USB: add device-tree support for interfaces

Add OF device-tree support for USB interfaces.

USB "interface nodes" are children of USB "device nodes" and are
identified by an interface number and a configuration value:

	&usb1 { /* host controller */
		dev1: device@1 { /* device at port 1 */
			compatible = "usb1234,5678";
			reg = <1>;

			#address-cells = <2>;
			#size-cells = <0>;

			interface@0,2 { /* interface 0 of configuration 2 */
				compatible = "usbif1234,5678.config2.0";
				reg = <0 2>;
			};
		};
	};

The configuration component is not included in the textual
representation of an interface-node unit address for configuration 1:

	&dev1 {
		interface@0 {	/* interface 0 of configuration 1 */
			compatible = "usbif1234,5678.config1.0";
			reg = <0 1>;
		};
	};

When a USB device of class 0 or 9 (hub) has only a single configuration
with a single interface, a special case "combined node" is used instead
of a device node with an interface node:

	&usb1 {
		device@2 {
			compatible = "usb1234,abcd";
			reg = <2>;
		};
	};

Combined nodes are shared by the two device structures representing the
USB device and its interface in the kernel's device model.

Note that, as for device nodes, the compatible strings for interface
nodes are currently not used.

For more details see "Open Firmware Recommended Practice: Universal
Serial Bus Version 1" and the binding documentation.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 5a8ab77bc367..f836bae1e485 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -18,6 +18,7 @@
 #include <linux/usb/cdc.h>
 #include <linux/usb/quirks.h>
 #include <linux/usb/hcd.h>	/* for usbcore internals */
+#include <linux/usb/of.h>
 #include <asm/byteorder.h>
 
 #include "usb.h"
@@ -1583,6 +1584,7 @@ static void usb_release_interface(struct device *dev)
 
 	kref_put(&intfc->ref, usb_release_interface_cache);
 	usb_put_dev(interface_to_usbdev(intf));
+	of_node_put(dev->of_node);
 	kfree(intf);
 }
 
@@ -1868,6 +1870,7 @@ free_interfaces:
 		struct usb_interface_cache *intfc;
 		struct usb_interface *intf;
 		struct usb_host_interface *alt;
+		u8 ifnum;
 
 		cp->interface[i] = intf = new_interfaces[i];
 		intfc = cp->intf_cache[i];
@@ -1886,11 +1889,17 @@ free_interfaces:
 		if (!alt)
 			alt = &intf->altsetting[0];
 
-		intf->intf_assoc =
-			find_iad(dev, cp, alt->desc.bInterfaceNumber);
+		ifnum = alt->desc.bInterfaceNumber;
+		intf->intf_assoc = find_iad(dev, cp, ifnum);
 		intf->cur_altsetting = alt;
 		usb_enable_interface(dev, intf, true);
 		intf->dev.parent = &dev->dev;
+		if (usb_of_has_combined_node(dev)) {
+			device_set_of_node_from_dev(&intf->dev, &dev->dev);
+		} else {
+			intf->dev.of_node = usb_of_get_interface_node(dev,
+					configuration, ifnum);
+		}
 		intf->dev.driver = NULL;
 		intf->dev.bus = &usb_bus_type;
 		intf->dev.type = &usb_if_device_type;
@@ -1905,9 +1914,8 @@ free_interfaces:
 		intf->minor = -1;
 		device_initialize(&intf->dev);
 		pm_runtime_no_callbacks(&intf->dev);
-		dev_set_name(&intf->dev, "%d-%s:%d.%d",
-			dev->bus->busnum, dev->devpath,
-			configuration, alt->desc.bInterfaceNumber);
+		dev_set_name(&intf->dev, "%d-%s:%d.%d", dev->bus->busnum,
+				dev->devpath, configuration, ifnum);
 		usb_get_dev(dev);
 	}
 	kfree(new_interfaces);