dpll: zl3073x: Implement input pin state setting in automatic mode

jira KERNEL-318
Rebuild_History Non-Buildable kernel-6.12.0-124.20.1.el10_1
commit-author Ivan Vecera <ivecera@redhat.com>
commit bf33c93

Implement input pin state setting when the DPLL is running in automatic
mode. Unlike manual mode, the DPLL mode switching is not used here and
the implementation uses special priority value (15) to make the given
pin non-selectable.

When the user sets state of the pin as disconnected the driver
internally sets its priority in HW to 15 that prevents the DPLL to
choose this input pin. Conversely, if the pin status is set to
selectable, the driver sets the pin priority in HW to the original saved
value.

	Signed-off-by: Ivan Vecera <ivecera@redhat.com>
	Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/20250704182202.1641943-12-ivecera@redhat.com
	Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit bf33c93)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>

Author: PlaidCat

drivers/dpll/zl3073x/dpll.c

@@ -439,6 +439,38 @@ zl3073x_dpll_input_pin_state_on_dpll_set(const struct dpll_pin *dpll_pin,
 
 		rc = zl3073x_dpll_selected_ref_set(zldpll, new_ref);
 		break;
+
+	case ZL_DPLL_MODE_REFSEL_MODE_AUTO:
+		if (state == DPLL_PIN_STATE_SELECTABLE) {
+			if (pin->selectable)
+				return 0; /* Pin is already selectable */
+
+			/* Restore pin priority in HW */
+			rc = zl3073x_dpll_ref_prio_set(pin, pin->prio);
+			if (rc)
+				return rc;
+
+			/* Mark pin as selectable */
+			pin->selectable = true;
+		} else if (state == DPLL_PIN_STATE_DISCONNECTED) {
+			if (!pin->selectable)
+				return 0; /* Pin is already disconnected */
+
+			/* Set pin priority to none in HW */
+			rc = zl3073x_dpll_ref_prio_set(pin,
+						       ZL_DPLL_REF_PRIO_NONE);
+			if (rc)
+				return rc;
+
+			/* Mark pin as non-selectable */
+			pin->selectable = false;
+		} else {
+			NL_SET_ERR_MSG(extack,
+				       "Invalid pin state for automatic mode");
+			return -EINVAL;
+		}
+		break;
+
 	default:
 		/* In other modes we cannot change input reference */
 		NL_SET_ERR_MSG(extack,