2 .\" Copyright (c) 2008 Hans Petter Selasky
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
15 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 .Nd "USB access library"
41 USB access library (libusb -lusb)
48 .Fn libusb20_tr_close "struct libusb20_transfer *xfer"
50 .Fn libusb20_tr_open "struct libusb20_transfer *xfer" "uint32_t max_buf_size" "uint32_t max_frame_count" "uint8_t ep_no"
51 .Ft struct libusb20_transfer*
52 .Fn libusb20_tr_get_pointer "struct libusb20_device *pdev" "uint16_t tr_index"
54 .Fn libusb20_tr_get_time_complete "struct libusb20_transfer *xfer"
56 .Fn libusb20_tr_get_actual_frames "struct libusb20_transfer *xfer"
58 .Fn libusb20_tr_get_actual_length "struct libusb20_transfer *xfer"
60 .Fn libusb20_tr_get_max_frames "struct libusb20_transfer *xfer"
62 .Fn libusb20_tr_get_max_packet_length "struct libusb20_transfer *xfer"
64 .Fn libusb20_tr_get_max_total_length "struct libusb20_transfer *xfer"
66 .Fn libusb20_tr_get_status "struct libusb20_transfer *xfer"
68 .Fn libusb20_tr_pending "struct libusb20_transfer *xfer"
70 .Fn libusb20_tr_callback_wrapper "struct libusb20_transfer *xfer"
72 .Fn libusb20_tr_clear_stall_sync "struct libusb20_transfer *xfer"
74 .Fn libusb20_tr_drain "struct libusb20_transfer *xfer"
76 .Fn libusb20_tr_set_buffer "struct libusb20_transfer *xfer" "void *buffer" "uint16_t fr_index"
78 .Fn libusb20_tr_set_callback "struct libusb20_transfer *xfer" "libusb20_tr_callback_t *cb"
80 .Fn libusb20_tr_set_flags "struct libusb20_transfer *xfer" "uint8_t flags"
82 .Fn libusb20_tr_get_length "struct libusb20_transfer *xfer" "uint16_t fr_index"
84 .Fn libusb20_tr_set_length "struct libusb20_transfer *xfer" "uint32_t length" "uint16_t fr_index"
86 .Fn libusb20_tr_set_priv_sc0 "struct libusb20_transfer *xfer" "void *sc0"
88 .Fn libusb20_tr_set_priv_sc1 "struct libusb20_transfer *xfer" "void *sc1"
90 .Fn libusb20_tr_set_timeout "struct libusb20_transfer *xfer" "uint32_t timeout"
92 .Fn libusb20_tr_set_total_frames "struct libusb20_transfer *xfer" "uint32_t nframes"
94 .Fn libusb20_tr_setup_bulk "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout"
96 .Fn libusb20_tr_setup_control "struct libusb20_transfer *xfer" "void *psetup" "void *pbuf" "uint32_t timeout"
98 .Fn libusb20_tr_setup_intr "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout"
100 .Fn libusb20_tr_setup_isoc "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint61_t fr_index"
102 .Fn libusb20_tr_bulk_intr_sync "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t *pactlen" "uint32_t timeout"
104 .Fn libusb20_tr_start "struct libusb20_transfer *xfer"
106 .Fn libusb20_tr_stop "struct libusb20_transfer *xfer"
108 .Fn libusb20_tr_submit "struct libusb20_transfer *xfer"
110 .Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer"
112 .Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer"
114 .Fn libusb20_dev_get_backend_name "struct libusb20_device *"
116 .Fn libusb20_dev_get_port_path "struct libusb20_device *pdev" "uint8_t *buf" "uint8_t bufsize"
118 .Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo"
120 .Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len"
122 .Fn libusb20_dev_get_desc "struct libusb20_device *pdev"
124 .Fn libusb20_dev_close "struct libusb20_device *pdev"
126 .Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index"
128 .Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex"
130 .Fn libusb20_dev_get_debug "struct libusb20_device *pdev"
132 .Fn libusb20_dev_get_fd "struct libusb20_device *pdev"
134 .Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index"
136 .Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max"
138 .Fn libusb20_dev_process "struct libusb20_device *pdev"
140 .Fn libusb20_dev_request_sync "struct libusb20_device *pdev" "struct LIBUSB20_CONTROL_SETUP_DECODED *setup" "void *data" "uint16_t *pactlen" "uint32_t timeout" "uint8_t flags"
142 .Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len"
144 .Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len"
146 .Fn libusb20_dev_reset "struct libusb20_device *pdev"
148 .Fn libusb20_dev_check_connected "struct libusb20_device *pdev"
