Hi,
Roger Quadros <rogerq@xxxxxx> writes:
>>>> Stefan Agner <stefan@xxxxxxxx> writes:
>>>
>>>>> According to the device tree bindings the vcc-supply is optional.
>>>
>>> This is nonsense unless the device can work without this supply. Given
>>> that the supply is called VCC that doesn't seem entirely likely.
>>
>> Afaik it is kind of a generic device tree binding, I guess the physical
>> device can have various appearances and properties...
>>
>> A quick survey showed several device trees which do not specify
>> vcc-supply...
>>
>> That said, I checked the device at hand, and it actually has a USB PHY
>> power supply inputs, but the device tree does not model them.
>>
>>>>> + nop->vcc = devm_regulator_get_optional(dev, "vcc");
>>>>> if (IS_ERR(nop->vcc)) {
>>>>> dev_dbg(dev, "Error getting vcc regulator: %ld\n",
>>>>> PTR_ERR(nop->vcc));
>>>>> - if (needs_vcc)
>>>>> - return -EPROBE_DEFER;
>>>>> + if (needs_vcc || PTR_ERR(nop->vcc) == -EPROBE_DEFER)
>>>>> + return PTR_ERR(nop->vcc);
>>>
>>>> does this look okay from a regulator API perspective?
>>>
>>> That's how to use _get_optional() but it's really unusual that you
>>> should be using _get_optional().
>>
>> Despite the above findings, I still think it is the right thing to do as
>> long as we specify vcc-supply to be optional.
>>
>
> I think the right behaviour would be that if vcc-supply is specified
> in the DT then failure to get that supply is a serious failure and
> probe should fail.
>
> So the correct fix would be to call devm_regulator_get() only if
> needs_vcc is true.
The way it is, AFAICT, regulator fwk will return a dummy regulator for
cases where supply isn't in DT.
--
balbi
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