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From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Maarten Zanders <maarten@zanders.be>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	 Pratyush Yadav <pratyush@kernel.org>,
	 linux-mtd@lists.infradead.org
Subject: Re: [spi-nor] Macronix MX25L requires CR read opcode 0x15 (not 0x35)
Date: Tue, 02 Jun 2026 15:16:19 +0200	[thread overview]
Message-ID: <87bjdt13rw.fsf@bootlin.com> (raw)
In-Reply-To: <CAPB_pELpdie+=VB3h3tqZCkdTd9cKyhnYNmXjeP1vYODDricLw@mail.gmail.com> (Maarten Zanders's message of "Fri, 22 Aug 2025 14:03:02 +0200")

Hello,

On 22/08/2025 at 14:03:02 +02, Maarten Zanders <maarten@zanders.be> wrote:

> Hi all,
>
> On the Macronix MX25L12833F (ID 0xC22018) & others of this family/mfg,
> the CR (condition register) must be read with opcode 0x15. The driver
> currently uses 0x35, which the chip does not recognize.
>
> Datasheet: https://www.macronix.com/Lists/Datasheet/Attachments/8934/MX25L12833F,%203V,%20128Mb,%20v1.0.pdf
> (p.27, RDCR).
>
> With 0x35 the data line floats and the driver reads CR as 0xFF
> (depending on previous state of the line or pull up/down). This value
> is then written back in spi_nor_write_16bit_sr_and_check(), setting CR
> to 0xFF. One consequence is flipping the OTP Top/Bottom protection
> bit, so from then on, locking the top block actually locks the bottom
> sector. This breaks bootloader updates (in my case) and similar flows.
>
> Possible fixes:
> - Make CR read opcode configurable per device.

FYI I just proposed a series which goes into that direction, with quite
a deep rework of the QER SFDP field handling. This rework allows on a
per chip basis to indicate:
- what are the status operations supported
- what are the opcodes for these operations

Link: https://lore.kernel.org/linux-mtd/20260529-winbond-v7-1-spi-nor-rv-addition-v1-0-f3ae18502d5a@bootlin.com/T/#m0058d07965ba8c91a2438c5512e2b7b2693a6909

Thanks,
Miquèl

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      parent reply	other threads:[~2026-06-02 13:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-22 12:03 [spi-nor] Macronix MX25L requires CR read opcode 0x15 (not 0x35) Maarten Zanders
2025-09-01 14:46 ` Pratyush Yadav
2025-09-02 11:18   ` Maarten Zanders
2025-09-09 15:29     ` Pratyush Yadav
2025-09-10 11:21       ` Maarten Zanders
2026-06-02 13:16 ` Miquel Raynal [this message]

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