Kernel driver `pc87360.o' ========================= Status: Alpha, untested. Supported chips: * National Semiconductor PC87360, PC87363, PC87364, PC87365 and PC87366 Addresses scanned: none, address read from Super I/O config space Datasheets: http://www.national.com/pf/PC/PC87360.html http://www.national.com/pf/PC/PC87363.html http://www.national.com/pf/PC/PC87364.html http://www.national.com/pf/PC/PC87365.html http://www.national.com/pf/PC/PC87366.html Authors: Jean Delvare Module Parameters ----------------- None. Description ----------- The National Semiconductor PC87360 Super I/O chip contains monitoring and PWM control circuitry for two fans. The PC87363 chip is similar, and the PC87364 chip has monitoring and PWM control for a third fan. The National Semiconductor PC87365 and PC87366 Super I/O chips are complete hardware monitoring chipsets, not only controling and monitoring three fans, but also monitoring eleven voltage inputs and two (PC87365) or three (PC87366) remote temperatures. For now, the driver doesn't handle these features and treat these two chips as PC87364. Fan rotation speeds are reported in RPM (revolutions per minute). An alarm is triggered if the rotation speed has dropped below a programmable limit. Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to give the readings more range or accuracy. Not all RPM values can accurately be represented, so some rounding is done. With a divider of 2, the lowest representable value is around 1900 RPM. See doc/fan-divisors for details. A different alarm is also triggered if the fan speed is too low to be measured. It is suggested to increase the fan divisor in this case. PWM values are from 0 to 255. 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. Limitations ----------- This driver only supports fans at the moment. The datasheets suggests that some values (fan mins, fan divisors) shouldn't be changed once the monitoring has started, but we ignore that recommendation. We'll reconsider if it actually causes trouble.