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Date: Wed, 29 May 2024 09:33:10 +0100
From: Conor Dooley <conor.dooley@microchip.com>
To: Nuno =?iso-8859-1?Q?S=E1?= <noname.nuno@gmail.com>
CC: Conor Dooley <conor@kernel.org>, David Lechner <dlechner@baylibre.com>,
	Mark Brown <broonie@kernel.org>, Jonathan Cameron <jic23@kernel.org>, Rob
 Herring <robh@kernel.org>, Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor
 Dooley <conor+dt@kernel.org>, Nuno =?iso-8859-1?Q?S=E1?=
	<nuno.sa@analog.com>, Michael Hennerich <Michael.Hennerich@analog.com>,
	Lars-Peter Clausen <lars@metafoo.de>, David Jander <david@protonic.nl>,
	Martin Sperl <kernel@martin.sperl.org>, <linux-spi@vger.kernel.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-iio@vger.kernel.org>
Subject: Re: [PATCH RFC v2 1/8] spi: dt-bindings: spi-peripheral-props: add
 spi-offloads property
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On Wed, May 29, 2024 at 10:07:37AM +0200, Nuno S=E1 wrote:
> On Sun, 2024-05-26 at 18:35 +0100, Conor Dooley wrote:
> > On Thu, May 23, 2024 at 02:15:35PM +0200, Nuno S=E1 wrote:
> > > On Wed, 2024-05-22 at 19:24 +0100, Conor Dooley wrote:
> >=20
> > > >=20
> > > > To remind myself, "Application 2" featured an offload engine design=
ed
> > > > specifically to work with a particular data format that would strip=
 a
> > > > CRC byte and check the validity of the data stream.
> > > >=20
> > >=20
> > > I think the data manipulation is not really a property of the engine.=
 Typically
> > > data
> > > going out of the offload engine goes into another "data reorder" bloc=
k that is
> > > pure
> > > HW.
> > >=20
> > > > I think you're right something like that is a stretch to say that t=
hat
> > > > is a feature of the SPI controller - but I still don't believe that
> > > > modelling it as part of the ADC is correct. I don't fully understan=
d the
> > > > io-backends and how they work yet, but the features you describe th=
ere
> > > > seem like something that should/could be modelled as one, with its =
own
> > > > node and compatible etc. Describing custom RTL stuff ain't always
> > > > strightforward, but the stuff from Analog is versioned and document=
ed
> > > > etc so it shouldn't be quite that hard.
> > > >=20
> > >=20
> > > Putting this in io-backends is likely a stretch but one thing to add =
is that the
> > > peripheral is always (I think) kind of the consumer of the resources.
> >=20
> > Could you explain you think why making some additional processing done =
to
> > the data an io-backend is a stretch? Where else can this RTL be
> > represented? hint: it's not part of the ADC, just like how if you have
> > some custom RTL that does video processing that is not part of the
> > camera!
>=20
> Maybe we are speaking about two different things... I do agree with the v=
ideo
> processing example you gave but for this case I'm not sure there#s any da=
ta
> manipulation involved. i mean, there is but nothing controlled by SW at t=
his point.
> Or maybe there's already a future usecase that I'm not aware about (maybe=
 the CRC
> stuff David mentioned).

Yes, this was about the CRC or other additional processing - the quoted
text should really make this clear.

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