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 * IT8721F/IT8758E 26 Prefix: 'it8721' 27 Addresses scanned: from Super I/O config space (8 I/O ports) 28 Datasheet: Not publicly available 29 * IT8728F 30 Prefix: 'it8728' 31 Addresses scanned: from Super I/O config space (8 I/O ports) 32 Datasheet: Not publicly available 33 * SiS950 [clone of IT8705F] 34 Prefix: 'it87' 35 Addresses scanned: from Super I/O config space (8 I/O ports) 36 Datasheet: No longer be available 37 38Authors: 39 Christophe Gauthron 40 Jean Delvare <khali@linux-fr.org> 41 42 43Module Parameters 44----------------- 45 46* update_vbat: int 47 48 0 if vbat should report power on value, 1 if vbat should be updated after 49 each read. Default is 0. On some boards the battery voltage is provided 50 by either the battery or the onboard power supply. Only the first reading 51 at power on will be the actual battery voltage (which the chip does 52 automatically). On other boards the battery voltage is always fed to 53 the chip so can be read at any time. Excessive reading may decrease 54 battery life but no information is given in the datasheet. 55 56* fix_pwm_polarity int 57 58 Force PWM polarity to active high (DANGEROUS). Some chips are 59 misconfigured by BIOS - PWM values would be inverted. This option tries 60 to fix this. Please contact your BIOS manufacturer and ask him for fix. 61 62 63Hardware Interfaces 64------------------- 65 66All the chips suported by this driver are LPC Super-I/O chips, accessed 67through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an 68SMBus interface to the hardware monitoring functions. This driver no 69longer supports this interface though, as it is slower and less reliable 70than the ISA access, and was only available on a small number of 71motherboard models. 72 73 74Description 75----------- 76 77This driver implements support for the IT8705F, IT8712F, IT8716F, 78IT8718F, IT8720F, IT8721F, IT8726F, IT8728F, IT8758E and SiS950 chips. 79 80These chips are 'Super I/O chips', supporting floppy disks, infrared ports, 81joysticks and other miscellaneous stuff. For hardware monitoring, they 82include an 'environment controller' with 3 temperature sensors, 3 fan 83rotation speed sensors, 8 voltage sensors, associated alarms, and chassis 84intrusion detection. 85 86The IT8712F and IT8716F additionally feature VID inputs, used to report 87the Vcore voltage of the processor. The early IT8712F have 5 VID pins, 88the IT8716F and late IT8712F have 6. They are shared with other functions 89though, so the functionality may not be available on a given system. 90 91The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value 92is stored in the Super-I/O configuration space. Due to technical limitations, 93this value can currently only be read once at initialization time, so 94the driver won't notice and report changes in the VID value. The two 95upper VID bits share their pins with voltage inputs (in5 and in6) so you 96can't have both on a given board. 97 98The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions 99have support for 2 additional fans. The additional fans are supported by the 100driver. 101 102The IT8716F, IT8718F, IT8720F and IT8721F/IT8758E, and late IT8712F and 103IT8705F also have optional 16-bit tachometer counters for fans 1 to 3. This 104is better (no more fan clock divider mess) but not compatible with the older 105chips and revisions. The 16-bit tachometer mode is enabled by the driver when 106one of the above chips is detected. 107 108The IT8726F is just bit enhanced IT8716F with additional hardware 109for AMD power sequencing. Therefore the chip will appear as IT8716F 110to userspace applications. 111 112The IT8728F is considered compatible with the IT8721F, until a datasheet 113becomes available (hopefully.) 114 115Temperatures are measured in degrees Celsius. An alarm is triggered once 116when the Overtemperature Shutdown limit is crossed. 117 118Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 119triggered if the rotation speed has dropped below a programmable limit. When 12016-bit tachometer counters aren't used, fan readings can be divided by 121a programmable divider (1, 2, 4 or 8) to give the readings more range or 122accuracy. With a divider of 2, the lowest representable value is around 1232600 RPM. Not all RPM values can accurately be represented, so some rounding 124is done. 125 126Voltage sensors (also known as IN sensors) report their values in volts. An 127alarm is triggered if the voltage has crossed a programmable minimum or 128maximum limit. Note that minimum in this case always means 'closest to 129zero'; this is important for negative voltage measurements. All voltage 130inputs can measure voltages between 0 and 4.08 volts, with a resolution of 1310.016 volt (except IT8721F/IT8758E and IT8728F: 0.012 volt.) The battery 132voltage in8 does not have limit registers. 133 134On the IT8721F/IT8758E, some voltage inputs are internal and scaled inside 135the chip (in7, in8 and optionally in3). The driver handles this transparently 136so user-space doesn't have to care. 137 138The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: 139the voltage level your processor should work with. This is hardcoded by 140the mainboard and/or processor itself. It is a value in volts. 141 142If an alarm triggers, it will remain triggered until the hardware register 143is read at least once. This means that the cause for the alarm may already 144have disappeared! Note that in the current implementation, all hardware 145registers are read whenever any data is read (unless it is less than 1.5 146seconds since the last update). This means that you can easily miss 147once-only alarms. 148 149Out-of-limit readings can also result in beeping, if the chip is properly 150wired and configured. Beeping can be enabled or disabled per sensor type 151(temperatures, voltages and fans.) 152 153The IT87xx only updates its values each 1.5 seconds; reading it more often 154will do no harm, but will return 'old' values. 155 156To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, 157or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. 158Give 0 for unused sensor. Any other value is invalid. To configure this at 159startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; 1603 = thermal diode) 161 162 163Fan speed control 164----------------- 165 166The fan speed control features are limited to manual PWM mode. Automatic 167"Smart Guardian" mode control handling is only implemented for older chips 168(see below.) However if you want to go for "manual mode" just write 1 to 169pwmN_enable. 170 171If you are only able to control the fan speed with very small PWM values, 172try lowering the PWM base frequency (pwm1_freq). Depending on the fan, 173it may give you a somewhat greater control range. The same frequency is 174used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are 175read-only. 176 177 178Automatic fan speed control (old interface) 179------------------------------------------- 180 181The driver supports the old interface to automatic fan speed control 182which is implemented by IT8705F chips up to revision F and IT8712F 183chips up to revision G. 184 185This interface implements 4 temperature vs. PWM output trip points. 186The PWM output of trip point 4 is always the maximum value (fan running 187at full speed) while the PWM output of the other 3 trip points can be 188freely chosen. The temperature of all 4 trip points can be freely chosen. 189Additionally, trip point 1 has an hysteresis temperature attached, to 190prevent fast switching between fan on and off. 191 192The chip automatically computes the PWM output value based on the input 193temperature, based on this simple rule: if the temperature value is 194between trip point N and trip point N+1 then the PWM output value is 195the one of trip point N. The automatic control mode is less flexible 196than the manual control mode, but it reacts faster, is more robust and 197doesn't use CPU cycles. 198 199Trip points must be set properly before switching to automatic fan speed 200control mode. The driver will perform basic integrity checks before 201actually switching to automatic control mode. 202