Re: [PATCH] dt-bindings: nvmem: convert U-Boot env to a layout

From: Rafał Miłecki
Date: Mon Jul 08 2024 - 05:44:17 EST


On 8.07.2024 08:32, Miquel Raynal wrote:
zajec5@xxxxxxxxx wrote on Sat, 6 Jul 2024 00:58:21 +0200:

From: Rafał Miłecki <rafal@xxxxxxxxxx>

U-Boot environment variables can be stored in various data sources. MTD
is just one of available options. Refactor DT binding into a layout so
it can be used with UBI volumes and other NVMEM devices.

Link: https://lore.kernel.org/all/20231221173421.13737-1-zajec5@xxxxxxxxx/
Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
I'm sending this PATCH without Linux changes to see if this is the
right approach - for developers and (DT) maintainers to review it first.

My previous attempt (see above Link) turned out in refusal so I'm just
trying to save some time in case this one goes wrong as well.

Hopefully the included example (which I really think we should add)
explains well how I think this binding should be used with layouts.

If I get some positive feedback I'll work on V2 with actual Linux
changes.


I am still in favor of this change. I know from a binding perspective
it might be questionable; but from an OS perspective it makes total
sense to deprecated the old U-Boot env "device" driver in favor of this.

Please note that at this point I didn't decide to deprecate the old
binding (using "u-boot,env" for flash device partition). That would
require mixing "nvmem-layout" with "partitions" which I believe Rob
objected to.

My PATCH in its current form just allows reusing this binding with
"nvmem-layout"s which is needed for cases where we agreed to allow
"nvmem-layout" (UBI volumes and pure - non-MTD - NVMEM devices).

If we want to refactor this binding in MTD partitions context I hope we
can handle that at different time if we agree on some solution. I hope
and I don't think this should be a blocked for this PATCH.