Add USB HID joystick support (#3366)

machine/usb: add USB HID joystick support

10 files changed, 482 insertions, 14 deletions

diff --git a/src/examples/hid-joystick/main.go b/src/examples/hid-joystick/main.go
new file mode 100644
index 000000000..1271d997d
--- /dev/null
+++ b/src/examples/hid-joystick/main.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"log"
+	"machine/usb/joystick"
+	"math"
+	"time"
+)
+
+var js = joystick.Port()
+
+func main() {
+	log.SetFlags(log.Lmicroseconds)
+	ticker := time.NewTicker(10 * time.Millisecond)
+	cnt := 0
+	const f = 3.0
+	for range ticker.C {
+		t := float64(cnt) * 0.01
+		x := 32767 * math.Sin(2*math.Pi*f*t)
+		button := cnt%100 > 50
+		js.SetButton(2, button)
+		js.SetButton(3, !button)
+		js.SetAxis(0, int(x))
+		js.SendState()
+		cnt++
+	}
+}
diff --git a/src/machine/machine_rp2040_usb.go b/src/machine/machine_rp2040_usb.go
index 372080eec..cb3bb789d 100644
--- a/src/machine/machine_rp2040_usb.go
+++ b/src/machine/machine_rp2040_usb.go
@@ -151,7 +151,10 @@ func initEndpoint(ep, config uint32) {
 		usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
 
 	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointOut:
-		// TODO: not really anything, seems like...
+		val |= usbEpControlEndpointTypeInterrupt
+		usbDPSRAM.EPxControl[ep].Out.Set(val)
+		usbDPSRAM.EPxBufferControl[ep].Out.Set(USBBufferLen & usbBuf0CtrlLenMask)
+		usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
 
 	case usb.ENDPOINT_TYPE_BULK | usb.EndpointIn:
 		val |= usbEpControlEndpointTypeBulk
diff --git a/src/machine/usb.go b/src/machine/usb.go
index f49ee119e..7ed4ef35e 100644
--- a/src/machine/usb.go
+++ b/src/machine/usb.go
@@ -3,6 +3,8 @@
 package machine
 
 import (
+	"bytes"
+	"encoding/binary"
 	"errors"
 	"machine/usb"
 )
@@ -89,8 +91,9 @@ var (
 		usb.CDC_ENDPOINT_OUT:  (usb.ENDPOINT_TYPE_BULK | usb.EndpointOut),
 		usb.CDC_ENDPOINT_IN:   (usb.ENDPOINT_TYPE_BULK | usb.EndpointIn),
 		usb.HID_ENDPOINT_IN:   (usb.ENDPOINT_TYPE_DISABLE), // Interrupt In
-		usb.MIDI_ENDPOINT_OUT: (usb.ENDPOINT_TYPE_DISABLE), // Bulk Out
+		usb.HID_ENDPOINT_OUT:  (usb.ENDPOINT_TYPE_DISABLE), // Interrupt Out
 		usb.MIDI_ENDPOINT_IN:  (usb.ENDPOINT_TYPE_DISABLE), // Bulk In
+		usb.MIDI_ENDPOINT_OUT: (usb.ENDPOINT_TYPE_DISABLE), // Bulk Out
 	}
 )
 
