Quoting Rob Herring (2016-06-30 17:59:15)

On Tue, Jun 28, 2016 at 03:09:21PM -0700, Stephen Boyd wrote:

quoted

Quoting Rob Herring (2016-06-28 13:56:42)

quoted

On Sun, Jun 26, 2016 at 12:28:19AM -0700, Stephen Boyd wrote:

quoted

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: <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Stephen Boyd <redacted>
---
 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? 

Yes.

quoted

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.

You just need to confirm that there's no collision with child nodes like 
it assumes all children are ports.

Ok. It will work with the way usb_of_get_child_node() is written but it
doesn't seem like great DT design if we want to support usb-device
binding and ulpi bus at the same time, because we treat the controller
node as the usb bus.

&usb1 { 
        status = "okay";

        #address-cells = <1>;
        #size-cells = <0>;
	phys = <&uphy>;
	phy-names = "usb-phy";

        hub: genesys at 1 {
                compatible = "usb5e3,608";
                reg = <1>;
        };

	ulpi {
		uphy: phy {
			compatible = "phy";
		};
	};
}

In this example, the ulpi bus doesn't have a reg property because it
isn't a port.

Perhaps we can move the usb ports to a subnode like 'usb' so that we can
have two logical busses underneath the controller, one for usb and one
for ulpi? We would need backwards compatibility code that looks for a
ports directly underneath the usb controller node when #address-cells
and #size-cells are present, otherwise it should fall down into a
'usb' subnode.