Re: [PATCH 4/4] mtd: spi-nor: winbond: Enable Dual and Quad support for w25q64jvm

From: "Michael Walle" <mwalle@kernel.org>
To: "Eliav Farber" <farbere@amazon.com>, <tudor.ambarus@linaro.org>,
	<pratyush@kernel.org>, <miquel.raynal@bootlin.com>,
	<richard@nod.at>, <vigneshr@ti.com>,
	<linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] mtd: spi-nor: winbond: Enable Dual and Quad support for w25q64jvm
Date: Tue, 10 Feb 2026 08:48:06 +0100	[thread overview]
Message-ID: <DGB4745HRCFI.1DRYTHXURWZJO@kernel.org> (raw)
In-Reply-To: <20260208061919.30498-5-farbere@amazon.com>

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On Sun Feb 8, 2026 at 7:19 AM CET, Eliav Farber wrote:
> The w25q64jvm supports Dual and Quad SPI operations.
>
> Enable these capabilities by adding SPI_NOR_DUAL_READ and
> SPI_NOR_QUAD_READ to no_sfdp_flags.

Let me guess, you have a flash that actually has SFDP but it's not
parsed because the core (due to legacy reasons) skips it because
neither DUAL_READ nor QUAD_READ is set.

See also [1]. I'd prefer to always try to parse SFDP instead of
adding these legacy flags.

-michael

[1] https://lore.kernel.org/linux-mtd/DD10GE4EOCD7.CPTN7198QFUV@kernel.org/

>
> Reference:
> https://www.winbond.com/hq/support/documentation/levelOne.jsp?__locale=en&DocNo=DA00-W25Q64JV.1
>
> Signed-off-by: Eliav Farber <farbere@amazon.com>
> ---
>  drivers/mtd/spi-nor/winbond.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
> index eaa547d36aad..cb35ec6f110e 100644
> --- a/drivers/mtd/spi-nor/winbond.c
> +++ b/drivers/mtd/spi-nor/winbond.c
> @@ -297,7 +297,7 @@ static const struct flash_info winbond_nor_parts[] = {
>  		.name = "w25q64jvm",
>  		.size = SZ_8M,
>  		.flags = SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB,
> -		.no_sfdp_flags = SECT_4K,
> +		.no_sfdp_flags = SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ,
>  	}, {
>  		.id = SNOR_ID(0xef, 0x70, 0x18),
>  		.name = "w25q128jv",

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