samples/subsys/usb/webusb/src/webusb_serial.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*******************************************************************************
  *
  * Copyright(c) 2015,2016 Intel Corporation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  * * Redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in
  * the documentation and/or other materials provided with the
  * distribution.
  * * Neither the name of Intel Corporation nor the names of its
  * contributors may be used to endorse or promote products derived
  * from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************/

 /**
  * @file
  * @brief WebUSB enabled custom class driver
  *
  * This is a modified version of CDC ACM class driver
  * to support the WebUSB.
  */

 #define SYS_LOG_LEVEL 4
 #include <logging/sys_log.h>

 #include <zephyr.h>
 #include <init.h>
 #include <uart.h>
 #include <string.h>
 #include <misc/byteorder.h>
 #include <usb/usb_device.h>
 #include <usb/usb_common.h>
 #include "webusb_serial.h"

 /* Max packet size for Bulk endpoints */
 #define CDC_BULK_EP_MPS			64
 /* Max CDC ACM class request max data size */
 #define CDC_CLASS_REQ_MAX_DATA_SIZE	8
 /* Number of interfaces */
 #define WEBUSB_NUM_ITF			0x01
 /* Number of Endpoints in the custom interface */
 #define WEBUSB_NUM_EP			0x02
 #define WEBUSB_ENDP_OUT			0x02
 #define WEBUSB_ENDP_IN			0x83

 static struct webusb_req_handlers *req_handlers;

 u8_t interface_data[CDC_CLASS_REQ_MAX_DATA_SIZE];

 u8_t rx_buf[64];

 /* Structure representing the global USB description */
 struct dev_common_descriptor {
 	struct usb_device_descriptor device_descriptor;
 	struct usb_cfg_descriptor cfg_descr;
 	struct usb_cdc_acm_config {
 		struct usb_if_descriptor if0;
 		struct usb_ep_descriptor if0_in_ep;
 		struct usb_ep_descriptor if0_out_ep;
 	} __packed cdc_acm_cfg;
 	struct usb_string_desription {
 		struct usb_string_descriptor lang_descr;
 		struct usb_mfr_descriptor {
 			u8_t bLength;
 			u8_t bDescriptorType;
 			u8_t bString[0x0C - 2];
 		} __packed utf16le_mfr;

 		struct usb_product_descriptor {
 			u8_t bLength;
 			u8_t bDescriptorType;
 			u8_t bString[0x0E - 2];
 		} __packed utf16le_product;

 		struct usb_sn_descriptor {
 			u8_t bLength;
 			u8_t bDescriptorType;
 			u8_t bString[0x0C - 2];
 		} __packed utf16le_sn;
 	} __packed string_descr;
 	struct usb_desc_header term_descr;
 } __packed;

