1Kernel driver it87 2================== 3 4Supported chips: 5 * IT8705F 6 Prefix: 'it87' 7 Addresses scanned: from Super I/O config space (8 I/O ports) 8 Datasheet: Once publicly available at the ITE website, but no longer 9 * IT8712F 10 Prefix: 'it8712' 11 Addresses scanned: from Super I/O config space (8 I/O ports) 12 Datasheet: Once publicly available at the ITE website, but no longer 13 * IT8716F/IT8726F 14 Prefix: 'it8716' 15 Addresses scanned: from Super I/O config space (8 I/O ports) 16 Datasheet: Once publicly available at the ITE website, but no longer 17 * IT8718F 18 Prefix: 'it8718' 19 Addresses scanned: from Super I/O config space (8 I/O ports) 20 Datasheet: Once publicly available at the ITE website, but no longer 21 * IT8720F 22 Prefix: 'it8720' 23 Addresses scanned: from Super I/O config space (8 I/O ports) 24 Datasheet: Not publicly available 25 * SiS950 [clone of IT8705F] 26 Prefix: 'it87' 27 Addresses scanned: from Super I/O config space (8 I/O ports) 28 Datasheet: No longer be available 29 30Authors: 31 Christophe Gauthron 32 Jean Delvare <khali@linux-fr.org> 33 34 35Module Parameters 36----------------- 37 38* update_vbat: int 39 40 0 if vbat should report power on value, 1 if vbat should be updated after 41 each read. Default is 0. On some boards the battery voltage is provided 42 by either the battery or the onboard power supply. Only the first reading 43 at power on will be the actual battery voltage (which the chip does 44 automatically). On other boards the battery voltage is always fed to 45 the chip so can be read at any time. Excessive reading may decrease 46 battery life but no information is given in the datasheet. 47 48* fix_pwm_polarity int 49 50 Force PWM polarity to active high (DANGEROUS). Some chips are 51 misconfigured by BIOS - PWM values would be inverted. This option tries 52 to fix this. Please contact your BIOS manufacturer and ask him for fix. 53 54 55Hardware Interfaces 56------------------- 57 58All the chips suported by this driver are LPC Super-I/O chips, accessed 59through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an 60SMBus interface to the hardware monitoring functions. This driver no 61longer supports this interface though, as it is slower and less reliable 62than the ISA access, and was only available on a small number of 63motherboard models. 64 65 66Description 67----------- 68 69This driver implements support for the IT8705F, IT8712F, IT8716F, 70IT8718F, IT8720F, IT8726F and SiS950 chips. 71 72These chips are 'Super I/O chips', supporting floppy disks, infrared ports, 73joysticks and other miscellaneous stuff. For hardware monitoring, they 74include an 'environment controller' with 3 temperature sensors, 3 fan 75rotation speed sensors, 8 voltage sensors, and associated alarms. 76 77The IT8712F and IT8716F additionally feature VID inputs, used to report 78the Vcore voltage of the processor. The early IT8712F have 5 VID pins, 79the IT8716F and late IT8712F have 6. They are shared with other functions 80though, so the functionality may not be available on a given system. 81 82The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value 83is stored in the Super-I/O configuration space. Due to technical limitations, 84this value can currently only be read once at initialization time, so 85the driver won't notice and report changes in the VID value. The two 86upper VID bits share their pins with voltage inputs (in5 and in6) so you 87can't have both on a given board. 88 89The IT8716F, IT8718F, IT8720F and later IT8712F revisions have support for 902 additional fans. The additional fans are supported by the driver. 91 92The IT8716F, IT8718F and IT8720F, and late IT8712F and IT8705F also have 93optional 16-bit tachometer counters for fans 1 to 3. This is better (no more 94fan clock divider mess) but not compatible with the older chips and 95revisions. The 16-bit tachometer mode is enabled by the driver when one 96of the above chips is detected. 97 98The IT8726F is just bit enhanced IT8716F with additional hardware 99for AMD power sequencing. Therefore the chip will appear as IT8716F 100to userspace applications. 101 102Temperatures are measured in degrees Celsius. An alarm is triggered once 103when the Overtemperature Shutdown limit is crossed. 104 105Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 106triggered if the rotation speed has dropped below a programmable limit. When 10716-bit tachometer counters aren't used, fan readings can be divided by 108a programmable divider (1, 2, 4 or 8) to give the readings more range or 109accuracy. With a divider of 2, the lowest representable value is around 1102600 RPM. Not all RPM values can accurately be represented, so some rounding 111is done. 112 113Voltage sensors (also known as IN sensors) report their values in volts. An 114alarm is triggered if the voltage has crossed a programmable minimum or 115maximum limit. Note that minimum in this case always means 'closest to 116zero'; this is important for negative voltage measurements. All voltage 117inputs can measure voltages between 0 and 4.08 volts, with a resolution of 1180.016 volt. The battery voltage in8 does not have limit registers. 119 120The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: 121the voltage level your processor should work with. This is hardcoded by 122the mainboard and/or processor itself. It is a value in volts. 123 124If an alarm triggers, it will remain triggered until the hardware register 125is read at least once. This means that the cause for the alarm may already 126have disappeared! Note that in the current implementation, all hardware 127registers are read whenever any data is read (unless it is less than 1.5 128seconds since the last update). This means that you can easily miss 129once-only alarms. 130 131Out-of-limit readings can also result in beeping, if the chip is properly 132wired and configured. Beeping can be enabled or disabled per sensor type 133(temperatures, voltages and fans.) 134 135The IT87xx only updates its values each 1.5 seconds; reading it more often 136will do no harm, but will return 'old' values. 137 138To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, 139or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. 140Give 0 for unused sensor. Any other value is invalid. To configure this at 141startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; 1423 = thermal diode) 143 144 145Fan speed control 146----------------- 147 148The fan speed control features are limited to manual PWM mode. Automatic 149"Smart Guardian" mode control handling is only implemented for older chips 150(see below.) However if you want to go for "manual mode" just write 1 to 151pwmN_enable. 152 153If you are only able to control the fan speed with very small PWM values, 154try lowering the PWM base frequency (pwm1_freq). Depending on the fan, 155it may give you a somewhat greater control range. The same frequency is 156used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are 157read-only. 158 159 160Automatic fan speed control (old interface) 161------------------------------------------- 162 163The driver supports the old interface to automatic fan speed control 164which is implemented by IT8705F chips up to revision F and IT8712F 165chips up to revision G. 166 167This interface implements 4 temperature vs. PWM output trip points. 168The PWM output of trip point 4 is always the maximum value (fan running 169at full speed) while the PWM output of the other 3 trip points can be 170freely chosen. The temperature of all 4 trip points can be freely chosen. 171Additionally, trip point 1 has an hysteresis temperature attached, to 172prevent fast switching between fan on and off. 173 174The chip automatically computes the PWM output value based on the input 175temperature, based on this simple rule: if the temperature value is 176between trip point N and trip point N+1 then the PWM output value is 177the one of trip point N. The automatic control mode is less flexible 178than the manual control mode, but it reacts faster, is more robust and 179doesn't use CPU cycles. 180 181Trip points must be set properly before switching to automatic fan speed 182control mode. The driver will perform basic integrity checks before 183actually switching to automatic control mode. 184