Re: [PATCH v2] Documentation: DT: Document twl4030-madc-battery bindings.

[Belisko Marek]

Hi Mark,

On Mon, Sep 22, 2014 at 1:03 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> Hi,
>
> On Wed, Mar 05, 2014 at 08:52:19PM +0000, Marek Belisko wrote:
>> Signed-off-by: Marek Belisko <marek@xxxxxxxxxxxxx>
>> ---
>>  .../bindings/power_supply/twl4030_madc_battery.txt | 43 ++++++++++++++++++++++
>>  1 file changed, 43 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/power_supply/twl4030_madc_battery.txt
>>
>> 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..fd0b6d2
>> --- /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"
>
> I'm rather confused by this; the code seems to have stripped away all
> the twl4030 dependencies and this now seems to be a generic ADC battery
> status driver. So why does this need to be specific to twl4030?
You are right. Also possibly driver name is incorrect :). Better name could be
ti, madc-battery.
>
>> + - capacity : battery capacity in uAh
>
> I would make the units explicit in the name; "capacity" can be measured
> in many ways.
OK capacity_uAh should be fine I believe.
>
>> + - charging-calibration-data : list of voltage(mV):level(%) values
>> +     for charging calibration (see example)
>> + - discharging-calibration-data : list of voltage(mV):level(%) values
>> +     for discharging calibration (see example)
>
> Regardless of the prefixing of these property names, the specifics are
> unclear to me.
Do you suggest to rename it completely or is enough to add "ti, " prefix?
>
> Does this apply to vbat?
Yes bat is read and then interpolation algorithm is applied for
various power properties.
So mapping from voltage to percentage is defined in table.
>
> Is vbat guaranteed to read in mV?
Yes.
>
> Is any particular order required? The example seems to go be in
> descending percentage values.
There is done sorting in driver so ordering it's not necessary.
>
> Is any particular interpolation expected on behalf of the OS, or is this
> just an informative set of measurements that hte OS can use as it sees
> fit?
>
>> + - io-channels: Should contain IIO channel specifiers
>> +     for each element in io-channel-names.
>> +- io-channel-names: Should contain the following values:
All 3 statements was copied from rx51-battery and documentation is the same.
There is not unit for all channels just raw values which are then
converted in driver.
>> + * "temp" - The ADC channel for temperature reading
>
> Which units? Where is this used?
>
>> + * "ichg" - The ADC channel for battery charging status
>
> How exactly is this used to detect the charging status?
>
>> + * "vbat" - The ADC channel to measure the battery voltage
>> +
>> +Example:
>> +     madc-battery {
>> +             compatible = "ti,twl4030-madc-battery";
>> +             capacity = <1200000>;
>> +             charging-calibration-data = <4200 100
>> +                                          4100 75
>> +                                          4000 55
>> +                                          3900 25
>> +                                          3800 5
>> +                                          3700 2
>> +                                          3600 1
>> +                                          3300 0>;
>
> Please bracket list entries individually (as you've done with
> io-channels).
OK.
>
> Thanks,
> Mark.
>
>> +
>> +             discharging-calibration-data = <4200 100
>> +                                             4100 95
>> +                                             4000 70
>> +                                             3800 50
>> +                                             3700 10
>> +                                             3600 5
>> +                                             3300 0>;
>> +             io-channels = <&twl_madc 1>,
>> +                           <&twl_madc 10>,
>> +                           <&twl_madc 12>;
>> +             io-channel-names = "temp",
>> +                                "ichg",
>> +                                "vbat";
>> +     };
>> --
>> 1.8.3.2
>>
>>

Thanks,

Marek

-- 
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Marek Belisko - OPEN-NANDRA
Freelance Developer

Ruska Nova Ves 219 | Presov, 08005 Slovak Republic
Tel: +421 915 052 184
skype: marekwhite
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