| Kernel driver it87 |
| ================== |
| |
| Supported chips: |
| * 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 |
| * 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 <khali@linux-fr.org> |
| |
| |
| 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 suported 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 IT8705F, IT8712F, IT8716F, |
| IT8718F, IT8720F, IT8721F, IT8726F, IT8758E 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, and associated alarms. |
| |
| 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 and IT8721F/IT8758E, 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. |
| |
| 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 IT8721F/IT8758E: 0.012 volt.) The battery voltage in8 does |
| not have limit registers. |
| |
| On the IT8721F/IT8758E, some voltage inputs are internal and scaled inside |
| the chip (in7, in8 and optionally in3). 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. |