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Date: Fri, 4 Aug 2017 21:50:03 +0200 (CEST)
From: Stefan Wahren <stefan.wahren@i2se.com>
To: Marcel Holtmann <marcel@holtmann.org>
Cc: rjui@broadcom.com, sbranden@broadcom.com,
	Rob Herring <robh+dt@kernel.org>,
	Loic Poulain <loic.poulain@gmail.com>, f.fainelli@gmail.com,
	linux-rpi-kernel@lists.infradead.org,
	"open list:BLUETOOTH DRIVERS" <linux-bluetooth@vger.kernel.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	devicetree <devicetree@vger.kernel.org>
Message-ID: <653244764.121525.1501876203800@email.1und1.de>
In-Reply-To: <BB04C3A8-2BFC-44B7-AA84-E0B81F560B8C@holtmann.org>
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Subject: Re: [PATCH v2 3/3] Bluetooth: hci_bcm: Add serdev support
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List-ID: <linux-bluetooth.vger.kernel.org>


> Marcel Holtmann <marcel@holtmann.org> hat am 4. August 2017 um 21:45 geschrieben:
> 
> 
> Hi Stefan,
> 
> >>>>> Add basic support for Broadcom serial slave devices.
> >>>>> Probe the serial device, retrieve its maximum speed and
> >>>>> register a new hci uart device.
> >>>>> 
> >>>>> Tested/compatible with bcm43438 (RPi3).
> >>>>> 
> >>>>> Signed-off-by: Loic Poulain <loic.poulain@gmail.com>
> >>>>> ...
> >>>>> 
> >>>>> +static int bcm_serdev_probe(struct serdev_device *serdev)
> >>>>> +{
> >>>>> +	struct bcm_bt_device *bcmdev;
> >>>>> +	u32 speed;
> >>>>> +	int err;
> >>>>> +
> >>>>> +	bcmdev = devm_kzalloc(&serdev->dev, sizeof(*bcmdev), GFP_KERNEL);
> >>>>> +	if (!bcmdev)
> >>>>> +		return -ENOMEM;
> >>>>> +
> >>>>> +	bcmdev->hu.serdev = serdev;
> >>>>> +	serdev_device_set_drvdata(serdev, bcmdev);
> >>>>> +
> >>>>> +	err = of_property_read_u32(serdev->dev.of_node, "max-speed", &speed);
> >>>>> +	if (!err)
> >>>>> +		bcmdev->hu.oper_speed = speed;
> >>>>> +
> >>>>> +	return hci_uart_register_device(&bcmdev->hu, &bcm_proto);
> >>>>> +}
> >>>> 
> >>>> We do not need any GPIO for reset lines or anything else for the rPI3?
> >>>> 
> >>> 
> >>> unfortunately we don't have full schematics for RPI3, but according to firmware dt-blob.dts [1] there is a GPIO called BT_ON. This GPIO is controlled by the GPIO expander on the RPI3 board. The necessary driver for this expander is still out of tree (last mainlining attempt [2]).
> >> 
> >> so who handles this GPIO then right now (or any other GPIO for that matter)? I have seen Bluetooth being enabled and operational, but I really want to get this working in a plain upstream Fedora and without using hciattach or btattach.
> > 
> > The GPU firmware enables the GPIO and keeps this state. The mentioned expander driver should provide the ARM core (Linux) the necessary control.
> 
> what is the default behavior after reboot. BT_ON enabled or not?

AFAIK: enabled

> 
> Regards
> 
> Marcel
>