Re: [PATCH v1] mtd: spi-nor: unset quad_enable if SFDP doesn't specify it

From: Michael Walle
Date: Wed Jul 20 2022 - 09:49:08 EST


Am 2022-07-19 06:57, schrieb Tudor.Ambarus@xxxxxxxxxxxxx:
On 3/4/22 20:51, Michael Walle wrote:

Hi!

While the first version of JESD216 specify the opcode for 4 bit I/O
accesses, it lacks information on how to actually enable this mode.

For now, the one set in spi_nor_init_default_params() will be used.
But this one is likely wrong for some flashes, in particular the
Macronix MX25L12835F. Thus we need to clear the enable method when
parsing the SFDP. Flashes with such an SFDP revision will have to use a
flash (and SFDP revision) specific fixup.

This is equivalent to clearing the default QE method for all those flashes
that support SFDP, with implications for those that support SFDP Rev A.
If I continue the logic, I could remove the default QE method from
spi_nor_init_default_params(), but I don't think I would like that.
You could use a post_bfpt hook without explicitly clearing it here.

Would you please explain more why is clearing the default method better
than using a wrong default one, and why you chose to do this just for
the Rev A SFDP flashes and you didn't include the no-SFDP flashes as well?

Honestly, I don't care too much about this flash. I can't remember
any details from this 4 months old thread. Sorry. I guess it is
fine to drop this patch. If someone cares, she or he can
resurrect this one.

-michael