[PATCH v2 3/3] Bluetooth: hci_bcm: Add serdev support

[Stefan Wahren]

Hi Marcel,

> Marcel Holtmann <marcel at holtmann.org> hat am 4. August 2017 um 16:36 geschrieben:
> 
> 
> Hi Loic,
> 
> > 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 at 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]).

Regards
Stefan

[1] - https://github.com/raspberrypi/firmware/blob/master/extra/dt-blob.dts
[2] - http://lists.infradead.org/pipermail/linux-rpi-kernel/2017-March/005801.html