@@ -108,6 +111,8 @@ func sendDescriptor(setup usb.Setup) {
 			usbDescriptor = usb.DescriptorCDCHID
 		case (usbDescriptorConfig & usb.DescriptorConfigMIDI) > 0:
 			usbDescriptor = usb.DescriptorCDCMIDI
+		case (usbDescriptorConfig & usb.DescriptorConfigJoystick) > 0:
+			usbDescriptor = usb.DescriptorCDCJoystick
 		default:
 			usbDescriptor = usb.DescriptorCDC
 		}
@@ -260,3 +265,18 @@ func EnableMIDI(txHandler func(), rxHandler func([]byte), setupHandler func(usb.
 	usbRxHandler[usb.MIDI_ENDPOINT_OUT] = rxHandler
 	usbTxHandler[usb.MIDI_ENDPOINT_IN] = txHandler
 }
+
+// EnableJoystick enables HID. This function must be executed from the init().
+func EnableJoystick(txHandler func(), rxHandler func([]byte), setupHandler func(usb.Setup) bool, hidDesc []byte) {
+	idx := bytes.Index(usb.DescriptorCDCJoystick.Configuration, []byte{
+		0x09, 0x21, 0x11, 0x01, 0x00, 0x01, 0x22,
+	})
+	binary.LittleEndian.PutUint16(usb.DescriptorCDCJoystick.Configuration[idx+7:idx+9], uint16(len(hidDesc)))
+	usb.DescriptorCDCJoystick.HID[2] = hidDesc
+	usbDescriptorConfig |= usb.DescriptorConfigJoystick
+	endPoints[usb.HID_ENDPOINT_OUT] = (usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointOut)
+	usbRxHandler[usb.HID_ENDPOINT_OUT] = rxHandler
+	endPoints[usb.HID_ENDPOINT_IN] = (usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointIn)
+	usbTxHandler[usb.HID_ENDPOINT_IN] = txHandler
+	usbSetupHandler[usb.HID_INTERFACE] = setupHandler // 0x03 (HID - Human Interface Device)
+}
diff --git a/src/machine/usb/descriptor.go b/src/machine/usb/descriptor.go
index 17bf07709..3acb2e9a7 100644
--- a/src/machine/usb/descriptor.go
+++ b/src/machine/usb/descriptor.go
@@ -109,9 +109,58 @@ var DescriptorCDCMIDI = Descriptor{
 		0x06, 0x24, 0x02, 0x02, 0x02, 0x00,
 		0x09, 0x24, 0x03, 0x01, 0x03, 0x01, 0x02, 0x01, 0x00,
 		0x09, 0x24, 0x03, 0x02, 0x04, 0x01, 0x01, 0x01, 0x00,
-		0x09, 0x05, 0x05, 0x02, 0x40, 0x00, 0x00, 0x00, 0x00,
+		0x09, 0x05, 0x07, 0x02, 0x40, 0x00, 0x00, 0x00, 0x00,
 		0x05, 0x25, 0x01, 0x01, 0x01,
 		0x09, 0x05, 0x86, 0x02, 0x40, 0x00, 0x00, 0x00, 0x00,
 		0x05, 0x25, 0x01, 0x01, 0x03,
 	},
 }
+
+var DescriptorCDCJoystick = Descriptor{
+	Device: []byte{
+		0x12, 0x01, 0x00, 0x02, 0xef, 0x02, 0x01, 0x40,
+		0x41, 0x23, 0x36, 0x80, 0x00, 0x01, 0x01, 0x02,
+		0x03, 0x01,
+	},
+	Configuration: []byte{
+		// Configuration Descriptor Header
+		0x09, 0x02,
+		0x6b, 0x00, // Total Length: 0x006b(107)
+		0x03, 0x01, 0x00, 0xa0, 0xfa,
+		// InterfaceAssociation Descriptoy
+		0x08, 0x0b, 0x00, 0x02, 0x02, 0x02, 0x00, 0x00,
+		// InterfaceSescriptor(CDC-Ctrl)
+		0x09, 0x04, 0x00, 0x00, 0x01, 0x02, 0x02, 0x00, 0x00,
+		// Communication Descriptor
+		0x05, 0x24, 0x00, 0x10, 0x01,
+		// Communication Descriptor
+		0x05, 0x24, 0x01, 0x01, 0x01,
+		// Communication Descriptor
+		0x04, 0x24, 0x02, 0x06,
+		// Communication Descriptor
+		0x05, 0x24, 0x06, 0x00, 0x01,
+		// ENDPOINT Descriptor
+		0x07, 0x05, 0x81, 0x03, 0x10, 0x00, 0x40,
+		// InterfaceSescriptor(CDC-Data)
+		0x09, 0x04, 0x01, 0x00, 0x02, 0x0a, 0x00, 0x00, 0x00,
+		// ENDPOINT Descriptor
+		0x07, 0x05, 0x02, 0x02, 0x40, 0x00, 0x00,
+		// ENDPOINT Descriptor
+		0x07, 0x05, 0x83, 0x02, 0x40, 0x00, 0x00,
+		// InterfaceSescriptor(HID)
+		0x09, 0x04, 0x02, 0x00, 0x02, 0x03, 0x00, 0x00, 0x00,
+		// HID Descriptor
+		0x09,       // bLength: 9
+		0x21,       // bDescriptorType: 0x21(HID)
+		0x11, 0x01, // bcdHID: 0x111
+		0x00,       // bCountryCode: Not Supported
+		0x01,       // bNumDescriptors: 1
+		0x22,       // Type: HID Report
+		0x00, 0x00, // Length
+		// ENDPOINT Descriptor
+		0x07, 0x05, 0x84, 0x03, 0x40, 0x00, 0x01,
+		// ENDPOINT Descriptor
+		0x07, 0x05, 0x05, 0x03, 0x40, 0x00, 0x01,
+	},
+	HID: map[uint16][]byte{},
+}
diff --git a/src/machine/usb/hid/hid.go b/src/machine/usb/hid/hid.go
index 4f4072419..d0ad366f0 100644
--- a/src/machine/usb/hid/hid.go
+++ b/src/machine/usb/hid/hid.go
@@ -14,10 +14,11 @@ var (
 )
 
