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Date:   Tue, 3 Jan 2023 16:58:42 +0100
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc:     Michael Walle <michael@walle.cc>, Jonathan Corbet <corbet@lwn.net>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        Dan Carpenter <error27@gmail.com>
Subject: Re: [PATCH v5 00/21] nvmem: core: introduce NVMEM layouts
Message-ID: <20230103165842.2f693bfa@xps-13>
In-Reply-To: <cf00e248-1f2c-d4ce-868d-9f77b2c9b76f@linaro.org>
References: <20221206200740.3567551-1-michael@walle.cc>
        <20230103163902.218cb5c7@xps-13>
        <cf00e248-1f2c-d4ce-868d-9f77b2c9b76f@linaro.org>
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Hi Srinivas,

srinivas.kandagatla@linaro.org wrote on Tue, 3 Jan 2023 15:51:31 +0000:

> Hi Miquel,
>=20
> On 03/01/2023 15:39, Miquel Raynal wrote:
> > Hi Srinivas,
> >=20
> > michael@walle.cc wrote on Tue,  6 Dec 2022 21:07:19 +0100:
> >  =20
> >> This is now the third attempt to fetch the MAC addresses from the VPD
> >> for the Kontron sl28 boards. Previous discussions can be found here:
> >> https://lore.kernel.org/lkml/20211228142549.1275412-1-michael@walle.cc/
> >>
> >>
> >> NVMEM cells are typically added by board code or by the devicetree. But
> >> as the cells get more complex, there is (valid) push back from the
> >> devicetree maintainers to not put that handling in the devicetree.
> >>
> >> Therefore, introduce NVMEM layouts. They operate on the NVMEM device a=
nd
> >> can add cells during runtime. That way it is possible to add more comp=
lex
> >> cells than it is possible right now with the offset/length/bits
> >> description in the device tree. For example, you can have post process=
ing
> >> for individual cells (think of endian swapping, or ethernet offset
> >> handling).
> >>
> >> The imx-ocotp driver is the only user of the global post processing ho=
ok,
> >> convert it to nvmem layouts and drop the global post pocessing hook.
> >>
> >> For now, the layouts are selected by the device tree. But the idea is
> >> that also board files or other drivers could set a layout. Although no
> >> code for that exists yet.
> >>
> >> Thanks to Miquel, the device tree bindings are already approved and me=
rged.
> >>
> >> NVMEM layouts as modules?
> >> While possible in principle, it doesn't make any sense because the NVM=
EM
> >> core can't be compiled as a module. The layouts needs to be available =
at
> >> probe time. (That is also the reason why they get registered with
> >> subsys_initcall().) So if the NVMEM core would be a module, the layouts
> >> could be modules, too. =20
> >=20
> > I believe this series still applies even though -rc1 (and -rc2) are out
> > now, may we know if you consider merging it anytime soon or if there
> > are still discrepancies in the implementation you would like to
> > discuss? Otherwise I would really like to see this laying in -next a
> > few weeks before being sent out to Linus, just in case. =20
>=20
> Thanks for the work!
>=20
> Lets get some testing in -next.
>=20
>=20
> Applied now,

Excellent! Thanks a lot for the quick answer and thanks for applying,
let's see how it behaves.

Thanks,
Miqu=C3=A8l