Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 656 insertions, 0 deletions

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+Naming and data format standards for sysfs files
+================================================
+
+The libsensors library offers an interface to the raw sensors data
+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
+temperature sensor is connected to the CPU, or that the second fan is on
+the CPU. Also, some values reported by the chips need some computation
+before they make full sense. For example, most chips can only measure
+voltages between 0 and +4V. Other voltages are scaled back into that
+range using external resistors. Since the values of these resistors
+can change from motherboard to motherboard, the conversions cannot be
+hard coded into the driver and have to be done in user space.
+
+For this reason, even if we aim at a chip-independent libsensors, it will
+still require a configuration file (e.g. /etc/sensors.conf) for proper
+values conversion, labeling of inputs and hiding of unused inputs.
+
+An alternative method that some programs use is to access the sysfs
+files directly. This document briefly describes the standards that the
+drivers follow, so that an application program can scan for entries and
+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.
+
+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.
+The common scheme for files naming is: <type><number>_<item>. Usual
+types for sensor chips are "in" (voltage), "temp" (temperature) and
+"fan" (fan). Usual items are "input" (measured value), "max" (high
+threshold, "min" (low threshold). Numbering usually starts from 1,
+except for voltages which start from 0 (because most data sheets use
+this). A number is always used for elements that can be present more
+than once, even if there is a single element of the given type on the
+specific chip. Other files do not refer to a specific element, so
+they have a simple name, and no number.
+
+Alarms are direct indications read from the chips. The drivers do NOT
+make comparisons of readings to thresholds. This allows violations
+between readings to be caught and alarmed. The exact definition of an
+alarm (for example, whether a threshold must be met or must be exceeded
+to cause an alarm) is chip-dependent.
+
+When setting values of hwmon sysfs attributes, the string representation of
+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.
+
+-------------------------------------------------------------------------
+
+======= ===========================================
+`[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
+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
+*****************
+
+`name`
+		The chip name.
+
+`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.
+
+
+********
+Voltages
+********
+
+`in[0-*]_min`
+		Voltage min value.
+
+`in[0-*]_lcrit`
+		Voltage critical min value.
+
+`in[0-*]_max`
+		Voltage max value.
+
+`in[0-*]_crit`
+		Voltage critical max value.
+
+`in[0-*]_input`
+		Voltage input value.
+
+`in[0-*]_average`
+		Average voltage
+
+`in[0-*]_lowest`
+		Historical minimum voltage
+
+`in[0-*]_highest`
+		Historical maximum voltage
+
+`in[0-*]_reset_history`
+		Reset inX_lowest and inX_highest
+
+`in_reset_history`
+		Reset inX_lowest and inX_highest for all sensors
+
+`in[0-*]_label`
+		Suggested voltage channel label.
+
+`in[0-*]_enable`
+		Enable or disable the sensors.
+
+`cpu[0-*]_vid`
+		CPU core reference voltage.
+
+`vrm`
+		Voltage Regulator Module version number.
+
+`in[0-*]_rated_min`
+		Minimum rated voltage.
+
+`in[0-*]_rated_max`
+		Maximum rated voltage.
+
+Also see the Alarms section for status flags associated with voltages.
+
+
+****
+Fans
+****
+
+`fan[1-*]_min`
+		Fan minimum value
+
+`fan[1-*]_max`
+		Fan maximum value
+
+`fan[1-*]_input`
+		Fan input value.
+
+`fan[1-*]_div`
+		Fan divisor.
+
+`fan[1-*]_pulses`
+		Number of tachometer pulses per fan revolution.
+
+`fan[1-*]_target`
+		Desired fan speed
+
+`fan[1-*]_label`
+		Suggested fan channel label.
+
+`fan[1-*]_enable`
+		Enable or disable the sensors.
+
+Also see the Alarms section for status flags associated with fans.
+
+
+***
+PWM
+***
+
+`pwm[1-*]`
+		Pulse width modulation fan control.
+
+`pwm[1-*]_enable`
+		Fan speed control method.
+
+`pwm[1-*]_mode`
+		direct current or pulse-width modulation.
+
+`pwm[1-*]_freq`
+		Base PWM frequency in Hz.
+
+`pwm[1-*]_auto_channels_temp`
+		Select which temperature channels affect this PWM output in
+		auto mode.
+
+`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.
+
+`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.
+
+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
+************
+
+`temp[1-*]_type`
+		Sensor type selection.
+
+`temp[1-*]_max`
+		Temperature max value.
+
+`temp[1-*]_min`
+		Temperature min value.
+
+`temp[1-*]_max_hyst`
+		Temperature hysteresis value for max limit.
+
+`temp[1-*]_min_hyst`
+		Temperature hysteresis value for min limit.
+
+`temp[1-*]_input`
+		Temperature input value.
