Re: [RFC PATCH v2 03/12] mtd: spinand: perform controller tuning during probe

[Santhosh Kumar K]

Hi Miquel,

On 05/02/26 23:05, Miquel Raynal wrote:
> Hi Santhosh,
>
> On 13/01/2026 at 19:46:08 +0530, Santhosh Kumar K <s-k6@xxxxxx> wrote:
>
> > SPI controllers may need tuning for reliable high-speed operation.
> > Without it, controllers use conservative timing that limits performance.
> >
> > Call spi_mem_execute_tuning() during probe to optimize timing for
> > the device's read and write operations. Failures are non-fatal as
> > controllers fall back to default timing.
> >
> > Signed-off-by: Santhosh Kumar K <s-k6@xxxxxx>
> > ---
> >   drivers/mtd/nand/spi/core.c | 14 ++++++++++++++
> >   1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> > index 0346916b032b..2a45d1047736 100644
> > --- a/drivers/mtd/nand/spi/core.c
> > +++ b/drivers/mtd/nand/spi/core.c
> > @@ -1658,6 +1658,7 @@ static int spinand_probe(struct spi_mem *mem)
> >   {
> >   	struct spinand_device *spinand;
> >   	struct mtd_info *mtd;
> > +	struct spi_mem_op read_op, write_op;
> >   	int ret;
> >   
> >   	spinand = devm_kzalloc(&mem->spi->dev, sizeof(*spinand),
> > @@ -1676,6 +1677,19 @@ static int spinand_probe(struct spi_mem *mem)
> >   	if (ret)
> >   		return ret;
> >   
> > +	read_op = *spinand->op_templates.read_cache;
> > +	write_op = *spinand->op_templates.write_cache;
>
> These will become:
>
>   +	read_op = *spinand->op_templates->read_cache;
>   +	write_op = *spinand->op_templates->write_cache;
>
> after rebasing on nand/next or next -rc1.

Noted!

> > +
> > +	ret = spi_mem_execute_tuning(mem, &read_op, &write_op);
> > +	if (ret && ret != -EOPNOTSUPP) {
> > +		dev_warn(&mem->spi->dev, "Failed to execute PHY tuning: %d\n",
> > +			 ret);
> > +		/*
> > +		 * Tuning failure is non-fatal; the controller falls back to
> > +		 * default timing, reducing speed but ensuring operation.
> > +		 */
> > +	}
>
> Can we move the comment before spi_mem_execute_timing()? Then no more
> brackets needed and it will be easier to read (imo).

Yeah, I agree on the readability concern - will move them in v3.

Thanks,
Santhosh.

> LGTM otherwise.
>
> Thanks,
> Miquèl