150 .Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode"
152 .Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev"
154 .Fn libusb20_dev_get_power_usage "struct libusb20_device *pdev"
156 .Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index"
157 .Ft struct LIBUSB20_DEVICE_DESC_DECODED *
158 .Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev"
159 .Ft struct libusb20_config *
160 .Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index"
161 .Ft struct libusb20_device *
162 .Fn libusb20_dev_alloc "void"
164 .Fn libusb20_dev_get_address "struct libusb20_device *pdev"
166 .Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev"
168 .Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev"
170 .Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev"
172 .Fn libusb20_dev_get_mode "struct libusb20_device *pdev"
174 .Fn libusb20_dev_get_speed "struct libusb20_device *pdev"
176 .Fn libusb20_dev_get_config_index "struct libusb20_device *pdev"
178 .Fn libusb20_dev_free "struct libusb20_device *pdev"
180 .Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug"
182 .Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout"
184 .Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp"
186 .Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp"
188 .Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq"
190 .Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq"
192 .Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq"
194 .Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq"
195 .Ft struct libusb20_backend *
196 .Fn libusb20_be_alloc_default "void"
197 .Ft struct libusb20_backend *
198 .Fn libusb20_be_alloc_freebsd "void"
199 .Ft struct libusb20_backend *
200 .Fn libusb20_be_alloc_linux "void"
201 .Ft struct libusb20_device *
202 .Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
204 .Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
206 .Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
208 .Fn libusb20_be_free "struct libusb20_backend *pbe"
210 .Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off"
212 .Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off"
214 .Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded"
216 .Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded"
217 .Ft "const uint8_t *"
218 .Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc"
220 .Fn libusb20_strerror "int code"
222 .Fn libusb20_error_name "int code"
229 library implements functions to be able to easily access and control
230 USB through the USB file system interface.
233 interfaces are specific to the
235 usb stack and are not available on other operating systems, portable
236 applications should consider using
240 .Sh USB TRANSFER OPERATIONS
243 .Fn libusb20_tr_close
244 will release all kernel resources associated with an USB
247 This function returns zero upon success.
249 Non-zero return values indicate a LIBUSB20_ERROR value.
254 will allocate kernel buffer resources according to
258 associated with an USB
260 and bind the transfer to the specified
263 is the minimum buffer size which the data transport layer has to support.
268 library will use wMaxPacketSize to compute the buffer size.
269 This can be useful for isochronous transfers.
270 The actual buffer size can be greater than
273 .Fn libusb20_tr_get_max_total_length .
277 is OR'ed with LIBUSB20_MAX_FRAME_PRE_SCALE the remaining part of the
278 argument is converted from milliseconds into the actual number of
279 frames rounded up, when this function returns.
280 This flag is only valid for ISOCHRONOUS transfers and has no effect
281 for other transfer types.
282 The actual number of frames setup is found by calling
283 .Fn libusb20_tr_get_max_frames .
285 This function returns zero upon success.
287 Non-zero return values indicate a LIBUSB20_ERROR value.
291 .Fn libusb20_tr_get_pointer
292 will return a pointer to the allocated USB transfer according to the
298 This function returns NULL in case of failure.
302 .Fn libusb20_tr_get_time_complete
303 will return the completion time of an USB transfer in
304 millisecond units. This function is most useful for isochronous USB
305 transfers when doing echo cancelling.
