[PATCH] Bluetooth: btnxpuart: Check remote M.2 connector availability before pwrseq

From: Sherry Sun <[email protected]>

The current code uses of_graph_is_present() to decide whether to enter
the pwrseq path. However, of_graph_is_present() only checks for the
structural presence of a port/ports sub-node and does not check the
status property. This causes problems when a DT overlay disables the
remote M.2 connector node (e.g., switching from PCIe WiFi to SDIO WiFi):
the port node still exists, so of_graph_is_present() returns true, but
the pwrseq provider never registers because the connector is disabled,
leading to an infinite -EPROBE_DEFER loop.

Replace of_graph_is_present() with a new helper that traverses the OF
graph to the remote port parent (the M.2 connector node) and checks
of_device_is_available(). When the remote connector is disabled, the
pwrseq path is skipped, allowing the BT driver to fall through to the
direct bluetooth child node path.

Fixes: 3c48135c1397 ("Bluetooth: btnxpuart: Add M.2 Bluetooth device support using pwrseq")
Signed-off-by: Sherry Sun <[email protected]>
---
 drivers/bluetooth/btnxpuart.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 81cdd8da5636..e2b8f7997e4e 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -1809,6 +1809,28 @@ static void nxp_coredump_notify(struct hci_dev *hdev, int state)
 	kobject_uevent_env(&serdev->dev.kobj, KOBJ_CHANGE, envp);
 }
 
+/*
+ * Check if the remote M.2 connector device linked via OF graph is present
+ * and available. This is used to determine whether the pwrseq path should
+ * be taken. When the remote connector node is disabled (e.g., by a DT
+ * overlay switching from PCIe WiFi to SDIO WiFi), the pwrseq path is
+ * skipped, allowing the BT driver to use a direct bluetooth child node
+ * instead.
+ */
+static bool nxp_m2_connector_is_available(struct device *dev)
+{
+	struct device_node *ep __free(device_node) =
+		of_graph_get_next_endpoint(dev_of_node(dev), NULL);
+
+	if (!ep)
+		return false;
+
+	struct device_node *remote __free(device_node) =
+		of_graph_get_remote_port_parent(ep);
+
+	return remote && of_device_is_available(remote);
+}
+
 static int nxp_serdev_probe(struct serdev_device *serdev)
 {
 	struct hci_dev *hdev;
@@ -1863,7 +1885,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 		return err;
 	}
 
-	if (of_graph_is_present(dev_of_node(&serdev->ctrl->dev))) {
+	if (nxp_m2_connector_is_available(&serdev->ctrl->dev)) {
 		struct pwrseq_desc *pwrseq;
 
 		pwrseq = pwrseq_get(&serdev->ctrl->dev, "uart");

---
base-commit: 4477a78374a57c3809b172ad30cceabda48c47c6
change-id: 20260817-btnxpuart_m2-a9814969871b

Best regards,
-- 
Sherry Sun <[email protected]>