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From: Michael Walle <michael@walle.cc>
To: Nick <vincent@systemli.org>
Cc: Tudor.Ambarus@microchip.com, linux-mtd@lists.infradead.org,
	mail@david-bauer.net
Subject: Re: [PATCH 2/2] mtd: spi-nor: disable 16-bit-sr for macronix
Date: Wed, 19 Jan 2022 16:49:56 +0100	[thread overview]
Message-ID: <22bd791798d15d74060c44f65620921c@walle.cc> (raw)
In-Reply-To: <a187ec1b-3bae-659d-86c5-4e2b3403eca4@systemli.org>

Am 2021-12-31 10:10, schrieb Nick:
> I looked now through all datasheets I found and the sizes of the
> status register. However, I did not find any datasheet for the
> "mx66l1g55g".
> However, I am not sure if I maybe miss something to see if
> "SNOR_F_HAS_16BIT_SR" is supported. I only looked at the status
> register size.

How did you check that?

random example:
> mx66u51235f: 8bit
> https://www.macronix.com/Lists/Datasheet/Attachments/7674/MX66U51235F,%201.8V,%20512Mb,%20v1.1.pdf
> (slide 34)

Figure 23:
WRSR takes both status register and configuration register.

That being said. I'd prefer to have a sane default for that
flag - which is to _not_ set it by default. For now, we can
just remove the flag from spi_nor_init_default_params() and
move it into the manufacturer default init. Then we can
go through the flashes and remove the flag there.

This is mainly because it seems to be a legacy feature. To
quote the datasheet of the Winbond W25Q32FW [1]:

| The W25Q32FW is also backward compatible to Winbond’s previous
| generations of serial flash memories, in which the Status
| Register-1&2 can be written using a single “Write Status
| Register-1 (01h)” command.

-michael

[1] 
https://www.winbond.com/resource-files/w25q32fw%20revj%2004242018%20sfdp.pdf

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  parent reply	other threads:[~2022-01-19 15:50 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-27  9:16 [PATCH 1/2] mtd: spi-nor: locking support for MX25L6405D vincent
2021-12-27  9:16 ` [PATCH 2/2] mtd: spi-nor: disable 16-bit-sr for macronix vincent
2021-12-29 14:08   ` Tudor.Ambarus
2021-12-31  9:10     ` Nick
2021-12-31  9:50       ` Nick
2022-01-19 15:49       ` Michael Walle [this message]
2022-01-19 20:36         ` David Bauer
2022-01-20  8:08           ` Michael Walle

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