[PATCH] mtd: spi-nor: Support Dual and Quad Read on Macronix mx25u25635f

[Alexander Sverdlin]

Hello Michael,

>> According to datasheet both Dual and Quad Read is supported. The read test
>> shows x3.8 speed gain.
> 
> Does it have SFDP? Try adding PARSE_SFDP instead of the
> NO_SFDP_FLAGS.

Some issues with its SFDP were known:
https://patchwork.ozlabs.org/project/linux-mtd/patch/1492068234-9509-1-git-send-email-dev@kresin.me/
 
> Please post an SFDP dump of this flash [1].

>xxd -p /sys/bus/spi/devices/spi0.0/sfdp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>md5sum /sys/bus/spi/devices/spi0.0/sfdp
bc360997e729ce1f77f1ff728621d94f /sys/bus/spi/devices/spi0.0/sfdp

>cat /sys/bus/spi/devices/spi0.0/jedec_id
c22539

>cat /sys/bus/spi/devices/spi0.0/partname
mx25u25635f

>cat /sys/bus/spi/devices/spi0.0/manufacturer
macronix

-- 
Best regards,
Alexander Sverdlin.