Re: [PATCH 4/8] spi: fsl-qspi: add a clock disable quirk

[Alex Elder]

On 10/20/25 2:13 PM, Frank Li wrote:
> On Mon, Oct 20, 2025 at 11:51:47AM -0500, Alex Elder wrote:
> > The SpacemiT K1 SoC QSPI implementation needs to avoid shutting
> > off the clock when changing its rate.  Add a new quirk to indicate
> > the clock should not be disabled/enabled when changing its rate
> > for operations.
> >
> > Signed-off-by: Alex Elder <elder@xxxxxxxxxxxx>
> > ---
> >   drivers/spi/spi-fsl-qspi.c | 21 +++++++++++++++++----
> >   1 file changed, 17 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/spi/spi-fsl-qspi.c b/drivers/spi/spi-fsl-qspi.c
> > index 1e27647dd2a09..703a7df394c00 100644
> > --- a/drivers/spi/spi-fsl-qspi.c
> > +++ b/drivers/spi/spi-fsl-qspi.c
> > @@ -197,6 +197,11 @@
> >    */
> >   #define QUADSPI_QUIRK_USE_TDH_SETTING	BIT(5)
> >
> > +/*
> > + * Do not disable the "qspi" clock when changing its rate.
> > + */
> > +#define QUADSPI_QUIRK_NO_CLK_DISABLE	BIT(6)
>
> NO_CLK_DISALBE look likes not clk disable capability. Maybe
>
> QUADSPI_QUIRK_SKIP_CLK_DISABLE

OK, that's better.

> > +
> >   struct fsl_qspi_devtype_data {
> >   	unsigned int rxfifo;
> >   	unsigned int txfifo;
> > @@ -306,6 +311,11 @@ static inline int needs_tdh_setting(struct fsl_qspi *q)
> >   	return q->devtype_data->quirks & QUADSPI_QUIRK_USE_TDH_SETTING;
> >   }
> >
> > +static inline int needs_clk_disable(struct fsl_qspi *q)
>
> bool type?

Yes I agree with this suggestion.  However all of the other
needs_*() functions return int and are marked inline (neither
of which I would normally do).

You want me to add a patch to update the others too?  If I
do that it will look more like this:

static bool needs_swap_endian(struct fsl_qspi *q)
{
        return !!(q->devtype_data->quirks & QUADSPI_QUIRK_SWAP_ENDIAN);
}


					-Alex

> Frank
>
> > +{
> > +	return !(q->devtype_data->quirks & QUADSPI_QUIRK_NO_CLK_DISABLE);
> > +}
> > +
> >   /*
> >    * An IC bug makes it necessary to rearrange the 32-bit data.
> >    * Later chips, such as IMX6SLX, have fixed this bug.
> > @@ -536,15 +546,18 @@ static void fsl_qspi_select_mem(struct fsl_qspi *q, struct spi_device *spi,
> >   	if (needs_4x_clock(q))
> >   		rate *= 4;
> >
> > -	fsl_qspi_clk_disable_unprep(q);
> > +	if (needs_clk_disable(q))
> > +		fsl_qspi_clk_disable_unprep(q);
> >
> >   	ret = clk_set_rate(q->clk, rate);
> >   	if (ret)
> >   		return;
> >
> > -	ret = fsl_qspi_clk_prep_enable(q);
> > -	if (ret)
> > -		return;
> > +	if (needs_clk_disable(q)) {
> > +		ret = fsl_qspi_clk_prep_enable(q);
> > +		if (ret)
> > +			return;
> > +	}
> >
> >   	q->selected = spi_get_chipselect(spi, 0);
> >
> > --
> > 2.48.1