309 .Fn libusb20_tr_get_actual_frames
310 will return the actual number of USB frames after an USB
311 transfer completed. A value of zero means that no data was transferred.
315 .Fn libusb20_tr_get_actual_length
316 will return the sum of the actual length for all
317 transferred USB frames for the given USB transfer.
321 .Fn libusb20_tr_get_max_frames
322 will return the maximum number of USB frames that were
323 allocated when an USB transfer was setup for the given USB transfer.
327 .Fn libusb20_tr_get_max_packet_length
328 will return the maximum packet length in bytes
329 associated with the given USB transfer.
331 The packet length can be used round up buffer sizes so that short USB
332 packets are avoided for proxy buffers.
337 .Fn libusb20_tr_get_max_total_length
338 will return the maximum value for the data length sum of all USB
339 frames associated with an USB transfer.
340 In case of control transfers the value returned does not include the
341 length of the SETUP packet, 8 bytes, which is part of frame zero.
342 The returned value of this function is always aligned to the maximum
343 packet size, wMaxPacketSize, of the endpoint which the USB transfer is
348 .Fn libusb20_tr_get_status
349 will return the status of an USB transfer.
351 Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums.
355 .Fn libusb20_tr_pending
356 will return non-zero if the given USB transfer is
357 pending for completion.
359 Else this function returns zero.
363 .Fn libusb20_tr_callback_wrapper
364 This is an internal function used to wrap asynchronous USB callbacks.
368 .Fn libusb20_tr_clear_stall_sync
369 This is an internal function used to synchronously clear the stall on
370 the given USB transfer.
372 Please see the USB specification for more information on stall
375 If the given USB transfer is pending when this function is called, the
376 USB transfer will complete with an error after that this function has
381 .Fn libusb20_tr_drain
382 will stop the given USB transfer and will not return
383 until the USB transfer has been stopped in hardware.
387 .Fn libusb20_tr_set_buffer
390 pointer for the given USB transfer and
393 Typically the frame index is zero.
398 .Fn libusb20_tr_set_callback
399 is used to set the USB callback for asynchronous USB
402 The callback type is defined by libusb20_tr_callback_t.
406 .Fn libusb20_tr_set_flags
407 is used to set various USB flags for the given USB transfer.
409 .It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK
410 Report a short frame as error.
411 .It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK
412 Multiple short frames are not allowed.
413 .It LIBUSB20_TRANSFER_FORCE_SHORT
414 All transmitted frames are short terminated.
415 .It LIBUSB20_TRANSFER_DO_CLEAR_STALL
416 Will do a clear-stall before starting the transfer.
421 .Fn libusb20_tr_get_length
422 returns the length of the given USB frame by index.
423 After an USB transfer is complete the USB frame length will get updated to the actual transferred length.
427 .Fn libusb20_tr_set_length
428 sets the length of the given USB frame by index.
432 .Fn libusb20_tr_set_priv_sc0
433 sets private driver pointer number zero.
437 .Fn libusb20_tr_set_priv_sc1
438 sets private driver pointer number one.
442 .Fn libusb20_tr_set_timeout
443 sets the timeout for the given USB transfer.
445 A timeout value of zero means no timeout.
447 The timeout is given in milliseconds.
451 .Fn libusb20_tr_set_total_frames
452 sets the total number of frames that should be executed when the USB transfer is submitted.
454 The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer.
458 .Fn libusb20_tr_setup_bulk
459 is a helper function for setting up a single frame USB BULK transfer.
463 .Fn libusb20_tr_setup_control
464 is a helper function for setting up a single or dual
465 frame USB CONTROL transfer depending on the control transfer length.
469 .Fn libusb20_tr_setup_intr
470 is a helper function for setting up a single frame USB INTERRUPT transfer.
474 .Fn libusb20_tr_setup_isoc
475 is a helper function for setting up a multi frame USB ISOCHRONOUS transfer.
479 .Fn libusb20_tr_bulk_intr_sync
480 will perform a synchronous BULK or INTERRUPT transfer having length given by the
482 argument and buffer pointer given by the
484 argument on the USB transfer given by the
490 argument is non-NULL the actual transfer length will be stored at the given pointer destination.
