Re: [PATCH v2] mtd: spi-nor: handle unsupported FSR opcodes properly

[Mika Westerberg]

Hi,

On Thu, Jun 16, 2022 at 08:26:33PM +0000, Oleksandr Ocheretnyi -X (oocheret - GLOBALLOGIC INC at Cisco) wrote:
>    Hi Mika,
> 
>    >    ​However I remember you caught situation where
>    micron_st_nor_read_fsr()
>    >    returns -EOPNOTSUPP
>    >    (intel_spi_exec_mem_op callback returns -EOPNOTSUPP), according to
>    your
>    >    patch
>    >
>    [3]https://lore.kernel.org/linux-mtd/20220506105158.43613-1-mika.wester
>    >    berg@xxxxxxxxxxxxxxx/ I've noted in description body. So I think I
>    have
>    >    to cover both errorcodes, haven't I?
>    I was thinking that you change the both functions in Intel SPI to
>    return
> 
>    -ENOTSUPP, not just one.
> 
>    ​you know 'drivers/mtd/spi-nor' sources use -EOPNOTSUPP errorcode only,
>    however
> 
>    'drivers/spi' modules (where intel driver is located as well as
>    spi-mem.c) use both errorcodes many times
> 
>    (-EOPNOTSUPP and -ENOTSUPP).

Oh, indeed. I remembered that SPI-NOR core was using ENOTSUP but it was
SPI-MEM instead.

>    So maybe it is better to use -EOPNOTSUPP for intel driver file (what
>    uses -EOPNOTSUPP everywhere) and
> 
>    update the spi-mem.c with -EOPNOTSUPP as return value, how do you
>    think?

Yes, I think this is the correct approach. You need to be careful though
to make sure the callers of SPI-MEM functions do not get unexpected
values.