freebsd/lib/libusb20/libusb20.3

.\"
.\" Copyright (c) 2008 Hans Petter Selasky
.\"
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" $FreeBSD$
.\"
.Dd Oct 23, 2008
.Dt LIBUSB20 3
.Os
.Sh NAME
.Nm libusb20
.
.Nd "USB access library"
.
.
.Sh LIBRARY
.
.
USB access library (libusb20 -lusb20)
.
.
.
.Sh SYNOPSIS
.
.
.In libusb20.h
.
.
.Sh DESCRIPTION
.
The
.Nm
library implements functions to be able to easily access and control
USB through the USB file system interface.
.
.
.Sh USB TRANSFER OPERATIONS
.
.Pp
.
.Fn libusb20_tr_close
This function will release all kernel resources associated with an USB
.Fa xfer .
.
This function returns zero upon success.
.
Non-zero return values indicate a LIBUSB20_ERROR value.
.
.Pp
.
.Fn libusb20_tr_open
This function will allocate kernel resources like
.Fa MaxBufSize
and
.Fa MaxFrameCount
associated with an USB
.Fa xfer
and bind the transfer to the specified
.Fa ep_no .
.
This function returns zero upon success.
.
Non-zero return values indicate a LIBUSB20_ERROR value.
.
.Pp
.
.Fn libusb20_tr_get_pointer
This function will return a pointer to the allocated USB transfer according to the
.Fa pdev
and
.Fa tr_index
arguments.
.
This function returns NULL in case of failure.
.
.Pp
.
.Fn libusb20_tr_get_time_complete
This function will return the completion time of an USB transfer in
millisecond units. This function is most useful for isochronous USB
transfers when doing echo cancelling.
.
.Pp
.
.Fn libusb20_tr_get_actual_frames
This function will return the actual number of USB frames after an USB
transfer completed. A value of zero means that no data was transferred.
.
.Pp
.
.Fn libusb20_tr_get_actual_length
This function will return the sum of the actual length for all
transferred USB frames for the given USB transfer.
.
.Pp
.
.Fn libusb20_tr_get_max_frames
This function will return the maximum number of USB frames that were
allocated when an USB transfer was setup for the given USB transfer.
.
.Pp
.
.Fn libusb20_tr_get_max_packet_length
This function will return the maximum packet length in bytes
associated with the given USB transfer.
.
The packet length can be used round up buffer sizes so that short USB
packets are avoided for proxy buffers.
.
.
.Pp
.
.Fn libusb20_tr_get_max_total_length
This function will return the maximum value for the length sum of all
USB frames associated with an USB transfer.
.
.Pp
.
.Fn libusb20_tr_get_status
This function will return the status of an USB transfer.
.
Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums.
.
.Pp
.
.Fn libusb20_tr_pending
This function will return non-zero if the given USB transfer is
pending for completion.
.
Else this function returns zero.
.
.Pp
.
.Fn libusb20_tr_callback_wrapper
This is an internal function used to wrap asynchronous USB callbacks.
.
.Pp
.
.Fn libusb20_tr_clear_stall_sync
This is an internal function used to synchronously clear the stall on
the given USB transfer.
.
Please see the USB specification for more information on stall
clearing.
.
If the given USB transfer is pending when this function is called, the
USB transfer will complete with an error after that this function has
been called.
.
.Pp
.
.Fn libusb20_tr_drain
This function will stop the given USB transfer and will not return
until the USB transfer has been stopped in hardware.
.
.Pp
.
.Fn libusb20_tr_set_buffer
This function is used to set the
.Fa buffer
pointer for the given USB transfer and
.Fa fr_index .
.
Typically the frame index is zero.
.
.
.Pp
.
.Fn libusb20_tr_set_callback
This function is used to set the USB callback for asynchronous USB
transfers.
.
The callback type is defined by libusb20_tr_callback_t.
.
.Pp
.
.Fn libusb20_tr_set_flags
This function is used to set various USB flags for the given USB transfer.
.Bl -tag
.It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK
Report a short frame as error.
.It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK
Multiple short frames are not allowed.
.It LIBUSB20_TRANSFER_FORCE_SHORT
All transmitted frames are short terminated.
.It LIBUSB20_TRANSFER_DO_CLEAR_STALL
Will do a clear-stall before starting the transfer.
