Bluetooth: btusb: Use cmd_timeout to reset Realtek device

Realtek Bluetooth controller provides a BT_DIS reset pin for hardware
reset of it. The cmd_timeout is helpful on Realtek bluetooth controller
where the firmware gets stuck.
Signed-off-by: Alex Lu <alex_lu@realsil.com.cn>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -524,6 +524,36 @@ static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
 	gpiod_set_value_cansleep(reset_gpio, 0);
 }
 
+static void btusb_rtl_cmd_timeout(struct hci_dev *hdev)
+{
+	struct btusb_data *data = hci_get_drvdata(hdev);
+	struct gpio_desc *reset_gpio = data->reset_gpio;
+
+	if (++data->cmd_timeout_cnt < 5)
+		return;
+
+	if (!reset_gpio) {
+		bt_dev_err(hdev, "No gpio to reset Realtek device, ignoring");
+		return;
+	}
+
+	/* Toggle the hard reset line. The Realtek device is going to
+	 * yank itself off the USB and then replug. The cleanup is handled
+	 * correctly on the way out (standard USB disconnect), and the new
+	 * device is detected cleanly and bound to the driver again like
+	 * it should be.
+	 */
+	if (test_and_set_bit(BTUSB_HW_RESET_ACTIVE, &data->flags)) {
+		bt_dev_err(hdev, "last reset failed? Not resetting again");
+		return;
+	}
+
+	bt_dev_err(hdev, "Reset Realtek device via gpio");
+	gpiod_set_value_cansleep(reset_gpio, 0);
+	msleep(200);
+	gpiod_set_value_cansleep(reset_gpio, 1);
+}
+
 static inline void btusb_free_frags(struct btusb_data *data)
 {
 	unsigned long flags;
@@ -3783,6 +3813,7 @@ static int btusb_probe(struct usb_interface *intf,
 	if (id->driver_info & BTUSB_REALTEK) {
 		hdev->setup = btrtl_setup_realtek;
 		hdev->shutdown = btrtl_shutdown_realtek;
+		hdev->cmd_timeout = btusb_rtl_cmd_timeout;
 
 		/* Realtek devices lose their updated firmware over global
 		 * suspend that means host doesn't send SET_FEATURE