> This patch adds documentation for the new vt1211 Super-IO driver. My review: > --- linux-2.6.17-rc4-mm1-vanilla/Documentation/hwmon/vt1211 1970-01-01 00:00:00.000000000 +0000 > +++ linux-2.6.17-rc4-mm1/Documentation/hwmon/vt1211 2006-05-17 21:14:36.000000000 +0000 > @@ -0,0 +1,167 @@ > +Kernel driver vt1211 > +==================== > + > +Supported chips: > + * VIA VT1211 > + Prefix: 'vt1211' > + Addresses scanned: none, address read from Super-I/O config space > + Datasheet: Provided by VIA upon request and under NDA > + > +Authors: Juerg Haefliger <juergh at gmail.com> > + Lars Ekman <emil71se at yahoo.com> > + Mark D. Studebaker <mdsxyz123 at yahoo.com> Drop Mark, or add a statement "based on a driver written my Mark..." > + > +Thanks to Joseph Chan and Fiona Gatt from VIA for providing documentation and > +technical support. > + > + > +Description > +----------- > + > +The VIA VT1211 Super-I/O chip includes complete hardware monitoring > +capabilities. It monitors 2 dedicated temperature sensor inputs (temp1 and > +temp3), 2 dedicated voltages (in5 & in6) and 2 fans. Additionally, the chip > +implements 5 universal input channels (UCH1-5) that can be individually > +programmed to either monitor a voltage or a temperature. > + > +This chip also provides manual and automatic control of fan speeds. The driver > +supports these features but they haven't been very well tested yet (due to the > +fact that my EPIA M10000 doesn't have the fans connected to the PWM outputs of > +the VT1211 :-(). > + > +The following table shows the relationship between the vt1211 inputs and the > +sysfs nodes. > + > +Sensor Voltage Mode Temp Mode Default Use (from the datasheet) > +------ ------------ --------- -------------------------------- > +Reading 1 temp3 Intel thermal diode > +Reading 3 temp1 internal thermal diode > +UCH1/Reading2 in0 temp2 NTC type thermistor > +UCH2 in1 temp4 +2.5V > +UCH3 in2 temp5 VccP (processor core) > +UCH4 in3 temp6 +5V > +UCH5 in4 temp7 +12V > ++3.3V in5 Internal VCC (+3.3V) > +-12V in6 (reserved) > + > +Note that even though in6 is implemented in the driver, it is reserved as per > +the datasheet and doesn't return a meaningful value (always 0). I take it as a strong indication that it doesn't exist at all, and I'd drop it. > + > + > +Voltage Monitoring > +------------------ > + > +Voltages are sampled by an 8-bit ADC with a LSB of ~10mV. The supported input > +range is thus from 0 to 2.60V. Voltage values outside of this range need > +external scaling resistors. This external scaling needs to be compensated for > +via compute lines in sensors.conf, like: > + > +compute inx @*(1+R1/R2), @/(1+R1/R2) > + > +The board level scaling resistors according to VIA's recommendation are as > +follows. And this is of course totally dependent on the actual board > +implementation :-) You will have to find documentation for your own > +motherboard and edit sensors.conf accordingly. > + > + Expected > +Voltage R1 R2 Divider Raw Value > +----------------------------------------------- > ++2.5V 2K 10K 1.2 2083 mV > +VccP --- --- 1.0 1400 mV (1) > ++5V 14K 10K 2.4 2083 mV > ++12V 47K 10K 5.7 2105 mV > ++3.3V (int) 2K 3.4K 1.588 3300 mV (2) > ++3.3V (ext) 6.8K 10K 1.68 1964 mV > + > +(1) Depending on the CPU (1.4V is for a VIA C3 Nehemiah). > +(2) R1 and R2 for 3.3V (int) are internal to the VT1211 chip and the driver > + performs the scaling and returns the properly scaled voltage value. > + > +Each measured voltage has an associated low and high limit which triggers an > +alarm when crossed. > + > + > +Temperature Monitoring > +---------------------- > + > +Temperatures are reported in millidegree Celsius. Each measured temperature > +has a high limit which triggers an alarm if crossed. There is an associated > +hysteresis value with each temperature below which the temperature