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2 .\" Copyright (c) 2008 Hans Petter Selasky
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27 .\" $FreeBSD: head/lib/libusb/libusb20.3 276294 2014-12-27 08:31:52Z joel $
28 .\"
29 .Dd January 16, 2015
30 .Dt LIBUSB20 3
31 .Os
32 .Sh NAME
33 .Nm libusb20
34 .
35 .Nd "USB access library"
36 .
37 .
38 .Sh LIBRARY
39 .
40 .
41 .Lb libusb
42 .
43 .
44 .
45 .Sh SYNOPSIS
46 .In libusb20.h
47 .Ft int
48 .Fn libusb20_tr_close "struct libusb20_transfer *xfer"
49 .Ft int
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 int
52 .Fn libusb20_tr_open_stream "struct libusb20_transfer *xfer" "uint32_t max_buf_size" "uint32_t max_frame_count" "uint8_t ep_no" "uint16_t stream_id"
53 .Ft struct libusb20_transfer*
54 .Fn libusb20_tr_get_pointer "struct libusb20_device *pdev" "uint16_t tr_index"
55 .Ft uint16_t
56 .Fn libusb20_tr_get_time_complete "struct libusb20_transfer *xfer"
57 .Ft uint32_t
58 .Fn libusb20_tr_get_actual_frames "struct libusb20_transfer *xfer"
59 .Ft uint32_t
60 .Fn libusb20_tr_get_actual_length "struct libusb20_transfer *xfer"
61 .Ft uint32_t
62 .Fn libusb20_tr_get_max_frames "struct libusb20_transfer *xfer"
63 .Ft uint32_t
64 .Fn libusb20_tr_get_max_packet_length "struct libusb20_transfer *xfer"
65 .Ft uint32_t
66 .Fn libusb20_tr_get_max_total_length "struct libusb20_transfer *xfer"
67 .Ft uint8_t
68 .Fn libusb20_tr_get_status "struct libusb20_transfer *xfer"
69 .Ft uint8_t
70 .Fn libusb20_tr_pending "struct libusb20_transfer *xfer"
71 .Ft void
72 .Fn libusb20_tr_callback_wrapper "struct libusb20_transfer *xfer"
73 .Ft void
74 .Fn libusb20_tr_clear_stall_sync "struct libusb20_transfer *xfer"
75 .Ft void
76 .Fn libusb20_tr_drain "struct libusb20_transfer *xfer"
77 .Ft void
78 .Fn libusb20_tr_set_buffer "struct libusb20_transfer *xfer" "void *buffer" "uint16_t fr_index"
79 .Ft void
80 .Fn libusb20_tr_set_callback "struct libusb20_transfer *xfer" "libusb20_tr_callback_t *cb"
81 .Ft void
82 .Fn libusb20_tr_set_flags "struct libusb20_transfer *xfer" "uint8_t flags"
83 .Ft uint32_t
84 .Fn libusb20_tr_get_length "struct libusb20_transfer *xfer" "uint16_t fr_index"
85 .Ft void
86 .Fn libusb20_tr_set_length "struct libusb20_transfer *xfer" "uint32_t length" "uint16_t fr_index"
87 .Ft void
88 .Fn libusb20_tr_set_priv_sc0 "struct libusb20_transfer *xfer" "void *sc0"
89 .Ft void
90 .Fn libusb20_tr_set_priv_sc1 "struct libusb20_transfer *xfer" "void *sc1"
91 .Ft void
92 .Fn libusb20_tr_set_timeout "struct libusb20_transfer *xfer" "uint32_t timeout"
93 .Ft void
94 .Fn libusb20_tr_set_total_frames "struct libusb20_transfer *xfer" "uint32_t nframes"
95 .Ft void
96 .Fn libusb20_tr_setup_bulk "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout"
97 .Ft void
98 .Fn libusb20_tr_setup_control "struct libusb20_transfer *xfer" "void *psetup" "void *pbuf" "uint32_t timeout"
99 .Ft void
100 .Fn libusb20_tr_setup_intr "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout"
101 .Ft void
102 .Fn libusb20_tr_setup_isoc "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint16_t fr_index"
103 .Ft uint8_t
104 .Fn libusb20_tr_bulk_intr_sync "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t *pactlen" "uint32_t timeout"
105 .Ft void
106 .Fn libusb20_tr_start "struct libusb20_transfer *xfer"
107 .Ft void
108 .Fn libusb20_tr_stop "struct libusb20_transfer *xfer"
109 .Ft void
110 .Fn libusb20_tr_submit "struct libusb20_transfer *xfer"
111 .Ft void *
112 .Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer"
113 .Ft void *
114 .Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer"
115 .Ft const char *
116 .Fn libusb20_dev_get_backend_name "struct libusb20_device *"
117 .Ft int
118 .Fn libusb20_dev_get_port_path "struct libusb20_device *pdev" "uint8_t *buf" "uint8_t bufsize"
119 .Ft int
120 .Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo"
121 .Ft int
122 .Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len"