 const (
-	hidEndpoint = 4
+	hidEndpoint = usb.HID_ENDPOINT_IN
 
-	usb_SET_REPORT_TYPE = 33
-	usb_SET_IDLE        = 10
+	REPORT_TYPE_INPUT   = 1
+	REPORT_TYPE_OUTPUT  = 2
+	REPORT_TYPE_FEATURE = 3
 )
 
 type hidDevicer interface {
@@ -51,7 +52,7 @@ func handler() {
 
 func setupHandler(setup usb.Setup) bool {
 	ok := false
-	if setup.BmRequestType == usb_SET_REPORT_TYPE && setup.BRequest == usb_SET_IDLE {
+	if setup.BmRequestType == usb.SET_REPORT_TYPE && setup.BRequest == usb.SET_IDLE {
 		machine.SendZlp()
 		ok = true
 	}
diff --git a/src/machine/usb/joystick/buffer.go b/src/machine/usb/joystick/buffer.go
new file mode 100644
index 000000000..3610b52e3
--- /dev/null
+++ b/src/machine/usb/joystick/buffer.go
@@ -0,0 +1,52 @@
+package joystick
+
+import (
+	"runtime/volatile"
+)
+
+const bufferSize = 32
+
+// RingBuffer is ring buffer implementation inspired by post at
+// https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php
+type RingBuffer struct {
+	rxbuffer [bufferSize][16]byte
+	head     volatile.Register8
+	tail     volatile.Register8
+}
+
+// NewRingBuffer returns a new ring buffer.
+func NewRingBuffer() *RingBuffer {
+	return &RingBuffer{}
+}
+
+// Used returns how many bytes in buffer have been used.
+func (rb *RingBuffer) Used() uint8 {
+	return uint8(rb.head.Get() - rb.tail.Get())
+}
+
+// Put stores a byte in the buffer. If the buffer is already
+// full, the method will return false.
+func (rb *RingBuffer) Put(val []byte) bool {
+	if rb.Used() != bufferSize {
+		rb.head.Set(rb.head.Get() + 1)
+		copy(rb.rxbuffer[rb.head.Get()%bufferSize][:], val)
+		return true
+	}
+	return false
+}
+
+// Get returns a byte from the buffer. If the buffer is empty,
+// the method will return a false as the second value.
+func (rb *RingBuffer) Get() ([]byte, bool) {
+	if rb.Used() != 0 {
+		rb.tail.Set(rb.tail.Get() + 1)
+		return rb.rxbuffer[rb.tail.Get()%bufferSize][:], true
+	}
+	return nil, false
+}
+
+// Clear resets the head and tail pointer to zero.
+func (rb *RingBuffer) Clear() {
+	rb.head.Set(0)
+	rb.tail.Set(0)
+}
diff --git a/src/machine/usb/joystick/joystick.go b/src/machine/usb/joystick/joystick.go
new file mode 100644
index 000000000..9c12997b9
--- /dev/null
+++ b/src/machine/usb/joystick/joystick.go
@@ -0,0 +1,95 @@
+package joystick
+
+import (
+	"machine"
+	"machine/usb"
+)
+
+const (
+	jsEndpointOut = usb.HID_ENDPOINT_OUT // from PC
+	jsEndpointIn  = usb.HID_ENDPOINT_IN  // to PC
+)
+
+var js *Joystick
+
+type Joystick struct {
+	State
+	buf           *RingBuffer
+	waitTxc       bool
+	rxHandlerFunc func(b []byte)
+	setupFunc     func(setup usb.Setup) bool
+}
+
+func Enable(def Definitions, rxHandlerFunc func(b []byte),
+	setupFunc func(setup usb.Setup) bool, hidDesc []byte) *Joystick {
+	m := &Joystick{
+		buf:   NewRingBuffer(),
+		State: def.NewState(),
+	}
+	m.State = def.NewState()
+	if setupFunc == nil {
+		setupFunc = m.setupFunc
+	}
+	machine.EnableJoystick(m.handler, rxHandlerFunc, setupFunc, hidDesc)
+	js = m
+	return m
+}
+
+// Port returns the USB Joystick port.
+func Port() *Joystick {
+	if js == nil {
+		def := DefaultDefinitions()
+		js = &Joystick{
+			State: def.NewState(),
+			buf:   NewRingBuffer(),
+		}
+		machine.EnableJoystick(js.handler, nil, js.setupFunc, def.Descriptor())
+	}
