[PATCH RESEND] Bluetooth: btmtksdio: Lookup device node only as fallback

[Chen-Yu Tsai <wenst@chromium.org>]

If the device tree is properly written, the SDIO function device node
should be correctly defined, and the mmc core in Linux should correctly
tie it to the device being probed.

Only fall back to searching for the device node by compatible if the
original device node tied to the device is incorrect, as seen in older
device trees.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Resending after three and a half months.

This follows up on the MT7921S bluetooth binding and DT fixup patches [1].
This should not be backported.

[1] https://lore.kernel.org/linux-bluetooth/20240412073046.1192744-1-wenst@chromium.org/

 drivers/bluetooth/btmtksdio.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index cc097aedc1e1..a1dfcfe43d3a 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -1328,6 +1328,8 @@ static int btmtksdio_probe(struct sdio_func *func,
 {
 	struct btmtksdio_dev *bdev;
 	struct hci_dev *hdev;
+	struct device_node *old_node;
+	bool restore_node;
 	int err;
 
 	bdev = devm_kzalloc(&func->dev, sizeof(*bdev), GFP_KERNEL);
@@ -1411,13 +1413,24 @@ static int btmtksdio_probe(struct sdio_func *func,
 	if (err)
 		bt_dev_err(hdev, "failed to initialize device wakeup");
 
-	bdev->dev->of_node = of_find_compatible_node(NULL, NULL,
-						     "mediatek,mt7921s-bluetooth");
+	restore_node = false;
+	if (!of_device_is_compatible(bdev->dev->of_node, "mediatek,mt7921s-bluetooth")) {
+		restore_node = true;
+		old_node = bdev->dev->of_node;
+		bdev->dev->of_node = of_find_compatible_node(NULL, NULL,
+							     "mediatek,mt7921s-bluetooth");
+	}
+
 	bdev->reset = devm_gpiod_get_optional(bdev->dev, "reset",
 					      GPIOD_OUT_LOW);
 	if (IS_ERR(bdev->reset))
 		err = PTR_ERR(bdev->reset);
 
+	if (restore_node) {
+		of_node_put(bdev->dev->of_node);
+		bdev->dev->of_node = old_node;
+	}
+
 	return err;
 }
 
-- 
2.47.0.rc0.187.ge670bccf7e-goog