123 .Ft const char *
124 .Fn libusb20_dev_get_desc "struct libusb20_device *pdev"
125 .Ft int
126 .Fn libusb20_dev_close "struct libusb20_device *pdev"
127 .Ft int
128 .Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index"
129 .Ft int
130 .Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex"
131 .Ft int
132 .Fn libusb20_dev_get_debug "struct libusb20_device *pdev"
133 .Ft int
134 .Fn libusb20_dev_get_fd "struct libusb20_device *pdev"
135 .Ft int
136 .Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index"
137 .Ft int
138 .Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max"
139 .Ft int
140 .Fn libusb20_dev_process "struct libusb20_device *pdev"
141 .Ft int
142 .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"
143 .Ft int
144 .Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len"
145 .Ft int
146 .Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len"
147 .Ft int
148 .Fn libusb20_dev_reset "struct libusb20_device *pdev"
149 .Ft int
150 .Fn libusb20_dev_check_connected "struct libusb20_device *pdev"
151 .Ft int
152 .Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode"
153 .Ft uint8_t
154 .Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev"
155 .Ft uint16_t
156 .Fn libusb20_dev_get_power_usage "struct libusb20_device *pdev"
157 .Ft int
158 .Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index"
159 .Ft struct LIBUSB20_DEVICE_DESC_DECODED *
160 .Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev"
161 .Ft struct libusb20_config *
162 .Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index"
163 .Ft struct libusb20_device *
164 .Fn libusb20_dev_alloc "void"
165 .Ft uint8_t
166 .Fn libusb20_dev_get_address "struct libusb20_device *pdev"
167 .Ft uint8_t
168 .Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev"
169 .Ft uint8_t
170 .Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev"
171 .Ft uint8_t
172 .Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev"
173 .Ft uint8_t
174 .Fn libusb20_dev_get_mode "struct libusb20_device *pdev"
175 .Ft uint8_t
176 .Fn libusb20_dev_get_speed "struct libusb20_device *pdev"
177 .Ft uint8_t
178 .Fn libusb20_dev_get_config_index "struct libusb20_device *pdev"
179 .Ft void
180 .Fn libusb20_dev_free "struct libusb20_device *pdev"
181 .Ft void
182 .Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug"
183 .Ft void
184 .Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout"
185 .Ft int
186 .Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp"
187 .Ft int
188 .Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp"
189 .Ft int
190 .Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq"
191 .Ft int
192 .Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq"
193 .Ft int
194 .Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq"
195 .Ft int
196 .Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq"
197 .Ft struct libusb20_backend *
198 .Fn libusb20_be_alloc_default "void"
199 .Ft struct libusb20_backend *
200 .Fn libusb20_be_alloc_freebsd "void"
201 .Ft struct libusb20_backend *
202 .Fn libusb20_be_alloc_linux "void"
203 .Ft struct libusb20_device *
204 .Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
205 .Ft void
206 .Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
207 .Ft void
208 .Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
209 .Ft void
210 .Fn libusb20_be_free "struct libusb20_backend *pbe"
211 .Ft "const char *"
212 .Fn libusb20_strerror "int code"
213 .Ft "const char *"
214 .Fn libusb20_error_name "int code"
215 .In libusb20_desc.h
216 .Ft uint8_t
217 .Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off"
218 .Ft uint16_t
219 .Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off"
220 .Ft uint16_t
221 .Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded"
222 .Ft uint16_t
223 .Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded"
224 .Ft "const uint8_t *"
225 .Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc"
226 .
