Hi Pratyush,
p.yadav@xxxxxx wrote on Wed, 18 May 2022 11:37:05 +0530:
> +Cedric
>
> On 17/05/22 04:02PM, Miquel Raynal wrote:
> > Hi Pratyush,
> >
> > p.yadav@xxxxxx wrote on Fri, 12 Mar 2021 00:42:13 +0530:
> >
> > > Once the flash is initialized tell the controller it can run
> > > calibration procedures if needed. This can be useful when calibration is
> > > needed to run at higher clock speeds.
> > >
> > > Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
> > > ---
> > > drivers/mtd/spi-nor/core.c | 12 ++++++++++--
> > > 1 file changed, 10 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> > > index 88888df009f0..e0cbcaf1be89 100644
> > > --- a/drivers/mtd/spi-nor/core.c
> > > +++ b/drivers/mtd/spi-nor/core.c
> > > @@ -3650,6 +3650,7 @@ static int spi_nor_probe(struct spi_mem *spimem)
> > > * checking what's really supported using spi_mem_supports_op().
> > > */
> > > const struct spi_nor_hwcaps hwcaps = { .mask = SNOR_HWCAPS_ALL };
> > > + struct spi_mem_op op;
> > > char *flash_name;
> > > int ret;
> > >
> > > @@ -3709,8 +3710,15 @@ static int spi_nor_probe(struct spi_mem *spimem)
> > > if (ret)
> > > return ret;
> > >
> > > - return mtd_device_register(&nor->mtd, data ? data->parts : NULL,
> > > - data ? data->nr_parts : 0);
> > > + ret = mtd_device_register(&nor->mtd, data ? data->parts : NULL,
> > > + data ? data->nr_parts : 0);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + op = spi_nor_spimem_get_read_op(nor);
> >
> > Isn't this too specific? I really don't know much about spi-nors, but I
> > find odd to have this op being created here, why not moving this into
> > the _do_calibration() helper?
>
> Maybe the naming confused you but this is a function in the SPI NOR
> core, not in SPI MEM. SPI NOR supports both SPI MEM based controllers
> and "legacy" controllers, so the convention is to add the "spimem"
> prefix before SPI MEM specific functions. So I don't get the comment
> about it being too specific. It is too specific to what?
Mmh right, it's fine then.
>
> And how can spi_mem_do_calibration() know what op the flash uses to read
> data? SPI NOR or SPI NAND would know it, but not SPI MEM. That is why we
> pass in that information to spi_mem_do_calibration().
But here the op is "spi-nor wide", I would have expected a
per-device op. But that is not a big deal, that is something that can
also be updated later if needed I guess.
One last question, is there something that mtd_device_register() does
that is really needed for the calibration to work? Otherwise I would
rather prefer to have that calibration happening before the user gets
access to the device.
>
> >
> > > + spi_mem_do_calibration(nor->spimem, &op);
> >
> > A warning/info upon calibration error (not on the absence of the hook)
> > would be nice?
>
> Yes, agreed.
>
> >
> > > +
> > > + return 0;
> > > }
> > >
> > > static int spi_nor_remove(struct spi_mem *spimem)
> >
> > Otherwise I like the overall idea.
>
> Thanks for reviewing.
>
> >
> > Thanks,
> > Miquèl
>
Thanks,
Miquèl
