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Diffstat (limited to 'kernel/Documentation/hwmon/it87')
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1 files changed, 262 insertions, 0 deletions
diff --git a/kernel/Documentation/hwmon/it87 b/kernel/Documentation/hwmon/it87 new file mode 100644 index 000000000..e87294878 --- /dev/null +++ b/kernel/Documentation/hwmon/it87 @@ -0,0 +1,262 @@ +Kernel driver it87 +================== + +Supported chips: + * IT8603E/IT8623E + Prefix: 'it8603' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8620E + Prefix: 'it8620' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8705F + Prefix: 'it87' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Once publicly available at the ITE website, but no longer + * IT8712F + Prefix: 'it8712' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Once publicly available at the ITE website, but no longer + * IT8716F/IT8726F + Prefix: 'it8716' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Once publicly available at the ITE website, but no longer + * IT8718F + Prefix: 'it8718' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Once publicly available at the ITE website, but no longer + * IT8720F + Prefix: 'it8720' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8721F/IT8758E + Prefix: 'it8721' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8728F + Prefix: 'it8728' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8771E + Prefix: 'it8771' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8772E + Prefix: 'it8772' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8781F + Prefix: 'it8781' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8782F + Prefix: 'it8782' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8783E/F + Prefix: 'it8783' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8786E + Prefix: 'it8786' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * IT8790E + Prefix: 'it8790' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: Not publicly available + * SiS950 [clone of IT8705F] + Prefix: 'it87' + Addresses scanned: from Super I/O config space (8 I/O ports) + Datasheet: No longer be available + +Authors: + Christophe Gauthron + Jean Delvare <jdelvare@suse.de> + + +Module Parameters +----------------- + +* update_vbat: int + + 0 if vbat should report power on value, 1 if vbat should be updated after + each read. Default is 0. On some boards the battery voltage is provided + by either the battery or the onboard power supply. Only the first reading + at power on will be the actual battery voltage (which the chip does + automatically). On other boards the battery voltage is always fed to + the chip so can be read at any time. Excessive reading may decrease + battery life but no information is given in the datasheet. + +* fix_pwm_polarity int + + Force PWM polarity to active high (DANGEROUS). Some chips are + misconfigured by BIOS - PWM values would be inverted. This option tries + to fix this. Please contact your BIOS manufacturer and ask him for fix. + + +Hardware Interfaces +------------------- + +All the chips supported by this driver are LPC Super-I/O chips, accessed +through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an +SMBus interface to the hardware monitoring functions. This driver no +longer supports this interface though, as it is slower and less reliable +than the ISA access, and was only available on a small number of +motherboard models. + + +Description +----------- + +This driver implements support for the IT8603E, IT8620E, IT8623E, IT8705F, +IT8712F, IT8716F, IT8718F, IT8720F, IT8721F, IT8726F, IT8728F, IT8758E, +IT8771E, IT8772E, IT8781F, IT8782F, IT8783E/F, IT8786E, IT8790E, and SiS950 +chips. + +These chips are 'Super I/O chips', supporting floppy disks, infrared ports, +joysticks and other miscellaneous stuff. For hardware monitoring, they +include an 'environment controller' with 3 temperature sensors, 3 fan +rotation speed sensors, 8 voltage sensors, associated alarms, and chassis +intrusion detection. + +The IT8712F and IT8716F additionally feature VID inputs, used to report +the Vcore voltage of the processor. The early IT8712F have 5 VID pins, +the IT8716F and late IT8712F have 6. They are shared with other functions +though, so the functionality may not be available on a given system. + +The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value +is stored in the Super-I/O configuration space. Due to technical limitations, +this value can currently only be read once at initialization time, so +the driver won't notice and report changes in the VID value. The two +upper VID bits share their pins with voltage inputs (in5 and in6) so you +can't have both on a given board. + +The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions +have support for 2 additional fans. The additional fans are supported by the +driver. + +The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E, IT8781F, IT8782F, IT8783E/F, +and late IT8712F and IT8705F also have optional 16-bit tachometer counters +for fans 1 to 3. This is better (no more fan clock divider mess) but not +compatible with the older chips and revisions. The 16-bit tachometer mode +is enabled by the driver when one of the above chips is detected. + +The IT8726F is just bit enhanced IT8716F with additional hardware +for AMD power sequencing. Therefore the chip will appear as IT8716F +to userspace