Re: [PATCH v2] iio: iadc: Qualcomm SPMI PMIC current ADC driver

Ivan T. Ivanov
2014-09-29T08:38:22Z

On Sat, 2014-09-27 at 10:50 +0100, Jonathan Cameron wrote:
> On 25/09/14 20:21, Ivan T. Ivanov wrote:
> > On Thu, 2014-09-25 at 17:02 +0100, Mark Rutland wrote:
> >> On Thu, Sep 25, 2014 at 10:47:15AM +0100, Ivan T. Ivanov wrote:

<snip>

> >>
> >>>>>>> +- interrupts:
> >>>>>>> + Usage: optional
> >>>>>>> + Value type: <prop-encoded-array>
> >>>>>>> + Definition: End of conversion interrupt number. If property is
> >>>>>>> + missing driver will use polling to detect end of conversion
> >>>>>>> + completion.
> >>>>>>
> >>>>>> Driver details shouldn't be in the binding. If the driver can poll,
> >>>>>> that's good, but it should be dropped form this description.
> >>>>>>
> >>>>>
> >>>>> Will remove driver details.
> >>>>>
> >>>>>> Is this the only interrupt?
> >>>>>>
> >>>>>
> >>>>> Yes.
> >>>>>
> >>>>>> What do you mean be "End of conversion interrupt number"? Just describe
> >>>>>> what the interrupt logically is from the PoV of the device -- interrupts
> >>>>>> is a standard property so we don't need to be too explicit about the
> >>>>>> type.
> >>>>>
> >>>>> Badly worded. Just, "End of conversion interrupt"?
> >>>>
> >>>> The part I didn't understand was what was meant by "End of conversion",
> >>>> but dropping "number" is certainly better.
> >>>
> >>> It is clear now, right? End of ADC conversion.
> >>
> >> Sorry if I'm being thick here, but it's still somewhat confusing to me.
> >> That's a consequence of me not being familiar with the HW more than
> >> anything, I'm just missing simple details regarding the model of
> >> operation, suchs as exactly what the "end of ADC conversion" entails.
> >> There are a few things that could potentially mean depending on how the
> >> HW was designed and intended to be used.
> >>
> >> Does the device periodically sample, convert some number of values
> >> (possibly just 1), and trigger an interrupt to state that a buffer is
> >> full / values are available? Or is the interrupt triggered for some
> >> other reason?
> >
> > Interrupt is triggered after ADC convert analog signal to digital.
> > Other details are irrelevant, I believe.
> Often called a data ready interrupt. However, here it is per channel
> so perhaps that description is confusing as well...

Not exactly. There is only one interrupt. Simultaneous conversions are
not possible.

Regards,
Ivan