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Date:   Tue, 21 Aug 2018 13:39:16 +0200
From:   Alban <albeu@free.fr>
To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc:     Alban Bedel <albeu@free.fr>,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Jonathan Corbet <corbet@lwn.net>, Sekhar Nori <nsekhar@ti.com>,
        Kevin Hilman <khilman@kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Richard Weinberger <richard@nod.at>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        "David S . Miller" <davem@davemloft.net>,
        Naren <naren.kernel@gmail.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Lukas Wunner <lukas@wunner.de>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>,
        Sven Van Asbroeck <svendev@arcx.com>,
        Paolo Abeni <pabeni@redhat.com>, Rob Herring <robh@kernel.org>,
        David Lechner <david@lechnology.com>,
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        linux-i2c@vger.kernel.org, linux-mtd@lists.infradead.org,
        linux-omap@vger.kernel.org, netdev@vger.kernel.org,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via
 the nvmem API
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On Tue, 21 Aug 2018 10:50:07 +0100
Srinivas Kandagatla <srinivas.kandagatla@linaro.org> wrote:

> Just curious...Is there a reason why we can't do it like this?:
> Is this because of issue of #address-cells and #size-cells Or mtd=20
> bindings always prefer subnodes?
>=20
> 	mtdnode {
> 		reg =3D <0x0123000 0x40000>;
> 		#address-cells =3D <1>;
> 		#size-cells =3D <1>;
> 		cell@0 {
> 			compatible =3D "nvmem-cell";
> 			reg =3D <0x0 0x14>;
> 		};
>=20
> 		partitions {
> 			compatible =3D "fixed-partitions";
> 			#address-cells =3D <1>;
> 			#size-cells =3D <1>;
>=20
> 			partition@0 {
> 				reg =3D <0x0 0x20000>;
> 				cell@0 {
> 					compatible =3D "nvmem-cell";
> 					reg =3D <0x0 0x10>;
> 				};
> 			};
> 		};
> 	};

That would work, the MTD partitions parser ignore child nodes with a
compatible string when looking for "old style" partitions, see [1].
However we still have the a potential address space clash between the
nvmem cells and the main device binding.

Alban

[1]: https://elixir.bootlin.com/linux/latest/source/drivers/mtd/ofpart.c#L28

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