Bluetooth: mt7921s: Add .btmtk_get_codec_config_data

add .btmtk_get_codec_config_data to get codec configuration data.

In HFP offload usecase, controllers need to be set codec details before
opening SCO. This callback function is used to fetch vendor specific codec
config data.

This is a preliminary patch to add the WBS support to the MT7921 driver.
Reviewed-by: Mark Chen <markyawenchen@gmail.com>
Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btmtksdio.c

@@ -943,6 +943,55 @@ static int btmtksdio_get_data_path_id(struct hci_dev *hdev, __u8 *data_path_id)
 	return 0;
 }
 
+static int btmtksdio_get_codec_config_data(struct hci_dev *hdev,
+					   __u8 link, struct bt_codec *codec,
+					   __u8 *ven_len, __u8 **ven_data)
+{
+	int err = 0;
+
+	if (!ven_data || !ven_len)
+		return -EINVAL;
+
+	*ven_len = 0;
+	*ven_data = NULL;
+
+	if (link != ESCO_LINK) {
+		bt_dev_err(hdev, "Invalid link type(%u)", link);
+		return -EINVAL;
+	}
+
+	*ven_data = kmalloc(sizeof(__u8), GFP_KERNEL);
+	if (!ven_data) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	/* supports only CVSD and mSBC offload codecs */
+	switch (codec->id) {
+	case 0x02:
+		**ven_data = 0x00;
+		break;
+	case 0x05:
+		**ven_data = 0x01;
+		break;
+	default:
+		err = -EINVAL;
+		bt_dev_err(hdev, "Invalid codec id(%u)", codec->id);
+		goto error;
+	}
+	/* codec and its capabilities are pre-defined to ids
+	 * preset id = 0x00 represents CVSD codec with sampling rate 8K
+	 * preset id = 0x01 represents mSBC codec with sampling rate 16K
+	 */
+	*ven_len = sizeof(__u8);
+	return err;
+
+error:
+	kfree(*ven_data);
+	*ven_data = NULL;
+	return err;
+}
+
 static int btmtksdio_sco_setting(struct hci_dev *hdev)
 {
 	const struct btmtk_sco sco_setting = {
@@ -980,6 +1029,7 @@ static int btmtksdio_sco_setting(struct hci_dev *hdev)
 		return err;
 
 	hdev->get_data_path_id = btmtksdio_get_data_path_id;
+	hdev->get_codec_config_data = btmtksdio_get_codec_config_data;
 
 	return err;
 }