[usbd] Add usb audio class.

components/drivers/Kconfig

@@ -660,6 +660,9 @@ menu "Using USB"
                     config _RT_USB_DEVICE_WINUSB
                         bool "Enable to use device as winusb device"
                         select RT_USB_DEVICE_WINUSB
+                    config _RT_USB_DEVICE_AUDIO
+                        bool "Enable to use device as audio device"
+                        select RT_USB_DEVICE_AUDIO
                 endchoice
                 if RT_USB_DEVICE_COMPOSITE
                     config RT_USB_DEVICE_CDC
@@ -685,6 +688,9 @@ menu "Using USB"
                     config RT_USB_DEVICE_WINUSB
                         bool "Enable to use device as winusb device"
                         default n
+                    config RT_USB_DEVICE_AUDIO
+                        bool "Enable to use device as audio device"
+                        default n
                 endif
                 if RT_USB_DEVICE_CDC
                     config RT_VCOM_TASK_STK_SIZE
@@ -752,6 +758,24 @@ menu "Using USB"
                         bool "Use to HID device as media keyboard"
                         default y
                 endif
+                if RT_USB_DEVICE_AUDIO
+                    config RT_USB_DEVICE_AUDIO_MIC
+                        bool "Use usb mic device as audio device"
+                        default n
+                        if RT_USB_DEVICE_AUDIO_MIC
+                            config RT_USBD_MIC_DEVICE_NAME
+                            string "audio mic device name"
+                            default "mic0"
+                        endif
+                    config RT_USB_DEVICE_AUDIO_SPEAKER
+                        bool "Use usb speaker device as audio device"
+                        default n
+                        if RT_USB_DEVICE_AUDIO_SPEAKER
+                            config RT_USBD_SPEAKER_DEVICE_NAME
+                            string "audio speaker device name"
+                            default "sound0"
+                        endif
+                endif
         endif
     endmenu
 endmenu

components/drivers/usb/usbdevice/SConscript

@@ -24,6 +24,12 @@ if GetDepend('RT_USB_DEVICE_RNDIS'):
 
 if GetDepend('RT_USB_DEVICE_WINUSB'):
 	src += Glob('class/winusb.c')
+	
+if GetDepend('RT_USB_DEVICE_AUDIO_MIC'):
+	src += Glob('class/audio_mic.c')
+
+if GetDepend('RT_USB_DEVICE_AUDIO_SPEAKER'):
+	src += Glob('class/audio_speaker.c')
 
 CPPPATH = [cwd]