[PATCH v3] Bluetooth: btmtksdio: Add in-band wakeup support

[<sean.wang@mediatek.com>]

From: Sean Wang <sean.wang@mediatek.com>

Commit ce64b3e94919 ("Bluetooth: mt7921s: Support wake on bluetooth")
adds the wake on bluethooth via a dedicated GPIO.

Extend the wake-on-bluetooth to use the SDIO DAT1 pin (in-band wakeup),
when supported by the SDIO host driver.

Co-developed-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
v2: enhance the patch description and comments
v3: add a way suggested by the AngeloGioacchino Del Regno that look
    elegant and can avoid the addition of the BTMTKSDIO_INBAND_WAKEUP
    flag
---
 drivers/bluetooth/btmtksdio.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index d6700efcfe8c..f9a3444753c2 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -1282,6 +1282,13 @@ static void btmtksdio_cmd_timeout(struct hci_dev *hdev)
 	hci_reset_dev(hdev);
 }
 
+static bool btmtksdio_sdio_inband_wakeup(struct hci_dev *hdev)
+{
+	struct btmtksdio_dev *bdev = hci_get_drvdata(hdev);
+
+	return device_may_wakeup(bdev->dev);
+}
+
 static bool btmtksdio_sdio_wakeup(struct hci_dev *hdev)
 {
 	struct btmtksdio_dev *bdev = hci_get_drvdata(hdev);
@@ -1349,6 +1356,14 @@ static int btmtksdio_probe(struct sdio_func *func,
 	hdev->shutdown = btmtksdio_shutdown;
 	hdev->send     = btmtksdio_send_frame;
 	hdev->wakeup   = btmtksdio_sdio_wakeup;
+	/*
+	 * If SDIO controller supports wake on Bluetooth, sending a wakeon
+	 * command is not necessary.
+	 */
+	if (device_can_wakeup(func->card->host->parent))
+		hdev->wakeup = btmtksdio_sdio_inband_wakeup;
+	else
+		hdev->wakeup = btmtksdio_sdio_wakeup;
 	hdev->set_bdaddr = btmtk_set_bdaddr;
 
 	SET_HCIDEV_DEV(hdev, &func->dev);
-- 
2.25.1