usb: typec: Registering real device entries for the muxes

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Mon, Apr 01, 2019 at 12:34:29PM +0200, Greg KH wrote:
> On Mon, Apr 01, 2019 at 01:15:53PM +0300, Heikki Krogerus wrote:
> > Registering real device entries (struct device) for the mode
> > muxes as well as for the orientation switches.
> > 
> > The Type-C mux code was deliberately attempting to avoid
> > creation of separate device entries for the orientation
> > switch and the mode switch (alternate modes) because they
> > are not physical devices. They are functions of a single
> > physical multiplexer/demultiplexer switch device.
> > 
> > Unfortunately because of the dependency we still have on the
> > underlying mux device driver, we had to put in hacks like
> > the one in the commit 3e3b81965cbf ("usb: typec: mux: Take
> > care of driver module reference counting") to make sure the
> > driver does not disappear from underneath us. Even with
> > those hacks we were still left with a potential NUll pointer
> > dereference scenario, so just creating the device entries,
> > and letting the core take care of the dependencies. No more
> > hacks needed.
> > 
> > Fixes: 3e3b81965cbf ("usb: typec: mux: Take care of driver module reference counting")
> > Cc: v4.19.x <stable@vger.kernel.org> # v4.19.x+
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> 
> This looks good to me, nice work!
> 
> But, it would be nice if someone who has this hardware can test it to
> verify it does actually work :)

This alone does not work on Intel Cherrytrail platforms. I need to make
the Intel Cherrytrail MFD driver (intel_cht_int33fe.c) to use the new
device names that we now have for the muxes. Sorry for the mistake.

I'll resend this and include the needed modifications to
intel_cht_int33fe.c. Hans should be able to test this once I do that. I
hope he has time.


thanks,