Re: [PATCH v3 6/6] dt-bindings: nvmem: add YAML schema for the ONIE tlv layout

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Rob Herring <robh@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>,
	devicetree@vger.kernel.org,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	linux-kernel@vger.kernel.org,
	Robert Marko <robert.marko@sartura.hr>,
	Luka Perkov <luka.perkov@sartura.hr>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Michael Walle <michael@walle.cc>,
	linux-arm-kernel@lists.infradead.org,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Christian Eggers <ceggers@arri.de>,
	Cory Tusar <cory.tusar@pid1solutions.com>
Subject: Re: [PATCH v3 6/6] dt-bindings: nvmem: add YAML schema for the ONIE tlv layout
Date: Thu, 10 Nov 2022 09:50:34 +0100	[thread overview]
Message-ID: <20221110095034.7a80163a@xps-13> (raw)
In-Reply-To: <20221110040055.GA3436769-robh@kernel.org>

Hi Rob,

robh@kernel.org wrote on Wed, 9 Nov 2022 22:00:55 -0600:

> On Fri, Nov 04, 2022 at 05:38:33PM +0100, Miquel Raynal wrote:
> > Add a schema for the ONIE tlv NVMEM layout that can be found on any ONIE
> > compatible networking device.
> > 
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> >  .../bindings/nvmem/layouts/nvmem-layout.yaml  |   1 +
> >  .../nvmem/layouts/onie,tlv-layout.yaml        | 115 ++++++++++++++++++
> >  2 files changed, 116 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/nvmem/layouts/onie,tlv-layout.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml b/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> > index f64ea2fa362d..8512ee538c4c 100644
> > --- a/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> > +++ b/Documentation/devicetree/bindings/nvmem/layouts/nvmem-layout.yaml
> > @@ -19,6 +19,7 @@ description: |
> >  
> >  oneOf:
> >    - $ref: kontron,sl28-vpd.yaml
> > +  - $ref: onie,tlv-layout.yaml
> >  
> >  properties:
> >    compatible: true
> > diff --git a/Documentation/devicetree/bindings/nvmem/layouts/onie,tlv-layout.yaml b/Documentation/devicetree/bindings/nvmem/layouts/onie,tlv-layout.yaml
> > new file mode 100644
> > index 000000000000..1d91277324ac
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/nvmem/layouts/onie,tlv-layout.yaml
> > @@ -0,0 +1,115 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/nvmem/layouts/onie,tlv-layout.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: NVMEM layout of the ONIE tlv table
> > +
> > +maintainers:
> > +  - Miquel Raynal <miquel.raynal@bootlin.com>
> > +
> > +description:
> > +  Modern networking hardware implementing the Open Compute Project ONIE
> > +  infrastructure shall provide a non-volatile memory with a table whose the
> > +  content is well specified and gives many information about the manufacturer
> > +  (name, country of manufacture, etc) as well as device caracteristics (serial
> > +  number, hardware version, mac addresses, etc). The underlaying device type
> > +  (flash, EEPROM,...) is not specified. The exact location of each value is also
> > +  dynamic and should be discovered at run time because it depends on the
> > +  parameters the manufacturer decided to embed.
> > +
> > +properties:
> > +  compatible:
> > +    const: onie,tlv-layout
> > +
> > +  product-name: true  
> 
> This is a node? If so, you need:
> 
> type: object
> additionalProperties: false

I thought referencing a schema under a property would be enough?

Indeed in nvmem.yaml we create the property nvmem-layout and make it
reference nvmem-layout.yaml. Then, in nvmem-layout.yaml:

	 oneOf:
	  - $ref: kontron,sl28-vpd.yaml
	  - $ref: onie,tlv-layout.yaml

we reference the different layouts that may apply (very much like what
you proposed to list the mtd partition parsers, if I got it right).

Isn't it enough?

Then if you look below there is an "additionalProperties: false"
defined.

> > +
> > +  part-number: true
> > +

[...]

> > +  service-tag: true
> > +
> > +  vendor-extension: true
> > +
> > +required:
> > +  - compatible
> > +
> > +additionalProperties: false

(here)

> > +
> > +examples:
> > +  - |
> > +    spi {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        eeprom@56 {
> > +            compatible = "atmel,24c64";
> > +            read-only;
> > +            reg = <0x56>;
> > +
> > +            nvmem-layout {
> > +                compatible = "onie,tlv-layout";
> > +
> > +                serial-number {
> > +                };
> > +            };
> > +        };
> > +    };
> > +
> > +  - |
> > +    spi {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        flash@0 {
> > +            compatible = "m25p80", "jedec,spi-nor";
> > +            reg = <0>;
> > +
> > +            otp {
> > +                compatible = "user-otp";
> > +
> > +                nvmem-layout {
> > +                    compatible = "onie,tlv-layout";
> > +
> > +                    mac-address {
> > +                        #nvmem-cell-cells = <1>;
> > +                    };
> > +                };
> > +            };
> > +        };
> > +    };
> > +...
> > -- 
> > 2.34.1
> > 
> >   

Thanks,
Miquèl