[PATCH AUTOSEL 5.4 133/350] Bluetooth: hci_bcm: Fix RTS handling during startup

[Sasha Levin]

From: Stefan Wahren <wahrenst@xxxxxxx>

[ Upstream commit 3347a80965b38f096b1d6f995c00c9c9e53d4b8b ]

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@xxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/bluetooth/hci_bcm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 7646636f2d183..0f73f6a686cb7 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -445,9 +445,11 @@ 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;
 	}
-- 
2.20.1