linux-kernel - Re: [PATCH v9 6/6] mtd: spi-nor: add support for Macronix Octal flash

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Message-ID: <CAPhrvRR2_j=KhFJHWyU48z998q0wkoZJYCBAUuv8ejp7xnkWiQ@mail.gmail.com>
Date: Thu, 26 Sep 2024 11:06:41 +0800
From: Alvin Zhou <alvinzhou.tw@...il.com>
To: Miquel Raynal <miquel.raynal@...tlin.com>
Cc: Tudor Ambarus <tudor.ambarus@...aro.org>, linux-mtd@...ts.infradead.org, 
	linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org, pratyush@...nel.org, 
	mwalle@...nel.org, richard@....at, vigneshr@...com, broonie@...nel.org, 
	chengminglin@...c.com.tw, leoyu@...c.com.tw, 
	AlvinZhou <alvinzhou@...c.com.tw>, JaimeLiao <jaimeliao@...c.com.tw>, 
	Bough Chen <haibo.chen@....com>
Subject: Re: [PATCH v9 6/6] mtd: spi-nor: add support for Macronix Octal flash

Hi Miquel,

Miquel Raynal <miquel.raynal@...tlin.com> 於 2024年9月25日 週三 下午5:57寫道：
>
> Hi Alvin,
>
> tudor.ambarus@...aro.org wrote on Tue, 24 Sep 2024 08:17:26 +0100:
>
> > On 9/24/24 7:36 AM, Tudor Ambarus wrote:
> > >
> > >
> > > On 9/24/24 7:26 AM, Tudor Ambarus wrote:
> > >>
> > >>
> > >> On 9/24/24 4:25 AM, Alvin Zhou wrote:
> > >>> Hi Tudor,
> > >>>
> > >>> Tudor Ambarus <tudor.ambarus@...aro.org> 於 2024年9月23日 週一 下午2:54寫道：
> > >>>>
> > >>>> Hi, Alvin,
> > >>>>
> > >>>> I quickly skimmed over the previous 5 patches and they are looking fine.
> > >>>>
> > >>>> I don't get this patch however.
> > >>>>
> > >>>> On 7/18/24 4:46 AM, AlvinZhou wrote:
> > >>>>> From: AlvinZhou <alvinzhou@...c.com.tw>
> > >>>>>
> > >>>>> Adding Manufacture ID 0xC2 in last of ID table because of
> > >>>>> Octal Flash need manufacturer fixup for enabling/disabling
> > >>>>> Octal DTR mode.
> > >>>>>
> > >>>>> Signed-off-by: JaimeLiao <jaimeliao@...c.com.tw>
> > >>>>> Signed-off-by: AlvinZhou <alvinzhou@...c.com.tw>
> > >>>>> ---
> > >>>>>  drivers/mtd/spi-nor/macronix.c | 4 +++-
> > >>>>>  1 file changed, 3 insertions(+), 1 deletion(-)
> > >>>>>
> > >>>>> diff --git a/drivers/mtd/spi-nor/macronix.c b/drivers/mtd/spi-nor/macronix.c
> > >>>>> index f039819a5252..1a8ccebdfe0e 100644
> > >>>>> --- a/drivers/mtd/spi-nor/macronix.c
> > >>>>> +++ b/drivers/mtd/spi-nor/macronix.c
> > >>>>> @@ -200,7 +200,9 @@ static const struct flash_info macronix_nor_parts[] = {
> > >>>>>               .name = "mx25l3255e",
> > >>>>>               .size = SZ_4M,
> > >>>>>               .no_sfdp_flags = SECT_4K,
> > >>>>> -     }
> > >>>>> +     },
> > >>>>> +     /* Need the manufacturer fixups, Keep this last */
> > >>>>> +     { .id = SNOR_ID(0xc2) }
> > >>>>>  };
> > >>>>>
> > >>>>
> > >>>> Could you please elaborate why you need just the manufacturer id here? I
> > >>>> would have expected to see a specific flash entry instead.
> > >>>
> > >>> Grateful to Michael for the valuable suggestion. This addition of the
> > >>> Macronix manufacturer ID enables the fixup functions such as
> > >>> macronix_nor_set_octal_dtr to be executed without the need to
> > >>> create separate ID entries for each Octal DTR NOR Flash in the
> > >>> flash_info.
> > >>>
> > >>
> > >> Ah, nice. Okay then. I'm going to review the rest of the patches. They
> > >> look promising ;).
> > >
> > > ah, but then you'll always have a matched ID, so you break the generic
> > > flash probing for macronix. Is that correct?
> >
> > Answering myself: it's fine. Generic flash probe just fills a name,
> > which we don't really care about.
>
> I was also a bit surprised by the diff, would you mind filling a more
> complete with details on the actual goal of this entry (having all
> Macronix flashes to get the fixups, without creating separate ID
> entries for each of the flashes)

Thank you for the reminder, I will incorporate more detailed
explanations.

>
> Thanks,
> Miquèl

Thanks,
Alvin