494 argument is non-zero the transfer will timeout after the given value in milliseconds.
496 This function does not change the transfer flags, like short packet not ok.
498 This function returns zero on success else a LIBUSB20_TRANSFER_XXX value is returned.
502 .Fn libusb20_tr_start
503 will get the USB transfer started, if not already
506 This function will not get the transfer queued in hardware.
508 This function is non-blocking.
513 will get the USB transfer stopped, if not already stopped.
515 This function is non-blocking, which means that the actual stop can
516 happen after the return of this function.
520 .Fn libusb20_tr_submit
521 will get the USB transfer queued in hardware.
526 .Fn libusb20_tr_get_priv_sc0
527 returns private driver pointer number zero associated
528 with an USB transfer.
533 .Fn libusb20_tr_get_priv_sc1
534 returns private driver pointer number one associated
535 with an USB transfer.
538 .Sh USB DEVICE OPERATIONS
541 .Fn libusb20_dev_get_backend_name
542 returns a zero terminated string describing the backend used.
546 .Fn libusb20_dev_get_port_path
547 retrieves the list of USB port numbers which the datastream for a given USB device follows.
548 The first port number is the Root HUB port number.
549 Then children port numbers follow.
550 The Root HUB device itself has a port path length of zero.
551 Valid port numbers start at one and range until and including 255.
552 Typically there should not be more than 16 levels, due to electrical and protocol limitations.
553 This functions returns the number of actual port levels upon success
554 else a LIBUSB20_ERROR value is returned which are always negative.
555 If the actual number of port levels is greater than the maximum
556 specified, a LIBUSB20_ERROR value is returned.
560 .Fn libusb20_dev_get_info
561 retrieves the BSD specific usb_device_info structure into the memory location given by
563 The USB device given by
565 must be opened before this function will succeed.
566 This function returns zero on success else a LIBUSB20_ERROR value is returned.
570 .Fn libusb20_dev_get_iface_desc
571 retrieves the kernel interface description for the given USB
573 The format of the USB interface description is: "drivername<unit>: <description>"
574 The description string is always zero terminated.
575 A zero length string is written in case no driver is attached to the given interface.
576 The USB device given by
578 must be opened before this function will succeed.
579 This function returns zero on success else a LIBUSB20_ERROR value is returned.
583 .Fn libusb20_dev_get_desc
584 returns a zero terminated string describing the given USB device.
585 The format of the string is: "drivername<unit>: <description>"
589 .Fn libusb20_dev_close
590 will close the given USB device.
592 This function returns zero on success else a LIBUSB20_ERROR value is
597 .Fn libusb20_dev_detach_kernel_driver
598 will try to detach the kernel driver for the USB interface given by
601 This function returns zero on success else a LIBUSB20_ERROR value is
606 .Fn libusb20_dev_set_config_index
607 will try to set the configuration index on an USB
610 The first configuration index is zero.
612 The un-configure index is 255.
614 This function returns zero on success else a LIBUSB20_ERROR value is returned.
618 .Fn libusb20_dev_get_debug
619 returns the debug level of an USB device.
623 .Fn libusb20_dev_get_fd
624 returns the file descriptor of the given USB device.
626 A negative value is returned when no file descriptor is present.
628 The file descriptor can be used for polling purposes.
632 .Fn libusb20_dev_kernel_driver_active
633 returns zero if a kernel driver is active on the given USB interface.
635 Else a LIBUSB20_ERROR value is returned.
639 .Fn libusb20_dev_open
640 opens an USB device so that setting up USB transfers
643 The number of USB transfers can be zero which means only control
644 transfers are allowed.
646 This function returns zero on success else a LIBUSB20_ERROR value is
649 A return value of LIBUSB20_ERROR_BUSY means that the device is already
654 .Fn libusb20_dev_process
655 is called to sync kernel USB transfers with userland USB
658 This function returns zero on success else a LIBUSB20_ERROR value is
659 returned typically indicating that the given USB device has been
664 .Fn libusb20_dev_request_sync
665 will perform a synchronous control request on the given
668 Before this call will succeed the USB device must be opened.
671 is a pointer to a decoded and host endian SETUP packet.
