1*4882a593SmuzhiyunKernel driver pc87427 2*4882a593Smuzhiyun===================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunSupported chips: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun * National Semiconductor PC87427 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun Prefix: 'pc87427' 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun Addresses scanned: none, address read from Super I/O config space 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun Datasheet: No longer available 13*4882a593Smuzhiyun 14*4882a593SmuzhiyunAuthor: Jean Delvare <jdelvare@suse.de> 15*4882a593Smuzhiyun 16*4882a593SmuzhiyunThanks to Amir Habibi at Candelis for setting up a test system, and to 17*4882a593SmuzhiyunMichael Kress for testing several iterations of this driver. 18*4882a593Smuzhiyun 19*4882a593Smuzhiyun 20*4882a593SmuzhiyunDescription 21*4882a593Smuzhiyun----------- 22*4882a593Smuzhiyun 23*4882a593SmuzhiyunThe National Semiconductor Super I/O chip includes complete hardware 24*4882a593Smuzhiyunmonitoring capabilities. It can monitor up to 18 voltages, 8 fans and 25*4882a593Smuzhiyun6 temperature sensors. Only the fans and temperatures are supported at 26*4882a593Smuzhiyunthe moment, voltages aren't. 27*4882a593Smuzhiyun 28*4882a593SmuzhiyunThis chip also has fan controlling features (up to 4 PWM outputs), 29*4882a593Smuzhiyunwhich are partly supported by this driver. 30*4882a593Smuzhiyun 31*4882a593SmuzhiyunThe driver assumes that no more than one chip is present, which seems 32*4882a593Smuzhiyunreasonable. 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun 35*4882a593SmuzhiyunFan Monitoring 36*4882a593Smuzhiyun-------------- 37*4882a593Smuzhiyun 38*4882a593SmuzhiyunFan rotation speeds are reported as 14-bit values from a gated clock 39*4882a593Smuzhiyunsignal. Speeds down to 83 RPM can be measured. 40*4882a593Smuzhiyun 41*4882a593SmuzhiyunAn alarm is triggered if the rotation speed drops below a programmable 42*4882a593Smuzhiyunlimit. Another alarm is triggered if the speed is too low to be measured 43*4882a593Smuzhiyun(including stalled or missing fan). 44*4882a593Smuzhiyun 45*4882a593Smuzhiyun 46*4882a593SmuzhiyunFan Speed Control 47*4882a593Smuzhiyun----------------- 48*4882a593Smuzhiyun 49*4882a593SmuzhiyunFan speed can be controlled by PWM outputs. There are 4 possible modes: 50*4882a593Smuzhiyunalways off, always on, manual and automatic. The latter isn't supported 51*4882a593Smuzhiyunby the driver: you can only return to that mode if it was the original 52*4882a593Smuzhiyunsetting, and the configuration interface is missing. 53*4882a593Smuzhiyun 54*4882a593Smuzhiyun 55*4882a593SmuzhiyunTemperature Monitoring 56*4882a593Smuzhiyun---------------------- 57*4882a593Smuzhiyun 58*4882a593SmuzhiyunThe PC87427 relies on external sensors (following the SensorPath 59*4882a593Smuzhiyunstandard), so the resolution and range depend on the type of sensor 60*4882a593Smuzhiyunconnected. The integer part can be 8-bit or 9-bit, and can be signed or 61*4882a593Smuzhiyunnot. I couldn't find a way to figure out the external sensor data 62*4882a593Smuzhiyuntemperature format, so user-space adjustment (typically by a factor 2) 63*4882a593Smuzhiyunmay be required. 64