This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

USB device stack¶

USB Vendor and Product identifiers
USB device controller drivers
- USB Device Controller API
USB device core layer
- USB Device Core Layer API
USB device class drivers
- Implementing non standard USB class
Testing USB over USP/IP in native_posix
USB Human Interface Devices (HID) support
- HID Item helpers
- HID Mouse and Keyboard report descriptors
HID Class Device API

USB Vendor and Product identifiers ¶

The USB Vendor ID for the Zephyr project is 0x2FE3. The default USB Product ID for the Zephyr project is 0x100. The USB bcdDevice Device Release Number represents the Zephyr kernel major and minor versions as a binary coded decimal value. When a vendor integrates the Zephyr USB subsystem into a product, the vendor must use the USB Vendor and Product ID assigned to them. A vendor integrating the Zephyr USB subsystem in a product must not use the Vendor ID of the Zephyr project.

The USB maintainer, if one is assigned, or otherwise the Zephyr Technical Steering Committee, may allocate other USB Product IDs based on well-motivated and documented requests.

Each USB sample has its own unique Product ID. When adding a new sample, add a new entry in samples/subsys/usb/usb_pid.Kconfig and a Kconfig file inside your sample subdirectory. The following Product IDs are currently used:

:kconfig:`CONFIG_USB_PID_CDC_ACM_SAMPLE`
:kconfig:`CONFIG_USB_PID_CDC_ACM_COMPOSITE_SAMPLE`
:kconfig:`CONFIG_USB_PID_HID_CDC_SAMPLE`
:kconfig:`CONFIG_USB_PID_CONSOLE_SAMPLE`
:kconfig:`CONFIG_USB_PID_DFU_SAMPLE`
:kconfig:`CONFIG_USB_PID_HID_SAMPLE`
:kconfig:`CONFIG_USB_PID_HID_MOUSE_SAMPLE`
:kconfig:`CONFIG_USB_PID_MASS_SAMPLE`
:kconfig:`CONFIG_USB_PID_TESTUSB_SAMPLE`
:kconfig:`CONFIG_USB_PID_WEBUSB_SAMPLE`
:kconfig:`CONFIG_USB_PID_BLE_HCI_H4_SAMPLE`

USB device controller drivers ¶

The Device Controller Driver Layer implements the low level control routines to deal directly with the hardware. All device controller drivers should implement the APIs described in file usb_dc.h. This allows the integration of new USB device controllers to be done without changing the upper layers.

USB Device Controller API ¶

group _usb_device_controller_api

USB Device Controller API.

Typedefs

typedef void (*usb_dc_ep_callback)(uint8_t ep, enum usb_dc_ep_cb_status_code cb_status)¶: Callback function signature for the USB Endpoint status

typedef void (*usb_dc_status_callback)(enum usb_dc_status_code cb_status, const uint8_t *param)¶: Callback function signature for the device

Enums

enum usb_dc_status_code¶

USB Driver Status Codes.

Status codes reported by the registered device status callback.

Values:

enumerator USB_DC_ERROR¶: USB error reported by the controller

enumerator USB_DC_RESET¶: USB reset

enumerator USB_DC_CONNECTED¶: USB connection established, hardware enumeration is completed

enumerator USB_DC_CONFIGURED¶: USB configuration done

enumerator USB_DC_DISCONNECTED¶: USB connection lost

enumerator USB_DC_SUSPEND¶: USB connection suspended by the HOST

enumerator USB_DC_RESUME¶: USB connection resumed by the HOST

enumerator USB_DC_INTERFACE¶: USB interface selected

enumerator USB_DC_SET_HALT¶: Set Feature ENDPOINT_HALT received

enumerator USB_DC_CLEAR_HALT¶: Clear Feature ENDPOINT_HALT received

enumerator USB_DC_SOF¶: Start of Frame received

enumerator USB_DC_UNKNOWN¶: Initial USB connection status

enum usb_dc_ep_cb_status_code¶

USB Endpoint Callback Status Codes.

Status Codes reported by the registered endpoint callback.

Values:

enumerator USB_DC_EP_SETUP¶: SETUP received

enumerator USB_DC_EP_DATA_OUT¶: Out transaction on this EP, data is available for read

enumerator USB_DC_EP_DATA_IN¶: In transaction done on this EP

enum usb_dc_ep_transfer_type¶

USB Endpoint Transfer Type.

Values:

enumerator USB_DC_EP_CONTROL = 0¶: Control type endpoint

enumerator USB_DC_EP_ISOCHRONOUS¶: Isochronous type endpoint

enumerator USB_DC_EP_BULK¶: Bulk type endpoint

enumerator USB_DC_EP_INTERRUPT¶: Interrupt type endpoint

enum usb_dc_ep_synchronozation_type¶

USB Endpoint Synchronization Type.

Note

Valid only for Isochronous Endpoints

Values:

enumerator USB_DC_EP_NO_SYNCHRONIZATION = (0U << 2U)¶: No Synchronization

enumerator USB_DC_EP_ASYNCHRONOUS = (1U << 2U)¶: Asynchronous

enumerator USB_DC_EP_ADAPTIVE = (2U << 2U)¶: Adaptive

enumerator USB_DC_EP_SYNCHRONOUS = (3U << 2U)¶: Synchronous

Functions

int usb_dc_attach(void)¶

Attach USB for device connection.

Function to attach USB for device connection. Upon success, the USB PLL is enabled, and the USB device is now capable of transmitting and receiving on the USB bus and of generating interrupts.

Returns: 0 on success, negative errno code on fail.

int usb_dc_detach(void)¶

Detach the USB device.

Function to detach the USB device. Upon success, the USB hardware PLL is powered down and USB communication is disabled.

