Re: Driver for something that's neither a device nor an interface driver?

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Sep 27, 2019 at 07:44:08PM +0200, Bastien Nocera wrote:
> On Fri, 2019-09-27 at 19:38 +0200, Greg KH wrote:
> > What does the usb descriptors for the device look like?  Is it only
> > the
> > "default" control endpoint and no interfaces?  What does the output
> > of
> > 'usbdevices' show for the device?
> 
> The device in question can be an iPhone, an iPod Classic/Nano, or an
> iPad, amongst others, and they usually have useful interfaces, such as
> mass storage for the older ones, or ethernet, PTP, etc.

Ah.  Then why do you have to do this from a kernel driver?  Why can't
you do this from userspace?

> > Normally you just bind to the "default" interface for the device, and
> > all is good, there should be a few other drivers in the tree that do
> > this, but I can't think of one off the top of my head at the moment.
> 
> All the interfaces (in the different configurations) are used for
> something in the case of the iPhone 6S I'm trying to use.
> 
> I've attached the output of "lsusb -v" for the device below.

What about interface "9", the "Apple USB Multiplexor"?  What driver
binds to that thing?  It's a vendor-specific protocol, so there
shouldn't be any class driver assigned to it, unlike most of the other
interfaces.

thanks,

greg k-h