Re: [PATCH v3 3/6] Documentation: DT: Document twl4030-madc-battery bindings

Pavel Machek
2015-03-17T10:01:42Z

On Tue 2015-03-17 10:07:12, Dr. H. Nikolaus Schaller wrote:
>
> Am 17.03.2015 um 09:47 schrieb Pavel Machek <pavel@ucw.cz>:
>
> > Hi!
> >
> >>>> diff --git a/Documentation/devicetree/bindings/power_supply/twl4030_madc_battery.txt b/Documentation/devicetree/bindings/power_supply/twl4030_madc_battery.txt
> >>>> new file mode 100644
> >>>> index 0000000..bb3580c
> >>>> --- /dev/null
> >>>> +++ b/Documentation/devicetree/bindings/power_supply/twl4030_madc_battery.txt
> >>>> @@ -0,0 +1,43 @@
> >>>> +twl4030_madc_battery
> >>>> +
> >>>> +Required properties:
> >>>> + - compatible : "ti,twl4030-madc-battery"
> >>>> + - capacity-uah : battery capacity in uAh
> >>>
> >>> Could we make it capacity-uAh ?
> >> This name was suggested by Mark Rutland [1] and naming convention
> >> should be all lowercase. There exists already bindings
> >> without uppercase (e.g. ti,bb-uamp) so I would keep it consistent.
> >
> > Messing up SI units due to "convention" is _stupid_. Don't do it.
> >
> >>> to introduce coefficients for temperature and discharge rate?
> >> What do you mean? Nothing like that is used in current driver why do
> >> we need to add it?
> >
> > Well, conversion between Li-ion's voltage and state of charge at 0
> > current is well known:
> >
> > def percent(m, v):
> > u = 0.0387-(1.4523*(3.7835-v))
> > if u < 0:
> > return 0
> > return (0.1966+math.sqrt(u))*100
>
> I forgot to ask: does the kernel have a sqrt() function?

This could be good enough.

https://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.0/2.6.0-mm1/broken-out/fix-sqrt.patch

Pavel
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