Re: [PATCH v22 17/18] dt-bindings: mtd: pl353-nand: Describe this hardware controller

From: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Tudor Ambarus <Tudor.Ambarus@microchip.com>,
	linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
	Michal Simek <monstr@monstr.eu>,
	Naga Sureshkumar Relli <nagasure@xilinx.com>,
	Amit Kumar Mahapatra <akumarma@xilinx.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, helmut.grohne@intenta.de,
	Srinivas Goud <sgoud@xilinx.com>,
	Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Subject: Re: [PATCH v22 17/18] dt-bindings: mtd: pl353-nand: Describe this hardware controller
Date: Wed, 9 Jun 2021 21:32:51 -0500	[thread overview]
Message-ID: <20210610023251.GA648931@robh.at.kernel.org> (raw)
In-Reply-To: <6fb9c0e4-43cb-d224-0ebe-568f62ac35b1@canonical.com>

On Wed, Jun 09, 2021 at 03:57:05PM +0200, Krzysztof Kozlowski wrote:
> On 09/06/2021 15:36, Miquel Raynal wrote:
> > Hi Krzysztof,
> > 
> > Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> wrote on Wed, 9
> > Jun 2021 14:01:10 +0200:
> > 
> >> On 09/06/2021 10:01, Miquel Raynal wrote:
> >>> Add a yaml description of this NAND controller which is described as a
> >>> subnode of the SMC bus.
> >>>
> >>> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> >>> ---
> >>>  .../bindings/mtd/arm,pl353-nand-r2p1.yaml     | 57 +++++++++++++++++++
> >>>  1 file changed, 57 insertions(+)
> >>>  create mode 100644 Documentation/devicetree/bindings/mtd/arm,pl353-nand-r2p1.yaml
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/mtd/arm,pl353-nand-r2p1.yaml b/Documentation/devicetree/bindings/mtd/arm,pl353-nand-r2p1.yaml
> >>> new file mode 100644
> >>> index 000000000000..e72fa14b4385
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/mtd/arm,pl353-nand-r2p1.yaml
> >>> @@ -0,0 +1,57 @@
> >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>> +%YAML 1.2
> >>> +---
> >>> +$id: http://devicetree.org/schemas/mtd/arm,pl353-nand-r2p1.yaml#
> >>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >>> +
> >>> +title: PL353 NAND Controller device tree bindings
> >>> +
> >>> +allOf:
> >>> +  - $ref: "nand-controller.yaml"
> >>> +
> >>> +maintainers:
> >>> +  - Miquel Raynal <miquel.raynal@bootlin.com>
> >>> +  - Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
> >>> +
> >>> +properties:
> >>> +  compatible:
> >>> +    items:
> >>> +      - enum:  
> >>
> >> That's not an enum, but simple const without items.
> > 
> > Ok.
> > 
> >>
> >>> +          - arm,pl353-nand-r2p1
> >>> +
> >>> +  reg:
> >>> +    items:
> >>> +      - items:
> >>> +          - description: CS with regard to the parent ranges property
> >>> +          - description: Offset of the memory region requested by the device
> >>> +          - description: Length of the memory region requested by the device  
> >>
> >> Doesn't it depend on parent's address/size cells?
> > 
> > Yes, but as the child nodes are not defined in the parent's binding
> > (ie. the SMC) I think it's interesting to have them defined here, no?
> 
> The trouble is if parent decides to have different address/size cells.
> The schema will stop matching. I am actually not that sure if such case
> is real since the pl353 NAND part will usually be connected to pl353
> SMC. However the schema now hard-codes specific dependency against
> parent schema/node.
> 
> Rob,
> Maybe you have here some thoughts?

I think it is fine given the parent child coupling.

Rob

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