+	return js
+}
+
+func (m *Joystick) sendUSBPacket(b []byte) {
+	machine.SendUSBInPacket(jsEndpointIn, b)
+}
+
+// from InterruptIn
+func (m *Joystick) handler() {
+	m.waitTxc = false
+	if b, ok := m.buf.Get(); ok {
+		m.waitTxc = true
+		m.sendUSBPacket(b)
+	}
+}
+
+func (m *Joystick) setup(setup usb.Setup) bool {
+	if setup.BmRequestType == usb.SET_REPORT_TYPE && setup.BRequest == usb.SET_IDLE {
+		machine.SendZlp()
+		return true
+	}
+	return false
+}
+
+func (m *Joystick) rxHandler(b []byte) {
+	if m.rxHandlerFunc != nil {
+		m.rxHandlerFunc(b)
+	}
+}
+
+func (m *Joystick) tx(b []byte) {
+	if m.waitTxc {
+		m.buf.Put(b)
+	} else {
+		m.waitTxc = true
+		m.sendUSBPacket(b)
+	}
+}
+
+// to InterruptOut
+func (m *Joystick) SendReport(reportID byte, b []byte) {
+	m.tx(append([]byte{reportID}, b...))
+}
+
+func (m *Joystick) SendState() {
+	b, _ := m.State.MarshalBinary()
+	m.tx(b)
+}
diff --git a/src/machine/usb/joystick/state.go b/src/machine/usb/joystick/state.go
new file mode 100644
index 000000000..51b7e6c40
--- /dev/null
+++ b/src/machine/usb/joystick/state.go
@@ -0,0 +1,213 @@
+package joystick
+
+import "encoding/binary"
+
+type HatDirection uint8
+
+const (
+	HatUp HatDirection = iota
+	HatRightUp
+	HatRight
+	HatRightDown
+	HatDown
+	HatLeftDown
+	HatLeft
+	HatLeftUp
+	HatCenter
+)
+
+type Constraint struct {
+	MinIn  int
+	MaxIn  int
+	MinOut int16
+	MaxOut int16
+}
+
+type AxisValue struct {
+	constraint Constraint
+	Value      int
+}
+
+func fit(x, in_min, in_max int, out_min, out_max int16) int16 {
+	return int16((x-in_min)*(int(out_max)-int(out_min))/(in_max-in_min) + int(out_min))
+}
+
+func fitf(x, in_min, in_max, out_min, out_max float32) float32 {
+	return x - in_min*(out_max-out_min)/(in_max-in_min) + out_min
+}
+
+func limit(v, max int) int {
+	if v > max {
+		v = max
+	} else if v < -max {
+		v = -max
+	}
+	return v
+}
+
+type Definitions struct {
+	ReportID     byte
+	ButtonCnt    int
+	HatSwitchCnt int
+	AxisDefs     []Constraint
+	descriptor   []byte
+}
+
+func (c Definitions) Descriptor() []byte {
+	if len(c.descriptor) > 0 {
+		return c.descriptor
+	}
+	// TODO: build hid descriptor
+	return nil
+}
+
+func (c Definitions) NewState() State {
+	bufSize := 1
+	axises := make([]*AxisValue, 0, len(c.AxisDefs))
+	for _, v := range c.AxisDefs {
+
+		axises = append(axises, &AxisValue{
+			constraint: v,
+			Value:      0,
+		})
+	}
+	btnSize := (c.ButtonCnt + 7) / 8
+	bufSize += btnSize
+	if c.HatSwitchCnt > 0 {
+		bufSize++
+	}
+	bufSize += len(axises) * 2
+	initBuf := make([]byte, bufSize)
+	initBuf[0] = c.ReportID
+	return State{
+		buf:         initBuf,
+		Buttons:     make([]byte, btnSize),
+		HatSwitches: make([]HatDirection, c.HatSwitchCnt),
+		Axises:      axises,
+	}
+}
+
+type State struct {
+	buf         []byte
+	Buttons     []byte
+	HatSwitches []HatDirection
+	Axises      []*AxisValue
+}
+
+func (s State) MarshalBinary() ([]byte, error) {
+	s.buf = s.buf[0:1]
+	s.buf = append(s.buf, s.Buttons...)
+	if len(s.HatSwitches) > 0 {
+		hat := byte(0)
+		for _, v := range s.HatSwitches {
+			hat <<= 4
+			hat |= byte(v & 0xf)
+		}
+		s.buf = append(s.buf, hat)
+	}
+	for _, v := range s.Axises {
+		c := v.constraint
+		val := fit(v.Value, c.MinIn, c.MaxIn, c.MinOut, c.MaxOut)
+		s.buf = binary.LittleEndian.AppendUint16(s.buf, uint16(val))
