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.
-------------------------------------------------------------------------
Read/write values may be read-only for some chips, depending on the
hardware implementation.
-All entries are optional, and should only be created in a given driver
-if the chip has the feature.
+All entries (except name) are optional, and should only be created in a
+given driver if the chip has the feature.
+
+
+********
+* Name *
+********
+
+name The chip name.
+ This should be a short, lowercase string, not containing
+ spaces nor dashes, representing the chip name. This is
+ the only mandatory attribute.
+ I2C devices get this attribute created automatically.
+ RO
+
************
* Voltages *
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.
-
- Typical usage:
- in0_* CPU #1 voltage (not scaled)
- in1_* CPU #2 voltage (not scaled)
- in2_* 3.3V nominal (not scaled)
- in3_* 5.0V nominal (scaled)
- in4_* 12.0V nominal (scaled)
- in5_* -12.0V nominal (scaled)
- in6_* -5.0V nominal (scaled)
- in7_* varies
- in8_* varies
+ These drivers will output the actual voltage. Rule of
+ thumb: drivers should report the voltage values at the
+ "pins" of the chip.
+
+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
cpu[0-*]_vid CPU core reference voltage.
Unit: millivolt
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
+
Also see the Alarms section for status flags associated with fans.
255 is max or 100%.
pwm[1-*]_enable
- Switch PWM on and off.
- Not always present even if pwmN is.
- 0: turn off
- 1: turn on in manual mode
- 2+: turn on in automatic mode
+ 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
****************
temp[1-*]_type Sensor type selection.
- Integers 1 to 6 or thermistor Beta value (typically 3435)
+ Integers 1 to 6
RW
1: PII/Celeron Diode
2: 3904 transistor
3: thermal diode
- 4: thermistor (default/unknown Beta)
+ 4: thermistor
5: AMD AMDSI
6: Intel PECI
Not all types are supported by all chips
from the critical value.
RW
-temp[1-4]_offset
+temp[1-*]_offset
Temperature offset which is added to the temperature reading
by the chip.
Unit: millidegree Celsius
Read/Write value.
- If there are multiple temperature sensors, temp1_* is
- generally the sensor inside the chip itself,
- reported as "motherboard temperature". temp2_* to
- temp4_* are generally sensors external to the chip
- itself, for example the thermal diode inside the CPU or
- a thermistor nearby.
+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
Some chips measure temperature using external thermistors and an ADC, and
report the temperature measurement as a voltage. Converting this voltage
supports it. When this boolean has value 1, the measurement for that
channel should not be trusted.
-in[0-*]_input_fault
-fan[1-*]_input_fault
-temp[1-*]_input_fault
+in[0-*]_fault
+fan[1-*]_fault
+temp[1-*]_fault
Input fault condition
0: no fault occured
1: fault condition
RW
-*********
-* Other *
-*********
-
-eeprom Raw EEPROM data in binary form.
- RO
-
-pec Enable or disable PEC (SMBus only)
- 0: disable
- 1: enable
- 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 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.
+
+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);
+ /* 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 */
git.openpandora.org / pandora-kernel.git / blobdiff