Re: [PATCH net-next v7 05/12] net: phylink: support late PCS provider attach

[Christian Marangi <ansuelsmth@gmail.com>]

On Mon, Jun 15, 2026 at 04:29:04PM +0200, Maxime Chevallier wrote:
> 
> 
> On 6/15/26 16:10, Christian Marangi wrote:
> > On Mon, Jun 15, 2026 at 04:07:03PM +0200, Maxime Chevallier wrote:
> >> Hi Christian,
> >>
> >> On 6/15/26 14:29, Christian Marangi wrote:
> >>> Add support for late PCS provider attachment to a phylink instance.
> >>> This works by creating a global notifier for the PCS provider and
> >>> making each phylink instance that makes use of fwnode subscribe to
> >>> this notifier.
> >>>
> >>> The PCS notifier will emit the event FWNODE_PCS_PROVIDER_ADD every time
> >>> a new PCS provider is added.
> >>>
> >>> phylink will then react to this event and will call the new function
> >>> fwnode_phylink_pcs_get_from_fwnode() that will check if the PCS fwnode
> >>> provided by the event is present in the pcs-handle property of the
> >>> phylink instance.
> >>>
> >>> If a related PCS is found, then such PCS is added to the phylink
> >>> instance PCS list.
> >>>
> >>> Then we link the PCS to the phylink instance and we refresh the supported
> >>> interfaces of the phylink instance.
> >>>
> >>> Finally we check if we are in a major_config_failed scenario and trigger
> >>> an interface reconfiguration in the next phylink resolve.
> >>>
> >>> In the example scenario where the link was previously torn down due to
> >>> removal of PCS, the link will be established again as the PCS came back
> >>> and is now available to phylink.
> >>>
> >>> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> >>> ---
> >>
> >> [...]
> >>
> >>> @@ -2151,6 +2204,10 @@ void phylink_destroy(struct phylink *pl)
> >>>  	if (pl->link_gpio)
> >>>  		gpiod_put(pl->link_gpio);
> >>>  
> >>> +	/* Unregister notifier for late PCS attach */
> >>> +	if (pl->fwnode_pcs_nb.notifier_call)
> >>> +		unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
> >>
> >> I wanted to try this out, but I get :
> >>
> >> drivers/net/phy/phylink.c:2218:17: error: implicit declaration of function ‘unregister_fwnode_pcs_notifier’; did you mean ‘register_fwnode_pcs_notifier’? [-Werror=implicit-function-declaration]
> >>  2218 |                 unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
> >>       |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>       |                 register_fwnode_pcs_notifier
> >>
> >> I guess you either need to stub this, or there's a missing Kconfig
> >> dependency somewhere
> >>
> > 
> > Hi yes if you want toi test just enable CONFIG_FWNODE_PCS. I forgot to add
> > the static declaration for unregister_fwnode_pcs_notifier. 
> 
> I'll give it a go with this yeah, I have a few devices here I'd like to
> try this on.
> 
> Can you CC me for the next rounds ?
> 

Sure, if you can would be good to check also the other commit if everything
is logically correct.

BTW by checking test from patchwork I can see also another fix is needed if
you want to test this revision.

phylink_create()

-if (config->num_possible_pcs && pl->mac_ops->mac_select_pcs) {
+if (config->num_possible_pcs && mac_ops->mac_select_pcs) {

Aside from these change I expect the current legacy code to be not
affected by these change.

-- 
	Ansuel