Bluetooth: hci_h5: Add power reset via gpio in h5_btrtl_open

Add power reset for bluetooth via enable-gpios in h5_btrtl_open function.

While testing the RTL8822CS SDIO WiFi/BT adapter, it was found that in
some cases the kernel could not initialize BT firmware. However,
manually resetting the adapter via gpio (off/on sequence) allows it to
start correctly.
Apparently, when the system starts, the adapter is in an undefined state
(including unknown gpio state after starting uboot). A forced reset helps
to initialize the adapter in most cases. It has been found experimentally
that 100 ms is sufficient for a reset.

Signed-off-by: Vyacheslav Bocharov <adeep@lexina.in>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index 34286ffe0568fd7033d32f7be86cbb2c70d6032b..fdf504b0d265d78987a30143da21f33fab1c9482 100644 (file)
--- a/drivers/bluetooth/hci_h5.c
+++ b/drivers/bluetooth/hci_h5.c
@@ -966,6 +966,11 @@ static void h5_btrtl_open(struct h5 *h5)
                pm_runtime_enable(&h5->hu->serdev->dev);
        }
 
+       /* The controller needs reset to startup */
+       gpiod_set_value_cansleep(h5->enable_gpio, 0);
+       gpiod_set_value_cansleep(h5->device_wake_gpio, 0);
+       msleep(100);
+
        /* The controller needs up to 500ms to wakeup */
        gpiod_set_value_cansleep(h5->enable_gpio, 1);
        gpiod_set_value_cansleep(h5->device_wake_gpio, 1);