.El
.
.Pp
.
.Fn libusb20_tr_set_length
This function sets the length of a given USB transfer and frame index.
.
.Pp
.
.Fn libusb20_tr_set_priv_sc0
This function sets private driver pointer number zero.
.
.Pp
.
.Fn libusb20_tr_set_priv_sc1
This function sets private driver pointer number one.
.
.Pp
.
.Fn libusb20_tr_set_timeout
This function sets the timeout for the given USB transfer.
.
A timeout value of zero means no timeout.
.
The timeout is given in milliseconds.
.
.Pp
.
.Fn libusb20_tr_set_total_frames
This function sets the total number of frames that should be executed when the USB transfer is submitted.
.
The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer.
.
.Pp
.
.Fn libusb20_tr_setup_bulk
This function is a helper function for setting up a single frame USB BULK transfer.
.
.Pp
.
.Fn libusb20_tr_setup_control
This function is a helper function for setting up a single or dual
frame USB CONTROL transfer depending on the control transfer length.
.
.Pp
.
.Fn libusb20_tr_setup_intr
This function is a helper function for setting up a single frame USB INTERRUPT transfer.
.
.Pp
.
.Fn libusb20_tr_setup_isoc
This function is a helper function for setting up a multi frame USB ISOCHRONOUS transfer.
.
.Pp
.
.Fn libusb20_tr_start
This function will get the USB transfer started, if not already
started.
.
This function will not get the transfer queued in hardware.
.
This function is non-blocking.
.
.Pp
.
.Fn libusb20_tr_stop
This function will get the USB transfer stopped, if not already stopped.
.
This function is non-blocking, which means that the actual stop can
happen after the return of this function.
.
.Pp
.
.Fn libusb20_tr_submit
This function will get the USB transfer queued in hardware.
.
.
.Pp
.
.Fn libusb20_tr_get_priv_sc0
This function returns private driver pointer number zero associated
with an USB transfer.
.
.
.Pp
.
.Fn libusb20_tr_get_priv_sc1
This function returns private driver pointer number one associated
with an USB transfer.
.
.
.Sh USB DEVICE OPERATIONS
.
.Pp
.
.Fn libusb20_dev_get_backend_name
This function returns a zero terminated string describing the backend used.
.
.Pp
.
.Fn libusb20_dev_get_desc
This function returns a zero terminated string describing the given USB device.
.
.Pp
.
.Fn libusb20_dev_claim_interface
This function will try to claim the given USB interface given by
.Fa iface_index .
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_close
This function will close the given USB device.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_detach_kernel_driver
This function will try to detach the kernel driver for the USB interface given by
.Fa iface_index .
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_set_config_index
This function will try to set the configuration index on an USB
device.
.
The first configuration index is zero.
.
The un-configure index is 255.
.
This function returns zero on success else a LIBUSB20_ERROR value is returned.
.
.Pp
.
.Fn libusb20_dev_get_debug
This function returns the debug level of an USB device.
.
.Pp
.
.Fn libusb20_dev_get_fd
This function returns the file descriptor of the given USB device.
.
A negative value is returned when no file descriptor is present.
.
The file descriptor can be used for polling purposes.
.
.Pp
.
.Fn libusb20_dev_kernel_driver_active
This function returns a non-zero value if a kernel driver is active on
the given USB interface.
.
Else zero is returned.
.
.Pp
.
.Fn libusb20_dev_open
This function opens an USB device so that setting up USB transfers
becomes possible.
.
The number of USB transfers can be zero which means only control
transfers are allowed.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
A return value of LIBUSB20_ERROR_BUSY means that the device is already
opened.
.
.Pp
.
.Fn libusb20_dev_process
This function is called to sync kernel USB transfers with userland USB
transfers.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned typically indicating that the given USB device has been
detached.
.
.Pp
.
.Fn libusb20_dev_release_interface
This function will try to release a claimed USB interface for the specified USB device.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_request_sync
This function will perform a synchronous control request on the given
USB device.
.
Before this call will succeed the USB device must be opened.
.
.Fa setup
is a pointer to a decoded and host endian SETUP packet.
.Fa data
is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL.
.Fa pactlen
is a pointer to a variable that will hold the actual transfer length after the control transaction is complete.
