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 * SiS950 [clone of IT8705F] 30 Prefix: 'it87' 31 Addresses scanned: from Super I/O config space (8 I/O ports) 32 Datasheet: No longer be available 33 34Authors: 35 Christophe Gauthron 36 Jean Delvare <khali@linux-fr.org> 37 38 39Module Parameters 40----------------- 41 42* update_vbat: int 43 44 0 if vbat should report power on value, 1 if vbat should be updated after 45 each read. Default is 0. On some boards the battery voltage is provided 46 by either the battery or the onboard power supply. Only the first reading 47 at power on will be the actual battery voltage (which the chip does 48 automatically). On other boards the battery voltage is always fed to 49 the chip so can be read at any time. Excessive reading may decrease 50 battery life but no information is given in the datasheet. 51 52* fix_pwm_polarity int 53 54 Force PWM polarity to active high (DANGEROUS). Some chips are 55 misconfigured by BIOS - PWM values would be inverted. This option tries 56 to fix this. Please contact your BIOS manufacturer and ask him for fix. 57 58 59Hardware Interfaces 60------------------- 61 62All the chips suported by this driver are LPC Super-I/O chips, accessed 63through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an 64SMBus interface to the hardware monitoring functions. This driver no 65longer supports this interface though, as it is slower and less reliable 66than the ISA access, and was only available on a small number of 67motherboard models. 68 69 70Description 71----------- 72 73This driver implements support for the IT8705F, IT8712F, IT8716F, 74IT8718F, IT8720F, IT8721F, IT8726F, IT8758E and SiS950 chips. 75 76These chips are 'Super I/O chips', supporting floppy disks, infrared ports, 77joysticks and other miscellaneous stuff. For hardware monitoring, they 78include an 'environment controller' with 3 temperature sensors, 3 fan 79rotation speed sensors, 8 voltage sensors, and associated alarms. 80 81The IT8712F and IT8716F additionally feature VID inputs, used to report 82the Vcore voltage of the processor. The early IT8712F have 5 VID pins, 83the IT8716F and late IT8712F have 6. They are shared with other functions 84though, so the functionality may not be available on a given system. 85 86The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value 87is stored in the Super-I/O configuration space. Due to technical limitations, 88this value can currently only be read once at initialization time, so 89the driver won't notice and report changes in the VID value. The two 90upper VID bits share their pins with voltage inputs (in5 and in6) so you 91can't have both on a given board. 92 93The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions 94have support for 2 additional fans. The additional fans are supported by the 95driver. 96 97The IT8716F, IT8718F, IT8720F and IT8721F/IT8758E, and late IT8712F and 98IT8705F also have optional 16-bit tachometer counters for fans 1 to 3. This 99is better (no more fan clock divider mess) but not compatible with the older 100chips and revisions. The 16-bit tachometer mode is enabled by the driver when 101one of the above chips is detected. 102 103The IT8726F is just bit enhanced IT8716F with additional hardware 104for AMD power sequencing. Therefore the chip will appear as IT8716F 105to userspace applications. 106 107Temperatures are measured in degrees Celsius. An alarm is triggered once 108when the Overtemperature Shutdown limit is crossed. 109 110Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 111triggered if the rotation speed has dropped below a programmable limit. When 11216-bit tachometer counters aren't used, fan readings can be divided by 113a programmable divider (1, 2, 4 or 8) to give the readings more range or 114accuracy. With a divider of 2, the lowest representable value is around 1152600 RPM. Not all RPM values can accurately be represented, so some rounding 116is done. 117 118Voltage sensors (also known as IN sensors) report their values in volts. An 119alarm is triggered if the voltage has crossed a programmable minimum or 120maximum limit. Note that minimum in this case always means 'closest to 121zero'; this is important for negative voltage measurements. All voltage 122inputs can measure voltages between 0 and 4.08 volts, with a resolution of 1230.016 volt (except IT8721F/IT8758E: 0.012 volt.) The battery voltage in8 does 124not have limit registers. 125 126On the IT8721F/IT8758E, some voltage inputs are internal and scaled inside 127the chip (in7, in8 and optionally in3). The driver handles this transparently 128so user-space doesn't have to care. 129 130The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: 131the voltage level your processor should work with. This is hardcoded by 132the mainboard and/or processor itself. It is a value in volts. 133 134If an alarm triggers, it will remain triggered until the hardware register 135is read at least once. This means that the cause for the alarm may already 136have disappeared! Note that in the current implementation, all hardware 137registers are read whenever any data is read (unless it is less than 1.5 138seconds since the last update). This means that you can easily miss 139once-only alarms. 140 141Out-of-limit readings can also result in beeping, if the chip is properly 142wired and configured. Beeping can be enabled or disabled per sensor type 143(temperatures, voltages and fans.) 144 145The IT87xx only updates its values each 1.5 seconds; reading it more often 146will do no harm, but will return 'old' values. 147 148To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, 149or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. 150Give 0 for unused sensor. Any other value is invalid. To configure this at 151startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; 1523 = thermal diode) 153 154 155Fan speed control 156----------------- 157 158The fan speed control features are limited to manual PWM mode. Automatic 159"Smart Guardian" mode control handling is only implemented for older chips 160(see below.) However if you want to go for "manual mode" just write 1 to 161pwmN_enable. 162 163If you are only able to control the fan speed with very small PWM values, 164try lowering the PWM base frequency (pwm1_freq). Depending on the fan, 165it may give you a somewhat greater control range. The same frequency is 166used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are 167read-only. 168 169 170Automatic fan speed control (old interface) 171------------------------------------------- 172 173The driver supports the old interface to automatic fan speed control 174which is implemented by IT8705F chips up to revision F and IT8712F 175chips up to revision G. 176 177This interface implements 4 temperature vs. PWM output trip points. 178The PWM output of trip point 4 is always the maximum value (fan running 179at full speed) while the PWM output of the other 3 trip points can be 180freely chosen. The temperature of all 4 trip points can be freely chosen. 181Additionally, trip point 1 has an hysteresis temperature attached, to 182prevent fast switching between fan on and off. 183 184The chip automatically computes the PWM output value based on the input 185temperature, based on this simple rule: if the temperature value is 186between trip point N and trip point N+1 then the PWM output value is 187the one of trip point N. The automatic control mode is less flexible 188than the manual control mode, but it reacts faster, is more robust and 189doesn't use CPU cycles. 190 191Trip points must be set properly before switching to automatic fan speed 192control mode. The driver will perform basic integrity checks before 193actually switching to automatic control mode. 194