673 is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL.
675 is a pointer to a variable that will hold the actual transfer length after the control transaction is complete.
677 is the transaction timeout given in milliseconds.
678 A timeout of zero means no timeout.
680 is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK.
682 This function returns zero on success else a LIBUSB20_ERROR value is
687 .Fn libusb20_dev_req_string_sync
688 will synchronously request an USB string by language ID
689 and string index into the given buffer limited by a maximum length.
691 This function returns zero on success else a LIBUSB20_ERROR value is
696 .Fn libusb20_dev_req_string_simple_sync
697 will synchronously request an USB string using the
698 default language ID and convert the string into ASCII before storing
699 the string into the given buffer limited by a maximum length which
700 includes the terminating zero.
702 This function returns zero on success else a LIBUSB20_ERROR value is
708 .Fn libusb20_dev_reset
709 will try to BUS reset the given USB device and restore
710 the last set USB configuration.
712 This function returns zero on success else a LIBUSB20_ERROR value is
718 .Fn libusb20_dev_check_connected
719 will check if an opened USB device is still connected.
721 This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned.
726 .Fn libusb20_dev_set_power_mode
727 sets the power mode of the USB device.
731 .It LIBUSB20_POWER_OFF
732 .It LIBUSB20_POWER_ON
733 .It LIBUSB20_POWER_SAVE
734 .It LIBUSB20_POWER_SUSPEND
735 .It LIBUSB20_POWER_RESUME
738 This function returns zero on success else a LIBUSB20_ERROR value is
743 .Fn libusb20_dev_get_power_mode
744 returns the currently selected power mode for the given
749 .Fn libusb20_dev_get_power_usage
750 returns the reported power usage in milliamps for the given USB device.
751 A power usage of zero typically means that the device is self powered.
755 .Fn libusb20_dev_set_alt_index
756 will try to set the given alternate index for the given
759 This function returns zero on success else a LIBUSB20_ERROR value is
764 .Fn libusb20_dev_get_device_desc
765 returns a pointer to the decoded and host endian version
766 of the device descriptor.
768 The USB device need not be opened when calling this function.
772 .Fn libusb20_dev_alloc_config
773 will read out and decode the USB config descriptor for
774 the given USB device and config index. This function returns a pointer
775 to the decoded configuration which must eventually be passed to
776 free(). NULL is returned in case of failure.
780 .Fn libusb20_dev_alloc
781 is an internal function to allocate a new USB device.
785 .Fn libusb20_dev_get_address
786 returns the internal and not necessarily the real
787 hardware address of the given USB device.
788 Valid addresses start at one.
792 .Fn libusb20_dev_get_parent_address
793 returns the internal and not necessarily the real hardware address of
794 the given parent USB HUB device.
795 This value is zero for the root HUB which usually has a device address
797 Valid addresses start at one.
801 .Fn libusb20_dev_get_parent_port
802 returns the port number on the parent USB HUB device.
803 This value is zero for the root HUB which usually has a device address
805 Valid port numbers start at one.
809 .Fn libusb20_dev_get_bus_number
810 returns the internal bus number which the given USB
812 Valid bus numbers start at zero.
816 .Fn libusb20_dev_get_mode
817 returns the current operation mode of the USB entity.
819 Valid return values are:
821 .It LIBUSB20_MODE_HOST
822 .It LIBUSB20_MODE_DEVICE
827 .Fn libusb20_dev_get_speed
828 returns the current speed of the given USB device.