227 .
228 .Sh DESCRIPTION
229 .
230 The
231 .Nm
232 library implements functions to be able to easily access and control
233 USB through the USB file system interface.
234 The
235 .Nm
236 interfaces are specific to the
237 .Fx
238 usb stack and are not available on other operating systems, portable
239 applications should consider using
240 .Xr libusb 3 .
241 .
242 .
243 .Sh USB TRANSFER OPERATIONS
244 .
245 .
246 .Fn libusb20_tr_close
247 will release all kernel resources associated with an USB
248 .Fa xfer .
249 .
250 This function returns zero upon success.
251 .
252 Non-zero return values indicate a LIBUSB20_ERROR value.
253 .
254 .Pp
255 .
256 .Fn libusb20_tr_open
257 will allocate kernel buffer resources according to
258 .Fa max_buf_size
259 and
260 .Fa max_frame_count
261 associated with an USB
262 .Fa pxfer
263 and bind the transfer to the specified
264 .Fa ep_no .
265 .Fa max_buf_size
266 is the minimum buffer size which the data transport layer has to support.
267 If
268 .Fa max_buf_size
269 is zero, the
270 .Nm
271 library will use wMaxPacketSize to compute the buffer size.
272 This can be useful for isochronous transfers.
273 The actual buffer size can be greater than
274 .Fa max_buf_size
275 and is returned by
276 .Fn libusb20_tr_get_max_total_length .
277 .
278 If
279 .Fa max_frame_count
280 is OR'ed with LIBUSB20_MAX_FRAME_PRE_SCALE the remaining part of the
281 argument is converted from milliseconds into the actual number of
282 frames rounded up, when this function returns.
283 This flag is only valid for ISOCHRONOUS transfers and has no effect
284 for other transfer types.
285 The actual number of frames setup is found by calling
286 .Fn libusb20_tr_get_max_frames .
287 .
288 This function returns zero upon success.
289 .
290 Non-zero return values indicate a LIBUSB20_ERROR value.
291 .
292 .Pp
293 .
294 .Fn libusb20_tr_open_stream
295 is identical to
296 .Fn libusb20_tr_open
297 except that a stream ID can be specified for BULK endpoints having
298 such a feature.
299 .Fn libusb20_tr_open
300 can be used to open stream ID zero.
301 .
302 .Pp
303 .
304 .Fn libusb20_tr_get_pointer
305 will return a pointer to the allocated USB transfer according to the
306 .Fa pdev
307 and
308 .Fa tr_index
309 arguments.
310 .
311 This function returns NULL in case of failure.
312 .
313 .Pp
314 .
315 .Fn libusb20_tr_get_time_complete
316 will return the completion time of an USB transfer in
317 millisecond units. This function is most useful for isochronous USB
318 transfers when doing echo cancelling.
319 .
320 .Pp
321 .
322 .Fn libusb20_tr_get_actual_frames
323 will return the actual number of USB frames after an USB
324 transfer completed. A value of zero means that no data was transferred.
325 .
326 .Pp
327 .
328 .Fn libusb20_tr_get_actual_length
329 will return the sum of the actual length for all
330 transferred USB frames for the given USB transfer.
331 .
332 .Pp
333 .
334 .Fn libusb20_tr_get_max_frames
335 will return the maximum number of USB frames that were
336 allocated when an USB transfer was setup for the given USB transfer.
337 .
338 .Pp
339 .
340 .Fn libusb20_tr_get_max_packet_length
341 will return the maximum packet length in bytes
342 associated with the given USB transfer.
343 .
344 The packet length can be used round up buffer sizes so that short USB
345 packets are avoided for proxy buffers.
346 .
347 .
348 .Pp
349 .
350 .Fn libusb20_tr_get_max_total_length
351 will return the maximum value for the data length sum of all USB
352 frames associated with an USB transfer.
353 In case of control transfers the value returned does not include the
354 length of the SETUP packet, 8 bytes, which is part of frame zero.
355 The returned value of this function is always aligned to the maximum
356 packet size, wMaxPacketSize, of the endpoint which the USB transfer is
357 bound to.
358 .
359 .Pp
360 .
361 .Fn libusb20_tr_get_status
362 will return the status of an USB transfer.
