Add support for HID Keyboard LEDs

src/machine/usb/hid/hid.go

@@ -36,6 +36,12 @@ func SetHandler(d hidDevicer) {
 	if size == 0 {
 		machine.ConfigureUSBEndpoint(descriptor.CDCHID,
 			[]usb.EndpointConfig{
+				{
+					Index:     usb.HID_ENDPOINT_OUT,
+					IsIn:      false,
+					Type:      usb.ENDPOINT_TYPE_INTERRUPT,
+					RxHandler: rxHandler,
+				},
 				{
 					Index:     usb.HID_ENDPOINT_IN,
 					IsIn:      true,

src/machine/usb/hid/keyboard/keyboard.go

@@ -92,6 +92,9 @@ func (kb *keyboard) TxHandler() bool {
 }
 
 func (kb *keyboard) RxHandler(b []byte) bool {
+	if len(b) >= 2 && b[0] == 2 /* ReportID */ {
+		kb.led = b[1]
+	}
 	return false
 }
 
@@ -106,6 +109,18 @@ func (kb *keyboard) tx(b []byte) {
 	}
 }
 
+func (kb *keyboard) NumLockLed() bool {
+	return kb.led&1 != 0
+}
+
+func (kb *keyboard) CapsLockLed() bool {
+	return kb.led&2 != 0
+}
+
+func (kb *keyboard) ScrollLockLed() bool {
+	return kb.led&4 != 0
+}
+
 func (kb *keyboard) ready() bool {
 	return true
 }