Re: [PATCH v3 1/6] dt-bindings: nvme: Document nvme-card compatible

From: Christian Marangi <ansuelsmth@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Joern Engel <joern@lazybastard.org>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Sagi Grimberg <sagi@grimberg.me>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
	linux-nvme@lists.infradead.org
Subject: Re: [PATCH v3 1/6] dt-bindings: nvme: Document nvme-card compatible
Date: Tue, 6 Aug 2024 14:55:13 +0200	[thread overview]
Message-ID: <66b21d35.050a0220.3799b3.7e8c@mx.google.com> (raw)
In-Reply-To: <20240806124224.GA10156@lst.de>

On Tue, Aug 06, 2024 at 02:42:24PM +0200, Christoph Hellwig wrote:
> On Tue, Aug 06, 2024 at 01:41:11PM +0200, Christian Marangi wrote:
> > Document new nvme-card compatible to permit defining fixed-partition in
> > DT by the use of the block2mtd module to use block devices as MTD.
>  
> What does nvme card mean?  Is this about nvmem or nvme?  If this is nvme,
> are you talking about nvme-pci?  Why would that needs a device binding
> when it is a PCI device?
>

It's similar to how it's done with mmc and it's to keep the property
consistent with block devices.

emmc have something like

mmc {
	mmc-card {
		specific-property;

		partitions...
	};
};

The same will be with nvme with

nvme {
	compatible = "pci_id"

	nvme-card {
		quirks maybe in the future?
		partitions...
	};
};

The following implementation permits in block2mtd to not complicate the
implementation with all the add_disk functions works with parenting
struct and how they are initialized.

(alternative is to have in block2mtd all kind of extra logic with switch
case to check for major block ID that deviates from a common schema)

-- 
	Ansuel

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