+	}
+	return s.buf, nil
+}
+
+func (s State) Button(index int) bool {
+	idx := index / 8
+	bit := uint8(1 << (index % 8))
+	return s.Buttons[idx]&bit > 0
+}
+
+func (s State) SetButton(index int, push bool) {
+	idx := index / 8
+	bit := uint8(1 << (index % 8))
+	b := s.Buttons[idx]
+	b &= ^bit
+	if push {
+		b |= bit
+	}
+	s.Buttons[idx] = b
+}
+
+func (s State) Hat(index int) HatDirection {
+	return s.HatSwitches[index]
+}
+
+func (s State) SetHat(index int, dir HatDirection) {
+	s.HatSwitches[index] = dir
+}
+
+func (s State) Axis(index int) int {
+	return s.Axises[index].Value
+}
+
+func (s State) SetAxis(index int, v int) {
+	s.Axises[index].Value = v
+}
+
+func DefaultDefinitions() Definitions {
+	return Definitions{
+		ReportID:     1,
+		ButtonCnt:    16,
+		HatSwitchCnt: 1,
+		AxisDefs: []Constraint{
+			{MinIn: -32767, MaxIn: 32767, MinOut: -32767, MaxOut: 32767},
+			{MinIn: -32767, MaxIn: 32767, MinOut: -32767, MaxOut: 32767},
+			{MinIn: -32767, MaxIn: 32767, MinOut: -32767, MaxOut: 32767},
+			{MinIn: -32767, MaxIn: 32767, MinOut: -32767, MaxOut: 32767},
+			{MinIn: -32767, MaxIn: 32767, MinOut: -32767, MaxOut: 32767},
+			{MinIn: -32767, MaxIn: 32767, MinOut: -32767, MaxOut: 32767},
+		},
+		descriptor: []byte{
+			0x05, 0x01,
+			0x09, 0x04,
+			0xa1, 0x01, // COLLECTION (Application)
+			0x85, 0x01, // REPORT_ID (1)
+			0x05, 0x09, // USAGE_PAGE (Button)
+			0x19, 0x01, // USAGE_MINIMUM (Button 1)
+			0x29, 0x10, // USAGE_MAXIMUM (Button 16)
+			0x15, 0x00, // LOGICAL_MINIMUM (0)
+			0x25, 0x01, // LOGICAL_MAXIMUM (1)
+			0x75, 0x01, // REPORT_SIZE (1)
+			0x95, 0x10, // REPORT_COUNT (16)
+			0x55, 0x00, // Unit Exponent (-16)
+			0x65, 0x00, // Unit (0x00)
+			0x81, 0x02, // INPUT (Data/Var/Abs)
+			0x05, 0x01, // USAGE_PAGE (Generic Desktop Controls)
+			0x09, 0x39, // USAGE(Hat Switch)
+			0x15, 0x00, // LOGICAL_MINIMUM (0)
+			0x25, 0x07, // LOGICAL_MAXIMUM (7)
+			0x35, 0x00, // PHYSICAL_MINIMUM (0)
+			0x46, 0x3b, 0x01, // PHYSICAL_MAXIMUM(315)
+			0x65, 0x14, // UNIT (Eng Rot:Angular Pos)
+			0x75, 0x04, // REPORT_SIZE (4)
+			0x95, 0x01, // REPORT_COUNT (1)
+			0x81, 0x02, // INPUT (Data/Var/Abs)
+			0x09, 0x39, // USAGE(Hat Switch)
+			0x15, 0x00, // LOGICAL_MINIMUM (0)
+			0x25, 0x07, // LOGICAL_MAXIMUM (7)
+			0x35, 0x00, // PHYSICAL_MINIMUM (0)
+			0x46, 0x3b, 0x01, // PHYSICAL_MAXIMUM(315)
+			0x65, 0x14, // UNIT (Eng Rot:Angular Pos)
+			0x75, 0x04, // REPORT_SIZE (4)
+			0x95, 0x01, // REPORT_COUNT (1)
+			0x81, 0x02, // INPUT (Data/Var/Abs)
+			0x09, 0x01, // USAGE (Pointer)
+			0x16, 0x01, 0x80, // LOGICAL_MINIMUM (-32767)
+			0x26, 0xff, 0x7f, // LOGICAL_MAXIMUM (32767)
+			0x75, 0x10, // REPORT_SIZE (16bits)
+			0x95, 0x06, // REPORT_COUNT (6)
+			0xa1, 0x00, // COLLECTION (Physical)
+			0x09, 0x30, // USAGE(X)
+			0x09, 0x31, // USAGE(Y)
+			0x09, 0x32, // USAGE(Z)
+			0x09, 0x33, // USAGE(RX)
+			0x09, 0x34, // USAGE(RY)
+			0x09, 0x35, // USAGE(RZ)
+			0x81, 0x02, // INPUT (Data/Var/Abs)
+			0xc0, // END_COLLECTION
+			0xc0, // END_COLLECTION
+		},
+	}
+}
diff --git a/src/machine/usb/midi/midi.go b/src/machine/usb/midi/midi.go
index 58f802b51..c0796be49 100644
--- a/src/machine/usb/midi/midi.go
+++ b/src/machine/usb/midi/midi.go
@@ -2,11 +2,12 @@ package midi
 
