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

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Dominique,

On 10/08/2026 at 17:28:32 +09, Dominique MARTINET <dominique.martinet@atmark-techno.com> 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

Thanks for all the feedback, Sadre, can you please propose an udpate
with these details and changes?

> (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/

If it has continuous read, it requires the flag and a hook to
enable/disable the feature. The existing Winbond helper may already be
enough for it. You can test it with a recent version of mtd-utils, I
added options to nanddump, nandbiterrs and flash_speed for that.

If Sadre dooesn't do it, you can propose a follow-up patch.

Thanks,
Miquèl