Re: [PATCH v4 1/7] dt-bindings: mtd: jedec,spi-nor: allow the SFDP to be exposed via NVMEM

[Miquel Raynal <miquel.raynal@bootlin.com>]

On 02/07/2026 at 11:37:23 -05, Rob Herring <robh@kernel.org> wrote:

> On Thu, Jul 02, 2026 at 06:55:15AM +0000, Manikandan.M@microchip.com wrote:
>> Hi Krzysztof,
>> 
>> On 7/2/26 11:46 AM, Krzysztof Kozlowski wrote:
>> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>> > 
>> > On Tue, Jun 30, 2026 at 02:54:00PM +0530, Manikandan Muralidharan wrote:
>> >> Add an optional "sfdp" child node (compatible "jedec,sfdp") that
>> >> describes the SFDP as a read-only NVMEM provider via nvmem.yaml, so its
>> > 
>> > What is SFDP?
>> > 
>> SFDP is the Serial Flash Discoverable Parameters -- a JEDEC-standardised
>> (JESD216) read-only parameter table present in most SPI NOR flashes, the 
>> table contents provide basic information about the flash. There are 
>> standard tables which are specified by the JEDEC standard and there are 
>> vendor tables.
>
> Is SFDP present or not discoverable? Or we have a table of discoverable 
> parameters that itself is not discoverable.

SFDP is almost always there. I don't think there are any non SFDP chips
manufactured today (?). The thing is, even if we don't need to define it
in DT, we might need to point to it in order to extract eg. a unique ID
or a MAC address through the NVMEM interface.

SFDP is split into several sub-tables, the first one is mandatory, but
then there are optional tables which can be discovered dynamically.

Thanks,
Miquèl