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 * IT8771E 34 Prefix: 'it8771' 35 Addresses scanned: from Super I/O config space (8 I/O ports) 36 Datasheet: Not publicly available 37 * IT8772E 38 Prefix: 'it8772' 39 Addresses scanned: from Super I/O config space (8 I/O ports) 40 Datasheet: Not publicly available 41 * IT8782F 42 Prefix: 'it8782' 43 Addresses scanned: from Super I/O config space (8 I/O ports) 44 Datasheet: Not publicly available 45 * IT8783E/F 46 Prefix: 'it8783' 47 Addresses scanned: from Super I/O config space (8 I/O ports) 48 Datasheet: Not publicly available 49 * SiS950 [clone of IT8705F] 50 Prefix: 'it87' 51 Addresses scanned: from Super I/O config space (8 I/O ports) 52 Datasheet: No longer be available 53 54Authors: 55 Christophe Gauthron 56 Jean Delvare <khali@linux-fr.org> 57 58 59Module Parameters 60----------------- 61 62* update_vbat: int 63 64 0 if vbat should report power on value, 1 if vbat should be updated after 65 each read. Default is 0. On some boards the battery voltage is provided 66 by either the battery or the onboard power supply. Only the first reading 67 at power on will be the actual battery voltage (which the chip does 68 automatically). On other boards the battery voltage is always fed to 69 the chip so can be read at any time. Excessive reading may decrease 70 battery life but no information is given in the datasheet. 71 72* fix_pwm_polarity int 73 74 Force PWM polarity to active high (DANGEROUS). Some chips are 75 misconfigured by BIOS - PWM values would be inverted. This option tries 76 to fix this. Please contact your BIOS manufacturer and ask him for fix. 77 78 79Hardware Interfaces 80------------------- 81 82All the chips supported by this driver are LPC Super-I/O chips, accessed 83through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an 84SMBus interface to the hardware monitoring functions. This driver no 85longer supports this interface though, as it is slower and less reliable 86than the ISA access, and was only available on a small number of 87motherboard models. 88 89 90Description 91----------- 92 93This driver implements support for the IT8705F, IT8712F, IT8716F, 94IT8718F, IT8720F, IT8721F, IT8726F, IT8728F, IT8758E, IT8771E, IT8772E, 95IT8782F, IT8783E/F, and SiS950 chips. 96 97These chips are 'Super I/O chips', supporting floppy disks, infrared ports, 98joysticks and other miscellaneous stuff. For hardware monitoring, they 99include an 'environment controller' with 3 temperature sensors, 3 fan 100rotation speed sensors, 8 voltage sensors, associated alarms, and chassis 101intrusion detection. 102 103The IT8712F and IT8716F additionally feature VID inputs, used to report 104the Vcore voltage of the processor. The early IT8712F have 5 VID pins, 105the IT8716F and late IT8712F have 6. They are shared with other functions 106though, so the functionality may not be available on a given system. 107 108The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value 109is stored in the Super-I/O configuration space. Due to technical limitations, 110this value can currently only be read once at initialization time, so 111the driver won't notice and report changes in the VID value. The two 112upper VID bits share their pins with voltage inputs (in5 and in6) so you 113can't have both on a given board. 114 115The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E and later IT8712F revisions 116have support for 2 additional fans. The additional fans are supported by the 117driver. 118 119The IT8716F, IT8718F, IT8720F, IT8721F/IT8758E, IT8782F, IT8783E/F, and late 120IT8712F and IT8705F also have optional 16-bit tachometer counters for fans 1 to 1213. This is better (no more fan clock divider mess) but not compatible with the 122older chips and revisions. The 16-bit tachometer mode is enabled by the driver 123when one of the above chips is detected. 124 125The IT8726F is just bit enhanced IT8716F with additional hardware 126for AMD power sequencing. Therefore the chip will appear as IT8716F 127to userspace applications. 128 129The IT8728F, IT8771E, and IT8772E are considered compatible with the IT8721F, 130until a datasheet becomes available (hopefully.) 131 132Temperatures are measured in degrees Celsius. An alarm is triggered once 133when the Overtemperature Shutdown limit is crossed. 