Hi Rob,
Am 2021-04-20 16:08, schrieb Rob Herring:
On Fri, Apr 16, 2021 at 09:26:03PM +0200, Michael Walle wrote:
Am 2021-04-16 20:44, schrieb Rob Herring:
> On Fri, Apr 16, 2021 at 01:49:23PM +0200, Michael Walle wrote:
> > The goal is to fetch a (base) MAC address from the OTP region of a
> > SPI NOR
> > flash.
> >
> > This is the first part, where I try to add the nvmem provider
> > support to
> > the MTD core.
> >
> > I'm not sure about the device tree bindings. Consider the following
> > two
> > variants:
> >
> > (1)
> > flash@0 {
> > ..
> >
> > otp {
> > compatible = "mtd-user-otp";
>
> mtd is a linuxism. Why not just 'nvmem-cells' here or as a fallback if
> we come up with a better name?
There are two different compatibles: "mtd-user-otp" and
"mtd-factory-otp"
to differentiate what kind of OTP should be used (and both are
possible
at the same time). Thus nvmem-cells alone won't be enough. We could
drop
the "mtd-" prefix though.
Is there a benefit of having the following?
compatible = "user-otp", "nvmem-cells";
Yes. I assume 'user-otp' tells you something about the region and
'nvmem-cells' tells you that there are child nodes of nvmem data. Of
course 'user-otp' could imply 'nvmem-cells' as you did. I'm fine with
either way.
Ah, if I use both compatibles, then the
Documentation/devicetree/bindings/mtd/partitions/nvmem-cells.yaml
schema kicks in, which mandates 'compatible = "nvmem-cells";' and I
get the following errors:
CHECK Documentation/devicetree/bindings/mtd/mtd.example.dt.yaml
/home/mwalle/repos/b-linux-arm64/Documentation/devicetree/bindings/mtd/mtd.example.dt.yaml:
otp-1: compatible:0: 'nvmem-cells' was expected
From schema:
/home/mwalle/repos/linux-mw/Documentation/devicetree/bindings/mtd/partitions/nvmem-cells.yaml
/home/mwalle/repos/b-linux-arm64/Documentation/devicetree/bindings/mtd/mtd.example.dt.yaml:
otp-1: compatible: ['factory-otp', 'nvmem-cells'] is too long
From schema:
/home/mwalle/repos/linux-mw/Documentation/devicetree/bindings/mtd/partitions/nvmem-cells.yaml
/home/mwalle/repos/b-linux-arm64/Documentation/devicetree/bindings/mtd/mtd.example.dt.yaml:
otp-1: compatible: Additional items are not allowed ('nvmem-cells' was
unexpected)
From schema:
/home/mwalle/repos/linux-mw/Documentation/devicetree/bindings/mtd/partitions/nvmem-cells.yaml
Is there a way around that?
-michael
