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Diffstat (limited to 'Documentation/hwmon/sysfs-interface.rst')
| -rw-r--r-- | Documentation/hwmon/sysfs-interface.rst | 608 |
1 files changed, 54 insertions, 554 deletions
diff --git a/Documentation/hwmon/sysfs-interface.rst b/Documentation/hwmon/sysfs-interface.rst index 678c9c60b5a3..f76e9f8cc1ad 100644 --- a/Documentation/hwmon/sysfs-interface.rst +++ b/Documentation/hwmon/sysfs-interface.rst @@ -65,6 +65,14 @@ the desired value must be written, note that strings which are not a number are interpreted as 0! For more on how written strings are interpreted see the "sysfs attribute writes interpretation" section at the end of this file. +Attribute access +---------------- + +Hardware monitoring sysfs attributes are displayed by unrestricted userspace +applications. For this reason, all standard ABI attributes shall be world +readable. Writeable standard ABI attributes shall be writeable only for +privileged users. + ------------------------------------------------------------------------- ======= =========================================== @@ -81,6 +89,8 @@ hardware implementation. All entries (except name) are optional, and should only be created in a given driver if the chip has the feature. +See Documentation/ABI/testing/sysfs-class-hwmon for a complete description +of the attributes. ***************** Global attributes @@ -88,22 +98,13 @@ Global attributes `name` The chip name. - This should be a short, lowercase string, not containing - whitespace, dashes, or the wildcard character '*'. - This attribute represents the chip name. It is the only - mandatory attribute. - I2C devices get this attribute created automatically. - RO +`label` + A descriptive label that allows to uniquely identify a device + within the system. `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. ******** @@ -113,148 +114,51 @@ Voltages `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 - - Voltage measured on the chip pin. - - Actual voltage depends on the scaling resistors on the - motherboard, as recommended in the chip datasheet. - - This varies by chip and by motherboard. - Because of this variation, values are generally NOT scaled - by the chip driver, and must be done by the application. - However, some drivers (notably lm87 and via686a) - do scale, because of internal resistors built into a chip. - These drivers will output the actual voltage. Rule of - 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 - this voltage channel is being used for, and user-space - doesn't. In all other cases, the label is provided by - user-space. - - RO - `in[0-*]_enable` Enable or disable the sensors. - When disabled the sensor read will return -ENODATA. - - - 1: Enable - - 0: Disable - - RW - `cpu[0-*]_vid` CPU core reference voltage. - Unit: millivolt - - RO - - Not always correct. - `vrm` Voltage Regulator Module version number. - RW (but changing it should no more be necessary) - - Originally the VRM standard version multiplied by 10, but now - an arbitrary number, as not all standards have a version - number. - - Affects the way the driver calculates the CPU core reference - voltage from the vid pins. - `in[0-*]_rated_min` Minimum rated voltage. - Unit: millivolt - - RO - `in[0-*]_rated_max` Maximum rated voltage. - Unit: millivolt - - RO - Also see the Alarms section for status flags associated with voltages. @@ -265,83 +169,27 @@ Fans `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 - `fan[1-*]_div` Fan divisor. - Integer value in powers of two (1, 2, 4, 8, 16, 32, 64, 128). - - RW - - Some chips only support values 1, 2, 4 and 8. - 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) - - RW - - Only makes sense if the chip supports closed-loop fan speed - control based on the measured fan speed. - `fan[1-*]_label` Suggested fan channel label. - Text string - - Should only be created if the driver has hints about what - this fan channel is being used for, and user-space doesn't. - In all other cases, the label is provided by user-space. - - RO - `fan[1-*]_enable` Enable or disable the sensors. - When disabled the sensor read will return -ENODATA. - - - 1: Enable - - 0: Disable - - RW - Also see the Alarms section for status flags associated with fans. @@ -352,63 +200,25 @@ PWM `pwm[1-*]` Pulse width modulation fan control. - Integer value in the range 0 to 255 - - RW - - 255 is max or 100%. - `pwm[1-*]_enable` - Fan speed control method: - - - 0: no fan speed control (i.e. fan at full speed) - - 1: manual fan speed