Re: [PATCH v4 08/16] spi: cadence-quadspi: add PHY tuning support

[Santhosh Kumar K]

Hello Mark,

Apologies for the delayed response.

On 19/06/26 23:03, Mark Brown wrote:
> On Thu, Jun 18, 2026 at 01:07:17PM +0530, Santhosh Kumar K wrote:
> > The Cadence QSPI controller supports a delay-line PHY for high-speed
> > operation. Without calibration the PHY is unused and read capture relies
> > on a fixed delay, limiting throughput at frequencies above the base
> > operating speed.
>
> > +static int cqspi_get_phy_pattern_offset(struct device *dev, u32 *offset)
> > +{
> > +	struct device_node *np, *flash_np = NULL, *part_np;
> > +	const __be32 *reg;
> > +	int len;
> > +
> > +	if (!dev || !dev->of_node)
> > +		return -EINVAL;
> > +
> > +	for_each_child_of_node(dev->of_node, np) {
> > +		if (of_node_name_prefix(np, "flash")) {
> > +			flash_np = np;
> > +			break;
> > +		}
> > +	}
>
> This isn't going to do the right thing if there's more than one flash,
> that doesn't seem a super sensible hardware configuration but I'm not
> sure I see anything stopping it being set up and system integrators do
> enjoy differentiating.

Oops, I missed this while testing with only a single flash connected.

Thanks for catching it, I'll update the driver to store the offset
during cqspi_of_get_flash_pdata(), which should resolve the issue.

Thanks,
Santhosh.