[PATCH v2] Bluetooth: btusb: Use cmd_timeout to reset Realtek device

[Alex Lu <alex_lu@realsil.com.cn>]

From: Alex Lu <alex_lu@realsil.com.cn>

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>
---
Changes in v2
  - Provide a dedicated btusb_rtl_cmd_timeout in case of Realtek hardware

 drivers/bluetooth/btusb.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 31d3febed187..4ac012df5666 100644
--- a/drivers/bluetooth/btusb.c
+++ b/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
-- 
2.21.0