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[198.48.202.89]) by smtp.gmail.com with ESMTPSA id n81sm3338846qke.16.2021.05.31.06.36.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 31 May 2021 06:36:56 -0700 (PDT) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 31 May 2021 09:36:56 -0400 Message-Id: Cc: , , , Subject: Re: [PATCH v1 4/9] iio: afe: rescale: add offset support From: "Liam Beguin" To: "Peter Rosin" , , , References: <20210530005917.20953-1-liambeguin@gmail.com> <20210530005917.20953-5-liambeguin@gmail.com> <0769aaae-8925-d943-e57d-c787d560a8dc@axentia.se> In-Reply-To: <0769aaae-8925-d943-e57d-c787d560a8dc@axentia.se> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On Mon May 31, 2021 at 4:52 AM EDT, Peter Rosin wrote: > Hi! > > Thanks for the patch! > > On 2021-05-30 02:59, Liam Beguin wrote: > > From: Liam Beguin > >=20 > > This is a preparatory change required for the addition of temperature > > sensing front ends. > > I think this is too simplistic. I think that if the upstream iio-dev has > an offset, it should be dealt with (i.e. be rescaled). The rescale > driver > cannot ignore such an upstream offset and then throw in some other > unrelated offset of its own. That would be thoroughly confusing. I'm not sure I fully understand. The upstream offset should be dealt with when calling iio_read_channel_processed(). That was my main motivation behind using the IIO core to get a processed value. > > Also, I see no reason of expose an offset channel if there is no offset. You're right, I'll add conditions to only expose an offset when required. Liam > > Cheers, > Peter > > > Signed-off-by: Liam Beguin > > --- > > drivers/iio/afe/iio-rescale.c | 12 ++++++++++-- > > 1 file changed, 10 insertions(+), 2 deletions(-) > >=20 > > diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescal= e.c > > index 4d0813b274d1..3bd1f11f21db 100644 > > --- a/drivers/iio/afe/iio-rescale.c > > +++ b/drivers/iio/afe/iio-rescale.c > > @@ -31,6 +31,7 @@ struct rescale { > > struct iio_chan_spec_ext_info *ext_info; > > s32 numerator; > > s32 denominator; > > + s32 offset; > > }; > > =20 > > static int rescale_read_raw(struct iio_dev *indio_dev, > > @@ -52,6 +53,10 @@ static int rescale_read_raw(struct iio_dev *indio_de= v, > > *val2 =3D rescale->denominator; > > =20 > > return IIO_VAL_FRACTIONAL; > > + case IIO_CHAN_INFO_OFFSET: > > + *val =3D rescale->offset; > > + > > + return IIO_VAL_INT; > > default: > > return -EINVAL; > > } > > @@ -119,8 +124,10 @@ static int rescale_configure_channel(struct device= *dev, > > return -EINVAL; > > } > > =20 > > - chan->info_mask_separate =3D BIT(IIO_CHAN_INFO_RAW) | > > - BIT(IIO_CHAN_INFO_SCALE); > > + chan->info_mask_separate =3D > > + BIT(IIO_CHAN_INFO_RAW) | > > + BIT(IIO_CHAN_INFO_SCALE) | > > + BIT(IIO_CHAN_INFO_OFFSET); > > =20 > > if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW)) > > chan->info_mask_separate_available |=3D BIT(IIO_CHAN_INFO_RAW); > > @@ -280,6 +287,7 @@ static int rescale_probe(struct platform_device *pd= ev) > > rescale->cfg =3D of_device_get_match_data(dev); > > rescale->numerator =3D 1; > > rescale->denominator =3D 1; > > + rescale->offset =3D 0; > > =20 > > ret =3D rescale->cfg->props(dev, rescale); > > if (ret) > >=20