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

[Stefan Wahren]

> Marcel Holtmann <marcel at 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 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]).
> >> 
> >> 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
>