Re: [PATCH v3 02/13] spi: dt-bindings: cdns,qspi-nor: add PHY tuning pattern partition property

From: Rob Herring

Date: Tue Jun 02 2026 - 12:56:14 EST


On Wed, May 27, 2026 at 11:25:16PM +0530, Santhosh Kumar K wrote:
> PHY tuning requires a known data pattern to be readable from flash.
> When no partition is explicitly identified, the controller must search
> all available partitions to locate the pattern by label, which adds
> overhead and relies on label naming conventions outside the
> controller's control.

I agree 'label' is not the best choice. Software should not care what
'label' contains. It should really be 'compatible' instead.

> Add cdns,phy-pattern-partition, a phandle property that allows the DT
> author to directly reference the flash partition holding the PHY tuning
> pattern. The controller uses this partition during calibration, avoiding
> the partition search entirely.

Do you have any data that this approach being "direct" is faster? In
fact, it might be worse. Instead of searching just the limited number of
partition subnodes, you now search the entire tree for a matching
phandle value. We do have phandle caching, so that might save you here.

Rob