1*7ebd8b66SMauro Carvalho ChehabKernel driver pc87427 2*7ebd8b66SMauro Carvalho Chehab===================== 3*7ebd8b66SMauro Carvalho Chehab 4*7ebd8b66SMauro Carvalho ChehabSupported chips: 5*7ebd8b66SMauro Carvalho Chehab 6*7ebd8b66SMauro Carvalho Chehab * National Semiconductor PC87427 7*7ebd8b66SMauro Carvalho Chehab 8*7ebd8b66SMauro Carvalho Chehab Prefix: 'pc87427' 9*7ebd8b66SMauro Carvalho Chehab 10*7ebd8b66SMauro Carvalho Chehab Addresses scanned: none, address read from Super I/O config space 11*7ebd8b66SMauro Carvalho Chehab 12*7ebd8b66SMauro Carvalho Chehab Datasheet: No longer available 13*7ebd8b66SMauro Carvalho Chehab 14*7ebd8b66SMauro Carvalho ChehabAuthor: Jean Delvare <jdelvare@suse.de> 15*7ebd8b66SMauro Carvalho Chehab 16*7ebd8b66SMauro Carvalho ChehabThanks to Amir Habibi at Candelis for setting up a test system, and to 17*7ebd8b66SMauro Carvalho ChehabMichael Kress for testing several iterations of this driver. 18*7ebd8b66SMauro Carvalho Chehab 19*7ebd8b66SMauro Carvalho Chehab 20*7ebd8b66SMauro Carvalho ChehabDescription 21*7ebd8b66SMauro Carvalho Chehab----------- 22*7ebd8b66SMauro Carvalho Chehab 23*7ebd8b66SMauro Carvalho ChehabThe National Semiconductor Super I/O chip includes complete hardware 24*7ebd8b66SMauro Carvalho Chehabmonitoring capabilities. It can monitor up to 18 voltages, 8 fans and 25*7ebd8b66SMauro Carvalho Chehab6 temperature sensors. Only the fans and temperatures are supported at 26*7ebd8b66SMauro Carvalho Chehabthe moment, voltages aren't. 27*7ebd8b66SMauro Carvalho Chehab 28*7ebd8b66SMauro Carvalho ChehabThis chip also has fan controlling features (up to 4 PWM outputs), 29*7ebd8b66SMauro Carvalho Chehabwhich are partly supported by this driver. 30*7ebd8b66SMauro Carvalho Chehab 31*7ebd8b66SMauro Carvalho ChehabThe driver assumes that no more than one chip is present, which seems 32*7ebd8b66SMauro Carvalho Chehabreasonable. 33*7ebd8b66SMauro Carvalho Chehab 34*7ebd8b66SMauro Carvalho Chehab 35*7ebd8b66SMauro Carvalho ChehabFan Monitoring 36*7ebd8b66SMauro Carvalho Chehab-------------- 37*7ebd8b66SMauro Carvalho Chehab 38*7ebd8b66SMauro Carvalho ChehabFan rotation speeds are reported as 14-bit values from a gated clock 39*7ebd8b66SMauro Carvalho Chehabsignal. Speeds down to 83 RPM can be measured. 40*7ebd8b66SMauro Carvalho Chehab 41*7ebd8b66SMauro Carvalho ChehabAn alarm is triggered if the rotation speed drops below a programmable 42*7ebd8b66SMauro Carvalho Chehablimit. Another alarm is triggered if the speed is too low to be measured 43*7ebd8b66SMauro Carvalho Chehab(including stalled or missing fan). 44*7ebd8b66SMauro Carvalho Chehab 45*7ebd8b66SMauro Carvalho Chehab 46*7ebd8b66SMauro Carvalho ChehabFan Speed Control 47*7ebd8b66SMauro Carvalho Chehab----------------- 48*7ebd8b66SMauro Carvalho Chehab 49*7ebd8b66SMauro Carvalho ChehabFan speed can be controlled by PWM outputs. There are 4 possible modes: 50*7ebd8b66SMauro Carvalho Chehabalways off, always on, manual and automatic. The latter isn't supported 51*7ebd8b66SMauro Carvalho Chehabby the driver: you can only return to that mode if it was the original 52*7ebd8b66SMauro Carvalho Chehabsetting, and the configuration interface is missing. 53*7ebd8b66SMauro Carvalho Chehab 54*7ebd8b66SMauro Carvalho Chehab 55*7ebd8b66SMauro Carvalho ChehabTemperature Monitoring 56*7ebd8b66SMauro Carvalho Chehab---------------------- 57*7ebd8b66SMauro Carvalho Chehab 58*7ebd8b66SMauro Carvalho ChehabThe PC87427 relies on external sensors (following the SensorPath 59*7ebd8b66SMauro Carvalho Chehabstandard), so the resolution and range depend on the type of sensor 60*7ebd8b66SMauro Carvalho Chehabconnected. The integer part can be 8-bit or 9-bit, and can be signed or 61*7ebd8b66SMauro Carvalho Chehabnot. I couldn't find a way to figure out the external sensor data 62*7ebd8b66SMauro Carvalho Chehabtemperature format, so user-space adjustment (typically by a factor 2) 63*7ebd8b66SMauro Carvalho Chehabmay be required. 64