363 .
364 Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums.
365 .
366 .Pp
367 .
368 .Fn libusb20_tr_pending
369 will return non-zero if the given USB transfer is
370 pending for completion.
371 .
372 Else this function returns zero.
373 .
374 .Pp
375 .
376 .Fn libusb20_tr_callback_wrapper
377 This is an internal function used to wrap asynchronous USB callbacks.
378 .
379 .Pp
380 .
381 .Fn libusb20_tr_clear_stall_sync
382 This is an internal function used to synchronously clear the stall on
383 the given USB transfer.
384 .
385 Please see the USB specification for more information on stall
386 clearing.
387 .
388 If the given USB transfer is pending when this function is called, the
389 USB transfer will complete with an error after that this function has
390 been called.
391 .
392 .Pp
393 .
394 .Fn libusb20_tr_drain
395 will stop the given USB transfer and will not return
396 until the USB transfer has been stopped in hardware.
397 .
398 .Pp
399 .
400 .Fn libusb20_tr_set_buffer
401 is used to set the
402 .Fa buffer
403 pointer for the given USB transfer and
404 .Fa fr_index .
405 .
406 Typically the frame index is zero.
407 .
408 .
409 .Pp
410 .
411 .Fn libusb20_tr_set_callback
412 is used to set the USB callback for asynchronous USB
413 transfers.
414 .
415 The callback type is defined by libusb20_tr_callback_t.
416 .
417 .Pp
418 .
419 .Fn libusb20_tr_set_flags
420 is used to set various USB flags for the given USB transfer.
421 .Bl -tag -width "LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK"
422 .It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK
423 Report a short frame as error.
424 .It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK
425 Multiple short frames are not allowed.
426 .It LIBUSB20_TRANSFER_FORCE_SHORT
427 All transmitted frames are short terminated.
428 .It LIBUSB20_TRANSFER_DO_CLEAR_STALL
429 Will do a clear-stall before starting the transfer.
430 .El
431 .
432 .Pp
433 .
434 .Fn libusb20_tr_get_length
435 returns the length of the given USB frame by index.
436 After an USB transfer is complete the USB frame length will get updated to the actual transferred length.
437 .
438 .Pp
439 .
440 .Fn libusb20_tr_set_length
441 sets the length of the given USB frame by index.
442 .
443 .Pp
444 .
445 .Fn libusb20_tr_set_priv_sc0
446 sets private driver pointer number zero.
447 .
448 .Pp
449 .
450 .Fn libusb20_tr_set_priv_sc1
451 sets private driver pointer number one.
452 .
453 .Pp
454 .
455 .Fn libusb20_tr_set_timeout
456 sets the timeout for the given USB transfer.
457 .
458 A timeout value of zero means no timeout.
459 .
460 The timeout is given in milliseconds.
461 .
462 .Pp
463 .
464 .Fn libusb20_tr_set_total_frames
465 sets the total number of frames that should be executed when the USB transfer is submitted.
466 .
467 The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer.
468 .
469 .Pp
470 .
471 .Fn libusb20_tr_setup_bulk
472 is a helper function for setting up a single frame USB BULK transfer.
473 .
474 .Pp
475 .
476 .Fn libusb20_tr_setup_control
477 is a helper function for setting up a single or dual
478 frame USB CONTROL transfer depending on the control transfer length.
479 .
480 .Pp
481 .
482 .Fn libusb20_tr_setup_intr
483 is a helper function for setting up a single frame USB INTERRUPT transfer.
484 .
485 .Pp
486 .
487 .Fn libusb20_tr_setup_isoc
488 is a helper function for setting up a multi frame USB ISOCHRONOUS transfer.
489 .
490 .Pp
491 .
492 .Fn libusb20_tr_bulk_intr_sync
493 will perform a synchronous BULK or INTERRUPT transfer having length given by the
494 .Fa length
495 argument and buffer pointer given by the
496 .Fa pbuf
497 argument on the USB transfer given by the
498 .Fa xfer
499 argument.
500 .
501 If the
502 .Fa pactlen
503 argument is non-NULL the actual transfer length will be stored at the given pointer destination.
504 .
505 If the
506 .Fa timeout
507 argument is non-zero the transfer will timeout after the given value in milliseconds.