 static struct dev_common_descriptor webusb_serial_usb_description = {
 	/* Device descriptor */
 	.device_descriptor = {
 		.bLength = sizeof(struct usb_device_descriptor),
 		.bDescriptorType = USB_DEVICE_DESC,
 		.bcdUSB = sys_cpu_to_le16(USB_2_1),
 		.bDeviceClass = 0,
 		.bDeviceSubClass = 0,
 		.bDeviceProtocol = 0,
 		.bMaxPacketSize0 = MAX_PACKET_SIZE0,
 		.idVendor = sys_cpu_to_le16((u16_t)CONFIG_USB_DEVICE_VID),
 		.idProduct = sys_cpu_to_le16((u16_t)CONFIG_USB_DEVICE_PID),
 		.bcdDevice = sys_cpu_to_le16(BCDDEVICE_RELNUM),
 		.iManufacturer = 1,
 		.iProduct = 2,
 		.iSerialNumber = 3,
 		.bNumConfigurations = 1,
 	},
 	/* Configuration descriptor */
 	.cfg_descr = {
 		.bLength = sizeof(struct usb_cfg_descriptor),
 		.bDescriptorType = USB_CONFIGURATION_DESC,
 		.wTotalLength = sizeof(struct dev_common_descriptor)
 			      - sizeof(struct usb_device_descriptor)
 			      - sizeof(struct usb_string_desription)
 			      - sizeof(struct usb_desc_header),
 		.bNumInterfaces = WEBUSB_NUM_ITF,
 		.bConfigurationValue = 1,
 		.iConfiguration = 0,
 		.bmAttributes = USB_CONFIGURATION_ATTRIBUTES,
 		.bMaxPower = MAX_LOW_POWER,
 	},
 	.cdc_acm_cfg = {
 		/* Interface descriptor */
 		.if0 = {
 			.bLength = sizeof(struct usb_if_descriptor),
 			.bDescriptorType = USB_INTERFACE_DESC,
 			.bInterfaceNumber = 0,
 			.bAlternateSetting = 0,
 			.bNumEndpoints = WEBUSB_NUM_EP,
 			.bInterfaceClass = CUSTOM_CLASS,
 			.bInterfaceSubClass = 0,
 			.bInterfaceProtocol = 0,
 			.iInterface = 0,
 		},
 		/* First Endpoint IN */
 		.if0_in_ep = {
 			.bLength = sizeof(struct usb_ep_descriptor),
 			.bDescriptorType = USB_ENDPOINT_DESC,
 			.bEndpointAddress = WEBUSB_ENDP_IN,
 			.bmAttributes = USB_DC_EP_BULK,
 			.wMaxPacketSize = sys_cpu_to_le16(CDC_BULK_EP_MPS),
 			.bInterval = 0x00,
 		},
 		/* Second Endpoint OUT */
 		.if0_out_ep = {
 			.bLength = sizeof(struct usb_ep_descriptor),
 			.bDescriptorType = USB_ENDPOINT_DESC,
 			.bEndpointAddress = WEBUSB_ENDP_OUT,
 			.bmAttributes = USB_DC_EP_BULK,
 			.wMaxPacketSize = sys_cpu_to_le16(CDC_BULK_EP_MPS),
 			.bInterval = 0x00,
 		},
 	},
 	.string_descr = {
 		.lang_descr = {
 			.bLength = sizeof(struct usb_string_descriptor),
 			.bDescriptorType = USB_STRING_DESC,
 			.bString = sys_cpu_to_le16(0x0409),
 		},
 		/* Manufacturer String Descriptor */
 		.utf16le_mfr = {
 			.bLength = 0x0C,
 			.bDescriptorType = USB_STRING_DESC,
 			.bString = {'I', 0, 'n', 0, 't', 0, 'e', 0, 'l', 0,},
 		},
 		/* Product String Descriptor */
 		.utf16le_product = {
 			.bLength = 0x0E,
 			.bDescriptorType = USB_STRING_DESC,
 			.bString = {'W', 0, 'e', 0, 'b', 0, 'U', 0, 'S', 0,
 				    'B', 0,},
 		},
 		/* Serial Number String Descriptor */
 		.utf16le_sn = {
 			.bLength = 0x0C,
 			.bDescriptorType = USB_STRING_DESC,
 			.bString = {'0', 0, '0', 0, '.', 0, '0', 0, '1', 0,},
 		},
 	},

 	.term_descr = {
 		.bLength = 0,
 		.bDescriptorType = 0,
 	},
 };

 /**
  * @brief Custom handler for standard requests in order to
  *        catch the request and return the WebUSB Platform
  *        Capability Descriptor.
  *
  * @param pSetup    Information about the request to execute.
  * @param len       Size of the buffer.
  * @param data      Buffer containing the request result.
  *
  * @return  0 on success, negative errno code on fail.
  */
 int webusb_serial_custom_handle_req(struct usb_setup_packet *pSetup,
 		s32_t *len, u8_t **data)
 {
 	SYS_LOG_DBG("");

