Re: [PATCH v4 2/2] iio: adc: ad7380: new driver for AD7380 ADCs

[Jonathan Cameron]

On Mon, 19 Feb 2024 13:47:03 -0600
David Lechner <dlechner@xxxxxxxxxxxx> wrote:

> On Wed, Jan 10, 2024 at 2:29 PM David Lechner <dlechner@xxxxxxxxxxxx> wrote:
> 
> ...
> 
> > +
> > +/* fully differential */
> > +DEFINE_AD7380_DIFFERENTIAL_2_CHANNEL(ad7380_channels, 16);
> > +DEFINE_AD7380_DIFFERENTIAL_2_CHANNEL(ad7381_channels, 14);
> > +/* pseudo differential */
> > +DEFINE_AD7380_DIFFERENTIAL_2_CHANNEL(ad7383_channels, 16);
> > +DEFINE_AD7380_DIFFERENTIAL_2_CHANNEL(ad7384_channels, 14);
> > +  
> 
> Similar question to [1] in light of [2]: Since AD7383 and AD7384 are
> pseudo-differential, should we handle them differently? I.e. add
> aina-supply and ainb-supply DT properties for the negative inputs
> (typically a V_REF / 2 supply) and remove the differential flag from
> the channel spec.
> 
> [1]: https://lore.kernel.org/linux-iio/CAMknhBH2Pqa9xpPxnTCxJegVTbOG-QDeJA4YrQUPfj+hfSs73A@xxxxxxxxxxxxxx/
> [2]: https://lore.kernel.org/linux-iio/CAMknhBF5mAsN1c-194Qwa5oKmqKzef2khXnqA1cSdKpWHKWp0w@xxxxxxxxxxxxxx/

Yes. I think that gives a more intuitive interface for users.
I don't think we need to 'fix' any drivers already upstream as
presenting these as differential is not an ABI error as far as I
am concerned. It's just less than ideal choices given our views
now! (as a result of these discussions on what pseudo differential
means in practice)

Jonathan