Re: [PATCH 1/2] mtd: spinand: winbond: add support for W25N04LW

On Mon, Aug 10, 2026 at 05:28:32PM +0900, Dominique MARTINET wrote:
> Md Sadre Alam wrote on Fri, Aug 07, 2026 at 12:13:38PM +0530:
> > Add support for Winbond W25N04LW 4Gbit SPI-NAND.
> > It has 8-bit on-die ECC and a 4096+256 byte page
> > (4096 byte main area, 128 byte usable OOB once
> > on-chip ECC hides the 128 byte parity area),
> > organized as 2048 blocks of 64 pages each, unlike
> > the existing 2048 byte page W25N04KV/W25N04KW parts.
> 
> This is pretty good timing, I was just looking at sending a patch for
> W25N04LW myself!
> 
> I agree with Miquèl that your patch looks odd, you wrote
> > +		     NAND_MEMORG(1, 4096, 128, 64, 2048, 40, 1, 1, 1),
> but the erase blocks are 256K long so it should be
> +		     NAND_MEMORG(1, 4096, 256, 64, 2048, 40, 1, 1, 1),
> 
> did you actually test this device?
> 
> If it helps, the datasheet for W25N04LWZExx / W25N04LWTBxx is freely
> available from digikey here[1]
> [1] https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/7182/W25N04LWZExx_W25N04LWTBxx_RevD_2025-08-05.pdf
> 
> (And it also supports continuous read, so I'm curious to see if it'd
> work with the recent continous read support from Miquèl[2] merged in
> 7.2... I'm not familiar with the subsystem so will need a bit of time to
> plug all the hooks in properly)
> [2] https://lore.kernel.org/linux-mtd/20260429-winbond-v6-18-rc1-cont-read-v3-0-0f38b3c229ad@bootlin.com/
> 
> 
> FWIW, I've confirmed it works with the following diff (at least up to
> the point of creating an ubi volume and booting from it); happy to send
> this as a patch if this has indeed not been tested
This device was supported in our downstream tree and was tested there. I
picked that patch and posted it upstream assuming the configuration was
already correct.
The `128` in:
NAND_MEMORG(1, 4096, 128, 64, 2048, 40, 1, 1, 1)
was my mistake. It should indeed be `256`, matching the 4096 + 256 page
layout in the W25N04LW datasheet.
Please go ahead and post your tested patch. I do not currently have this
device available to retest the upstream version.

Thanks,
Alam.


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