Re: [PATCH v5 1/3] dt-bindings: mtd: partitions: Support label only partition

[Ansuel Smith <ansuelsmth@gmail.com>]

On Thu, Jun 09, 2022 at 12:32:52PM -0600, Rob Herring wrote:
> On Mon, Jun 06, 2022 at 05:14:15PM +0200, Ansuel Smith wrote:
> > Document new partition nodes that declare only the label instead of the
> > reg used to provide an OF node for partition registred at runtime by
> > parsers. This is required for nvmem system to declare and detect
> > nvmem-cells.
> > 
> > With these special partitions, the reg / offset is not required.
> > The label binding is used to match the partition allocated by the
> > parser at runtime and the parser will provide reg and offset of the mtd.
> > 
> > NVMEM will use the data from the parser and provide the NVMEM cells
> > declared in the DTS, "connecting" the dynamic partition with a
> > static declaration of cells in them.
> > 
> > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> > ---
> >  .../bindings/mtd/partitions/partition.yaml       | 16 ++++++++++++++--
> >  1 file changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
> > index e1ac08064425..bff6fb980e6b 100644
> > --- a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
> > +++ b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
> > @@ -11,6 +11,13 @@ description: |
> >    relative offset and size specified. Depending on partition function extra
> >    properties can be used.
> >  
> > +  A partition may be dynamically allocated by a specific parser at runtime.
> > +  In this specific case, the label is required instead of the reg.
> > +  This is used to assign an OF node to the dynamiccally allocated partition
> > +  so that subsystem like NVMEM can provide an OF node and declare NVMEM cells.
> > +  The OF node will be assigned only if the partition label declared match the
> > +  one assigned by the parser at runtime.
> > +
> >  maintainers:
> >    - Rafał Miłecki <rafal@milecki.pl>
> >  
> > @@ -22,6 +29,8 @@ properties:
> >    label:
> >      description: The label / name for this partition. If omitted, the label
> >        is taken from the node name (excluding the unit address).
> > +      With dynamically allocated partition the label is required and won't
> > +      fallback to the node name.
> 
> Generally, label is never required being something for humans rather 
> than the s/w to consume. I don't see any reason why we can't still use 
> the node name (with 'partition-' stripped off).
> 

How to enforce the use of 'partition-'? Should the driver then check the
node name and reject any wrong node name (and return error)?


> If the purpose is to define what the partition contains, then 
> 'compatible' is the right thing for that.
>

Introducing a compatible means creating another scheme I think or we can
add that special compatible in the partition scheme?

> >  
> >    read-only:
> >      description: This parameter, if present, is a hint that this partition
> > @@ -41,7 +50,10 @@ properties:
> >        immune to paired-pages corruptions
> >      type: boolean
> >  
> > -required:
> > -  - reg
> > +if:
> > +  not:
> > +    required: [ reg ]
> > +then:
> > +  required: [ label ]
> >  
> >  additionalProperties: true
> > -- 
> > 2.36.1
> > 
> > 

-- 
	Ansuel