--- /dev/null
+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.
Code Review / kvmfornfv.git / blobdiff