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Subject: Re: [PATCH V4 01/10] bluetooth: hci_bcm: Fix RTS handling during
 startup
To:     Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Ray Jui <rjui@broadcom.com>,
        Scott Branden <sbranden@broadcom.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Eric Anholt <eric@anholt.net>, devicetree@vger.kernel.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        linux-bluetooth@vger.kernel.org,
        bcm-kernel-feedback-list@broadcom.com,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org
References: <1570375708-26965-1-git-send-email-wahrenst@gmx.net>
 <1570375708-26965-2-git-send-email-wahrenst@gmx.net>
From:   Stefan Wahren <wahrenst@gmx.net>
Message-ID: <61789264-a4c2-ac85-9d74-d186213ec70a@gmx.net>
Date:   Sun, 20 Oct 2019 23:17:28 +0200
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Hi Marcel,
hi Johan,

Am 06.10.19 um 17:28 schrieb Stefan Wahren:
> 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>
> ---
>  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 7646636..0f73f6a 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;
>  	}
> --
> 2.7.4

would be nice to get some feedback about this.

Regards
Stefan