Returns: 0 on success, negative errno code on fail.

int usb_dc_reset(void)¶

Reset the USB device.

This function returns the USB device and firmware back to it’s initial state. N.B. the USB PLL is handled by the usb_detach function

Returns: 0 on success, negative errno code on fail.

int usb_dc_set_address(const uint8_t addr)¶

Set USB device address.

Parameters

addr – [in] Device address

Returns

0 on success, negative errno code on fail.

void usb_dc_set_status_callback(const usb_dc_status_callback cb)¶

Set USB device controller status callback.

Function to set USB device controller status callback. The registered callback is used to report changes in the status of the device controller. The status code are described by the usb_dc_status_code enumeration.

Parameters

cb – [in] Callback function

int usb_dc_ep_check_cap(const struct usb_dc_ep_cfg_data *const cfg)¶

check endpoint capabilities

Function to check capabilities of an endpoint. usb_dc_ep_cfg_data structure provides the endpoint configuration parameters: endpoint address, endpoint maximum packet size and endpoint type. The driver should check endpoint capabilities and return 0 if the endpoint configuration is possible.

Parameters

cfg – [in] Endpoint config

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_configure(const struct usb_dc_ep_cfg_data *const cfg)¶

Configure endpoint.

Function to configure an endpoint. usb_dc_ep_cfg_data structure provides the endpoint configuration parameters: endpoint address, endpoint maximum packet size and endpoint type.

Parameters

cfg – [in] Endpoint config

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_set_stall(const uint8_t ep)¶

Set stall condition for the selected endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_clear_stall(const uint8_t ep)¶

Clear stall condition for the selected endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_is_stalled(const uint8_t ep, uint8_t *const stalled)¶

Check if the selected endpoint is stalled.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
stalled – [out] Endpoint stall status

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_halt(const uint8_t ep)¶

Halt the selected endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_enable(const uint8_t ep)¶

Enable the selected endpoint.

Function to enable the selected endpoint. Upon success interrupts are enabled for the corresponding endpoint and the endpoint is ready for transmitting/receiving data.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_disable(const uint8_t ep)¶

Disable the selected endpoint.

Function to disable the selected endpoint. Upon success interrupts are disabled for the corresponding endpoint and the endpoint is no longer able for transmitting/receiving data.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_flush(const uint8_t ep)¶

Flush the selected endpoint.

This function flushes the FIFOs for the selected endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_write(const uint8_t ep, const uint8_t *const data, const uint32_t data_len, uint32_t *const ret_bytes)¶

Write data to the specified endpoint.

This function is called to write data to the specified endpoint. The supplied usb_ep_callback function will be called when data is transmitted out.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data to write
data_len – [in] Length of the data requested to write. This may be zero for a zero length status packet.
ret_bytes – [out] Bytes scheduled for transmission. This value may be NULL if the application expects all bytes to be written

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_read(const uint8_t ep, uint8_t *const data, const uint32_t max_data_len, uint32_t *const read_bytes)¶

Read data from the specified endpoint.

This function is called by the endpoint handler function, after an OUT interrupt has been received for that EP. The application must only call this function through the supplied usb_ep_callback function. This function clears the ENDPOINT NAK, if all data in the endpoint FIFO has been read, so as to accept more data from host.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data buffer to write to
max_data_len – [in] Max length of data to read
read_bytes – [out] Number of bytes read. If data is NULL and max_data_len is 0 the number of bytes available for read should be returned.

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_set_callback(const uint8_t ep, const usb_dc_ep_callback cb)¶

Set callback function for the specified endpoint.

Function to set callback function for notification of data received and available to application or transmit done on the selected endpoint, NULL if callback not required by application code. The callback status code is described by usb_dc_ep_cb_status_code.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
cb – [in] Callback function

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_read_wait(uint8_t ep, uint8_t *data, uint32_t max_data_len, uint32_t *read_bytes)¶

Read data from the specified endpoint.

This is similar to usb_dc_ep_read, the difference being that, it doesn’t clear the endpoint NAKs so that the consumer is not bogged down by further upcalls till he is done with the processing of the data. The caller should reactivate ep by invoking usb_dc_ep_read_continue() do so.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data buffer to write to
max_data_len – [in] Max length of data to read
read_bytes – [out] Number of bytes read. If data is NULL and max_data_len is 0 the number of bytes available for read should be returned.

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_read_continue(uint8_t ep)¶

Continue reading data from the endpoint.

Clear the endpoint NAK and enable the endpoint to accept more data from the host. Usually called after usb_dc_ep_read_wait() when the consumer is fine to accept more data. Thus these calls together act as a flow control mechanism.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

int usb_dc_ep_mps(uint8_t ep)¶

Get endpoint max packet size.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

Enpoint max packet size (mps)

int usb_dc_wakeup_request(void)¶

Start the host wake up procedure.

Function to wake up the host if it’s currently in sleep mode.

Returns: 0 on success, negative errno code on fail.

struct usb_dc_ep_cfg_data¶

#include <usb_dc.h>

USB Endpoint Configuration.

Structure containing the USB endpoint configuration.

Public Members

uint8_t ep_addr¶: The number associated with the EP in the device configuration structure IN EP = 0x80 | <endpoint number> OUT EP = 0x00 | <endpoint number>

uint16_t ep_mps¶: Endpoint max packet size

enum usb_dc_ep_transfer_type ep_type¶: Endpoint Transfer Type. May be Bulk, Interrupt, Control or Isochronous

USB device core layer ¶

The USB Device core layer is a hardware independent interface between USB device controller driver and USB device class drivers or customer applications. It’s a port of the LPCUSB device stack. It provides the following functionalities:

Responds to standard device requests and returns standard descriptors, essentially handling ‘Chapter 9’ processing, specifically the standard device requests in table 9-3 from the universal serial bus specification revision 2.0.
Provides a programming interface to be used by USB device classes or customer applications. The APIs are described in the usb_device.h file.
Uses the APIs provided by the device controller drivers to interact with the USB device controller.

