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Date:   Thu, 07 Oct 2021 09:08:18 +0200
From:   Michael Walle <michael@walle.cc>
To:     Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Cc:     Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <p.yadav@ti.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: (EXT) Re: [PATCH 1/2] mtd: spi-nor: micron-st: sync flags of
 mt25ql02g and mt25qu02g with other mt25q
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 <f3dbab898e9f1946129e5733095bdf3c@walle.cc>
 <3258026683c916a3a42e98ba76628228cddacb23.camel@ew.tq-group.com>
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Am 2021-10-06 14:32, schrieb Matthias Schiffer:
> On Tue, 2021-07-27 at 09:09 +0200, Michael Walle wrote:
>> Am 2021-07-23 13:27, schrieb Matthias Schiffer:
>> > All mt25q variants have the same features.
>> >
>> > Unlike the smaller variants, no n25q with 2G exists, so we don't need
>> > to
>> > match on the extended ID to distinguish n25q and mt25q series for these
>> > models.
>> 
>> But why shouldn't we? What if there will be another flash with
>> the same first three id bytes?
> 
> How do you suggest we proceed here? At the moment there are entries
> matching on 0x20b[ab]22 (ignoring the extended ID) with the name
> mt25q[lu]02g.
> 
> Should I change these entries to match on on the extended ID
> 0x20b[ab]22 / 0x104400 instead when I add the bits for the features
> specific to the variant, removing support for other 0x20b[ab]22
> variants that may or may not actually exist? Keeping both entries (with
> and without extended ID match) would preserve compatiblity with such
> variants, but this approach seems problematic to me as well, as I can't
> even give a name to the more generic entries (and there is no natural
> extension of the n25q naming scheme to a 2G variant).

Mh, what do you think of adding three entries and make the last one,
the one with the short id, as a fallback so to speak. This should
retrain backwards compatibility, right? It should probably have a
comment because the order will matter then.

-michael