Modify EndpointInfo to provide meaningful data rather than raw USB

descriptor values. E.g. for the user, the distinction between
MaxIsoPkt and MaxPktSize is irrelevant, only the calculated max packet
size matters.

usb/config.go

@@ -17,37 +17,31 @@ package usb
 
 import (
 	"fmt"
+	"strings"
+	"time"
 )
 
 type EndpointInfo struct {
-	Address       uint8
-	Attributes    uint8
-	MaxPacketSize uint16
-	MaxIsoPacket  uint32
-	PollInterval  uint8
-	RefreshRate   uint8
-	SynchAddress  uint8
-}
-
-func (e EndpointInfo) Number() int {
-	return int(e.Address & EndpointNumMask)
-}
-
-func (e EndpointInfo) TransferType() TransferType {
-	return TransferType(e.Attributes & TransferTypeMask)
-}
-
-func (e EndpointInfo) Direction() EndpointDirection {
-	return EndpointDirection(e.Address & EndpointDirectionMask)
+	Number        uint8
+	Direction     EndpointDirection
+	MaxPacketSize uint32
+	TransferType  TransferType
+	PollInterval  time.Duration
+	IsoSyncType   IsoSyncType
+	UsageType     UsageType
 }
 
 func (e EndpointInfo) String() string {
-	return fmt.Sprintf("Endpoint #%d %-3s %s - %s %s [%d %d]",
-		e.Number(), e.Direction(), e.TransferType(),
-		IsoSyncType(e.Attributes)&IsoSyncTypeMask,
-		IsoUsageType(e.Attributes)&IsoUsageTypeMask,
-		e.MaxPacketSize, e.MaxIsoPacket,
-	)
+	ret := make([]string, 0, 3)
+	ret = append(ret, fmt.Sprintf("Endpoint #%d %s (address 0x%02x) %s", e.Number, e.Direction, uint8(e.Number)|uint8(e.Direction), e.TransferType))
+	switch e.TransferType {
+	case TransferTypeIsochronous:
+		ret = append(ret, fmt.Sprintf("- %s %s", e.IsoSyncType, e.UsageType))
+	case TransferTypeInterrupt:
+		ret = append(ret, fmt.Sprintf("- %s", e.UsageType))
+	}
+	ret = append(ret, fmt.Sprintf("[%d bytes]", e.MaxPacketSize))
+	return strings.Join(ret, " ")
 }
 
 type InterfaceInfo struct {