USB Device Core Layer API ¶

There are two ways to transmit data, using the ‘low’ level read/write API or the ‘high’ level transfer API.

Low level API: To transmit data to the host, the class driver should call usb_write(). Upon completion the registered endpoint callback will be called. Before sending another packet the class driver should wait for the completion of the previous write. When data is received, the registered endpoint callback is called. usb_read() should be used for retrieving the received data. For CDC ACM sample driver this happens via the OUT bulk endpoint handler (cdc_acm_bulk_out) mentioned in the endpoint array (cdc_acm_ep_data).
High level API: The usb_transfer method can be used to transfer data to/from the host. The transfer API will automatically split the data transmission into one or more USB transaction(s), depending endpoint max packet size. The class driver does not have to implement endpoint callback and should set this callback to the generic usb_transfer_ep_callback.

group _usb_device_core_api

USB Device Core Layer API.

Defines

USB_TRANS_READ¶

USB_TRANS_WRITE¶

USB_TRANS_NO_ZLP¶

Typedefs

typedef void (*usb_ep_callback)(uint8_t ep, enum usb_dc_ep_cb_status_code cb_status)¶: Callback function signature for the USB Endpoint status.

typedef int (*usb_request_handler)(struct usb_setup_packet *setup, int32_t *transfer_len, uint8_t **payload_data)¶

Callback function signature for class specific requests.

Function which handles Class specific requests corresponding to an interface number specified in the device descriptor table. For host to device direction the ‘len’ and ‘payload_data’ contain the length of the received data and the pointer to the received data respectively. For device to host class requests, ‘len’ and ‘payload_data’ should be set by the callback function with the length and the address of the data to be transmitted buffer respectively.

typedef void (*usb_interface_config)(struct usb_desc_header *head, uint8_t bInterfaceNumber)¶: Function for interface runtime configuration.

typedef void (*usb_transfer_callback)(uint8_t ep, int tsize, void *priv)¶: Callback function signature for transfer completion.

Functions

int usb_set_config(const uint8_t *usb_descriptor)¶

Configure USB controller.

Function to configure USB controller. Configuration parameters must be valid or an error is returned

Parameters

usb_descriptor – [in] USB descriptor table

Returns

0 on success, negative errno code on fail

int usb_deconfig(void)¶

Deconfigure USB controller.

This function returns the USB device to it’s initial state

Returns: 0 on success, negative errno code on fail

int usb_enable(usb_dc_status_callback status_cb)¶

Enable the USB subsystem and associated hardware.

This function initializes the USB core subsystem and enables the corresponding hardware so that it can begin transmitting and receiving on the USB bus, as well as generating interrupts.

Class-specific initialization and registration must be performed by the user before invoking this, so that any data or events on the bus are processed correctly by the associated class handling code.

Parameters

status_cb – [in] Callback registered by user to notify about USB device controller state.

Returns

0 on success, negative errno code on fail.

int usb_disable(void)¶

Disable the USB device.

Function to disable the USB device. Upon success, the specified USB interface is clock gated in hardware, it is no longer capable of generating interrupts.

Returns: 0 on success, negative errno code on fail

int usb_write(uint8_t ep, const uint8_t *data, uint32_t data_len, uint32_t *bytes_ret)¶

Write data to the specified endpoint.

Function to write data to the specified endpoint. The supplied usb_ep_callback will be called when transmission is done.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data to write
data_len – [in] Length of data requested to write. This may be zero for a zero length status packet.
bytes_ret – [out] Bytes written to the EP FIFO. This value may be NULL if the application expects all bytes to be written

Returns

0 on success, negative errno code on fail

int usb_read(uint8_t ep, uint8_t *data, uint32_t max_data_len, uint32_t *ret_bytes)¶

Read data from the specified endpoint.

This function is called by the Endpoint handler function, after an OUT interrupt has been received for that EP. The application must only call this function through the supplied usb_ep_callback function.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data buffer to write to
max_data_len – [in] Max length of data to read
ret_bytes – [out] Number of bytes read. If data is NULL and max_data_len is 0 the number of bytes available for read is returned.

Returns

0 on success, negative errno code on fail

int usb_ep_set_stall(uint8_t ep)¶

Set STALL condition on the specified endpoint.

This function is called by USB device class handler code to set stall condition on endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail

int usb_ep_clear_stall(uint8_t ep)¶

Clears STALL condition on the specified endpoint.

This function is called by USB device class handler code to clear stall condition on endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail

int usb_ep_read_wait(uint8_t ep, uint8_t *data, uint32_t max_data_len, uint32_t *read_bytes)¶

Read data from the specified endpoint.

This is similar to usb_ep_read, the difference being that, it doesn’t clear the endpoint NAKs so that the consumer is not bogged down by further upcalls till he is done with the processing of the data. The caller should reactivate ep by invoking usb_ep_read_continue() do so.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] pointer to data buffer to write to
max_data_len – [in] max length of data to read
read_bytes – [out] Number of bytes read. If data is NULL and max_data_len is 0 the number of bytes available for read should be returned.

Returns

0 on success, negative errno code on fail.

int usb_ep_read_continue(uint8_t ep)¶

Continue reading data from the endpoint.

Clear the endpoint NAK and enable the endpoint to accept more data from the host. Usually called after usb_ep_read_wait() when the consumer is fine to accept more data. Thus these calls together acts as flow control mechanism.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

void usb_transfer_ep_callback(uint8_t ep, enum usb_dc_ep_cb_status_code)¶

Transfer management endpoint callback.