has to drop > +before the alarm is cleared. > + > +All temperature channels except temp1 are external. Temp1 is the VT1211 > +internal thermal diode and the driver does all the scaling for temp1 and > +returns the temperature in millidegree Celcius. For the external channels, > +scaling needs to be performed in user-land via sensors.conf and depending on > +the boad implementation: > + > +compute tempx (@-Offset)/Gain, (@*Gain)+Offset [for thermal diodes] > + > +According to the VIA VT1211 BIOS porting guide, the following values should be > +used: > + > +Diode Type Offset Gain > +---------- ------ ---- > +Intel CPU 88.638 0.9528 > +VIA C3 Ezra 83.869 0.9528 > +VIA C3 Ezra-T 73.869 0.9528 Odd, in sensors.conf we have a different fomula, supposedly for Intel CPUs: offset 65, gain 0.9686. It presumably comes from an older BIOS porting guide? Might be worth documenting. Not a word on thermistor-based measurements? > + > + > +Fan Speed Control > +----------------- > + > +The VT1211 provides 2 programmable PWM outputs to control the speeds of 2 fans > +. Writing a 2 to any of the two pwm[1..2]_enable sysfs nodes will put the PWM Move the dot at the end of previous line. [1..2] is usually written [1-2] in the rest of our documentation. > +controller in automatic mode. Note that there is only a single controller that > +controls both PWM outputs but each PWM output can be individually enabled and > +disabled. The possible operating modes for the 2 PWM outputs are as follows: > + > +pwm1_enable pwm2_enable | pwm1 pwm2 > +---------------------------------------------------- > +0 0 | off off > +0 1 | off manual > +1 0 | manual off > +1 1 | manual manual > +2 0 | automatic off > +0 2 | off automatic > +2 2 | automatic automatic This table doesn't help much IMHO. What is really important to say is that you can't mix manual and automatic modes. > + > +Each PWM has 4 associated distinctiv output duty-cycles: full, high, low and That would be distinctive or (better I think) distinct. > +off. Full and off are internally hard-wired to 255 (100%) and 0 (0%), > +respectively. High and low can be programmed via > +pwm[1..2]_auto_point[2..3]_pwm. Each PWM output can be associated with a > +different thermal input but - and here's the weird part - only one set of > +thermal thresholds exist that control both PWMs output duty cycles (??). The Why these question marks? > +thermal thresholds are accessible via pwm[1..2]_auto_point[1..4]_temp. Note > +that even though there are 2 sets of 4 auto points each, they map to the same > +registers in the VT1211. So programming one set is sufficient. > + > +PWM Auto Point PWM Output Duty-Cycle > +------------------------------------------------- > +pwm[1..2]_auto_point1_pwm full speed dc (255) > +pwm[1..2]_auto_point2_pwm high speed dc > +pwm[1..2]_auto_point3_pwm low speed dc > +pwm[1..2]_auto_point4_pwm off dc (0) "dc" is an unfortunate abbreviation for duty cycle. People could read it as "direct current", which is the other fan speed control method. Pretty confusing. > + > +Temp Auto Point Thermal Threshold > +------------------------------------------------- > +pwm[1..2]_auto_point1_temp full speed temp > +pwm[1..2]_auto_point2_temp high speed temp > +pwm[1..2]_auto_point3_temp low speed temp > +pwm[1..2]_auto_point4_temp off temp > + > +Long story short, the controller inmplements the following algorithm to set the Typo: implements. > +PWM output duty-cycle based on the input temperature: > + > + Output Duty-Cycle > +Thermal Threshold (Rising Temp) (Falling Temp) > +-------------------------------------------------- > + full speed dc full speed dc > +full speed temp > + high speed dc full speed dc > +high speed temp > + low speed dc high speed dc > +low speed temp > + off dc low speed dc > +off temp > + off dc off dc Very good doc, well done. -- Jean Delvare
