Re: [PATCH v7 3/4] dt-bindings: power: supply: qcom_bms: Add bindings

[Sebastian Reichel]

On Thu, Sep 20, 2018 at 08:13:52PM +0100, Craig wrote:
> On 20 September 2018 17:58:47 BST, Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx> wrote:
> >[Dropped a couple of people from CC, added Baolin]
> >
> >Hi Craig, Baolin and Rob,
> >
> >On Thu, Sep 20, 2018 at 03:32:29PM +0100, Craig wrote:
> >> On 16 September 2018 13:10:45 BST, Sebastian Reichel
> ><sebastian.reichel@xxxxxxxxxxxxx> wrote:
> >> >Sorry for my long delay in reviewing this. I like the binding,
> >> >but the "qcom," specific properties should become common properties
> >> >in
> >> >
> >> >Documentation/devicetree/bindings/power/supply/battery.txt
> >> >and referenced via monitored-battery.
> >
> >> Thanks for the review, what bindings for ocv would you prefer? The
> >> spreadtrum ones or mine?
> >
> >Most importantly I want to see only one generic binding supporting
> >both use cases. As far as I can see there are two major differences:
> >
> >1. Qcom uses legend properties and SC27XX embedds this into data
> >2. Qcom supports temperature based mapping
> >
> >The second point is easy: Not having temperature information can
> >be a subset of the data with temperature info. The main thing to
> >discuss are the legend properties. I suppose we have these
> >proposals:
> >
> >Proposal A (from Qcom BMS binding):
> >
> >ocv-capacity-legend = /bits/ 8 <100 95 90 85 80 75 70 65 60 55 50 45
> >...>;
> >ocv-temp-legend-celsius = /bits/ 8 <(-10) 0 25 50 65>;
> >ocv-lut-microvolt = <43050000 43050000 43030000 42990000
> >
> >Proposal B (from SC27XX binding):
> >
> >ocv-cap-table = <4185 100>, <4113 95>, <4066 90>, <4022 85> ...;
> >
> >I prefer the second binding (with mV -> uV), but I think it becomes
> >messy when temperature is added. What do you think about the
> >following proposal (derived from pinctrl style):
> >
> >Proposal C:
> >
> >ocv-capacity-table-temperatures = <(-10) 0 10>;
> >ocv-capacity-table-0 = <4185000 100>, <4113000 95>, <4066000 90>, ...;
> >ocv-capacity-table-1 = <4200000 100>, <4185000 95>, <4113000 90>, ...;
> >ocv-capacity-table-2 = <4250000 100>, <4200000 95>, <4185000 90>, ...;
> >
> >-- Sebastian
> 
> C looks good to me however I do kinda think it should be
> millivolts as I don't think any hardware reads in microvolts and
> the zeroes make it look quite ugly

I agree, that it looks a bit ugly in the table. Nevertheless I think we
should use microvolts, since that is being used by all other properties.

-- Sebastian

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