 	/* Call the callback */
 	if ((req_handlers && req_handlers->custom_handler) &&
 		(!req_handlers->custom_handler(pSetup, len, data)))
 		return 0;

 	return -ENOTSUP;
 }

 /**
  * @brief Handler called for WebUSB vendor specific commands.
  *
  * @param pSetup    Information about the request to execute.
  * @param len       Size of the buffer.
  * @param data      Buffer containing the request result.
  *
  * @return  0 on success, negative errno code on fail.
  */
 int webusb_serial_vendor_handle_req(struct usb_setup_packet *pSetup,
 		s32_t *len, u8_t **data)
 {
 	/* Call the callback */
 	if ((req_handlers && req_handlers->vendor_handler) &&
 		(!req_handlers->vendor_handler(pSetup, len, data)))
 		return 0;

 	return -ENOTSUP;
 }

 /**
  * @brief Register Custom and Vendor request callbacks
  *
  * This function registers Custom and Vendor request callbacks
  * for handling the device requests.
  *
  * @param [in] handlers Pointer to WebUSB request handlers structure
  *
  * @return N/A
  */
 void webusb_register_request_handlers(struct webusb_req_handlers *handlers)
 {
 	req_handlers = handlers;
 }

 static void webusb_write_cb(u8_t ep, int size, void *priv)
 {
 	SYS_LOG_DBG("ep %x size %u", ep, size);
 }

 static void webusb_read_cb(u8_t ep, int size, void *priv)
 {
 	SYS_LOG_DBG("ep %x size %u", ep, size);

 	if (size <= 0) {
 		goto done;
 	}

 	usb_transfer(WEBUSB_ENDP_IN, rx_buf, size, USB_TRANS_WRITE,
 		     webusb_write_cb, NULL);
 done:
 	usb_transfer(WEBUSB_ENDP_OUT, rx_buf, sizeof(rx_buf), USB_TRANS_READ,
 		     webusb_read_cb, NULL);
 }

 /**
  * @brief Callback used to know the USB connection status
  *
  * @param status USB device status code.
  *
  * @return  N/A.
  */
 static void webusb_serial_dev_status_cb(enum usb_dc_status_code status,
 					u8_t *param)
 {
 	ARG_UNUSED(param);

 	SYS_LOG_DBG("");

 	/* Check the USB status and do needed action if required */
 	switch (status) {
 	case USB_DC_ERROR:
 		SYS_LOG_DBG("USB device error");
 		break;
 	case USB_DC_RESET:
 		SYS_LOG_DBG("USB device reset detected");
 		break;
 	case USB_DC_CONNECTED:
 		SYS_LOG_DBG("USB device connected");
 		break;
 	case USB_DC_CONFIGURED:
 		SYS_LOG_DBG("USB device configured");
 		webusb_read_cb(WEBUSB_ENDP_OUT, 0, NULL);
 		break;
 	case USB_DC_DISCONNECTED:
 		SYS_LOG_DBG("USB device disconnected");
 		break;
 	case USB_DC_SUSPEND:
 		SYS_LOG_DBG("USB device supended");
 		break;
 	case USB_DC_RESUME:
 		SYS_LOG_DBG("USB device resumed");
 		break;
 	case USB_DC_UNKNOWN:
 	default:
 		SYS_LOG_DBG("USB unknown state");
 		break;
 	}
 }

 /* Describe EndPoints configuration */
 static struct usb_ep_cfg_data webusb_serial_ep_data[] = {
 	{
 		.ep_cb	= usb_transfer_ep_callback,
 		.ep_addr = WEBUSB_ENDP_OUT
 	},
 	{
 		.ep_cb = usb_transfer_ep_callback,
 		.ep_addr = WEBUSB_ENDP_IN
 	}
 };

 /* Configuration of the CDC-ACM Device send to the USB Driver */
 static struct usb_cfg_data webusb_serial_config = {
 	.usb_device_description = (u8_t *)&webusb_serial_usb_description,
 	.cb_usb_status = webusb_serial_dev_status_cb,
 	.interface = {
 		.class_handler = NULL,
 		.custom_handler = webusb_serial_custom_handle_req,
 		.vendor_handler = webusb_serial_vendor_handle_req,
 		.payload_data = NULL,
 	},
 	.num_endpoints = ARRAY_SIZE(webusb_serial_ep_data),
 	.endpoint = webusb_serial_ep_data
 };

 int webusb_serial_init(void)
 {
 	int ret;

 	SYS_LOG_DBG("");

 	webusb_serial_config.interface.payload_data = interface_data;

