Bluetooth: mt7921s: Support wake on bluetooth

Enable wake on bluetooth on mt7921s that can be supported since the
firmware with version 20211129211059 was added, and the patch would
not cause any harm even when the old firmware is applied.

The patch was tested by setting up an HID or HOGP profile to connect a
Bluetooth keyboard and mouse, then putting the system to suspend, then
trying to wake up the system by moving the Bluetooth keyboard or mouse,
and then checking if the system can wake up and be brought back to
the normal state.

Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Mark Chen <mark-yw.chen@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btmtk.h

@@ -68,6 +68,14 @@ struct btmtk_tci_sleep {
 	u8 time_compensation;
 } __packed;
 
+struct btmtk_wakeon {
+	u8 mode;
+	u8 gpo;
+	u8 active_high;
+	__le16 enable_delay;
+	__le16 wakeup_delay;
+} __packed;
+
 struct btmtk_hci_wmt_params {
 	u8 op;
 	u8 flag;

drivers/bluetooth/btmtksdio.c

@@ -958,6 +958,32 @@ static int btmtksdio_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 	return 0;
 }
 
+static bool btmtksdio_sdio_wakeup(struct hci_dev *hdev)
+{
+	struct btmtksdio_dev *bdev = hci_get_drvdata(hdev);
+	bool may_wakeup = device_may_wakeup(bdev->dev);
+	const struct btmtk_wakeon bt_awake = {
+		.mode = 0x1,
+		.gpo = 0,
+		.active_high = 0x1,
+		.enable_delay = cpu_to_le16(0xc80),
+		.wakeup_delay = cpu_to_le16(0x20),
+	};
+
+	if (may_wakeup && bdev->data->chipid == 0x7921) {
+		struct sk_buff *skb;
+
+		skb =  __hci_cmd_sync(hdev, 0xfc27, sizeof(bt_awake),
+				      &bt_awake, HCI_CMD_TIMEOUT);
+		if (IS_ERR(skb))
+			may_wakeup = false;
+
+		kfree_skb(skb);
+	}
+
+	return may_wakeup;
+}
+
 static int btmtksdio_probe(struct sdio_func *func,
 			   const struct sdio_device_id *id)
 {
@@ -997,6 +1023,7 @@ static int btmtksdio_probe(struct sdio_func *func,
 	hdev->setup    = btmtksdio_setup;
 	hdev->shutdown = btmtksdio_shutdown;
 	hdev->send     = btmtksdio_send_frame;
+	hdev->wakeup   = btmtksdio_sdio_wakeup;
 	hdev->set_bdaddr = btmtk_set_bdaddr;
 
 	SET_HCIDEV_DEV(hdev, &func->dev);
@@ -1032,7 +1059,11 @@ static int btmtksdio_probe(struct sdio_func *func,
 	 */
 	pm_runtime_put_noidle(bdev->dev);
 
-	return 0;
+	err = device_init_wakeup(bdev->dev, true);
+	if (err)
+		bt_dev_err(hdev, "failed to initialize device wakeup");
+
+	return err;
 }
 
 static void btmtksdio_remove(struct sdio_func *func)