If a USB class driver wants to use high-level transfer functions, driver needs to register this callback as usb endpoint callback.

int usb_transfer(uint8_t ep, uint8_t *data, size_t dlen, unsigned int flags, usb_transfer_callback cb, void *priv)¶

Start a transfer.

Start a usb transfer to/from the data buffer. This function is asynchronous and can be executed in IRQ context. The provided callback will be called on transfer completion (or error) in thread context.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data buffer to write-to/read-from
dlen – [in] Size of data buffer
flags – [in] Transfer flags (USB_TRANS_READ, USB_TRANS_WRITE…)
cb – [in] Function called on transfer completion/failure
priv – [in] Data passed back to the transfer completion callback

Returns

0 on success, negative errno code on fail.

int usb_transfer_sync(uint8_t ep, uint8_t *data, size_t dlen, unsigned int flags)¶

Start a transfer and block-wait for completion.

Synchronous version of usb_transfer, wait for transfer completion before returning.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table
data – [in] Pointer to data buffer to write-to/read-from
dlen – [in] Size of data buffer
flags – [in] Transfer flags

Returns

number of bytes transferred on success, negative errno code on fail.

void usb_cancel_transfer(uint8_t ep)¶

Cancel any ongoing transfer on the specified endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

0 on success, negative errno code on fail.

void usb_cancel_transfers(void)¶: Cancel all ongoing transfers.

bool usb_transfer_is_busy(uint8_t ep)¶

Check that transfer is ongoing for the endpoint.

Parameters

ep – [in] Endpoint address corresponding to the one listed in the device configuration table

Returns

true if transfer is ongoing, false otherwise.

int usb_wakeup_request(void)¶

Start the USB remote wakeup procedure.

Function to request a remote wakeup. This feature must be enabled in configuration, otherwise it will always return -ENOTSUP error.

Returns: 0 on success, negative errno code on fail, i.e. when the bus is already active.

struct usb_ep_cfg_data¶

#include <usb_device.h>

USB Endpoint Configuration.

This structure contains configuration for the endpoint.

Public Members

usb_ep_callback ep_cb¶: Callback function for notification of data received and available to application or transmit done, NULL if callback not required by application code

uint8_t ep_addr¶: The number associated with the EP in the device configuration structure IN EP = 0x80 | <endpoint number> OUT EP = 0x00 | <endpoint number>

struct usb_interface_cfg_data¶

#include <usb_device.h>

USB Interface Configuration.

This structure contains USB interface configuration.

Public Members

usb_request_handler class_handler¶: Handler for USB Class specific Control (EP 0) communications

usb_request_handler vendor_handler¶: Handler for USB Vendor specific commands

usb_request_handler custom_handler¶: The custom request handler gets a first chance at handling the request before it is handed over to the ‘chapter 9’ request handler. return 0 on success, -EINVAL if the request has not been handled by the custom handler and instead needs to be handled by the core USB stack. Any other error code to denote failure within the custom handler.

struct usb_cfg_data¶

#include <usb_device.h>

USB device configuration.

The Application instantiates this with given parameters added using the “usb_set_config” function. Once this function is called changes to this structure will result in undefined behavior. This structure may only be updated after calls to usb_deconfig

Public Members

const uint8_t *usb_device_description¶: USB device description, see http://www.beyondlogic.org/usbnutshell/usb5.shtml#DeviceDescriptors

void *interface_descriptor¶: Pointer to interface descriptor

usb_interface_config interface_config¶: Function for interface runtime configuration

void (*cb_usb_status)(struct usb_cfg_data *cfg, enum usb_dc_status_code cb_status, const uint8_t *param)¶: Callback to be notified on USB connection status change

struct usb_interface_cfg_data interface¶: USB interface (Class) handler and storage space

uint8_t num_endpoints¶: Number of individual endpoints in the device configuration

struct usb_ep_cfg_data *endpoint¶: Pointer to an array of endpoint structs of length equal to the number of EP associated with the device description, not including control endpoints

USB device class drivers ¶

Zephyr USB Device Stack supports many standard classes, such as HID, MSC Ethernet over USB, DFU, Bluetooth.

Implementing non standard USB class ¶

Configuration of USB Device is done in the stack layer.

The following structures and callbacks need to be defined:

Part of USB Descriptor table
USB Endpoint configuration table
USB Device configuration structure
Endpoint callbacks
Optionally class, vendor and custom handlers

For example, for USB loopback application:

struct usb_loopback_config {
	struct usb_if_descriptor if0;
	struct usb_ep_descriptor if0_out_ep;
	struct usb_ep_descriptor if0_in_ep;
} __packed;

USBD_CLASS_DESCR_DEFINE(primary, 0) struct usb_loopback_config loopback_cfg = {
	/* Interface descriptor 0 */
	.if0 = {
		.bLength = sizeof(struct usb_if_descriptor),
		.bDescriptorType = USB_DESC_INTERFACE,
		.bInterfaceNumber = 0,
		.bAlternateSetting = 0,
		.bNumEndpoints = 2,
		.bInterfaceClass = USB_BCC_VENDOR,
		.bInterfaceSubClass = 0,
		.bInterfaceProtocol = 0,
		.iInterface = 0,
	},

	/* Data Endpoint OUT */
	.if0_out_ep = {
		.bLength = sizeof(struct usb_ep_descriptor),
		.bDescriptorType = USB_DESC_ENDPOINT,
		.bEndpointAddress = LOOPBACK_OUT_EP_ADDR,
		.bmAttributes = USB_DC_EP_BULK,
		.wMaxPacketSize = sys_cpu_to_le16(CONFIG_LOOPBACK_BULK_EP_MPS),
		.bInterval = 0x00,
	},