 	/* Initialize the WebUSB driver with the right configuration */
 	ret = usb_set_config(&webusb_serial_config);
 	if (ret < 0) {
 		SYS_LOG_ERR("Failed to config USB");
 		return ret;
 	}

 	/* Enable WebUSB driver */
 	ret = usb_enable(&webusb_serial_config);
 	if (ret < 0) {
 		SYS_LOG_ERR("Failed to enable USB");
 		return ret;
 	}

 	return 0;
 }
	/*******************************************************************************
	*
	* Copyright(c) 2015,2016 Intel Corporation.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Intel Corporation nor the names of its
	* contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	******************************************************************************/

	/**
	* @file
	* @brief WebUSB enabled custom class driver
	*
	* This is a modified version of CDC ACM class driver
	* to support the WebUSB.
	*/

	#define SYS_LOG_LEVEL 4
	#include <logging/sys_log.h>

	#include <zephyr.h>
	#include <init.h>
	#include <uart.h>
	#include <string.h>
	#include <misc/byteorder.h>
	#include <usb/usb_device.h>
	#include <usb/usb_common.h>
	#include "webusb_serial.h"

	/* Max packet size for Bulk endpoints */
	#define CDC_BULK_EP_MPS 64
	/* Max CDC ACM class request max data size */
	#define CDC_CLASS_REQ_MAX_DATA_SIZE 8
	/* Number of interfaces */
	#define WEBUSB_NUM_ITF 0x01
	/* Number of Endpoints in the custom interface */
	#define WEBUSB_NUM_EP 0x02
	#define WEBUSB_ENDP_OUT 0x02
	#define WEBUSB_ENDP_IN 0x83

	static struct webusb_req_handlers *req_handlers;

	u8_t interface_data[CDC_CLASS_REQ_MAX_DATA_SIZE];

	u8_t rx_buf[64];

	/* Structure representing the global USB description */
	struct dev_common_descriptor {
	struct usb_device_descriptor device_descriptor;
	struct usb_cfg_descriptor cfg_descr;
	struct usb_cdc_acm_config {
	struct usb_if_descriptor if0;
	struct usb_ep_descriptor if0_in_ep;
	struct usb_ep_descriptor if0_out_ep;
	} __packed cdc_acm_cfg;
	struct usb_string_desription {
	struct usb_string_descriptor lang_descr;
	struct usb_mfr_descriptor {
	u8_t bLength;
	u8_t bDescriptorType;
	u8_t bString[0x0C - 2];
	} __packed utf16le_mfr;

	struct usb_product_descriptor {
	u8_t bLength;
	u8_t bDescriptorType;
	u8_t bString[0x0E - 2];
	} __packed utf16le_product;

	struct usb_sn_descriptor {
	u8_t bLength;
	u8_t bDescriptorType;
	u8_t bString[0x0C - 2];
	} __packed utf16le_sn;
	} __packed string_descr;
	struct usb_desc_header term_descr;
	} __packed;

