Bluetooth: hci_bcm: Fix RTS handling during startup

commit 3347a80965b38f096b1d6f995c00c9c9e53d4b8b upstream.

The RPi 4 uses the hardware handshake lines for CYW43455, but the chip
doesn't react to HCI requests during DT probe. The reason is the inproper
handling of the RTS line during startup. According to the startup
signaling sequence in the CYW43455 datasheet, the hosts RTS line must
be driven after BT_REG_ON and BT_HOST_WAKE.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 94ed734..f204ae6 100644 (file)
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -448,9 +448,11 @@ static int bcm_open(struct hci_uart *hu)
 
 out:
        if (bcm->dev) {
+               hci_uart_set_flow_control(hu, true);
                hu->init_speed = bcm->dev->init_speed;
                hu->oper_speed = bcm->dev->oper_speed;
                err = bcm_gpio_set_power(bcm->dev, true);
+               hci_uart_set_flow_control(hu, false);
                if (err)
                        goto err_unset_hu;
        }