508 .
509 This function does not change the transfer flags, like short packet not ok.
510 .
511 This function returns zero on success else a LIBUSB20_TRANSFER_XXX value is returned.
512 .
513 .Pp
514 .
515 .Fn libusb20_tr_start
516 will get the USB transfer started, if not already
517 started.
518 .
519 This function will not get the transfer queued in hardware.
520 .
521 This function is non-blocking.
522 .
523 .Pp
524 .
525 .Fn libusb20_tr_stop
526 will get the USB transfer stopped, if not already stopped.
527 .
528 This function is non-blocking, which means that the actual stop can
529 happen after the return of this function.
530 .
531 .Pp
532 .
533 .Fn libusb20_tr_submit
534 will get the USB transfer queued in hardware.
535 .
536 .
537 .Pp
538 .
539 .Fn libusb20_tr_get_priv_sc0
540 returns private driver pointer number zero associated
541 with an USB transfer.
542 .
543 .
544 .Pp
545 .
546 .Fn libusb20_tr_get_priv_sc1
547 returns private driver pointer number one associated
548 with an USB transfer.
549 .
550 .
551 .Sh USB DEVICE OPERATIONS
552 .
553 .
554 .Fn libusb20_dev_get_backend_name
555 returns a zero terminated string describing the backend used.
556 .
557 .Pp
558 .
559 .Fn libusb20_dev_get_port_path
560 retrieves the list of USB port numbers which the datastream for a given USB device follows.
561 The first port number is the Root HUB port number.
562 Then children port numbers follow.
563 The Root HUB device itself has a port path length of zero.
564 Valid port numbers start at one and range until and including 255.
565 Typically there should not be more than 16 levels, due to electrical and protocol limitations.
566 This functions returns the number of actual port levels upon success
567 else a LIBUSB20_ERROR value is returned which are always negative.
568 If the actual number of port levels is greater than the maximum
569 specified, a LIBUSB20_ERROR value is returned.
570 .
571 .Pp
572 .
573 .Fn libusb20_dev_get_info
574 retrieves the BSD specific usb_device_info structure into the memory location given by
575 .Fa pinfo .
576 The USB device given by
577 .Fa pdev
578 must be opened before this function will succeed.
579 This function returns zero on success else a LIBUSB20_ERROR value is returned.
580 .
581 .Pp
582 .
583 .Fn libusb20_dev_get_iface_desc
584 retrieves the kernel interface description for the given USB
585 .Fa iface_index .
586 The format of the USB interface description is: "drivername<unit>: <description>"
587 The description string is always zero terminated.
588 A zero length string is written in case no driver is attached to the given interface.
589 The USB device given by
590 .Fa pdev
591 must be opened before this function will succeed.
592 This function returns zero on success else a LIBUSB20_ERROR value is returned.
593 .
594 .Pp
595 .
596 .Fn libusb20_dev_get_desc
597 returns a zero terminated string describing the given USB device.
598 The format of the string is: "drivername<unit>: <description>"
599 .
600 .Pp
601 .
602 .Fn libusb20_dev_close
603 will close the given USB device.
604 .
605 This function returns zero on success else a LIBUSB20_ERROR value is
606 returned.
607 .
608 .Pp
609 .
610 .Fn libusb20_dev_detach_kernel_driver
611 will try to detach the kernel driver for the USB interface given by
612 .Fa iface_index .
613 .
614 This function returns zero on success else a LIBUSB20_ERROR value is
615 returned.
616 .
617 .Pp
618 .
619 .Fn libusb20_dev_set_config_index
620 will try to set the configuration index on an USB
621 device.
622 .
623 The first configuration index is zero.
624 .
625 The un-configure index is 255.
626 .
627 This function returns zero on success else a LIBUSB20_ERROR value is returned.
628 .
629 .Pp
630 .
631 .Fn libusb20_dev_get_debug
632 returns the debug level of an USB device.
633 .
634 .Pp
635 .
636 .Fn libusb20_dev_get_fd
637 returns the file descriptor of the given USB device.
638 .
639 A negative value is returned when no file descriptor is present.
640 .
641 The file descriptor can be used for polling purposes.
642 .