.Fa timeout
is the transaction timeout given in milliseconds.
A timeout of zero means no timeout.
.Fa flags
is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_req_string_sync
This function will synchronously request an USB string by language ID
and string index into the given buffer limited by a maximum length.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_req_string_simple_sync
This function will synchronously request an USB string using the
default language ID and convert the string into ASCII before storing
the string into the given buffer limited by a maximum length which
includes the terminating zero.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.
.Pp
.
.Fn libusb20_dev_reset
This function will try to BUS reset the given USB device and restore
the last set USB configuration.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_set_power_mode
This function sets the power mode of the USB device.
.
Valid power modes:
.Bl -tag
.It LIBUSB20_POWER_OFF
.It LIBUSB20_POWER_ON
.It LIBUSB20_POWER_SAVE
.It LIBUSB20_POWER_SUSPEND
.It LIBUSB20_POWER_RESUME
.El
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_get_power_mode
This function returns the currently selected power mode for the given
USB device.
.
.Pp
.
.Fn libusb20_dev_set_alt_index
This function will try to set the given alternate index for the given
USB interface index.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_set_owner
This function will set the ownership of the given USB device.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_set_perm
This function will set the permissions of the given USB device.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_set_iface_owner
This function will set the ownership of the given USB interface.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_set_iface_perm
This function will set the permissions of the given USB interface.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_get_owner
This function will retrieve the current USB device ownership.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_get_perm
This function will retrieve the current USB device permissions.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_get_iface_owner
This function will retrieve the current USB interface ownership for
the given USB interface.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_get_iface_perm
This function will retrieve the current USB interface permissions for
the given USB interface.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_dev_get_device_desc
This function returns a pointer to the decoded and host endian version
of the device descriptor.
.
The USB device need not be opened when calling this function.
.
.Pp
.
.Fn libusb20_dev_alloc_config
This function will read out and decode the USB config descriptor for
the given USB device and config index. This function returns a pointer
to the decoded configuration which must eventually be passed to
free(). NULL is returned in case of failure.
.
.Pp
.
.Fn libusb20_dev_alloc(void)
This is an internal function to allocate a new USB device.
.
.Pp
.
.Fn libusb20_dev_get_address
This function returns the internal and not necessarily the real
hardware address of the given USB device.
.
.Pp
.
.Fn libusb20_dev_get_bus_number
This function return the internal bus number which the given USB
device belongs to.
.
.Pp
.
.Fn libusb20_dev_get_mode
This function returns the current operation mode of the USB entity.
.
Valid return values are:
.Bl -tag
.It LIBUSB20_MODE_HOST
.It LIBUSB20_MODE_DEVICE
.El
.
.Pp
.
.Fn libusb20_dev_get_speed
This function returns the current speed of the given USB device.
.
.Bl -tag
.It LIBUSB20_SPEED_UNKNOWN
.It LIBUSB20_SPEED_LOW
.It LIBUSB20_SPEED_FULL
.It LIBUSB20_SPEED_HIGH
.It LIBUSB20_SPEED_VARIABLE
.It LIBUSB20_SPEED_SUPER
.El
.
.Pp
.
.Fn libusb20_dev_get_config_index
This function returns the currently select config index for the given
USB device.
.
.Pp
.
.Fn libusb20_dev_free
This function will free the given USB device and all associated USB
transfers.
.
.Pp
.
.Fn libusb20_dev_set_debug
This function will set the debug level for the given USB device.
.
.Pp
.
.Fn libusb20_dev_wait_process
This function will wait until a pending USB transfer has completed on
the given USB device.
.
A timeout value can be specified which is passed on to the
.Xr 2 poll
function.
.
.Sh USB BUS OPERATIONS
.
.Fn libusb20_bus_set_owner
This function will set the ownership for the given USB bus.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_bus_set_perm
This function will set the permissions for the given USB bus.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_bus_get_owner
This function will retrieve the ownership for the given USB bus.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_bus_get_perm
This function will retrieve the permissions for the given USB bus.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.
.Sh USB BACKEND OPERATIONS
.
.Fn libusb20_be_get_dev_quirk
This function will return the device quirk according to
.Fa index
into the libusb20_quirk structure pointed to by
.Fa pq .
