[PATCH 02/21] usb: ulpi: Support device discovery via DT

[stephen.boyd@linaro.org (Stephen Boyd)]

Quoting Rob Herring (2016-06-28 13:56:42)
> On Sun, Jun 26, 2016 at 12:28:19AM -0700, Stephen Boyd wrote:
> > The qcom HSIC ulpi phy doesn't have any bits set in the vendor or
> > product id ulpi registers. This makes it impossible to make a
> > ulpi driver match against the id registers. Add support to
> > discover the ulpi phys via DT to help alleviate this problem.
> > We'll look for a ulpi bus node underneath the device registering
> > the ulpi viewport (or the parent of that device to support
> > chipidea's device layout) and then match up the phy node
> > underneath that with the ulpi device that's created.
> > 
> > The side benefit of this is that we can use standard DT
> > properties in the phy node like clks, regulators, gpios, etc.
> > because we don't have firmware like ACPI to turn these things on
> > for us. And we can use the DT phy binding to point our phy
> > consumer to the phy provider.
> > 
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > Cc: <devicetree@vger.kernel.org>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> > ---
> >  Documentation/devicetree/bindings/usb/ulpi.txt | 20 +++++++++
> >  drivers/usb/common/ulpi.c                      | 56 +++++++++++++++++++++++++-
> >  2 files changed, 74 insertions(+), 2 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/usb/ulpi.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/usb/ulpi.txt b/Documentation/devicetree/bindings/usb/ulpi.txt
> > new file mode 100644
> > index 000000000000..ca179dc4bd50
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/usb/ulpi.txt
> > @@ -0,0 +1,20 @@
> > +ULPI bus binding
> > +----------------
> > +
> > +Phys that are behind a ULPI connection can be described with the following
> > +binding. The host controller shall have a "ulpi" named node as a child, and
> > +that node shall have one enabled node underneath it representing the ulpi
> > +device on the bus.
> 
> This needs to co-exist with the USB bus binding which has the controller 
> ports for the child nodes. Maybe use the phy binding?

Which binding is that? bindings/usb/usb-device.txt? This ulpi binding is
to describe phys that are accessed through the ulpi "viewport" in the
usb controller. So controller ports don't come into the picture here.