Sensor value calculation formula

[Deng Tyler]

Hi all:
    Sensor reading, according to IPMI spec, is calculated as:

y = L[(Mx + B * 10^(bExp)) * 10^(rExp)]


   - y: the 'final value' as reported by IPMItool
   - x: 8 bits, unsigned, reading data encoded in IPMI response packet
   - M: 10 bits, signed integer multiplier, multiplierM in YAML
   - B: 10 bits, signed additive offset, offsetB in YAML
   - bExp: 4 bits, signed, bExp in YAML
   - rExp: 4 bits, signed, rExp in YAML

 ipmid calculate raw data by
double value = variant_ns::get<T>(propValue) * std::pow(10,
sensorInfo.scale - sensorInfo.exponentR);
auto rawData = static_cast<uint8_t>((value - sensorInfo.scaledOffset) /
sensorInfo.coefficientM);sue

I am confused about why process raw data with M and rExp? M, offsetB, bExp
and rExp shall just responded to ipmitool and calculate with raw
data. I thought raw data only need calculated by scale if raw data need to
be adjust before respond to ipmitool.
Now I met a problem, I have a raw data is 2100 and I want to display 12.0
in ipmitool sdr command. I don't know how to assign M, rExp and scale value
in yaml.
Could some one tell me how to translate sensor value? tks.

Tyler
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