control enabled (using `pwm[1-*]`) - - 2+: automatic fan speed control enabled - - Check individual chip documentation files for automatic mode - details. - - RW + Fan speed control method. `pwm[1-*]_mode` - - 0: DC mode (direct current) - - 1: PWM mode (pulse-width modulation) - - RW + direct current or pulse-width modulation. `pwm[1-*]_freq` Base PWM frequency in Hz. - Only possibly available when pwmN_mode is PWM, but not always - present even then. - - RW - `pwm[1-*]_auto_channels_temp` Select which temperature channels affect this PWM output in auto mode. - Bitfield, 1 is temp1, 2 is temp2, 4 is temp3 etc... - Which values are possible depend on the chip used. - - RW - `pwm[1-*]_auto_point[1-*]_pwm` / `pwm[1-*]_auto_point[1-*]_temp` / `pwm[1-*]_auto_point[1-*]_temp_hyst` Define the PWM vs temperature curve. - Number of trip points is chip-dependent. Use this for chips - which associate trip points to PWM output channels. - - RW - `temp[1-*]_auto_point[1-*]_pwm` / `temp[1-*]_auto_point[1-*]_temp` / `temp[1-*]_auto_point[1-*]_temp_hyst` Define the PWM vs temperature curve. - Number of trip points is chip-dependent. Use this for chips - which associate trip points 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 @@ -426,182 +236,70 @@ Temperatures `temp[1-*]_type` Sensor type selection. - Integers 1 to 6 - - RW - - - 1: CPU embedded diode - - 2: 3904 transistor - - 3: thermal diode - - 4: thermistor - - 5: AMD AMDSI - - 6: Intel PECI - - Not all types are supported by all chips - `temp[1-*]_max` Temperature max value. - Unit: millidegree Celsius (or millivolt, see below) - - RW - `temp[1-*]_min` Temperature min value. - Unit: millidegree Celsius - - RW - `temp[1-*]_max_hyst` Temperature hysteresis value for max limit. - Unit: millidegree Celsius - - Must be reported as an absolute temperature, NOT a delta - 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 + Temperature input value. `temp[1-*]_crit` Temperature critical max value, typically greater than corresponding temp_max values. - Unit: millidegree Celsius - - RW - `temp[1-*]_crit_hyst` Temperature hysteresis value for critical limit. - Unit: millidegree Celsius - - Must be reported as an absolute temperature, NOT a delta - 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 + two upper temperature limits. `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. - Unit: millidegree Celsius - - Read/Write value. - `temp[1-*]_label` Suggested temperature channel label. - Text string - - Should only be created if the driver has hints about what - this temperature channel is being used for, and user-space - doesn't. In all other cases, the label is provided by - 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 - `temp[1-*]_enable` Enable or disable the sensors. - When disabled the sensor read will return -ENODATA. - - - 1: Enable - - 0: Disable - - RW - `temp[1-*]_rated_min` Minimum rated temperature. - Unit: millidegree Celsius - - RO - `temp[1-*]_rated_max` Maximum rated temperature. - Unit: millidegree Celsius - - RO - 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 @@ -619,58 +317,28 @@ Currents ******** `curr[1-*]_max` - Current max value - - Unit: milliampere - - RW + Current max value. `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 + Current input value. `curr[1-*]_average` - Average current use - - Unit: milliampere - - RO + Average current use. `curr[1-*]_lowest` - Historical minimum current - - Unit: milliampere - - RO + Historical minimum current. `curr[1-*]_highest` - Historical maximum current - Unit: milliampere - RO + Historical maximum current. `curr[1-*]_reset_history` Reset currX_lowest and currX_highest @@ -678,34 +346,17 @@ Currents WO `curr_reset_history` - Reset currX_lowest and currX_highest for all sensors - - WO + Reset currX_lowest and currX_highest for all sensors. `curr[1-*]_enable` Enable or disable the sensors. - When disabled the sensor read will return -ENODATA. - - - 1: Enable - - 0: Disable - - RW - `curr[1-*]_rated_min` Minimum rated current. - Unit: milliampere - - RO - `curr[1-*]_rated_max` Maximum rated current. - Unit: milliampere - - RO - Also see the Alarms section for status flags associated with currents. ***** @@ -713,141 +364,62 @@ Power ***** `power[1-*]_average` - Average power use - - Unit: microWatt - - RO + Average power use. `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 use averaging interval. `power[1-*]_average_interval_max` - Maximum power use averaging interval - - Unit: milliseconds - - RO + Maximum power use averaging