spi-nor: maxronix MX25L12835F support

[Michael Walle]

Am 2021-02-16 10:27, schrieb Pratyush Yadav:
> On 15/02/21 10:53PM, Heiko Thiery wrote:
>> Hi all,
>> 
>> I faced an issue with a SPI flash on our board. We use a macronix
>> MX25L12835F [1]. Unfortunately this flash has the same JEDEC ID like
>> the MX25L12805D [2].
>> 
>> The newer MX25L12835F has support for dual/quad read mode and RDSFDP
>> while the older doesn't.
>> 
>> I thought that I could do a fixup with a device specific
>> post_bfpt_fixups() call but by now this seems not possible. The older
>> MX25L12805D has no flags set that allows a call to
>> spi_nor_sfdp_init_params() and implements the fixup.
>> 
>> Has anyone an idea how to solve this?
> 
> The post_sfdp fixup is always run regardless of whether the flash has
> SFDP or not. You can try putting your flash-specific fixups there.

Well the problem here is, that the SFDP setup is skipped though the
flash would support SFDP. If the jedec id wasn't already in the table,
there would be the flag SPI_NOR_QUAD_READ and the SFDP would be
parsed. But because there is already the legacy device (which likely
doesn't support SFDP) it really doesn't fit.

Its unclear to me, why the SFDP is only parsed if one of the
SPI_NOR_*_READ flags are set.

>> [1] 
>> https://www.macronix.com/Lists/Datasheet/Attachments/7397/MX25L12835F,%203V,%20128Mb,%20v1.6.pdf
>> [2] 
>> https://www.mxic.com.tw/Lists/Datasheet/Attachments/7321/MX25L12805D,%203V,%20128Mb,%20v1.2.pdf
> 
> Both these links are broken.

mh, they work for me.

-michael