Re: [PATCH v4 02/16] spi: dt-bindings: add spi-phy-pattern-partition property

Hello Krzysztof and Miquel,

Apologies for the delayed response.

On 22/06/26 22:41, Miquel Raynal wrote:
> Hello,
> 
>>> +  spi-phy-pattern-partition:
>>
>> Is this specific to SPI-based MTD/NAND or rather broader - specific to
>> MTD/NAND memories, regardless of interface? Feels like the second, thus
>> maybe should be placed into the NAND bindings.
>>
>> If the first, then in below description:
>>
>> s/PHY/SPI PHY/ to be clear that this is about SPI, not the memory
>> itself.
> 
> As far as I know, there is no raw NAND controller with such
> capability. In the raw/parallel NAND world, timings are well defined by
> the ONFI specification, it covers both the bus timings and the minimal
> requirements for the chips. There is a method to query what "timing mode"
> the NAND chip supports, and then we tune the controller registers to fit
> the highest supported timings (capped by possible controller limits).
> 
> In the SPI world it is different. No specific timing has ever been
> globally defined, so every manufacturer has its own capabilities which
> are not discoverable dynamically. The routing also weights a lot. I
> would say that we can safely keep this property SPI related, because it
> is about the SPI bus being used with optimized timings, rather than some
> kind of memory specific feature.
> 
> The reason why we need a property in those memories for the feature to
> work, is because we need to make data transfers with a known pattern,
> thus requiring to read the pattern from the internal array somehow.
> 
> Therefore, we shall indeed go for the s/PHY/SPI PHY/ naming indeed.

Agreed, will replace 'PHY' with 'SPI PHY' in the description.

Thanks,
Santhosh.

> 
> Thanks,
> Miquèl