[PATCH iwl-net v3] ice: fix missing dpll notification for SW pins

[Petr Oros <poros@redhat.com>]

ice_dpll_notify_changes() sends dpll_pin_change_ntf() only for the
direct CGU input pin stored in d->active_input. Software-controlled
pins (SMA/U.FL) are separate dpll_pin objects that wrap a backing CGU
input, but they never receive a change notification. As a result,
userspace consumers such as synce4l that monitor SMA pins via dpll
netlink never learn when the pin state transitions (e.g. from
SELECTABLE to CONNECTED), even though 'dpll pin show' reports the
correct state on demand.

When the active input changes, also send dpll_pin_change_ntf() for any
registered SMA/U.FL input pin whose backing CGU input matches the old
or new active input.

Fixes: 2dd5d03c77e2 ("ice: redesign dpll sma/u.fl pins control")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202602200046.SGwK2tWh-lkp@intel.com/
Signed-off-by: Petr Oros <poros@redhat.com>
---
v3:
- Add kdoc for the helper.
v2:
- Extract ice_dpll_sw_pin_needs_notify() helper for readability,
- Move loop variable into for() scope.

drivers/net/ethernet/intel/ice/ice_dpll.c | 29 +++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/ethernet/intel/ice/ice_dpll.c
index c2ad39bfe177db..a9db85a1026388 100644
--- a/drivers/net/ethernet/intel/ice/ice_dpll.c
+++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
@@ -2462,6 +2462,24 @@ static u64 ice_generate_clock_id(struct ice_pf *pf)
 	return pci_get_dsn(pf->pdev);
 }
 
+/**
+ * ice_dpll_sw_pin_needs_notify - check if SW pin needs change notification
+ * @p: pointer to SW pin (SMA or U.FL)
+ * @active: currently active input pin (or NULL)
+ * @old: previously active input pin (or NULL)
+ *
+ * Return: true if the SW pin is an input whose backing CGU pin matches either
+ * the old or new active input, meaning its state has changed.
+ */
+static bool
+ice_dpll_sw_pin_needs_notify(struct ice_dpll_pin *p,
+			     struct dpll_pin *active, struct dpll_pin *old)
+{
+	return p->pin &&
+	       p->direction == DPLL_PIN_DIRECTION_INPUT &&
+	       (p->input->pin == active || p->input->pin == old);
+}
+
 /**
  * ice_dpll_notify_changes - notify dpll subsystem about changes
  * @d: pointer do dpll
@@ -2470,6 +2488,7 @@ static u64 ice_generate_clock_id(struct ice_pf *pf)
  */
 static void ice_dpll_notify_changes(struct ice_dpll *d)
 {
+	struct ice_dplls *dplls = &d->pf->dplls;
 	bool pin_notified = false;
 
 	if (d->prev_dpll_state != d->dpll_state) {
@@ -2477,6 +2496,8 @@ static void ice_dpll_notify_changes(struct ice_dpll *d)
 		dpll_device_change_ntf(d->dpll);
 	}
 	if (d->prev_input != d->active_input) {
+		struct dpll_pin *old = d->prev_input;
+
 		if (d->prev_input)
 			dpll_pin_change_ntf(d->prev_input);
 		d->prev_input = d->active_input;
@@ -2484,6 +2505,14 @@ static void ice_dpll_notify_changes(struct ice_dpll *d)
 			dpll_pin_change_ntf(d->active_input);
 			pin_notified = true;
 		}
+		for (int i = 0; i < ICE_DPLL_PIN_SW_NUM; i++) {
+			if (ice_dpll_sw_pin_needs_notify(&dplls->sma[i],
+							 d->active_input, old))
+				dpll_pin_change_ntf(dplls->sma[i].pin);
+			if (ice_dpll_sw_pin_needs_notify(&dplls->ufl[i],
+							 d->active_input, old))
+				dpll_pin_change_ntf(dplls->ufl[i].pin);
+		}
 	}
 	if (d->prev_phase_offset != d->phase_offset) {
 		d->prev_phase_offset = d->phase_offset;
-- 
2.52.0