applications. + +The IT8728F, IT8771E, and IT8772E are considered compatible with the IT8721F, +until a datasheet becomes available (hopefully.) + +The IT8603E/IT8623E is a custom design, hardware monitoring part is similar to +IT8728F. It only supports 3 fans, 16-bit fan mode, and the full speed mode +of the fan is not supported (value 0 of pwmX_enable). + +The IT8620E is another custom design, hardware monitoring part is similar to +IT8728F. It only supports 16-bit fan mode. + +The IT8790E supports up to 3 fans. 16-bit fan mode is always enabled. + +Temperatures are measured in degrees Celsius. An alarm is triggered once +when the Overtemperature Shutdown limit is crossed. + +Fan rotation speeds are reported in RPM (rotations per minute). An alarm is +triggered if the rotation speed has dropped below a programmable limit. When +16-bit tachometer counters aren't used, fan readings can be divided by +a programmable divider (1, 2, 4 or 8) to give the readings more range or +accuracy. With a divider of 2, the lowest representable value is around +2600 RPM. Not all RPM values can accurately be represented, so some rounding +is done. + +Voltage sensors (also known as IN sensors) report their values in volts. An +alarm is triggered if the voltage has crossed a programmable minimum or +maximum limit. Note that minimum in this case always means 'closest to +zero'; this is important for negative voltage measurements. All voltage +inputs can measure voltages between 0 and 4.08 volts, with a resolution of +0.016 volt (except IT8603E, IT8721F/IT8758E and IT8728F: 0.012 volt.) The +battery voltage in8 does not have limit registers. + +On the IT8603E, IT8721F/IT8758E, IT8781F, IT8782F, and IT8783E/F, some +voltage inputs are internal and scaled inside the chip: +* in3 (optional) +* in7 (optional for IT8781F, IT8782F, and IT8783E/F) +* in8 (always) +* in9 (relevant for IT8603E only) +The driver handles this transparently so user-space doesn't have to care. + +The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: +the voltage level your processor should work with. This is hardcoded by +the mainboard and/or processor itself. It is a value in volts. + +If an alarm triggers, it will remain triggered until the hardware register +is read at least once. This means that the cause for the alarm may already +have disappeared! Note that in the current implementation, all hardware +registers are read whenever any data is read (unless it is less than 1.5 +seconds since the last update). This means that you can easily miss +once-only alarms. + +Out-of-limit readings can also result in beeping, if the chip is properly +wired and configured. Beeping can be enabled or disabled per sensor type +(temperatures, voltages and fans.) + +The IT87xx only updates its values each 1.5 seconds; reading it more often +will do no harm, but will return 'old' values. + +To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, +or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. +Give 0 for unused sensor. Any other value is invalid. To configure this at +startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; +3 = thermal diode) + + +Fan speed control +----------------- + +The fan speed control features are limited to manual PWM mode. Automatic +"Smart Guardian" mode control handling is only implemented for older chips +(see below.) However if you want to go for "manual mode" just write 1 to +pwmN_enable. + +If you are only able to control the fan speed with very small PWM values, +try lowering the PWM base frequency (pwm1_freq). Depending on the fan, +it may give you a somewhat greater control range. The same frequency is +used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are +read-only. + + +Automatic fan speed control (old interface) +------------------------------------------- + +The driver supports the old interface to automatic fan speed control +which is implemented by IT8705F chips up to revision F and IT8712F +chips up to revision G. + +This interface implements 4 temperature vs. PWM output trip points. +The PWM output of trip point 4 is always the maximum value (fan running +at full speed) while the PWM output of the other 3 trip points can be +freely chosen. The temperature of all 4 trip points can be freely chosen. +Additionally, trip point 1 has an hysteresis temperature attached, to +prevent fast switching between fan on and off. + +The chip automatically computes the PWM output value based on the input +temperature, based on this simple rule: if the temperature value is +between trip point N and trip point N+1 then the PWM output value is +the one of trip point N. The automatic control mode is less flexible +than the manual control mode, but it reacts faster, is more robust and +doesn't use CPU cycles. + +Trip points must be set properly before switching to automatic fan speed +control mode. The driver will perform basic integrity checks before +actually switching to automatic control mode. + + +Temperature offset attributes +----------------------------- + +The driver supports temp[1-3]_offset sysfs attributes to adjust the reported +temperature for thermal diodes or diode-connected thermal transistors. +If a temperature sensor is configured for thermistors, the attribute values +are ignored. If the thermal sensor type is Intel PECI, the temperature offset +must be programmed to the critical CPU temperature. |