[PATCH v2 0/3] USB: add generic onboard USB HUB driver

Peter Chen hzpeterchen at gmail.com
Tue Jan 5 19:20:27 PST 2016

On Tue, Jan 05, 2016 at 08:36:31AM -0600, Rob Herring wrote:
> > 2. There are MFD USB devices, which includes several interfaces under
> > USB device,
> > like i2c, gpios, etc. Due to lack of device tree support, USB
> > class/device driver doesn't know
> > which kinds of interfaces are needed for this board.
> Are you talking about a device hard wired on the same board or
> something like GPIOs on FTDI chip which could be hot-plugged in any
> host (including non-DT based)?

I talked about the case that the device hard wired on the board.
Hot-plug device's bus topology is unknown, we can't describe it
statically at dts.

> For the hotplug case, we will need a way to associate a DT overlay
> with the USB device and there may not even be a base DT to map the
> overlay into. In this case, the USB device's driver will need to load
> the overlay and trigger enumerating the child devices. Anyway, this is
> a separate issue from your problem.

Since both you and Alan agree with my problem should be fixed at
bootloader, I give the kernel solution up. 

The another thing I open to discuss is how to let USB devices know its
device node, the user reported issue that they can't handle interfaces
below in USB device since that.


Best Regards,
Peter Chen

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