linux-kernel - Re: [PATCH v3 2/4] power: supply: core: Introduce properties to present the battery OCV capacity table

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Message-ID: <CAMz4kuKo0jZ8YS7zx-t8hESedTYb094VLzdzNOpQd04M3kE4Dw@mail.gmail.com>
Date:   Sun, 14 Oct 2018 14:53:19 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Rob Herring <robh@...nel.org>
Cc:     Sebastian Reichel <sre@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Linux PM list <linux-pm@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, yuanjiang.yu@...soc.com,
        Mark Brown <broonie@...nel.org>,
        Craig Tatlor <ctatlor97@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v3 2/4] power: supply: core: Introduce properties to
 present the battery OCV capacity table

Hi Rob,

On 12 October 2018 at 22:35, Rob Herring <robh@...nel.org> wrote:
> On Thu, Sep 27, 2018 at 03:26:55PM +0800, Baolin Wang wrote:
>> Some battery driver will use the open circuit voltage (OCV) value to look
>> up the corresponding battery capacity percent in one certain degree Celsius.
>> Thus this patch provides some battery properties to present the OCV table
>> temperatures and OCV capacity table values. Moreover it also provides some
>> helper functions to use the OCV capacity table for users.
>>
>> Suggested-by: Sebastian Reichel <sre@...nel.org>
>> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
>> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
>> ---
>> Changes from v2:
>>  - Use type __be32 to calculate the table length.
>>  - Update error messages.
>>  - Add some helper functions.
>>
>> Changes from v1:
>>  - New patch in v2.
>> ---
>>  .../devicetree/bindings/power/supply/battery.txt   |   14 +++
>
> Please split binding patches.

Sure.

>
>>  drivers/power/supply/power_supply_core.c           |  125 +++++++++++++++++++-
>>  include/linux/power_supply.h                       |   19 +++
>>  3 files changed, 157 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt
>> index 938d027..cad38df 100644
>> --- a/Documentation/devicetree/bindings/power/supply/battery.txt
>> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt
>> @@ -23,6 +23,16 @@ Optional Properties:
>>   - constant-charge-current-max-microamp: maximum constant input current
>>   - constant-charge-voltage-max-microvolt: maximum constant input voltage
>>   - factory-internal-resistance-micro-ohms: battery factory internal resistance
>> + - ocv-capacity-table-0: An array providing the battery capacity percent
>> +   with corresponding open circuit voltage (OCV) of the battery, which
>> +   is used to look up battery capacity according to current OCV value.
>> + - ocv-capacity-table-1: Same as ocv-capacity-table-0
>> + ......
>> + - ocv-capacity-table-n: Same as ocv-capacity-table-0
>
> So it is tubles of (percent, voltage)? What's the units for voltage?

Yes. The units for voltage is microvolt, and I will add some words to
make it clear in next version.

>
> What determines the # of entries for each table? Do all tables have the
> same number of entries?

Not same, that depends on the battery drivers' requirement.

>> + - ocv-capacity-table-temperatures: An array containing the temperature
>> +   in degree Celsius, for each of the battery capacity lookup table.
>> +   The first temperature value specifies the OCV table 0, and the second
>> +   temperature value specifies the OCV table 1, and so on.
>
> This should have unit suffix. Perhaps just "ocv-capacity-celsius" to
> avoid being too long.

I am fine with this. Thanks for your comments.

Sebastian and Linusw, what do you think about Rob's suggestion? Thanks.

-- 
Baolin Wang
Best Regards