643 .Pp
644 .
645 .Fn libusb20_dev_kernel_driver_active
646 returns zero if a kernel driver is active on the given USB interface.
647 .
648 Else a LIBUSB20_ERROR value is returned.
649 .
650 .Pp
651 .
652 .Fn libusb20_dev_open
653 opens an USB device so that setting up USB transfers
654 becomes possible.
655 .
656 The number of USB transfers can be zero which means only control
657 transfers are allowed.
658 .
659 This function returns zero on success else a LIBUSB20_ERROR value is
660 returned.
661 .
662 A return value of LIBUSB20_ERROR_BUSY means that the device is already
663 opened.
664 .
665 .Pp
666 .
667 .Fn libusb20_dev_process
668 is called to sync kernel USB transfers with userland USB
669 transfers.
670 .
671 This function returns zero on success else a LIBUSB20_ERROR value is
672 returned typically indicating that the given USB device has been
673 detached.
674 .
675 .Pp
676 .
677 .Fn libusb20_dev_request_sync
678 will perform a synchronous control request on the given
679 USB device.
680 .
681 Before this call will succeed the USB device must be opened.
682 .
683 .Fa setup
684 is a pointer to a decoded and host endian SETUP packet.
685 .Fa data
686 is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL.
687 .Fa pactlen
688 is a pointer to a variable that will hold the actual transfer length after the control transaction is complete.
689 .Fa timeout
690 is the transaction timeout given in milliseconds.
691 A timeout of zero means no timeout.
692 .Fa flags
693 is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK.
694 .
695 This function returns zero on success else a LIBUSB20_ERROR value is
696 returned.
697 .
698 .Pp
699 .
700 .Fn libusb20_dev_req_string_sync
701 will synchronously request an USB string by language ID
702 and string index into the given buffer limited by a maximum length.
703 .
704 This function returns zero on success else a LIBUSB20_ERROR value is
705 returned.
706 .
707 .Pp
708 .
709 .Fn libusb20_dev_req_string_simple_sync
710 will synchronously request an USB string using the
711 default language ID and convert the string into ASCII before storing
712 the string into the given buffer limited by a maximum length which
713 includes the terminating zero.
714 .
715 This function returns zero on success else a LIBUSB20_ERROR value is
716 returned.
717 .
718 .
719 .Pp
720 .
721 .Fn libusb20_dev_reset
722 will try to BUS reset the given USB device and restore
723 the last set USB configuration.
724 .
725 This function returns zero on success else a LIBUSB20_ERROR value is
726 returned.
727 .
728 .
729 .Pp
730 .
731 .Fn libusb20_dev_check_connected
732 will check if an opened USB device is still connected.
733 .
734 This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned.
735 .
736 .
737 .Pp
738 .
739 .Fn libusb20_dev_set_power_mode
740 sets the power mode of the USB device.
741 .
742 Valid power modes:
743 .Bl -tag -width "LIBUSB20_POWER_OFF"
744 .It LIBUSB20_POWER_OFF
745 .It LIBUSB20_POWER_ON
746 .It LIBUSB20_POWER_SAVE
747 .It LIBUSB20_POWER_SUSPEND
748 .It LIBUSB20_POWER_RESUME
749 .El
750 .Pp
751 .
752 This function returns zero on success else a LIBUSB20_ERROR value is
753 returned.
754 .
755 .Pp
756 .
757 .Fn libusb20_dev_get_power_mode
758 returns the currently selected power mode for the given
759 USB device.
760 .
761 .Pp
762 .
763 .Fn libusb20_dev_get_power_usage
764 returns the reported power usage in milliamps for the given USB device.
765 A power usage of zero typically means that the device is self powered.
766 .
767 .Pp
768 .
769 .Fn libusb20_dev_set_alt_index
770 will try to set the given alternate index for the given
771 USB interface index.
772 .
773 This function returns zero on success else a LIBUSB20_ERROR value is
774 returned.
775 .
776 .Pp
777 .
778 .Fn libusb20_dev_get_device_desc
779 returns a pointer to the decoded and host endian version
780 of the device descriptor.
781 .
782 The USB device need not be opened when calling this function.
783 .
784 .Pp
785 .
