Re: [PATCH v2 3/4] dt-bindings: mtd: macronix,mx25l12833f: add SPI-NOR chip

[Erez <erezgeva2@gmail.com>]

On Mon, 1 Jul 2024 at 12:23, Tudor Ambarus <tudor.ambarus@linaro.org> wrote:
>
>
>
> On 7/1/24 11:15 AM, Tudor Ambarus wrote:
> >
> >
> > On 7/1/24 10:46 AM, Erez wrote:
> >> When using mx25l12805d, we do not read SFDP.
> >> As it uses the no-SFDP flags.
> >> When using mx25l12833f hardware with mx25l12805d driver, it did not
> >> try to read the SFDP.
> >> Yet mx25l12833f does have SFDP, when I remove the no-SFDP flags, the
> >> driver fetch the SFDP.
> >>
> >> Secondly SFDP does not contain OTP information.
> >>
> >> mx25l12805d has two OTP regions of 128 KiB and 384 KiB (yes asymmetric).
> >> While mx25l12833f has two OTP regions of 512 KiB.
> >>
> >> How do we handle it?
> >
> > You would first try to parse SFDP and initialize the flash based on
> > SFDP. If there's no SFDP then you fallback to the flags declared at
> > flash declaration. Esben had a try recently, see [1]. I don't know if
> > there's any progress in that direction.
> >
>
> And you can then decide which OTP org to use based on whether SFDP is
> present or not.

That can work, but sound like a hack.
Is that really that important to hack?
Just for OTP, that very few use?
And if in the future Macronix adds a newer one with the same JEDEC ID,
but a different OTP size?
Macronix does not consult with the Linux Kernel on these matters.

Anyhow as I do not have the hardware anymore, I can not do more
changes and test them.

Erez


>
> > Also, you haven't mentioned anything about the testing. Do you have the
> > flash?
> >
> > [1]
> > https://lore.kernel.org/linux-mtd/20240603-macronix-mx25l3205d-fixups-v2-0-ff98da26835c@geanix.com/