Re: Questions related to some drivers

[Giuliano Augusto Faulin Belinassi <giuliano.belinassi@usp.br>]

Hello,
Could you help us figure out what must be added/changed into the
staging/iio/adc/ad7780.c to remove it from staiging?

For instance, should we add an id field in ad7780_state struct that
represents ID1 and ID0 from the status bits (page 13 from datasheet)?
Or check the Status pattern bits PAT1, PAT0 for errors? Or something
else we can work on?

Thank you.
On Tue, Oct 23, 2018 at 6:51 AM Jonathan Cameron
<jic23@jic23.retrosnub.co.uk> wrote:
>
> On Mon, 22 Oct 2018 18:56:16 -0300
> Giuliano Augusto Faulin Belinassi <giuliano.belinassi@usp.br> wrote:
>
> > Hello,
> > I have some questions about the ad7780 driver.
> >
> >   * What is the val2 In the line 96 (*val2 = chan->scan_type.realbits
> > - 1;)? How it is used? Is it related to the 24-bits ADC precision?
>
> To understand that follow through what the code does when the type of a
> read_raw is IIO_VAL_FRACTIONAL_LOG2;
>
> >   * Why there is a subtraction in the line 99 ( *val -= (1 <<
> > (chan->scan_type.realbits - 1)); )? Is the *val initialized with 0? Is
> > that related to the formula described in the DATA OUTPUT CODING, at
> > page 12?
> > https://www.analog.com/media/en/technical-documentation/data-sheets/ad7780.pdf
>
> Yeah, that -= is definitely wrong.  Should just be an assignment to the
> negative value.  This is telling userspace that the raw value should be
> offset by half of it's maximum range before applying the scale to get
> a reading in the IIO base units (here mV IIRC).
>
> >
> > With regards
> >
> >
> > On Thu, Oct 18, 2018 at 8:41 AM Giuliano Belinassi
> > <giuliano.belinassi@gmail.com> wrote:
> > >
> > > On 10/18, Ardelean, Alexandru wrote:
> > >
> > > Thank you for the reply :-). We will put effort into at least one driver to
> > > remove it from staging.
> > >
> > > > Hey,
> > > >
> > > > Thanks for the notification.
> > > >
> > > > Yes, all these 3 drivers should be moved out of staging.
> > > >
> > > > We were planning to start working on them (to move them out of staging),
> > > > but priorities are shifting from one week to the other.
> > > > So, if you guys have the time and are willing to do it, please go ahead,
> > > > and add me, michael.hennerich@analog.com and stefan.popa@analog.com to the
> > > > CC when sending patches, and we will also take a look over your patches.
> > > >
> > > > If you haven't taken a look already, feel free to also take a look at our
> > > > wiki:
> > > > https://wiki.analog.com/resources/tools-software/linux-drivers-all
> > > > It's more technical for the SW side; it might help with some general info.
> > > > And the datasheets should be available on the analog.com/<product_id>
> > > > pages.
> > > >
> > > >
> > > > Thanks
> > > > Alex
> > > >
> > > >
> > > > On Wed, 2018-10-17 at 16:00 -0300, Giuliano Belinassi wrote:
> > > > > Hello,
> > > > >
> > > > > We are a student group and we want to contribute to the linux kernel. We
> > > > > are thinking in put effort to move a driver from staging to the main
> > > > > tree.
> > > > > We looked into three drivers:
> > > > >
> > > > >   * adc/ad7780.c
> > > > >   * adc/ad7816.c
> > > > >   * impedance-analyzer/ad5933.c
> > > > >
> > > > > Are these drivers still being worked on? The last commit referencing
> > > > > these
> > > > > drivers were on march 2018, but they are still in staging since 2010.
> > > > >
> > > > > We already know that we have to convert from the old api to the new one.
> > > > > It is
> > > > > OK for us to work on this? Is there something else we can do?
> > > > >
> > > > > Thank you
> > > > >
> > > >
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