Hi Miquel,
On 03/01/2023 15:39, Miquel Raynal wrote:
Hi Srinivas,
michael@xxxxxxxx wrote on Tue, 6 Dec 2022 21:07:19 +0100:
This is now the third attempt to fetch the MAC addresses from the VPD
for the Kontron sl28 boards. Previous discussions can be found here:
https://lore.kernel.org/lkml/20211228142549.1275412-1-michael@xxxxxxxx/
NVMEM cells are typically added by board code or by the devicetree. But
as the cells get more complex, there is (valid) push back from the
devicetree maintainers to not put that handling in the devicetree.
Therefore, introduce NVMEM layouts. They operate on the NVMEM device and
can add cells during runtime. That way it is possible to add more complex
cells than it is possible right now with the offset/length/bits
description in the device tree. For example, you can have post processing
for individual cells (think of endian swapping, or ethernet offset
handling).
The imx-ocotp driver is the only user of the global post processing hook,
convert it to nvmem layouts and drop the global post pocessing hook.
For now, the layouts are selected by the device tree. But the idea is
that also board files or other drivers could set a layout. Although no
code for that exists yet.
Thanks to Miquel, the device tree bindings are already approved and merged.
NVMEM layouts as modules?
While possible in principle, it doesn't make any sense because the NVMEM
core can't be compiled as a module. The layouts needs to be available at
probe time. (That is also the reason why they get registered with
subsys_initcall().) So if the NVMEM core would be a module, the layouts
could be modules, too.
I believe this series still applies even though -rc1 (and -rc2) are out
now, may we know if you consider merging it anytime soon or if there
are still discrepancies in the implementation you would like to
discuss? Otherwise I would really like to see this laying in -next a
few weeks before being sent out to Linus, just in case.
Thanks for the work!
Lets get some testing in -next.
Applied now,
--srini
Thanks,
Miquèl
