On Wed, Sep 22, 2021 at 09:22:33AM +0200, Krzysztof Adamski wrote: > Dnia Tue, Sep 21, 2021 at 05:58:31AM -0700, Guenter Roeck napisał(a): > > > > > > ti,n-factor > > > > n-factor isn't just supported by TI sensors, though it isn't always called > > n-factor. Maxim (eg MAX6581) uses the term "ideality factor", though they > > also refer to the factor as "N" in the datasheet. > > > > So question is if we make this ti,n-factor and maxim,n-factor, or if we make > > it generic and define some kind of generic units. Thoughts ? My personal > > preference would be a generic definition, but is not a strong preference. > > That was exactly my way of thinking here - many sensors have n-factor > parameter and this is the name I see most often. > > That being said, maybe it should be "nfactor" instead of "n-factor", as > this is what tmp513 is using? > > > In regard to units, the n-factor is, as the name says, a factor. Default > > value is 1.008. The value range for MAX6581 is 0.999 to 1.030. For TMP421 > > it is 0.706542 to 1.747977. So the scondary question is if the value > > written should be the register value (as proposed here) or the absolute > > factor (eg in micro-units). > > Since expressing the fractional values in DT isn't well supported and > (at least here) hardware guys like to think in terms of register values > so this is what I proposed. Also, I just noticed that, for example, > TMP531 is using register values as well. > I never see "someone else does that" as valid argument. Also, DT does support fractional values, via units. It is perfectly valid to describe a voltage as micro-volt, for example. If the agreement is to use raw register values, I think the property name should be prefixed with the vendor name, since it won't be a standard property. I'll defer on Rob for that, though. Thanks, Guenter