	static struct dev_common_descriptor webusb_serial_usb_description = {
	/* Device descriptor */
	.device_descriptor = {
	.bLength = sizeof(struct usb_device_descriptor),
	.bDescriptorType = USB_DEVICE_DESC,
	.bcdUSB = sys_cpu_to_le16(USB_2_1),
	.bDeviceClass = 0,
	.bDeviceSubClass = 0,
	.bDeviceProtocol = 0,
	.bMaxPacketSize0 = MAX_PACKET_SIZE0,
	.idVendor = sys_cpu_to_le16((u16_t)CONFIG_USB_DEVICE_VID),
	.idProduct = sys_cpu_to_le16((u16_t)CONFIG_USB_DEVICE_PID),
	.bcdDevice = sys_cpu_to_le16(BCDDEVICE_RELNUM),
	.iManufacturer = 1,
	.iProduct = 2,
	.iSerialNumber = 3,
	.bNumConfigurations = 1,
	},
	/* Configuration descriptor */
	.cfg_descr = {
	.bLength = sizeof(struct usb_cfg_descriptor),
	.bDescriptorType = USB_CONFIGURATION_DESC,
	.wTotalLength = sizeof(struct dev_common_descriptor)
	- sizeof(struct usb_device_descriptor)
	- sizeof(struct usb_string_desription)
	- sizeof(struct usb_desc_header),
	.bNumInterfaces = WEBUSB_NUM_ITF,
	.bConfigurationValue = 1,
	.iConfiguration = 0,
	.bmAttributes = USB_CONFIGURATION_ATTRIBUTES,
	.bMaxPower = MAX_LOW_POWER,
	},
	.cdc_acm_cfg = {
	/* Interface descriptor */
	.if0 = {
	.bLength = sizeof(struct usb_if_descriptor),
	.bDescriptorType = USB_INTERFACE_DESC,
	.bInterfaceNumber = 0,
	.bAlternateSetting = 0,
	.bNumEndpoints = WEBUSB_NUM_EP,
	.bInterfaceClass = CUSTOM_CLASS,
	.bInterfaceSubClass = 0,
	.bInterfaceProtocol = 0,
	.iInterface = 0,
	},
	/* First Endpoint IN */
	.if0_in_ep = {
	.bLength = sizeof(struct usb_ep_descriptor),
	.bDescriptorType = USB_ENDPOINT_DESC,
	.bEndpointAddress = WEBUSB_ENDP_IN,
	.bmAttributes = USB_DC_EP_BULK,
	.wMaxPacketSize = sys_cpu_to_le16(CDC_BULK_EP_MPS),
	.bInterval = 0x00,
	},
	/* Second Endpoint OUT */
	.if0_out_ep = {
	.bLength = sizeof(struct usb_ep_descriptor),
	.bDescriptorType = USB_ENDPOINT_DESC,
	.bEndpointAddress = WEBUSB_ENDP_OUT,
	.bmAttributes = USB_DC_EP_BULK,
	.wMaxPacketSize = sys_cpu_to_le16(CDC_BULK_EP_MPS),
	.bInterval = 0x00,
	},
	},
	.string_descr = {
	.lang_descr = {
	.bLength = sizeof(struct usb_string_descriptor),
	.bDescriptorType = USB_STRING_DESC,
	.bString = sys_cpu_to_le16(0x0409),
	},
	/* Manufacturer String Descriptor */
	.utf16le_mfr = {
	.bLength = 0x0C,
	.bDescriptorType = USB_STRING_DESC,
	.bString = {'I', 0, 'n', 0, 't', 0, 'e', 0, 'l', 0,},
	},
	/* Product String Descriptor */
	.utf16le_product = {
	.bLength = 0x0E,
	.bDescriptorType = USB_STRING_DESC,
	.bString = {'W', 0, 'e', 0, 'b', 0, 'U', 0, 'S', 0,
	'B', 0,},
	},
	/* Serial Number String Descriptor */
	.utf16le_sn = {
	.bLength = 0x0C,
	.bDescriptorType = USB_STRING_DESC,
	.bString = {'0', 0, '0', 0, '.', 0, '0', 0, '1', 0,},
	},
	},

	.term_descr = {
	.bLength = 0,
	.bDescriptorType = 0,
	},
	};

	/**
	* @brief Custom handler for standard requests in order to
	* catch the request and return the WebUSB Platform
	* Capability Descriptor.
	*
	* @param pSetup Information about the request to execute.
	* @param len Size of the buffer.
	* @param data Buffer containing the request result.
	*
	* @return 0 on success, negative errno code on fail.
	*/
	int webusb_serial_custom_handle_req(struct usb_setup_packet *pSetup,
	s32_t len, u8_t *data)
	{
	SYS_LOG_DBG("");

	/* Call the callback */
	if ((req_handlers && req_handlers->custom_handler) &&
	(!req_handlers->custom_handler(pSetup, len, data)))
	return 0;

	return -ENOTSUP;
	}

	/**
	* @brief Handler called for WebUSB vendor specific commands.
	*
	* @param pSetup Information about the request to execute.
	* @param len Size of the buffer.
	* @param data Buffer containing the request result.
	*
	* @return 0 on success, negative errno code on fail.
	*/
	int webusb_serial_vendor_handle_req(struct usb_setup_packet *pSetup,
	s32_t len, u8_t *data)
	{
	/* Call the callback */
	if ((req_handlers && req_handlers->vendor_handler) &&
	(!req_handlers->vendor_handler(pSetup, len, data)))
	return 0;