	/* Data Endpoint IN */
	.if0_in_ep = {
		.bLength = sizeof(struct usb_ep_descriptor),
		.bDescriptorType = USB_DESC_ENDPOINT,
		.bEndpointAddress = LOOPBACK_IN_EP_ADDR,
		.bmAttributes = USB_DC_EP_BULK,
		.wMaxPacketSize = sys_cpu_to_le16(CONFIG_LOOPBACK_BULK_EP_MPS),
		.bInterval = 0x00,
	},
};

Endpoint configuration:

static struct usb_ep_cfg_data ep_cfg[] = {
	{
		.ep_cb = loopback_out_cb,
		.ep_addr = LOOPBACK_OUT_EP_ADDR,
	},
	{
		.ep_cb = loopback_in_cb,
		.ep_addr = LOOPBACK_IN_EP_ADDR,
	},
};

USB Device configuration structure:

USBD_CFG_DATA_DEFINE(primary, loopback) struct usb_cfg_data loopback_config = {
	.usb_device_description = NULL,
	.interface_config = loopback_interface_config,
	.interface_descriptor = &loopback_cfg.if0,
	.cb_usb_status = loopback_status_cb,
	.interface = {
		.class_handler = NULL,
		.custom_handler = NULL,
		.vendor_handler = loopback_vendor_handler,
	},
	.num_endpoints = ARRAY_SIZE(ep_cfg),
	.endpoint = ep_cfg,
};

The vendor device requests are forwarded by the USB stack core driver to the class driver through the registered vendor handler.

For the loopback class driver, loopback_vendor_handler() processes the vendor requests:

static int loopback_vendor_handler(struct usb_setup_packet *setup,
				   int32_t *len, uint8_t **data)
{
	LOG_DBG("Class request: bRequest 0x%x bmRequestType 0x%x len %d",
		setup->bRequest, setup->bmRequestType, *len);

	if (setup->RequestType.recipient != USB_REQTYPE_RECIPIENT_DEVICE) {
		return -ENOTSUP;
	}

	if (usb_reqtype_is_to_device(setup) &&
	    setup->bRequest == 0x5b) {
		LOG_DBG("Host-to-Device, data %p", *data);
		/*
		 * Copy request data in loopback_buf buffer and reuse
		 * it later in control device-to-host transfer.
		 */
		memcpy(loopback_buf, *data,
		       MIN(sizeof(loopback_buf), setup->wLength));
		return 0;
	}

	if ((usb_reqtype_is_to_host(setup)) &&
	    (setup->bRequest == 0x5c)) {
		LOG_DBG("Device-to-Host, wLength %d, data %p",
			setup->wLength, *data);
		*data = loopback_buf;
		*len = MIN(sizeof(loopback_buf), setup->wLength);
		return 0;
	}

	return -ENOTSUP;
}

The class driver waits for the USB_DC_CONFIGURED device status code before transmitting any data.

Testing USB over USP/IP in native_posix ¶

Virtual USB controller implemented through USB/IP might be used to test USB Device stack. Follow general build procedure to build USB sample for the native_posix configuration.

Run built sample with:

west build -t run

In a terminal window, run the following command to list USB devices:

$ usbip list -r localhost
Exportable USB devices
======================
 - 127.0.0.1
        1-1: unknown vendor : unknown product (2fe3:0100)
           : /sys/devices/pci0000:00/0000:00:01.2/usb1/1-1
           : (Defined at Interface level) (00/00/00)
           :  0 - Vendor Specific Class / unknown subclass / unknown protocol (ff/00/00)

In a terminal window, run the following command to attach USB device:

$ sudo usbip attach -r localhost -b 1-1

The USB device should be connected to your Linux host, and verified with the following commands:

$ sudo usbip port
Imported USB devices
====================
Port 00: <Port in Use> at Full Speed(12Mbps)
       unknown vendor : unknown product (2fe3:0100)
       7-1 -> usbip://localhost:3240/1-1
           -> remote bus/dev 001/002
$ lsusb -d 2fe3:0100
Bus 007 Device 004: ID 2fe3:0100

USB Human Interface Devices (HID) support ¶

HID Item helpers ¶

HID item helper macros can be used to compose a HID Report Descriptor. The names correspond to those used in the USB HID Specification.

Example of a HID Report Descriptor:

static const uint8_t hid_report_desc[] = {
    HID_USAGE_PAGE(HID_USAGE_GEN_DESKTOP),
    HID_USAGE(HID_USAGE_GEN_DESKTOP_UNDEFINED),
    HID_COLLECTION(HID_COLLECTION_APPLICATION),
    HID_LOGICAL_MIN8(0),
    /* logical maximum 255 */
    HID_LOGICAL_MAX16(0xFF, 0x00),
    HID_REPORT_ID(1),
    HID_REPORT_SIZE(8),
    HID_REPORT_COUNT(1),
    HID_USAGE(HID_USAGE_GEN_DESKTOP_UNDEFINED),
    /* HID_INPUT (Data, Variable, Absolute) */
    HID_INPUT(0x02),
    HID_END_COLLECTION,
};

group usb_hid_items

Defines

HID_ITEM(bTag, bType, bSize)¶

Define HID short item.

Parameters

bTag – Item tag
bType – Item type
bSize – Item data size

Returns

HID Input item

HID_INPUT(a)¶

Define HID Input item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Input item data

Returns

HID Input item

HID_OUTPUT(a)¶

Define HID Output item with the data length of one byte.