786 .Fn libusb20_dev_alloc_config
787 will read out and decode the USB config descriptor for
788 the given USB device and config index. This function returns a pointer
789 to the decoded configuration which must eventually be passed to
790 free(). NULL is returned in case of failure.
791 .
792 .Pp
793 .
794 .Fn libusb20_dev_alloc
795 is an internal function to allocate a new USB device.
796 .
797 .Pp
798 .
799 .Fn libusb20_dev_get_address
800 returns the internal and not necessarily the real
801 hardware address of the given USB device.
802 Valid addresses start at one.
803 .
804 .Pp
805 .
806 .Fn libusb20_dev_get_parent_address
807 returns the internal and not necessarily the real hardware address of
808 the given parent USB HUB device.
809 This value is zero for the root HUB which usually has a device address
810 equal to one.
811 Valid addresses start at one.
812 .
813 .Pp
814 .
815 .Fn libusb20_dev_get_parent_port
816 returns the port number on the parent USB HUB device.
817 This value is zero for the root HUB which usually has a device address
818 equal to one.
819 Valid port numbers start at one.
820 .
821 .Pp
822 .
823 .Fn libusb20_dev_get_bus_number
824 returns the internal bus number which the given USB
825 device belongs to.
826 Valid bus numbers start at zero.
827 .
828 .Pp
829 .
830 .Fn libusb20_dev_get_mode
831 returns the current operation mode of the USB entity.
832 .
833 Valid return values are:
834 .Bl -tag -width "LIBUSB20_MODE_DEVICE"
835 .It LIBUSB20_MODE_HOST
836 .It LIBUSB20_MODE_DEVICE
837 .El
838 .
839 .Pp
840 .
841 .Fn libusb20_dev_get_speed
842 returns the current speed of the given USB device.
843 .
844 .Bl -tag -width "LIBUSB20_SPEED_VARIABLE"
845 .It LIBUSB20_SPEED_UNKNOWN
846 .It LIBUSB20_SPEED_LOW
847 .It LIBUSB20_SPEED_FULL
848 .It LIBUSB20_SPEED_HIGH
849 .It LIBUSB20_SPEED_VARIABLE
850 .It LIBUSB20_SPEED_SUPER
851 .El
852 .
853 .Pp
854 .
855 .Fn libusb20_dev_get_config_index
856 returns the currently selected config index for the given
857 USB device.
858 .
859 .Pp
860 .
861 .Fn libusb20_dev_free
862 will free the given USB device and all associated USB
863 transfers.
864 .
865 .Pp
866 .
867 .Fn libusb20_dev_set_debug
868 will set the debug level for the given USB device.
869 .
870 .Pp
871 .
872 .Fn libusb20_dev_wait_process
873 will wait until a pending USB transfer has completed on
874 the given USB device.
875 .
876 A timeout value can be specified which is passed on to the
877 .Xr poll 2
878 function.
879 .
880 .Sh USB BACKEND OPERATIONS
881 .
882 .Fn libusb20_be_get_template
883 will return the currently selected global USB device
884 side mode template into the integer pointer
885 .Fa ptemp .
886 This function returns zero on success else a LIBUSB20_ERROR value is
887 returned.
888 .
889 .Pp
890 .
891 .Fn libusb20_be_set_template
892 will set the global USB device side mode template to
893 .Fa temp .
894 The new template is not activated until after the next USB
895 enumeration.
896 The template number decides how the USB device will present itself to
897 the USB Host, like Mass Storage Device, USB Ethernet Device.
898 .\"Also see the
899 .\".Xr usb2_template 4
900 .\"module.
901 This function returns zero on success else a LIBUSB20_ERROR value is
902 returned.
903 .
904 .Pp
905 .
906 .Fn libusb20_be_get_dev_quirk
907 will return the device quirk according to
908 .Fa index
909 into the libusb20_quirk structure pointed to by
910 .Fa pq .
911 This function returns zero on success else a LIBUSB20_ERROR value is
912 returned.
913 .
914 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
915 returned.
916 .
917 .Pp
918 .
919 .Fn libusb20_be_get_quirk_name
920 will return the quirk name according to
921 .Fa index
922 into the libusb20_quirk structure pointed to by
923 .Fa pq .