	return -ENOTSUP;
	}

	/**
	* @brief Register Custom and Vendor request callbacks
	*
	* This function registers Custom and Vendor request callbacks
	* for handling the device requests.
	*
	* @param [in] handlers Pointer to WebUSB request handlers structure
	*
	* @return N/A
	*/
	void webusb_register_request_handlers(struct webusb_req_handlers *handlers)
	{
	req_handlers = handlers;
	}

	static void webusb_write_cb(u8_t ep, int size, void *priv)
	{
	SYS_LOG_DBG("ep %x size %u", ep, size);
	}

	static void webusb_read_cb(u8_t ep, int size, void *priv)
	{
	SYS_LOG_DBG("ep %x size %u", ep, size);

	if (size <= 0) {
	goto done;
	}

	usb_transfer(WEBUSB_ENDP_IN, rx_buf, size, USB_TRANS_WRITE,
	webusb_write_cb, NULL);
	done:
	usb_transfer(WEBUSB_ENDP_OUT, rx_buf, sizeof(rx_buf), USB_TRANS_READ,
	webusb_read_cb, NULL);
	}

	/**
	* @brief Callback used to know the USB connection status
	*
	* @param status USB device status code.
	*
	* @return N/A.
	*/
	static void webusb_serial_dev_status_cb(enum usb_dc_status_code status,
	u8_t *param)
	{
	ARG_UNUSED(param);

	SYS_LOG_DBG("");

	/* Check the USB status and do needed action if required */
	switch (status) {
	case USB_DC_ERROR:
	SYS_LOG_DBG("USB device error");
	break;
	case USB_DC_RESET:
	SYS_LOG_DBG("USB device reset detected");
	break;
	case USB_DC_CONNECTED:
	SYS_LOG_DBG("USB device connected");
	break;
	case USB_DC_CONFIGURED:
	SYS_LOG_DBG("USB device configured");
	webusb_read_cb(WEBUSB_ENDP_OUT, 0, NULL);
	break;
	case USB_DC_DISCONNECTED:
	SYS_LOG_DBG("USB device disconnected");
	break;
	case USB_DC_SUSPEND:
	SYS_LOG_DBG("USB device supended");
	break;
	case USB_DC_RESUME:
	SYS_LOG_DBG("USB device resumed");
	break;
	case USB_DC_UNKNOWN:
	default:
	SYS_LOG_DBG("USB unknown state");
	break;
	}
	}

	/* Describe EndPoints configuration */
	static struct usb_ep_cfg_data webusb_serial_ep_data[] = {
	{
	.ep_cb = usb_transfer_ep_callback,
	.ep_addr = WEBUSB_ENDP_OUT
	},
	{
	.ep_cb = usb_transfer_ep_callback,
	.ep_addr = WEBUSB_ENDP_IN
	}
	};

	/* Configuration of the CDC-ACM Device send to the USB Driver */
	static struct usb_cfg_data webusb_serial_config = {
	.usb_device_description = (u8_t *)&webusb_serial_usb_description,
	.cb_usb_status = webusb_serial_dev_status_cb,
	.interface = {
	.class_handler = NULL,
	.custom_handler = webusb_serial_custom_handle_req,
	.vendor_handler = webusb_serial_vendor_handle_req,
	.payload_data = NULL,
	},
	.num_endpoints = ARRAY_SIZE(webusb_serial_ep_data),
	.endpoint = webusb_serial_ep_data
	};

	int webusb_serial_init(void)
	{
	int ret;

	SYS_LOG_DBG("");

	webusb_serial_config.interface.payload_data = interface_data;

	/* Initialize the WebUSB driver with the right configuration */
	ret = usb_set_config(&webusb_serial_config);
	if (ret < 0) {
	SYS_LOG_ERR("Failed to config USB");
	return ret;
	}

	/* Enable WebUSB driver */
	ret = usb_enable(&webusb_serial_config);
	if (ret < 0) {
	SYS_LOG_ERR("Failed to enable USB");
	return ret;
	}

	return 0;
	}