For usage examples, see HID_KEYBOARD_REPORT_DESC()

Parameters

a – Output item data

Returns

HID Output item

HID_FEATURE(a)¶

Define HID Feature item with the data length of one byte.

Parameters

a – Feature item data

Returns

HID Feature item

HID_COLLECTION(a)¶

Define HID Collection item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Collection item data

Returns

HID Collection item

HID_END_COLLECTION¶

Define HID End Collection (non-data) item.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Returns: HID End Collection item

HID_USAGE_PAGE(page)¶

Define HID Usage Page item.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

page – Usage Page

Returns

HID Usage Page item

HID_LOGICAL_MIN8(a)¶

Define HID Logical Minimum item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Minimum value in logical units

Returns

HID Logical Minimum item

HID_LOGICAL_MAX8(a)¶

Define HID Logical Maximum item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Maximum value in logical units

Returns

HID Logical Maximum item

HID_LOGICAL_MIN16(a, b)¶

Define HID Logical Minimum item with the data length of two bytes.

Parameters

a – Minimum value lower byte
b – Minimum value higher byte

Returns

HID Logical Minimum item

HID_LOGICAL_MAX16(a, b)¶

Define HID Logical Maximum item with the data length of two bytes.

Parameters

a – Minimum value lower byte
b – Minimum value higher byte

Returns

HID Logical Maximum item

HID_LOGICAL_MIN32(a, b, c, d)¶

Define HID Logical Minimum item with the data length of four bytes.

Parameters

a – Minimum value lower byte
b – Minimum value low middle byte
c – Minimum value high middle byte
d – Minimum value higher byte

Returns

HID Logical Minimum item

HID_LOGICAL_MAX32(a, b, c, d)¶

Define HID Logical Maximum item with the data length of four bytes.

Parameters

a – Minimum value lower byte
b – Minimum value low middle byte
c – Minimum value high middle byte
d – Minimum value higher byte

Returns

HID Logical Maximum item

HID_REPORT_SIZE(size)¶

Define HID Report Size item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

size – Report field size in bits

Returns

HID Report Size item

HID_REPORT_ID(id)¶

Define HID Report ID item with the data length of one byte.

Parameters

id – Report ID

Returns

HID Report ID item

HID_REPORT_COUNT(count)¶

Define HID Report Count item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

count – Number of data fields included in the report

Returns

HID Report Count item

HID_USAGE(idx)¶

Define HID Usage Index item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

idx – Number of data fields included in the report

Returns

HID Usage Index item

HID_USAGE_MIN8(a)¶

Define HID Usage Minimum item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Starting Usage

Returns

HID Usage Minimum item

HID_USAGE_MAX8(a)¶

Define HID Usage Maximum item with the data length of one byte.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Ending Usage

Returns

HID Usage Maximum item

HID_USAGE_MIN16(a, b)¶

Define HID Usage Minimum item with the data length of two bytes.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Starting Usage lower byte
b – Starting Usage higher byte

Returns

HID Usage Minimum item

HID_USAGE_MAX16(a, b)¶

Define HID Usage Maximum item with the data length of two bytes.

For usage examples, see HID_MOUSE_REPORT_DESC(), HID_KEYBOARD_REPORT_DESC()

Parameters

a – Ending Usage lower byte
b – Ending Usage higher byte

Returns

HID Usage Maximum item

group usb_hid_types

Defines

USB_DESC_HID¶: USB HID Class HID descriptor type

USB_DESC_HID_REPORT¶: USB HID Class Report descriptor type

USB_DESC_HID_PHYSICAL¶: USB HID Class physical descriptor type

USB_HID_GET_REPORT¶: USB HID Class GetReport bRequest value

USB_HID_GET_IDLE¶: USB HID Class GetIdle bRequest value

USB_HID_GET_PROTOCOL¶: USB HID Class GetProtocol bRequest value

USB_HID_SET_REPORT¶: USB HID Class SetReport bRequest value

USB_HID_SET_IDLE¶: USB HID Class SetIdle bRequest value

USB_HID_SET_PROTOCOL¶: USB HID Class SetProtocol bRequest value

HID_BOOT_IFACE_CODE_NONE¶: USB HID Boot Interface Protocol (bInterfaceProtocol) Code None

HID_BOOT_IFACE_CODE_KEYBOARD¶: USB HID Boot Interface Protocol (bInterfaceProtocol) Code Keyboard

HID_BOOT_IFACE_CODE_MOUSE¶: USB HID Boot Interface Protocol (bInterfaceProtocol) Code Mouse

