usb: Add Audio class related files

This commit adds files related to USB audio device class.

Signed-off-by: Emil Obalski <emil.obalski@nordicsemi.no>

include/usb/class/usb_audio.h

@@ -0,0 +1,20 @@
+/*
+ * USB audio class core header
+ *
+ * Copyright (c) 2020 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief USB Audio Device Class public header
+ *
+ * Header follows Device Class Definition for Audio Class
+ * Version 1.0 document (audio10.pdf).
+ */
+
+#ifndef ZEPHYR_INCLUDE_USB_CLASS_AUDIO_H_
+#define ZEPHYR_INCLUDE_USB_CLASS_AUDIO_H_
+
+#endif /* ZEPHYR_INCLUDE_USB_CLASS_AUDIO_H_ */

subsys/usb/class/CMakeLists.txt

@@ -7,5 +7,6 @@ zephyr_sources_ifdef(CONFIG_USB_DEVICE_BT_H4 bt_h4.c)
 zephyr_sources_ifdef(CONFIG_USB_DFU_CLASS usb_dfu.c)
 zephyr_sources_ifdef(CONFIG_USB_DEVICE_LOOPBACK loopback.c)
 
+add_subdirectory_ifdef(CONFIG_USB_DEVICE_AUDIO audio)
 add_subdirectory_ifdef(CONFIG_USB_DEVICE_NETWORK netusb)
 add_subdirectory_ifdef(CONFIG_USB_DEVICE_HID hid)

subsys/usb/class/Kconfig

@@ -125,6 +125,8 @@ source "subsys/usb/class/netusb/Kconfig"
 
 source "subsys/usb/class/hid/Kconfig"
 
+source "subsys/usb/class/audio/Kconfig"
+
 config USB_DFU_CLASS
 	bool "USB DFU Class Driver"
 	select MPU_ALLOW_FLASH_WRITE

subsys/usb/class/audio/CMakeLists.txt

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources(
+  audio.c
+  )

subsys/usb/class/audio/Kconfig

@@ -0,0 +1,13 @@
+# USB AUDIO configuration options
+
+# Copyright (c) 2019 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+config USB_DEVICE_AUDIO
+	bool "USB Audio Device Class Driver"
+	help
+	  USB audio device class driver
+
+if USB_DEVICE_AUDIO
+
+endif #USB_DEVICE_AUDIO

subsys/usb/class/audio/audio.c

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2020 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief Audio device class driver
+ *
+ * Driver for USB Audio device class driver
+ */