Subject: Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via the nvmem API

From: Alban <[email-masked]>
Date: Tue, 21 Aug 2018 13:39:16 +0200

On Tue, 21 Aug 2018 10:50:07 +0100
Srinivas Kandagatla <[email-masked]> wrote:

> Just curious...Is there a reason why we can't do it like this?:
> Is this because of issue of #address-cells and #size-cells Or mtd 
> bindings always prefer subnodes?
> 
> 	mtdnode {
> 		reg = <0x0123000 0x40000>;
> 		#address-cells = <1>;
> 		#size-cells = <1>;
> 		cell@0 {
> 			compatible = "nvmem-cell";
> 			reg = <0x0 0x14>;
> 		};
> 
> 		partitions {
> 			compatible = "fixed-partitions";
> 			#address-cells = <1>;
> 			#size-cells = <1>;
> 
> 			partition@0 {
> 				reg = <0x0 0x20000>;
> 				cell@0 {
> 					compatible = "nvmem-cell";
> 					reg = <0x0 0x10>;
> 				};
> 			};
> 		};
> 	};

That would work, the MTD partitions parser ignore child nodes with a
compatible string when looking for "old style" partitions, see [1].
However we still have the a potential address space clash between the
nvmem cells and the main device binding.

Alban

[1]: https://elixir.bootlin.com/linux/latest/source/drivers/mtd/ofpart.c#L28