Re: [RFC PATCH net-next v8 08/12] of: property: fw_devlink: Add support for "pcs-handle"

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] fwnode_property_get_reference_args() usage in newly added pcs.c causes -EINVAL on existing DTs due to lacking a cell count fallback.
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commit 91acc7e182a01f5abd0ae44dd757caf24a80257a
Author: Christian Marangi <ansuelsmth@gmail.com>

of: property: fw_devlink: Add support for "pcs-handle"

Add support for parsing PCS binding so that fw_devlink can
enforce the dependency with Ethernet port.

> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 136946f8b746f..e6584a2f705d2 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -1392,6 +1392,7 @@ DEFINE_SIMPLE_PROP(access_controllers, "access-controllers", "#access-controller
>  DEFINE_SIMPLE_PROP(pses, "pses", "#pse-cells")
>  DEFINE_SIMPLE_PROP(power_supplies, "power-supplies", NULL)
>  DEFINE_SIMPLE_PROP(mmc_pwrseq, "mmc-pwrseq", NULL)
> +DEFINE_SIMPLE_PROP(pcs_handle, "pcs-handle", "#pcs-cells")

[Severity: Medium]
While this fw_devlink integration correctly falls back to 0 cells (via
parse_prop_cells()) when #pcs-cells is missing, the newly added API in
drivers/net/pcs/pcs.c does not.

In drivers/net/pcs/pcs.c:fwnode_parse_pcsspec(), the fallback cell count is
hardcoded to -1:

	ret = fwnode_property_get_reference_args(fwnode, "pcs-handle",
						 "#pcs-cells",
						 -1, index, out_args);

Similarly, in drivers/net/pcs/pcs.c:fwnode_phylink_pcs_count():

		ret = fwnode_property_get_reference_args(fwnode, "pcs-handle",
							 "#pcs-cells",
							 -1, index, &out_args);

Passing -1 as the fallback cell count causes parsing to fail with -EINVAL on
existing devicetrees where the pcs-handle property points to a node without
#pcs-cells.

Could this create a regression for the pcs-handle binding, causing existing
MAC drivers that migrate to this new API to fail discovery of their PCS?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260618125752.1223-1-ansuelsmth@gmail.com?part=8