linux-kernel - Re: [RFC PATCH v3 6/9] power: supply: Add batinfo functions for OCV to SOC with 0.1% accuracy

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Date:   Fri, 19 Nov 2021 02:49:15 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     Matti Vaittinen <mazziesaccount@...il.com>,
        Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Lee Jones <lee.jones@...aro.org>, rostokus@...il.com,
        fan.chen@...iatek.com, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-power@...rohmeurope.com
Subject: Re: [RFC PATCH v3 6/9] power: supply: Add batinfo functions for OCV
 to SOC with 0.1% accuracy

On Tue, Nov 16, 2021 at 1:27 PM Matti Vaittinen
<matti.vaittinen@...rohmeurope.com> wrote:

> The battery info functions computing the state-of-charge (SOC) based
> on open-circuit-voltage (OCV) are returning SOC using units of 1%.
>
> Some capacity estimation computations require higher accuracy. Add
> functions that return SOC using units of 0.1% to reduce rounding error.
>
> Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>

That sounds useful.

> +int power_supply_ocv2dcap_simple(struct power_supply_battery_ocv_table *table,
> +                               int table_len, int ocv)
> +{
> +       int i, cap, tmp;

Why a whole new function? Just rename the original power_supply_ocv2cap_simple()
to power_supply_ocv2dcap_simple and patch it to return the finegrained value,
then add a wrapper that use that function but drops it down by one order
of magnitude.

> +int power_supply_batinfo_ocv2dcap(struct power_supply_battery_info *info,
> +                                 int ocv, int temp)

Same with this, saves a lot of code!

(Also will use my new interpolation routines since you refactor
on top of that.)

Yours,
Linus Walleij