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

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Rob,

robh@kernel.org wrote on Thu, 10 Nov 2022 08:05:45 -0600:

> On Thu, Nov 10, 2022 at 09:50:34AM +0100, Miquel Raynal wrote:
> > 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?  
> 
> No. It is enough to allow the property, but nothing defines what it must 
> be (a node) and what the node contains in the case of empty nodes. Try 
> adding 'product-name = "foo";' and it won't warn.

There was a misunderstanding on my side. I thought your comment was
about the nvmem-layout node. Actually you were commenting about all the
sub-nodes defining nvmem-cells inside, so I'm fully aligned with your
response.

However, if I understood it correctly, you basically said that:

	property:
	  $ref: foo.yaml

is not the same as:

	property:
	  type: object
	  $ref: foo.yaml

If that's the case, then should we consider dropping this patch (which
you agreed with in the first place)?

https://lore.kernel.org/linux-mtd/20221104164718.1290859-17-miquel.raynal@bootlin.com/T/#u 

Thanks,
Miquèl