Re: [PATCH v3 2/3] mtd: spi-nor: intel-spi: Convert to SPI MEM

[Pratyush Yadav <p.yadav@xxxxxx>]

On 20/10/21 11:41AM, Boris Brezillon wrote:
> On Wed, 13 Oct 2021 14:44:31 +0300
> Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote:
> 
> > The preferred way to implement SPI-NOR controller drivers is through SPI
> > subsubsystem utilizing the SPI MEM core functions. This converts the
> > Intel SPI flash controller driver over the SPI MEM by moving the driver
> > from SPI-NOR subsystem to SPI subsystem and in one go make it use the
> > SPI MEM functions. The driver name will be changed from intel-spi to
> > spi-intel to match the convention used in the SPI subsystem.
> > 
> 
> I skimmed over the driver changes, and I'm skeptical about this "let's
> convert all spi-nor controller drivers into spi-mem drivers even if
> they don't fit the spi-mem model" strategy. Clearly, the intel
> controller is much more limited than any other spi-mem controller (I
> mean feature-wise not perf-wise of course). The fact that you have to
> check the opcode to decide whether the operation is supported or not,
> or the way you deduce when to issue an erase vs a regular read/write is
> kind of hack-ish. Not saying we shouldn't support this case in spi-mem,
> but it should at least be done in a more controlled way. Maybe with an
> explicit array of supported spi_mem operations, and driver specific
> hooks for each of these operations so anything falling outside is
> clearly identified and rejected (we have this sort of things in the raw
> NAND framework).

I am curious about how we can solve this. Any pointers to 
functions/drivers in raw NAND framework that follow this model?

[...]

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.