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

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

[Sherry Sun (OSS)]

From: Sherry Sun <sherry.sun@nxp.com>

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 <sherry.sun@nxp.com>
---
 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 <sherry.sun@nxp.com>

RE: Bluetooth: btnxpuart: Check remote M.2 connector availability before pwrseq

[bluez.test.bot]

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This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=1146897

---Test result---

Test Summary:
CheckPatch                    PASS      0.59 seconds
VerifyFixes                   PASS      0.07 seconds
VerifySignedoff               PASS      0.07 seconds
GitLint                       PASS      0.21 seconds
SubjectPrefix                 PASS      0.07 seconds
BuildKernel                   PASS      27.78 seconds
CheckAllWarning               PASS      30.24 seconds
CheckSparse                   PASS      29.08 seconds
BuildKernel32                 PASS      27.00 seconds
CheckKernelLLVM               SKIP      0.00 seconds
TestRunnerSetup               PASS      520.32 seconds
IncrementalBuild              PASS      26.09 seconds

Details
##############################
Test: CheckKernelLLVM - SKIP
Desc: Build kernel with LLVM + context analysis
Output:
Clang not found


https://github.com/bluez/bluetooth-next/pull/594

---
Regards,
Linux Bluetooth