interval. `power[1-*]_average_interval_min` - Minimum power use averaging interval - - Unit: milliseconds - - RO + Minimum power use averaging interval. `power[1-*]_average_highest` - Historical average maximum power use - - Unit: microWatt - - RO + Historical average maximum power use `power[1-*]_average_lowest` - Historical average minimum power use - - Unit: microWatt - - RO + Historical average minimum power use `power[1-*]_average_max` - A poll notification is sent to - `power[1-*]_average` when power use - rises above this value. - - Unit: microWatt - - RW + A poll notification is sent to `power[1-*]_average` when + power use rises above this value. `power[1-*]_average_min` - A poll notification is sent to - `power[1-*]_average` when power use - sinks below this value. - - Unit: microWatt - - RW + A poll notification is sent to `power[1-*]_average` when + power use sinks below this value. `power[1-*]_input` - Instantaneous power use - - Unit: microWatt - - RO + Instantaneous power use. `power[1-*]_input_highest` - Historical maximum power use - - Unit: microWatt - - RO + Historical maximum power use `power[1-*]_input_lowest` - Historical minimum power use - - Unit: microWatt - - RO + Historical minimum power use. `power[1-*]_reset_history` - Reset input_highest, input_lowest, - average_highest and average_lowest. - - WO + Reset input_highest, input_lowest, average_highest and + average_lowest. `power[1-*]_accuracy` - Accuracy of the power meter. - - Unit: Percent - - RO + Accuracy of the power meter. `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 + If power use rises above this limit, the + system should take action to reduce power use. `power[1-*]_cap_hyst` - Margin of hysteresis built around capping and - notification. - - Unit: microWatt - - RW + Margin of hysteresis built around capping and notification. `power[1-*]_cap_max` - Maximum cap that can be set. - - Unit: microWatt - - RO + Maximum cap that can be set. `power[1-*]_cap_min` - Minimum cap that can be set. - - Unit: microWatt - - RO + Minimum cap that can be set. `power[1-*]_max` - Maximum power. - - Unit: microWatt - - RW + Maximum power. `power[1-*]_crit` Critical maximum power. @@ -915,37 +487,16 @@ Humidity ******** `humidity[1-*]_input` - Humidity - - Unit: milli-percent (per cent mille, pcm) - - RO - + Humidity. `humidity[1-*]_enable` - Enable or disable the sensors - - When disabled the sensor read will return - -ENODATA. - - - 1: Enable - - 0: Disable - - RW + Enable or disable the sensors. `humidity[1-*]_rated_min` - Minimum rated humidity. - - Unit: milli-percent (per cent mille, pcm) - - RO + Minimum rated humidity. `humidity[1-*]_rated_max` - Maximum rated humidity. - - Unit: milli-percent (per cent mille, pcm) - - RO + Maximum rated humidity. ****** Alarms @@ -996,30 +547,15 @@ supports it. When this boolean has value 1, the measurement for that channel should not be trusted. `fan[1-*]_fault` / `temp[1-*]_fault` - Input fault condition - - - 0: no fault occurred - - 1: fault condition - - RO + Input fault condition. Some chips also offer the possibility to get beeped when an alarm occurs: `beep_enable` - Master beep enable - - - 0: no beeps - - 1: beeps - - RW + Master beep enable. `in[0-*]_beep`, `curr[1-*]_beep`, `fan[1-*]_beep`, `temp[1-*]_beep`, - Channel beep - - - 0: disable - - 1: enable - - RW + Channel beep. In theory, a chip could provide per-limit beep masking, but no such chip was seen so far. @@ -1031,29 +567,8 @@ for compatibility reasons: `alarms` Alarm bitmask. - RO - - Integer representation of one to four bytes. - - A '1' bit means an alarm. - - Chips should be programmed for 'comparator' mode so that - the alarm will 'come back' after you read the register - if it is still valid. - - Generally a direct representation of a chip's internal - alarm registers; there is no standard for the position - of individual bits. For this reason, the use of this - interface file for new drivers is discouraged. Use - `individual *_alarm` and `*_fault` files instead. - Bits are defined in kernel/include/sensors.h. - `beep_mask` Bitmask for beep. - Same format as 'alarms' with the same bit locations, - use discouraged for the same reason. Use individual - `*_beep` files instead. - RW ******************* @@ -1061,25 +576,10 @@ 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. + Chassis intrusion detection. `intrusion[0-*]_beep` - Chassis intrusion beep - - 0: disable - 1: enable - - RW + Chassis intrusion beep. **************************** Average sample configuration |