+
+`temp[1-*]_crit`
+		Temperature critical max value, typically greater than
+		corresponding temp_max values.
+
+`temp[1-*]_crit_hyst`
+		Temperature hysteresis value for critical limit.
+
+`temp[1-*]_emergency`
+		Temperature emergency max value, for chips supporting more than
+		two upper temperature limits.
+
+`temp[1-*]_emergency_hyst`
+		Temperature hysteresis value for emergency limit.
+
+`temp[1-*]_lcrit`
+		Temperature critical min value, typically lower than
+		corresponding temp_min values.
+
+`temp[1-*]_lcrit_hyst`
+		Temperature hysteresis value for critical min limit.
+
+`temp[1-*]_offset`
+		Temperature offset which is added to the temperature reading
+		by the chip.
+
+`temp[1-*]_label`
+		Suggested temperature channel label.
+
+`temp[1-*]_lowest`
+		Historical minimum temperature
+
+`temp[1-*]_highest`
+		Historical maximum temperature
+
+`temp[1-*]_reset_history`
+		Reset temp_lowest and temp_highest
+
+`temp_reset_history`
+		Reset temp_lowest and temp_highest for all sensors
+
+`temp[1-*]_enable`
+		Enable or disable the sensors.
+
+`temp[1-*]_rated_min`
+		Minimum rated temperature.
+
+`temp[1-*]_rated_max`
+		Maximum rated temperature.
+
+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
+mathematical functions not available in the kernel, so the conversion
+must occur in user space. For these chips, all temp* files described
+above should contain values expressed in millivolt instead of millidegree
+Celsius. In other words, such temperature channels are handled as voltage
+channels by the driver.
+
+Also see the Alarms section for status flags associated with temperatures.
+
+
+********
+Currents
+********
+
+`curr[1-*]_max`
+		Current max value.
+
+`curr[1-*]_min`
+		Current min value.
+
+`curr[1-*]_lcrit`
+		Current critical low value
+
+`curr[1-*]_crit`
+		Current critical high value.
+
+`curr[1-*]_input`
+		Current input value.
+
+`curr[1-*]_average`
+		Average current use.
+
+`curr[1-*]_lowest`
+		Historical minimum current.
+
+`curr[1-*]_highest`
+		Historical maximum current.
+
+`curr[1-*]_reset_history`
+		Reset currX_lowest and currX_highest
+
+		WO
+
+`curr_reset_history`
+		Reset currX_lowest and currX_highest for all sensors.
+
+`curr[1-*]_enable`
+		Enable or disable the sensors.
+
+`curr[1-*]_rated_min`
+		Minimum rated current.
+
+`curr[1-*]_rated_max`
+		Maximum rated current.
+
+Also see the Alarms section for status flags associated with currents.
+
+*****
+Power
+*****
+
+`power[1-*]_average`
+		Average power use.
+
+`power[1-*]_average_interval`
+		Power use averaging interval.
+
+`power[1-*]_average_interval_max`
+		Maximum power use averaging interval.
+
+`power[1-*]_average_interval_min`
+		Minimum power use averaging interval.
+
+`power[1-*]_average_highest`
+		Historical average maximum power use
+
+`power[1-*]_average_lowest`
+		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.
+
+`power[1-*]_average_min`
+		A poll notification is sent to `power[1-*]_average` when
+		power use sinks below this value.
+
+`power[1-*]_input`
+		Instantaneous power use.
+
+`power[1-*]_input_highest`
+		Historical maximum power use
+
+`power[1-*]_input_lowest`
+		Historical minimum power use.
+
+`power[1-*]_reset_history`
+		Reset input_highest, input_lowest, average_highest and
+		average_lowest.
+
+`power[1-*]_accuracy`
+		Accuracy of the power meter.
+
+`power[1-*]_cap`
+		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.
+
+`power[1-*]_cap_max`
+		Maximum cap that can be set.
+
+`power[1-*]_cap_min`
+		Minimum cap that can be set.
+
+`power[1-*]_max`
+		Maximum power.
+
+`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
+
+`power[1-*]_enable`
+				Enable or disable the sensors.
+
+				When disabled the sensor read will return
+				-ENODATA.
+
+				- 1: Enable
+				- 0: Disable
+
+				RW
+
+`power[1-*]_rated_min`
+				Minimum rated power.
+
+				Unit: microWatt
+
+				RO
+
+`power[1-*]_rated_max`
+				Maximum rated power.
+
+				Unit: microWatt
+
+				RO
+
+Also see the Alarms section for status flags associated with power readings.
+
+******
+Energy
+******
+
+`energy[1-*]_input`
+				Cumulative energy use
+
+				Unit: microJoule
+
+				RO
+
+`energy[1-*]_enable`
+				Enable or disable the sensors.
+
+				When disabled the sensor read will return
+				-ENODATA.