HID_PROTOCOL_BOOT¶: USB HID Class Boot protocol code

HID_PROTOCOL_REPORT¶: USB HID Class Report protocol code

HID_ITEM_TYPE_MAIN¶: HID Main item type

HID_ITEM_TYPE_GLOBAL¶: HID Global item type

HID_ITEM_TYPE_LOCAL¶: HID Local item type

HID_ITEM_TAG_INPUT¶: HID Input item tag

HID_ITEM_TAG_OUTPUT¶: HID Output item tag

HID_ITEM_TAG_COLLECTION¶: HID Collection item tag

HID_ITEM_TAG_FEATURE¶: HID Feature item tag

HID_ITEM_TAG_COLLECTION_END¶: HID End Collection item tag

HID_ITEM_TAG_USAGE_PAGE¶: HID Usage Page item tag

HID_ITEM_TAG_LOGICAL_MIN¶: HID Logical Minimum item tag

HID_ITEM_TAG_LOGICAL_MAX¶: HID Logical Maximum item tag

HID_ITEM_TAG_PHYSICAL_MIN¶: HID Physical Minimum item tag

HID_ITEM_TAG_PHYSICAL_MAX¶: HID Physical Maximum item tag

HID_ITEM_TAG_UNIT_EXPONENT¶: HID Unit Exponent item tag

HID_ITEM_TAG_UNIT¶: HID Unit item tag

HID_ITEM_TAG_REPORT_SIZE¶: HID Report Size item tag

HID_ITEM_TAG_REPORT_ID¶: HID Report ID item tag

HID_ITEM_TAG_REPORT_COUNT¶: HID Report count item tag

HID_ITEM_TAG_USAGE¶: HID Usage item tag

HID_ITEM_TAG_USAGE_MIN¶: HID Usage Minimum item tag

HID_ITEM_TAG_USAGE_MAX¶: HID Usage Maximum item tag

HID_COLLECTION_PHYSICAL¶: Physical collection type

HID_COLLECTION_APPLICATION¶: Application collection type

HID_USAGE_GEN_DESKTOP¶: HID Generic Desktop Controls Usage page

HID_USAGE_GEN_KEYBOARD¶: HID Keyboard Usage page

HID_USAGE_GEN_LEDS¶: HID LEDs Usage page

HID_USAGE_GEN_BUTTON¶: HID Button Usage page

HID_USAGE_GEN_DESKTOP_UNDEFINED¶: HID Generic Desktop Undefined Usage ID

HID_USAGE_GEN_DESKTOP_POINTER¶: HID Generic Desktop Pointer Usage ID

HID_USAGE_GEN_DESKTOP_MOUSE¶: HID Generic Desktop Mouse Usage ID

HID_USAGE_GEN_DESKTOP_JOYSTICK¶: HID Generic Desktop Joystick Usage ID

HID_USAGE_GEN_DESKTOP_GAMEPAD¶: HID Generic Desktop Gamepad Usage ID

HID_USAGE_GEN_DESKTOP_KEYBOARD¶: HID Generic Desktop Keyboard Usage ID

HID_USAGE_GEN_DESKTOP_KEYPAD¶: HID Generic Desktop Keypad Usage ID

HID_USAGE_GEN_DESKTOP_X¶: HID Generic Desktop X Usage ID

HID_USAGE_GEN_DESKTOP_Y¶: HID Generic Desktop Y Usage ID

HID_USAGE_GEN_DESKTOP_WHEEL¶: HID Generic Desktop Wheel Usage ID

HID Mouse and Keyboard report descriptors ¶

The pre-defined Mouse and Keyboard report descriptors can be used by a HID device implementation or simply as examples.

group usb_hid_mk_report_desc

Defines

HID_MOUSE_REPORT_DESC(bcnt)¶

Simple HID mouse report descriptor for n button mouse.

Parameters

bcnt – Button count. Allowed values from 1 to 8.

HID_KEYBOARD_REPORT_DESC()¶: Simple HID keyboard report descriptor.

Enums

enum hid_kbd_code¶

HID keyboard button codes.

Values:

