On Thu, Jul 07, 2016 at 03:20:54PM -0700, Stephen Boyd wrote: > The qcom HSIC ULPI phy doesn't have any bits set in the vendor or > product ID registers. This makes it impossible to make a ULPI > driver match against the ID registers. Add support to discover > the ULPI phys via DT/device properties to help alleviate this > problem. In the DT case, 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 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. > > Furthermore, this avoids any problems with reading the ID > registers before the phy is powered up. The ULPI bus supports > native enumeration by reading the vendor ID and product ID > registers at device creation time, but we can't be certain that > those register reads will succeed if the phy is not powered. > > If the ULPI spec had some generic power sequencing for these > registers we could put that into the ULPI bus layer and power up > the device before reading the ID registers. Unfortunately this > doesn't exist and the power sequence is usually device specific. > By having the vendor and product ID properties in ACPI or DT, we > can match up devices with drivers without having to read the > hardware before it's powered up and avoid this problem. > > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > Cc: <devicetree@xxxxxxxxxxxxxxx> > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > Signed-off-by: Stephen Boyd <stephen.boyd@xxxxxxxxxx> > --- > Documentation/devicetree/bindings/usb/ulpi.txt | 35 ++++++++++++ > drivers/usb/common/ulpi.c | 74 +++++++++++++++++++++++++- > 2 files changed, 107 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..c649ca5b0996 > --- /dev/null > +++ b/Documentation/devicetree/bindings/usb/ulpi.txt > @@ -0,0 +1,35 @@ > +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. > + > +PROPERTIES > +---------- > + > +- ulpi-vendor: > + Usage: optional > + Value type: <u16> > + Definition: The USB-IF assigned vendor id for this device > + > +- ulpi-product: > + Usage: required if ulpi-vendor is present > + Value type: <u16> > + Definition: The vendor assigned product id for this device > + > +EXAMPLE > +------- > + > +usb { > + compatible = "vendor,usb-controller"; > + > + ulpi { > + phy { > + compatible = "vendor,phy"; > + ulpi-vendor = /bits/ 16 <0x1d6b>; > + ulpi-product = /bits/ 16 <0x0002>; > + }; > + }; I'm still having concerns about describing both phys and devices. If I have a controller with 2 ports and 2 devices attached, I'd have something like this under the USB controller: ulpi { phy@1 { }; phy@2 { }; }; dev@1 { ... }; dev@2 { ... }; That doesn't seem the best, but I don't have a better suggestion. Maybe the device nodes need to go under the phy nodes? Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html