831 .It LIBUSB20_SPEED_UNKNOWN
832 .It LIBUSB20_SPEED_LOW
833 .It LIBUSB20_SPEED_FULL
834 .It LIBUSB20_SPEED_HIGH
835 .It LIBUSB20_SPEED_VARIABLE
836 .It LIBUSB20_SPEED_SUPER
841 .Fn libusb20_dev_get_config_index
842 returns the currently selected config index for the given
847 .Fn libusb20_dev_free
848 will free the given USB device and all associated USB
853 .Fn libusb20_dev_set_debug
854 will set the debug level for the given USB device.
858 .Fn libusb20_dev_wait_process
859 will wait until a pending USB transfer has completed on
860 the given USB device.
862 A timeout value can be specified which is passed on to the
866 .Sh USB BACKEND OPERATIONS
868 .Fn libusb20_be_get_template
869 will return the currently selected global USB device
870 side mode template into the integer pointer
872 This function returns zero on success else a LIBUSB20_ERROR value is
877 .Fn libusb20_be_set_template
878 will set the global USB device side mode template to
880 The new template is not activated until after the next USB
882 The template number decides how the USB device will present itself to
883 the USB Host, like Mass Storage Device, USB Ethernet Device. Also see
887 This function returns zero on success else a LIBUSB20_ERROR value is
892 .Fn libusb20_be_get_dev_quirk
893 will return the device quirk according to
895 into the libusb20_quirk structure pointed to by
897 This function returns zero on success else a LIBUSB20_ERROR value is
900 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
905 .Fn libusb20_be_get_quirk_name
906 will return the quirk name according to
908 into the libusb20_quirk structure pointed to by
910 This function returns zero on success else a LIBUSB20_ERROR value is
913 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
918 .Fn libusb20_be_add_dev_quirk
919 will add the libusb20_quirk structure pointed to by the
921 argument into the device quirk list.
923 This function returns zero on success else a LIBUSB20_ERROR value is
926 If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is
931 .Fn libusb20_be_remove_dev_quirk
932 will remove the quirk matching the libusb20_quirk structure pointed to by the
934 argument from the device quirk list.
936 This function returns zero on success else a LIBUSB20_ERROR value is
939 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
944 .Fn libusb20_be_alloc_default
945 .Fn libusb20_be_alloc_freebsd
946 .Fn libusb20_be_alloc_linux
947 These functions are used to allocate a specific USB backend or the
948 operating system default USB backend. Allocating a backend is a way to
949 scan for currently present USB devices.
953 .Fn libusb20_be_device_foreach
954 is used to iterate USB devices present in a USB backend.
956 The starting value of
960 This function returns the next USB device in the list.
962 If NULL is returned the end of the USB device list has been reached.
966 .Fn libusb20_be_dequeue_device
967 will dequeue the given USB device pointer from the
968 backend USB device list.
970 Dequeued USB devices will not be freed when the backend is freed.
974 .Fn libusb20_be_enqueue_device
975 will enqueue the given USB device pointer in the backend USB device list.
977 Enqueued USB devices will get freed when the backend is freed.
982 will free the given backend and all USB devices in its device list.
985 .Sh USB DESCRIPTOR PARSING
987 .Fn libusb20_me_get_1 pie offset
988 This function will return a byte at the given byte offset of a message
991 This function is safe against invalid offsets.
995 .Fn libusb20_me_get_2 pie offset
996 This function will return a little endian 16-bit value at the given byte offset of a message
999 This function is safe against invalid offsets.
1003 .Fn libusb20_me_encode pbuf len pdecoded
1004 This function will encode a so-called *DECODED structure into binary
1007 The total encoded length that will fit in the given buffer is
1010 If the buffer pointer is NULL no data will be written to the buffer
1015 .Fn libusb20_me_decode pbuf len pdecoded
1016 This function will decode a binary structure into a so-called *DECODED
1019 The total decoded length is returned.
1021 The buffer pointer cannot be NULL.
1026 .Fn libusb20_strerror "int code"
1027 Get the ASCII representation of the error given by the
1030 This function does not return NULL.
1033 .Fn libusb20_error_name "int code"
1034 Get the ASCII representation of the error enum given by the
1037 This function does not return NULL.
1055 API derives from the libusb project at sourceforge.