enumerator HID_KEY_A = 4¶

enumerator HID_KEY_B = 5¶

enumerator HID_KEY_C = 6¶

enumerator HID_KEY_D = 7¶

enumerator HID_KEY_E = 8¶

enumerator HID_KEY_F = 9¶

enumerator HID_KEY_G = 10¶

enumerator HID_KEY_H = 11¶

enumerator HID_KEY_I = 12¶

enumerator HID_KEY_J = 13¶

enumerator HID_KEY_K = 14¶

enumerator HID_KEY_L = 15¶

enumerator HID_KEY_M = 16¶

enumerator HID_KEY_N = 17¶

enumerator HID_KEY_O = 18¶

enumerator HID_KEY_P = 19¶

enumerator HID_KEY_Q = 20¶

enumerator HID_KEY_R = 21¶

enumerator HID_KEY_S = 22¶

enumerator HID_KEY_T = 23¶

enumerator HID_KEY_U = 24¶

enumerator HID_KEY_V = 25¶

enumerator HID_KEY_W = 26¶

enumerator HID_KEY_X = 27¶

enumerator HID_KEY_Y = 28¶

enumerator HID_KEY_Z = 29¶

enumerator HID_KEY_1 = 30¶

enumerator HID_KEY_2 = 31¶

enumerator HID_KEY_3 = 32¶

enumerator HID_KEY_4 = 33¶

enumerator HID_KEY_5 = 34¶

enumerator HID_KEY_6 = 35¶

enumerator HID_KEY_7 = 36¶

enumerator HID_KEY_8 = 37¶

enumerator HID_KEY_9 = 38¶

enumerator HID_KEY_0 = 39¶

enumerator HID_KEY_ENTER = 40¶

enumerator HID_KEY_ESC = 41¶

enumerator HID_KEY_BACKSPACE = 42¶

enumerator HID_KEY_TAB = 43¶

enumerator HID_KEY_SPACE = 44¶

enumerator HID_KEY_MINUS = 45¶

enumerator HID_KEY_EQUAL = 46¶

enumerator HID_KEY_LEFTBRACE = 47¶

enumerator HID_KEY_RIGHTBRACE = 48¶

enumerator HID_KEY_BACKSLASH = 49¶

enumerator HID_KEY_HASH = 50¶

enumerator HID_KEY_SEMICOLON = 51¶

enumerator HID_KEY_APOSTROPHE = 52¶

enumerator HID_KEY_GRAVE = 53¶

enumerator HID_KEY_COMMA = 54¶

enumerator HID_KEY_DOT = 55¶

enumerator HID_KEY_SLASH = 56¶

enumerator HID_KEY_CAPSLOCK = 57¶

enumerator HID_KEY_F1 = 58¶

enumerator HID_KEY_F2 = 59¶

enumerator HID_KEY_F3 = 60¶

enumerator HID_KEY_F4 = 61¶

enumerator HID_KEY_F5 = 62¶

enumerator HID_KEY_F6 = 63¶

enumerator HID_KEY_F7 = 64¶

enumerator HID_KEY_F8 = 65¶

enumerator HID_KEY_F9 = 66¶

enumerator HID_KEY_F10 = 67¶

enumerator HID_KEY_F11 = 68¶

enumerator HID_KEY_F12 = 69¶

enumerator HID_KEY_SYSRQ = 70¶

enumerator HID_KEY_SCROLLLOCK = 71¶

enumerator HID_KEY_PAUSE = 72¶

enumerator HID_KEY_INSERT = 73¶

enumerator HID_KEY_HOME = 74¶

enumerator HID_KEY_PAGEUP = 75¶

enumerator HID_KEY_DELETE = 76¶

enumerator HID_KEY_END = 77¶

enumerator HID_KEY_PAGEDOWN = 78¶

enumerator HID_KEY_RIGHT = 79¶

enumerator HID_KEY_LEFT = 80¶

enumerator HID_KEY_DOWN = 81¶

enumerator HID_KEY_UP = 82¶

enumerator HID_KEY_NUMLOCK = 83¶

enumerator HID_KEY_KPSLASH = 84¶

enumerator HID_KEY_KPASTERISK = 85¶

enumerator HID_KEY_KPMINUS = 86¶

enumerator HID_KEY_KPPLUS = 87¶

enumerator HID_KEY_KPENTER = 88¶

enumerator HID_KEY_KP_1 = 89¶

enumerator HID_KEY_KP_2 = 90¶

enumerator HID_KEY_KP_3 = 91¶

enumerator HID_KEY_KP_4 = 92¶

enumerator HID_KEY_KP_5 = 93¶

enumerator HID_KEY_KP_6 = 94¶

enumerator HID_KEY_KP_7 = 95¶

enumerator HID_KEY_KP_8 = 96¶

enumerator HID_KEY_KP_9 = 97¶

enumerator HID_KEY_KP_0 = 98¶

enum hid_kbd_modifier¶

HID keyboard modifiers.

Values:

enumerator HID_KBD_MODIFIER_NONE = 0x00¶

enumerator HID_KBD_MODIFIER_LEFT_CTRL = 0x01¶

enumerator HID_KBD_MODIFIER_LEFT_SHIFT = 0x02¶

enumerator HID_KBD_MODIFIER_LEFT_ALT = 0x04¶

enumerator HID_KBD_MODIFIER_LEFT_UI = 0x08¶

enumerator HID_KBD_MODIFIER_RIGHT_CTRL = 0x10¶

enumerator HID_KBD_MODIFIER_RIGHT_SHIFT = 0x20¶

enumerator HID_KBD_MODIFIER_RIGHT_ALT = 0x40¶

enumerator HID_KBD_MODIFIER_RIGHT_UI = 0x80¶

enum hid_kbd_led¶

HID keyboard LEDs.

Values:

enumerator HID_KBD_LED_NUM_LOCK = 0x01¶

enumerator HID_KBD_LED_CAPS_LOCK = 0x02¶

enumerator HID_KBD_LED_SCROLL_LOCK = 0x04¶

enumerator HID_KBD_LED_COMPOSE = 0x08¶

enumerator HID_KBD_LED_KANA = 0x10¶

HID Class Device API ¶

USB HID devices like mouse, keyboard, or any other specific device use this API.

group usb_hid_device_api

Typedefs

typedef int (*hid_cb_t)(const struct device *dev, struct usb_setup_packet *setup, int32_t *len, uint8_t **data)¶

typedef void (*hid_int_ready_callback)(const struct device *dev)¶

typedef void (*hid_protocol_cb_t)(const struct device *dev, uint8_t protocol)¶

typedef void (*hid_idle_cb_t)(const struct device *dev, uint16_t report_id)¶

Functions

void usb_hid_register_device(const struct device *dev, const uint8_t *desc, size_t size, const struct hid_ops *op)¶

Register HID device.

Parameters

dev – [in] Pointer to USB HID device
desc – [in] Pointer to HID report descriptor
size – [in] Size of HID report descriptor
op – [in] Pointer to USB HID device interrupt struct

int hid_int_ep_write(const struct device *dev, const uint8_t *data, uint32_t data_len, uint32_t *bytes_ret)¶

Write to USB HID interrupt endpoint buffer.

Parameters

dev – [in] Pointer to USB HID device
data – [in] Pointer to data buffer
data_len – [in] Length of data to copy
bytes_ret – [out] Bytes written to the EP buffer.

Returns

0 on success, negative errno code on fail.

int hid_int_ep_read(const struct device *dev, uint8_t *data, uint32_t max_data_len, uint32_t *ret_bytes)¶

Read from USB HID interrupt endpoint buffer.

Parameters

dev – [in] Pointer to USB HID device
data – [in] Pointer to data buffer
max_data_len – [in] Max length of data to copy
ret_bytes – [out] Number of bytes to copy. If data is NULL and ret_bytes is 0 the number of bytes available in the buffer will be returned.

Returns

0 on success, negative errno code on fail.

int usb_hid_set_proto_code(const struct device *dev, uint8_t proto_code)¶

Set USB HID class Protocol Code.

Should be called before usb_hid_init().

Parameters

dev – [in] Pointer to USB HID device
proto_code – [in] Protocol Code to be used for bInterfaceProtocol

Returns

0 on success, negative errno code on fail.

int usb_hid_init(const struct device *dev)¶

Initialize USB HID class support.

Parameters

dev – [in] Pointer to USB HID device

Returns

0 on success, negative errno code on fail.

struct hid_ops¶: #include <usb_hid.h>

USB HID device interface.