Re: [PATCH v3 1/3] nvmem: Update the OF binding to use a subnode for the cells list

From: Alban
Date: Tue Apr 17 2018 - 08:32:06 EST


On Mon, 16 Apr 2018 16:04:29 -0500
Rob Herring <robh@xxxxxxxxxx> wrote:

> On Sun, Mar 25, 2018 at 12:24:57AM +0100, Alban Bedel wrote:
> > Having the cells as subnodes of the provider device without any
> > compatible property might clash with other bindings. To avoid this
> > problem update the binding to have all the cells in a 'nvmem-cells'
> > subnode with a 'nvmem-cells' compatible string. This new binding
> > guarantee that we can turn any kind of device in a nvmem provider.
> >
> > While discouraged for new uses the old scheme is still supported for
> > backward compatibility.
> >
> > Signed-off-by: Alban Bedel <albeu@xxxxxxx>
> > ---
> > Documentation/devicetree/bindings/nvmem/nvmem.txt | 55 ++++++++++++++++-------
> > drivers/nvmem/core.c | 10 +++++
> > 2 files changed, 48 insertions(+), 17 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.txt b/Documentation/devicetree/bindings/nvmem/nvmem.txt
> > index fd06c09..6b723e7 100644
> > --- a/Documentation/devicetree/bindings/nvmem/nvmem.txt
> > +++ b/Documentation/devicetree/bindings/nvmem/nvmem.txt
> > @@ -11,14 +11,29 @@ these data from, and where they are stored on the storage device.
> > This document is here to document this.
> >
> > = Data providers =
> > -Contains bindings specific to provider drivers and data cells as children
> > -of this node.
> > +A data provider should have a subnode named 'nvmem-cells' that contains
> > +a subnodes for each data cells.
> > +
> > +For backward compatibility the nvmem data cells can be direct children
> > +of the data provider. This use is discouraged as it can conflict with
> > +other bindings.
>
> I don't think we need to go this far. Whether this is necessary depends
> on the provider.

It depend more on the drivers implementation. Sure as long as the
driver only support the nvmem API it doesn't matter, both binding are
fine. But if it ever need to support another API the bindings might
clash and the whole device binding will need to be updated. So all in
all I see very few value in still allowing the old binding for new
devices, or do you seen any problem with the new binding?

However if the consensus is to keep both styles I will rewrite this
paragraph as needed.

Alban

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