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From: David Lechner <dlechner@baylibre.com>
Date: Tue, 2 Apr 2024 09:00:10 -0500
Message-ID: <CAMknhBHf_9kFfLySJmRyoUS6UFfTeLW3bfEi1-3ApEDHyyVhCw@mail.gmail.com>
Subject: Re: [PATCH 6/6] iio: adc: ad7173: Add support for AD411x devices
To: dumitru.ceclan@analog.com
Cc: Lars-Peter Clausen <lars@metafoo.de>, Michael Hennerich <Michael.Hennerich@analog.com>, 
	Jonathan Cameron <jic23@kernel.org>, Rob Herring <robh@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	linux-iio@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Dumitru Ceclan <mitrutzceclan@gmail.com>
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On Mon, Apr 1, 2024 at 2:45=E2=80=AFPM David Lechner <dlechner@baylibre.com=
> wrote:
>
> On Mon, Apr 1, 2024 at 10:10=E2=80=AFAM Dumitru Ceclan via B4 Relay
> <devnull+dumitru.ceclan.analog.com@kernel.org> wrote:
> >
> > From: Dumitru Ceclan <dumitru.ceclan@analog.com>
> >
> > Add support for AD4111/AD4112/AD4114/AD4115/AD4116.
> >

..

> > @@ -1028,15 +1204,22 @@ static int ad7173_fw_parse_channel_config(struc=
t iio_dev *indio_dev)
> >                 *chan =3D ad7173_channel_template;
> >                 chan->address =3D chan_index;
> >                 chan->scan_index =3D chan_index;
> > -               chan->channel =3D ain[0];
> > -               chan->channel2 =3D ain[1];
> > -               chan->differential =3D true;
> >
> > -               chan_st_priv->ain =3D AD7173_CH_ADDRESS(ain[0], ain[1])=
;
> > +               if (reg >=3D AD4111_CURRENT_CHAN_CUTOFF) {
> > +                       chan->type =3D IIO_CURRENT;
> > +                       chan->channel =3D ain[0];
> > +                       chan_st_priv->ain =3D ad4111_current_channel_co=
nfig[ain[0]];
> > +               } else {
> > +                       chan->channel =3D ain[0];
> > +                       chan->channel2 =3D ain[1];
> > +                       chan->differential =3D true;
>
> Expecting chan->differential =3D false when ADCIN15 is configured for
> pseudo-differential inputs.
>
> Also, perhaps missed in previous reviews, I would expect
> chan->differential =3D false when channels are used as single-ended.
>

After sleeping on it, I came to the concision that these parts are
probably too complex to try to worry about differential vs.
pseudo-differential/single-ended (what the datasheet calls
single-ended is really pseudo-differential).

So I take back my comments about expecting differential =3D false in those =
cases.