From: "Popa, Stefan Serban" <StefanSerban.Popa@analog.com>
To: "jic23@kernel.org" <jic23@kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>
Cc: "knaack.h@gmx.de" <knaack.h@gmx.de>,
"lars@metafoo.de" <lars@metafoo.de>,
"pmeerw@pmeerw.net" <pmeerw@pmeerw.net>,
"Hennerich, Michael" <Michael.Hennerich@analog.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/3] iio: adc: Add ad7124 support
Date: Thu, 8 Nov 2018 16:48:02 +0000 [thread overview]
Message-ID: <1541695681.2091.10.camel@analog.com> (raw)
In-Reply-To: <CAL_Jsq+zc2RGWgkwXNk8qjJqjo+FpdPZUOOxd44mb8Cu7+EsaQ@mail.gmail.com>
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WARNING: multiple messages have this Message-ID (diff)
From: "Popa, Stefan Serban" <StefanSerban.Popa@analog.com>
To: "jic23@kernel.org" <jic23@kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>
Cc: "knaack.h@gmx.de" <knaack.h@gmx.de>,
"lars@metafoo.de" <lars@metafoo.de>,
"pmeerw@pmeerw.net" <pmeerw@pmeerw.net>,
"Hennerich, Michael" <Michael.Hennerich@analog.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/3] iio: adc: Add ad7124 support
Date: Thu, 8 Nov 2018 16:48:02 +0000 [thread overview]
Message-ID: <1541695681.2091.10.camel@analog.com> (raw)
In-Reply-To: <CAL_Jsq+zc2RGWgkwXNk8qjJqjo+FpdPZUOOxd44mb8Cu7+EsaQ@mail.gmail.com>
On Jo, 2018-11-08 at 10:34 -0600, Rob Herring wrote:
> On Thu, Nov 8, 2018 at 9:02 AM Popa, Stefan Serban
> <StefanSerban.Popa@analog.com> wrote:
> >
> >
> > On Sb, 2018-11-03 at 12:16 +0000, Jonathan Cameron wrote:
> > >
> > > On Mon, 29 Oct 2018 18:38:31 +0200
> > > Stefan Popa <stefan.popa@analog.com> wrote:
> > >
> > > >
> > > >
> > > > The ad7124-4 and ad7124-8 are a family of 4 and 8 channel sigma-
> > > > delta
> > > > ADCs
> > > > with 24-bit precision and reference.
> > > >
> > > > Three power modes are available which in turn affect the output
> > > > data
> > > > rate:
> > > > * Full power: 9.38 SPS to 19,200 SPS
> > > > * Mid power: 2.34 SPS to 4800 SPS
> > > > * Low power: 1.17 SPS to 2400 SPS
> > > >
> > > > The ad7124-4 can be configured to have four differential inputs,
> > > > while
> > > > ad7124-8 can have 8. Moreover, ad7124 also supports per channel
> > > > configuration. Each configuration consists of gain, reference
> > > > source,
> > > > output data rate and bipolar/unipolar configuration.
> > > >
> > > > Datasheets:
> > > > Link: http://www.analog.com/media/en/technical-documentation/data-s
> > > > heet
> > > > s/AD7124-4.pdf
> > > > Link: http://www.analog.com/media/en/technical-documentation/data-s
> > > > heet
> > > > s/ad7124-8.pdf
> > > >
> > > > Signed-off-by: Stefan Popa <stefan.popa@analog.com>
> > > Hi Stefan,
> > >
> > > The discussion around the DT binding has gotten me looking at bit
> > > more closely at that for this version.
> > >
> > > Some most comments in that section. Also a really minor ordering
> > > issue
> > > in
> > > remove which I'd just have fixed if we weren't going around again for
> > > the binding.
> > >
> > > Main binding thing is I don't think the odr value belongs in DT.
> > > Gain is more marginal (unless the part can actually be damaged by
> > > a wrong value - which I hope it can't!). I'm not that fussed
> > > as there are definitely reasons to specify a default scale to
> > > cover the reasonable range on a pin.
> > >
> > > Thanks,
> > >
> > > Jonathan
> > Hi Jonathan,
> >
> > Thank you for the review! So, how should I proceed?
> >
> > First, we need an adc.txt file where "bipolar" and something like
> > "diff-
> > channels" should be documented. Should the file be placed under
> > Documentation/devicetree/bindings/iio/adc?
> Yes.
>
> >
> > Regarding the "odr-hz" property, it totally makes sense to remove it
> > from
> > the DT. How about the "gain"? Should we leave it in the DT and also add
> > the
> > possibility to be configured from user space?
> Look at other bindings. I think there are others having gain. If not,
> then it probably should only be user space configurable. If so, then
> can it be a common property too.
>
> Rob
>
Hi Rob,
I found only a couple of examples using gain in other bindings, so I guess
it's not common practice. I will remove the gain as well from the DT and
set it with the default of 1.
@Jonathan: I think that IIO_CHAN_INFO_HARDWAREGAIN is the attribute that
can be used in user space?
Thank you!
-Stefan
next prev parent reply other threads:[~2018-11-09 2:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-29 16:38 [PATCH v3 2/3] iio: adc: Add ad7124 support Stefan Popa
2018-11-03 12:16 ` Jonathan Cameron
2018-11-03 12:16 ` Jonathan Cameron
2018-11-08 14:28 ` Popa, Stefan Serban
2018-11-08 14:28 ` Popa, Stefan Serban
2018-11-08 16:34 ` Rob Herring
2018-11-08 16:48 ` Popa, Stefan Serban [this message]
2018-11-08 16:48 ` Popa, Stefan Serban
2018-11-11 15:34 ` Jonathan Cameron
2018-11-11 15:34 ` Jonathan Cameron
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