134 135Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 136triggered if the rotation speed has dropped below a programmable limit. When 13716-bit tachometer counters aren't used, fan readings can be divided by 138a programmable divider (1, 2, 4 or 8) to give the readings more range or 139accuracy. With a divider of 2, the lowest representable value is around 1402600 RPM. Not all RPM values can accurately be represented, so some rounding 141is done. 142 143Voltage sensors (also known as IN sensors) report their values in volts. An 144alarm is triggered if the voltage has crossed a programmable minimum or 145maximum limit. Note that minimum in this case always means 'closest to 146zero'; this is important for negative voltage measurements. All voltage 147inputs can measure voltages between 0 and 4.08 volts, with a resolution of 1480.016 volt (except IT8721F/IT8758E and IT8728F: 0.012 volt.) The battery 149voltage in8 does not have limit registers. 150 151On the IT8721F/IT8758E, IT8782F, and IT8783E/F, some voltage inputs are 152internal and scaled inside the chip (in7 (optional for IT8782F and IT8783E/F), 153in8 and optionally in3). The driver handles this transparently so user-space 154doesn't have to care. 155 156The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value: 157the voltage level your processor should work with. This is hardcoded by 158the mainboard and/or processor itself. It is a value in volts. 159 160If an alarm triggers, it will remain triggered until the hardware register 161is read at least once. This means that the cause for the alarm may already 162have disappeared! Note that in the current implementation, all hardware 163registers are read whenever any data is read (unless it is less than 1.5 164seconds since the last update). This means that you can easily miss 165once-only alarms. 166 167Out-of-limit readings can also result in beeping, if the chip is properly 168wired and configured. Beeping can be enabled or disabled per sensor type 169(temperatures, voltages and fans.) 170 171The IT87xx only updates its values each 1.5 seconds; reading it more often 172will do no harm, but will return 'old' values. 173 174To change sensor N to a thermistor, 'echo 4 > tempN_type' where N is 1, 2, 175or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'. 176Give 0 for unused sensor. Any other value is invalid. To configure this at 177startup, consult lm_sensors's /etc/sensors.conf. (4 = thermistor; 1783 = thermal diode) 179 180 181Fan speed control 182----------------- 183 184The fan speed control features are limited to manual PWM mode. Automatic 185"Smart Guardian" mode control handling is only implemented for older chips 186(see below.) However if you want to go for "manual mode" just write 1 to 187pwmN_enable. 188 189If you are only able to control the fan speed with very small PWM values, 190try lowering the PWM base frequency (pwm1_freq). Depending on the fan, 191it may give you a somewhat greater control range. The same frequency is 192used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are 193read-only. 194 195 196Automatic fan speed control (old interface) 197------------------------------------------- 198 199The driver supports the old interface to automatic fan speed control 200which is implemented by IT8705F chips up to revision F and IT8712F 201chips up to revision G. 202 203This interface implements 4 temperature vs. PWM output trip points. 204The PWM output of trip point 4 is always the maximum value (fan running 205at full speed) while the PWM output of the other 3 trip points can be 206freely chosen. The temperature of all 4 trip points can be freely chosen. 207Additionally, trip point 1 has an hysteresis temperature attached, to 208prevent fast switching between fan on and off. 209 210The chip automatically computes the PWM output value based on the input 211temperature, based on this simple rule: if the temperature value is 212between trip point N and trip point N+1 then the PWM output value is 213the one of trip point N. The automatic control mode is less flexible 214than the manual control mode, but it reacts faster, is more robust and 215doesn't use CPU cycles. 216 217Trip points must be set properly before switching to automatic fan speed 218control mode. The driver will perform basic integrity checks before 219actually switching to automatic control mode. 220 221 222Temperature offset attributes 223----------------------------- 224 225The driver supports temp[1-3]_offset sysfs attributes to adjust the reported 226temperature for thermal diodes or diode-connected thermal transistors. 227If a temperature sensor is configured for thermistors, the attribute values 228are ignored. If the thermal sensor type is Intel PECI, the temperature offset 229must be programmed to the critical CPU temperature. 230