_hyst to PWM output channels. RW -OR - temp[1-*]_auto_point[1-*]_pwm temp[1-*]_auto_point[1-*]_temp temp[1-*]_auto_point[1-*]_temp_hyst @@ -236,6 +287,15 @@ temp[1-*]_auto_point[1-*]_temp_hyst to temperature channels. RW +There is a third case where trip points are associated to both PWM output +channels and temperature channels: the PWM values are associated to PWM +output channels while the temperature values are associated to temperature +channels. In that case, the result is determined by the mapping between +temperature inputs and PWM outputs. When several temperature inputs are +mapped to a given PWM output, this leads to several candidate PWM values. +The actual result is up to the chip, but in general the highest candidate +value (fastest fan speed) wins. + **************** * Temperatures * @@ -244,7 +304,7 @@ temp[1-*]_auto_point[1-*]_temp_hyst temp[1-*]_type Sensor type selection. Integers 1 to 6 RW - 1: PII/Celeron Diode + 1: CPU embedded diode 2: 3904 transistor 3: thermal diode 4: thermistor @@ -267,11 +327,18 @@ temp[1-*]_max_hyst from the max value. RW +temp[1-*]_min_hyst + Temperature hysteresis value for min limit. + Unit: millidegree Celsius + Must be reported as an absolute temperature, NOT a delta + from the min value. + RW + temp[1-*]_input Temperature input value. Unit: millidegree Celsius RO -temp[1-*]_crit Temperature critical value, typically greater than +temp[1-*]_crit Temperature critical max value, typically greater than corresponding temp_max values. Unit: millidegree Celsius RW @@ -283,6 +350,32 @@ temp[1-*]_crit_hyst from the critical value. RW +temp[1-*]_emergency + Temperature emergency max value, for chips supporting more than + two upper temperature limits. Must be equal or greater than + corresponding temp_crit values. + Unit: millidegree Celsius + RW + +temp[1-*]_emergency_hyst + Temperature hysteresis value for emergency limit. + Unit: millidegree Celsius + Must be reported as an absolute temperature, NOT a delta + from the emergency value. + RW + +temp[1-*]_lcrit Temperature critical min value, typically lower than + corresponding temp_min values. + Unit: millidegree Celsius + RW + +temp[1-*]_lcrit_hyst + Temperature hysteresis value for critical min limit. + Unit: millidegree Celsius + Must be reported as an absolute temperature, NOT a delta + from the critical min value. + RW + temp[1-*]_offset Temperature offset which is added to the temperature reading by the chip. @@ -297,6 +390,24 @@ temp[1-*]_label Suggested temperature channel label. user-space. RO +temp[1-*]_lowest + Historical minimum temperature + Unit: millidegree Celsius + RO + +temp[1-*]_highest + Historical maximum temperature + Unit: millidegree Celsius + RO + +temp[1-*]_reset_history + Reset temp_lowest and temp_highest + WO + +temp_reset_history + Reset temp_lowest and temp_highest for all sensors + WO + Some chips measure temperature using external thermistors and an ADC, and report the temperature measurement as a voltage. Converting this voltage back to a temperature (or the other way around for limits) requires @@ -313,9 +424,6 @@ Also see the Alarms section for status flags associated with temperatures. * Currents * ************ -Note that no known chip provides current measurements as of writing, -so this part is theoretical, so to say. - curr[1-*]_max Current max value Unit: milliampere RW @@ -324,10 +432,43 @@ curr[1-*]_min Current min value. Unit: milliampere RW +curr[1-*]_lcrit Current critical low value + Unit: milliampere + RW + +curr[1-*]_crit Current critical high value. + Unit: milliampere + RW + curr[1-*]_input Current input value Unit: milliampere RO +curr[1-*]_average + Average current use + Unit: milliampere + RO + +curr[1-*]_lowest + Historical minimum current + Unit: milliampere + RO + +curr[1-*]_highest + Historical maximum current + Unit: milliampere + RO + +curr[1-*]_reset_history + Reset currX_lowest and currX_highest + WO + +curr_reset_history + Reset currX_lowest and currX_highest for all sensors + WO + +Also see the Alarms section for status flags associated with currents. + ********* * Power * ********* @@ -336,6 +477,20 @@ power[1-*]_average Average power use Unit: microWatt RO +power[1-*]_average_interval Power use averaging interval. A poll + notification is sent to this file if the + hardware changes the averaging interval. + Unit: milliseconds + RW + +power[1-*]_average_interval_max Maximum power use averaging interval + Unit: milliseconds + RO + +power[1-*]_average_interval_min Minimum power use averaging interval + Unit: milliseconds + RO + power[1-*]_average_highest Historical average maximum power use Unit: microWatt RO @@ -344,6 +499,18 @@ power[1-*]_average_lowest Historical average minimum power use Unit: microWatt RO +power[1-*]_average_max A poll notification is sent to + power[1-*]_average when power use + rises above this value. + Unit: microWatt + RW + +power[1-*]_average_min A poll notification is sent to + power[1-*]_average when power use + sinks below this value. + Unit: microWatt + RW + power[1-*]_input Instantaneous power use Unit: microWatt RO @@ -360,6 +527,64 @@ power[1-*]_reset_history Reset input_highest, input_lowest, average_highest and average_lowest. WO +power[1-*]_accuracy Accuracy of the power meter. + Unit: Percent + RO + +power[1-*]_cap If power use rises above this limit, the + system should take action to reduce power use. + A poll notification is sent to this file if the + cap is changed by the hardware. The *_cap + files only appear if the cap is known to be + enforced by hardware. + Unit: microWatt + RW + +power[1-*]_cap_hyst Margin of hysteresis built around capping and + notification. + Unit: microWatt + RW + +power[1-*]_cap_max Maximum cap that can be set. + Unit: microWatt + RO + +power[1-*]_cap_min Minimum cap that can be set. + Unit: microWatt + RO + +power[1-*]_max Maximum power. + Unit: microWatt + RW + +power[1-*]_crit Critical maximum power. + If power rises to or above this limit, the + system is expected take drastic action to reduce + power consumption, such as a system shutdown or + a forced powerdown of some devices. + Unit: microWatt + RW + +Also see the Alarms section for status flags associated with power readings. + +********** +* Energy * +********** + +energy[1-*]_input Cumulative energy use + Unit: microJoule + RO + + +************ +* Humidity * +************ + +humidity[1-*]_input Humidity + Unit: milli-percent (per cent mille, pcm) + RO + + ********** * Alarms * ********** @@ -372,6 +597,8 @@ limit-related alarms, not both. The driver should just reflect the hardware implementation. in[0-*]_alarm +curr[1-*]_alarm +power[1-*]_alarm fan[1-*]_alarm temp[1-*]_alarm Channel alarm @@ -383,10 +610,22 @@ OR in[0-*]_min_alarm in[0-*]_max_alarm +in[0-*]_lcrit_alarm +in[0-*]_crit_alarm +curr[1-*]_min_alarm +curr[1-*]_max_alarm +curr[1-*]_lcrit_alarm +curr[1-*]_crit_alarm +power[1-*]_cap_alarm +power[1-*]_max_alarm +power[1-*]_crit_alarm fan[1-*]_min_alarm +fan[1-*]_max_alarm temp[1-*]_min_alarm temp[1-*]_max_alarm +temp[1-*]_lcrit_alarm temp[1-*]_crit_alarm +temp[1-*]_emergency_alarm Limit alarm 0: no alarm 1: alarm @@ -397,11 +636,10 @@ to notify open diodes, unconnected fans etc. where the hardware supports it. When this boolean has value 1, the measurement for that channel should not be trusted. -in[0-*]_fault fan[1-*]_fault temp[1-*]_fault Input fault condition - 0: no fault occured + 0: no fault occurred 1: fault condition RO @@ -413,6 +651,7 @@ beep_enable Master beep enable RW in[0-*]_beep +curr[1-*]_beep fan[1-*]_beep temp[1-*]_beep Channel beep @@ -448,6 +687,27 @@ beep_mask Bitmask for beep. RW +*********************** +* Intrusion detection * +*********************** + +intrusion[0-*]_alarm + Chassis intrusion detection + 0: OK + 1: intrusion detected + RW + Contrary to regular alarm flags which clear themselves + automatically when read, this one sticks until cleared by + the user. This is done by writing 0 to the file. Writing + other values is unsupported. + +intrusion[0-*]_beep + Chassis intrusion beep + 0: disable + 1: enable + RW + + sysfs attribute writes interpretation ------------------------------------- @@ -476,14 +736,14 @@ add/subtract if it has been divided before the add/subtract. What to do if a value is found to be invalid, depends on the type of the sysfs attribute that is being set. If it is a continuous setting like a tempX_max or inX_max attribute, then the value should be clamped to its -limits using SENSORS_LIMIT(value, min_limit, max_limit). If it is not -continuous like for example a tempX_type, then when an invalid value is -written, -EINVAL should be returned. +limits using clamp_val(value, min_limit, max_limit). If it is not continuous +like for example a tempX_type, then when an invalid value is written, +-EINVAL should be returned. Example1, temp1_max, register is a signed 8 bit value (-128 - 127 degrees): long v = simple_strtol(buf, NULL, 10) / 1000; - v = SENSORS_LIMIT(v, -128, 127); + v = clamp_val(v, -128, 127); /* write v to register */ Example2, fan divider setting, valid values 2, 4 and 8: |