On 2017-05-05 11:54, Andy Shevchenko wrote:
> On Fri, 2017-05-05 at 08:31 +0200, Jan Kiszka wrote:
>> This is an upstream port of an IIO driver for the TI ADC108S102 and
>> ADC128S102. The former can be found on the Intel Galileo Gen2 and the
>> Siemens SIMATIC IOT2000. For those boards, ACPI-based enumeration is
>> included.
>>
>> Due to the lack of regulators under ACPI, we need a special device
>> property to define the voltage provide to the VA pin of the ADC
>> ("va-millivolt"). For DT usage, the regulator "vref-supply" is
>> requested. Note that DT usage has not been tested.
>
> +1 to what Mika commented on this and just some additional information.
>
> Other than that looks pretty good.
>
>> Changes in v3:
>> - Reworked reference voltage handling, splitting up the different
>> ACPI
>> case from DT usage. This also means that the "va-millivolt"
>> (formerly and incorrectly called "ext-vin-microvolt") becomes
>> ACPI-only
>
> Just to be clean, there is *no* such thing as *XYZ-only* device
> properties. The idea behind them is to provide resource provider
> agnostic API to read properties.
Well, as along as ACPI does its own thing /wrt regulators, we have that
problem. But let's wait until someone designs an ACPI board with that
chip and a different reference voltage.
>
>> + if (st->reg)
>> + *val = regulator_get_voltage(st->reg)
>> / 1000;
>> + else
>> + *val = st->va_millivolt;
>> +
>
> Another way is to not just hard code the value, but create a fixed
> voltage regulator out of it. In this case you will have one way to get
> its value.
That's a good idea.
>
>> + st->reg = devm_regulator_get(&spi->dev, "vref");
>
> It should be _optional like I mentioned in one of previous review.
>
>> + if (!IS_ERR(st->reg))
>
> This is redundant
It's not for the existing code because regulator_disable doesn't test
this for us. It will be, though, when I switch back to making it
mandatory for everyone.
Jan
>
>> + regulator_disable(st->reg);
>
>> + if (!IS_ERR(st->reg))
>
> Ditto.
>
>> + regulator_disable(st->reg);
>
>
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Corporate Competence Center Embedded Linux
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