+
+				- 1: Enable
+				- 0: Disable
+
+				RW
+
+********
+Humidity
+********
+
+`humidity[1-*]_input`
+		Humidity.
+
+`humidity[1-*]_enable`
+		Enable or disable the sensors.
+
+`humidity[1-*]_rated_min`
+		Minimum rated humidity.
+
+`humidity[1-*]_rated_max`
+		Maximum rated humidity.
+
+******
+Alarms
+******
+
+Each channel or limit may have an associated alarm file, containing a
+boolean value. 1 means than an alarm condition exists, 0 means no alarm.
+
+Usually a given chip will either use channel-related alarms, or
+limit-related alarms, not both. The driver should just reflect the hardware
+implementation.
+
++-------------------------------+-----------------------+
+| **`in[0-*]_alarm`,		| Channel alarm		|
+| `curr[1-*]_alarm`,		|			|
+| `power[1-*]_alarm`,		|   - 0: no alarm	|
+| `fan[1-*]_alarm`,		|   - 1: alarm		|
+| `temp[1-*]_alarm`**		|			|
+|				|   RO			|
++-------------------------------+-----------------------+
+
+**OR**
+
++-------------------------------+-----------------------+
+| **`in[0-*]_min_alarm`,	| Limit alarm		|
+| `in[0-*]_max_alarm`,		|			|
+| `in[0-*]_lcrit_alarm`,	|   - 0: no alarm	|
+| `in[0-*]_crit_alarm`,		|   - 1: alarm		|
+| `curr[1-*]_min_alarm`,	|			|
+| `curr[1-*]_max_alarm`,	| RO			|
+| `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`**	|			|
++-------------------------------+-----------------------+
+
+Each input channel may have an associated fault file. This can be used
+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.
+
+`fan[1-*]_fault` / `temp[1-*]_fault`
+		Input fault condition.
+
+Some chips also offer the possibility to get beeped when an alarm occurs:
+
+`beep_enable`
+		Master beep enable.
+
+`in[0-*]_beep`, `curr[1-*]_beep`, `fan[1-*]_beep`, `temp[1-*]_beep`,
+		Channel beep.
+
+In theory, a chip could provide per-limit beep masking, but no such chip
+was seen so far.
+
+Old drivers provided a different, non-standard interface to alarms and
+beeps. These interface files are deprecated, but will be kept around
+for compatibility reasons:
+
+`alarms`
+		Alarm bitmask.
+
+`beep_mask`
+		Bitmask for beep.
+
+
+*******************
+Intrusion detection
+*******************
+
+`intrusion[0-*]_alarm`
+		Chassis intrusion detection.
+
+`intrusion[0-*]_beep`
+		Chassis intrusion beep.
+
+****************************
+Average sample configuration
+****************************
+
+Devices allowing for reading {in,power,curr,temp}_average values may export
+attributes for controlling number of samples used to compute average.
+
++--------------+---------------------------------------------------------------+
+| samples      | Sets number of average samples for all types of measurements. |
+|	       |							       |
+|	       | RW							       |
++--------------+---------------------------------------------------------------+
+| in_samples   | Sets number of average samples for specific type of	       |
+| power_samples| measurements.						       |
+| curr_samples |							       |
+| temp_samples | Note that on some devices it won't be possible to set all of  |
+|	       | them to different values so changing one might also change    |
+|	       | some others.						       |
+|	       |							       |
+|	       | RW							       |
++--------------+---------------------------------------------------------------+
+
+sysfs attribute writes interpretation
+-------------------------------------
+
+hwmon sysfs attributes always contain numbers, so the first thing to do is to
+convert the input to a number, there are 2 ways todo this depending whether
+the number can be negative or not::
+
+	unsigned long u = simple_strtoul(buf, NULL, 10);
+	long s = simple_strtol(buf, NULL, 10);
+
+With buf being the buffer with the user input being passed by the kernel.
+Notice that we do not use the second argument of strto[u]l, and thus cannot
+tell when 0 is returned, if this was really 0 or is caused by invalid input.
+This is done deliberately as checking this everywhere would add a lot of
+code to the kernel.
+
+Notice that it is important to always store the converted value in an
+unsigned long or long, so that no wrap around can happen before any further
+checking.
+
+After the input string is converted to an (unsigned) long, the value should be
+checked if its acceptable. Be careful with further conversions on the value
+before checking it for validity, as these conversions could still cause a wrap
+around before the check. For example do not multiply the result, and only
+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 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 = clamp_val(v, -128, 127);
+	/* write v to register */
+
+Example2, fan divider setting, valid values 2, 4 and 8::
+
+	unsigned long v = simple_strtoul(buf, NULL, 10);
+
+	switch (v) {
+	case 2: v = 1; break;
+	case 4: v = 2; break;
+	case 8: v = 3; break;
+	default:
+		return -EINVAL;
+	}
+	/* write v to register */