Re: [PATCH 3/5] dt-bindings: nvmem: allow referencing device defined cells by names

On Tue, Jan 04, 2022 at 09:56:01PM +0100, Rafał Miłecki wrote:

On 4.01.2022 21:50, Rafał Miłecki wrote:

quoted

On 4.01.2022 21:16, Rob Herring wrote:

quoted

On Thu, Dec 23, 2021 at 10:58:56PM +0100, Rafał Miłecki wrote:

quoted

On 23.12.2021 22:18, Rob Herring wrote:

quoted

On Thu, Dec 23, 2021 at 7:08 AM Rafał Miłecki [off-list ref] wrote:

quoted

From: Rafał Miłecki <rafal@milecki.pl>

Not every NVMEM has predefined cells at hardcoded addresses. Some
devices store cells in internal structs and custom formats. Referencing
such cells is still required to let other bindings use them.

Modify binding to require "reg" xor "label". The later one can be used
to match "dynamic" NVMEM cells by their names.

'label' is supposed to correspond to a sticker on a port or something
human identifiable. It generally should be something optional to
making the OS functional. Yes, there are already some abuses of that,
but this case is too far for me.

Good to learn that!

"name" is special & not allowed I think.

It's the node name essentially. Why is using node names not sufficient?
Do you have some specific examples?

I tried to explain in
[PATCH 1/5] dt-bindings: nvmem: add "label" property to allow more flexible cells names
that some vendors come with fancy names that can't fit node names.

I still don't see the issue. Why do you need 'more flexible cells 
names'? What problem does that solve?

quoted

Broadcom's NVRAM examples:
0:macaddr
1:macaddr
2:macaddr
0:ccode
1:ccode
2:ccode
0:regrev

In other words I'd like to have something like:

nvram@1eff0000 {
	compatible = "brcm,nvram";
	reg = <0x1eff0000 0x10000>;

	mac: cell-0 {
		label = "1:macaddr";
	};
};

ethernet@1000 {
	compatible = "brcm,ethernet";
	reg = <0x1000 0x1000>;
	nvmem-cells = <&mac>;
	nvmem-cell-names = "mac-address";
};

How does 'label' help here?

Note there's some other efforts around multiple mac addresses and how to 
interpret the nvmem data. Maybe that helps solve your problem.

Rob