924 This function returns zero on success else a LIBUSB20_ERROR value is
925 returned.
926 .
927 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
928 returned.
929 .
930 .Pp
931 .
932 .Fn libusb20_be_add_dev_quirk
933 will add the libusb20_quirk structure pointed to by the
934 .Fa pq
935 argument into the device quirk list.
936 .
937 This function returns zero on success else a LIBUSB20_ERROR value is
938 returned.
939 .
940 If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is
941 returned.
942 .
943 .Pp
944 .
945 .Fn libusb20_be_remove_dev_quirk
946 will remove the quirk matching the libusb20_quirk structure pointed to by the
947 .Fa pq
948 argument from the device quirk list.
949 .
950 This function returns zero on success else a LIBUSB20_ERROR value is
951 returned.
952 .
953 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
954 returned.
955 .
956 .Pp
957 .
958 .Fn libusb20_be_alloc_default
959 .Fn libusb20_be_alloc_freebsd
960 .Fn libusb20_be_alloc_linux
961 These functions are used to allocate a specific USB backend or the
962 operating system default USB backend. Allocating a backend is a way to
963 scan for currently present USB devices.
964 .
965 .Pp
966 .
967 .Fn libusb20_be_device_foreach
968 is used to iterate USB devices present in a USB backend.
969 .
970 The starting value of
971 .Fa pdev
972 is NULL.
973 .
974 This function returns the next USB device in the list.
975 .
976 If NULL is returned the end of the USB device list has been reached.
977 .
978 .Pp
979 .
980 .Fn libusb20_be_dequeue_device
981 will dequeue the given USB device pointer from the
982 backend USB device list.
983 .
984 Dequeued USB devices will not be freed when the backend is freed.
985 .
986 .Pp
987 .
988 .Fn libusb20_be_enqueue_device
989 will enqueue the given USB device pointer in the backend USB device list.
990 .
991 Enqueued USB devices will get freed when the backend is freed.
992 .
993 .Pp
994 .
995 .Fn libusb20_be_free
996 will free the given backend and all USB devices in its device list.
997 .
998 .
999 .Sh USB DESCRIPTOR PARSING
1000 .
1001 .Fn libusb20_me_get_1 pie offset
1002 This function will return a byte at the given byte offset of a message
1003 entity.
1004 .
1005 This function is safe against invalid offsets.
1006 .
1007 .Pp
1008 .
1009 .Fn libusb20_me_get_2 pie offset
1010 This function will return a little endian 16-bit value at the given byte offset of a message
1011 entity.
1012 .
1013 This function is safe against invalid offsets.
1014 .
1015 .Pp
1016 .
1017 .Fn libusb20_me_encode pbuf len pdecoded
1018 This function will encode a so-called *DECODED structure into binary
1019 format.
1020 .
1021 The total encoded length that will fit in the given buffer is
1022 returned.
1023 .
1024 If the buffer pointer is NULL no data will be written to the buffer
1025 location.
1026 .
1027 .Pp
1028 .
1029 .Fn libusb20_me_decode pbuf len pdecoded
1030 This function will decode a binary structure into a so-called *DECODED
1031 structure.
1032 .
1033 The total decoded length is returned.
1034 .
1035 The buffer pointer cannot be NULL.
1036 .
1037 .
1038 .Sh USB DEBUGGING
1039 .Ft const char *
1040 .Fn libusb20_strerror "int code"
1041 Get the ASCII representation of the error given by the
1042 .Fa code
1043 argument.
1044 This function does not return NULL.
1045 .Pp
1046 .Ft const char *
1047 .Fn libusb20_error_name "int code"
1048 Get the ASCII representation of the error enum given by the
1049 .Fa code
1050 argument.
1051 This function does not return NULL.
1052 .
1053 .Sh FILES
1054 .Bl -tag -width Pa
1055 .It Pa /dev/usb
1056 .El
1057 .Sh SEE ALSO
1058 .Xr libusb 3 ,
1059 .Xr usb 4 ,
1060 .Xr usbconfig 8 ,
1061 .Xr usbdump 8
1062 .
1063 .
1064 .Sh HISTORY
1065 .
1066 .
1067 Some parts of the
1068 .Nm
1069 API derives from the libusb project at sourceforge.