 import (
 	"machine"
+	"machine/usb"
 )
 
 const (
-	midiEndpointOut = 5 // from PC
-	midiEndpointIn  = 6 // to PC
+	midiEndpointOut = usb.MIDI_ENDPOINT_OUT // from PC
+	midiEndpointIn  = usb.MIDI_ENDPOINT_IN  // to PC
 )
 
 var Midi *midi
diff --git a/src/machine/usb/usb.go b/src/machine/usb/usb.go
index 592b32beb..8363fc361 100644
--- a/src/machine/usb/usb.go
+++ b/src/machine/usb/usb.go
@@ -9,6 +9,7 @@ const (
 	DescriptorConfigCDC = 1 << iota
 	DescriptorConfigHID
 	DescriptorConfigMIDI
+	DescriptorConfigJoystick
 )
 
 const (
@@ -35,7 +36,6 @@ const (
 	EndpointOut = 0x00
 	EndpointIn  = 0x80
 
-	NumberOfEndpoints  = 8
 	EndpointPacketSize = 64 // 64 for Full Speed, EPT size max is 1024
 
 	// standard requests
@@ -51,7 +51,12 @@ const (
 	SET_INTERFACE     = 11
 
 	// non standard requests
-	SET_IDLE = 10
+	GET_REPORT   = 1
+	GET_IDLE     = 2
+	GET_PROTOCOL = 3
+	SET_REPORT   = 9
+	SET_IDLE     = 10
+	SET_PROTOCOL = 11
 
 	DEVICE_CLASS_COMMUNICATIONS  = 0x02
 	DEVICE_CLASS_HUMAN_INTERFACE = 0x03
@@ -75,9 +80,11 @@ const (
 	CDC_ENDPOINT_ACM  = 1
 	CDC_ENDPOINT_OUT  = 2
 	CDC_ENDPOINT_IN   = 3
-	HID_ENDPOINT_IN   = 4
-	MIDI_ENDPOINT_OUT = 5
-	MIDI_ENDPOINT_IN  = 6
+	HID_ENDPOINT_IN   = 4 // for Interrupt In
+	HID_ENDPOINT_OUT  = 5 // for Interrupt Out
+	MIDI_ENDPOINT_IN  = 6 // for Bulk In
+	MIDI_ENDPOINT_OUT = 7 // for Bulk Out
+	NumberOfEndpoints = 8
 
 	// bmRequestType
 	REQUEST_HOSTTODEVICE = 0x00