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
returned.
.
.Pp
.
.Fn libusb20_be_get_quirk_name
This function will return the quirk name according to
.Fa index
into the libusb20_quirk structure pointed to by
.Fa pq .
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
returned.
.
.Pp
.
.Fn libusb20_be_add_dev_quirk
This function will add the libusb20_quirk structure pointed to by the
.Fa pq
argument into the device quirk list.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is
returned.
.
.Pp
.
.Fn libusb20_be_remove_dev_quirk
This function will remove the quirk matching the libusb20_quirk structure pointed to by the
.Fa pq
argument from the device quirk list.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
returned.
.
.Pp
.
.Fn libusb20_be_set_owner
This function will set the ownership for the given backend.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_be_set_perm
This function will set the permissions for the given backend.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_be_get_owner
This function will retrieve the ownership of the given backend.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_be_get_perm
This function will retrieve the permissions of the given backend.
.
.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
.
.Pp
.
.Fn libusb20_be_alloc
This is an internal function to allocate a USB backend.
.
.Pp
.Fn libusb20_be_alloc_default
.Fn libusb20_be_alloc_freebsd
.Fn libusb20_be_alloc_linux
These functions are used to allocate a specific USB backend or the
operating system default USB backend. Allocating a backend is a way to
scan for currently present USB devices.
.
.Pp
.
.Fn libusb20_be_device_foreach
This function is used to iterate USB devices present in a USB backend.
.
The starting value of
.Fa pdev
is NULL.
.
This function returns the next USB device in the list.
.
If NULL is returned the end of the USB device list has been reached.
.
.Pp
.
.Fn libusb20_be_dequeue_device
This function will dequeue the given USB device pointer from the
backend USB device list.
.
Dequeued USB devices will not be freed when the backend is freed.
.
.Pp
.
.Fn libusb20_be_enqueue_device
This function will enqueue the given USB device pointer in the backend USB device list.
.
Enqueued USB devices will get freed when the backend is freed.
.
.Pp
.
.Fn libusb20_be_free
This function will free the given backend and all USB devices in its device list.
.
.
.Sh USB DESCRIPTOR PARSING
.
.Fn libusb20_me_get_1
This function will return a byte at the given byte offset of a message
entity.
.
This function is safe against invalid offsets.
.
.Pp
.
.Fn libusb20_me_get_2
This function will return a little endian 16-bit value at the given byte offset of a message
entity.
.
This function is safe against invalid offsets.
.
.Pp
.
.Fn libusb20_me_encode
This function will encode a so-called *DECODED structure into binary
format.
.
The total encoded length that will fit in the given buffer is
returned.
.
If the buffer pointer is NULL no data will be written to the buffer
location.
.
.Pp
.
.Fn libusb20_me_decode
This function will decode a binary structure into a so-called *DECODED
structure.
.
The total decoded length is returned.
.
The buffer pointer cannot be NULL.
.
.
.Sh LIBUSB VERSION 0.1 COMPATIBILITY
.
.Fn usb_open
.Fn usb_close
.Fn usb_get_string
.Fn usb_get_string_simple
.Fn usb_get_descriptor_by_endpoint
.Fn usb_get_descriptor
.Fn usb_parse_descriptor
.Fn usb_parse_configuration
.Fn usb_destroy_configuration
.Fn usb_fetch_and_parse_descriptors
.Fn usb_bulk_write
.Fn usb_bulk_read
.Fn usb_interrupt_write
.Fn usb_interrupt_read
.Fn usb_control_msg
.Fn usb_set_configuration
.Fn usb_claim_interface
.Fn usb_release_interface
.Fn usb_set_altinterface
.Fn usb_resetep
.Fn usb_clear_halt
.Fn usb_reset
.Fn usb_strerror
.Fn usb_init
.Fn usb_set_debug
.Fn usb_find_busses
.Fn usb_find_devices
.Fn usb_device
.Fn usb_get_busses
These functions are compliant with LibUSB version 0.1.12.
.
.Sh FILES
.
.
/dev/usb
.Sh SEE ALSO
.Xr usb2_core 4 ,
.Xr usbconfig 8
.
.
.Sh HISTORY
.
.
Some parts of the
.Nm
API derives from the libusb project at sourceforge.