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

[Alex Lu]

From: Alex Lu <alex...@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...@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