Use Protocol type for USB interface protocol.

usb/config.go

@@ -86,7 +86,7 @@ type InterfaceSetup struct {
 	// IfClass is the USB-IF subclass code, as defined by the USB spec.
 	IfSubClass Class
 	// IfProtocol is USB protocol code, as defined by the USB spe.c
-	IfProtocol uint8
+	IfProtocol Protocol
 	// Endpoints has the list of endpoints available on this interface with
 	// this alternate setting.
 	Endpoints []EndpointInfo

usb/constants.go

@@ -19,6 +19,7 @@ package usb
 import "C"
 import "strconv"
 
+// Class represents a USB-IF class or subclass code.
 type Class uint8
 
 const (
@@ -58,6 +59,14 @@ func (c Class) String() string {
 	return strconv.Itoa(int(c))
 }
 
+// Protocol is the interface class protocol, qualified by the values
+// of interface class and subclass.
+type Protocol uint8
+
+func (p Protocol) String() string {
+	return strconv.Itoa(int(p))
+}
+
 type DescriptorType uint8
 
 const (

usb/descriptor.go

@@ -29,9 +29,9 @@ type Descriptor struct {
 	Product ID // The Product identifier
 
 	// Protocol information
-	Class    Class // The class of this device
-	SubClass Class // The sub-class (within the class) of this device
-	Protocol uint8 // The protocol (within the sub-class) of this device
+	Class    Class    // The class of this device
+	SubClass Class    // The sub-class (within the class) of this device
+	Protocol Protocol // The protocol (within the sub-class) of this device
 
 	// Configuration information
 	Configs []ConfigInfo

usb/libusb.go

@@ -245,7 +245,7 @@ func (libusbImpl) getDeviceDesc(d *libusbDevice) (*Descriptor, error) {
 					Alternate:  uint8(alt.bAlternateSetting),
 					IfClass:    Class(alt.bInterfaceClass),
 					IfSubClass: Class(alt.bInterfaceSubClass),
-					IfProtocol: uint8(alt.bInterfaceProtocol),
+					IfProtocol: Protocol(alt.bInterfaceProtocol),
 				}
 				var ends []C.struct_libusb_endpoint_descriptor
 				*(*reflect.SliceHeader)(unsafe.Pointer(&ends)) = reflect.SliceHeader{
@@ -278,7 +278,7 @@ func (libusbImpl) getDeviceDesc(d *libusbDevice) (*Descriptor, error) {
 		Product:  ID(desc.idProduct),
 		Class:    Class(desc.bDeviceClass),
 		SubClass: Class(desc.bDeviceSubClass),
-		Protocol: uint8(desc.bDeviceProtocol),
+		Protocol: Protocol(desc.bDeviceProtocol),
 		Configs:  cfgs,
 	}, nil
 }