1.\" 2.\" Copyright (c) 2008 Hans Petter Selasky 3.\" 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 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. 14.\" 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 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd October 14, 2010 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. 41USB access library (libusb -lusb) 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 struct libusb20_transfer* 52.Fn libusb20_tr_get_pointer "struct libusb20_device *pdev" "uint16_t tr_index" 53.Ft uint16_t 54.Fn libusb20_tr_get_time_complete "struct libusb20_transfer *xfer" 55.Ft uint32_t 56.Fn libusb20_tr_get_actual_frames "struct libusb20_transfer *xfer" 57.Ft uint32_t 58.Fn libusb20_tr_get_actual_length "struct libusb20_transfer *xfer" 59.Ft uint32_t 60.Fn libusb20_tr_get_max_frames "struct libusb20_transfer *xfer" 61.Ft uint32_t 62.Fn libusb20_tr_get_max_packet_length "struct libusb20_transfer *xfer" 63.Ft uint32_t 64.Fn libusb20_tr_get_max_total_length "struct libusb20_transfer *xfer" 65.Ft uint8_t 66.Fn libusb20_tr_get_status "struct libusb20_transfer *xfer" 67.Ft uint8_t 68.Fn libusb20_tr_pending "struct libusb20_transfer *xfer" 69.Ft void 70.Fn libusb20_tr_callback_wrapper "struct libusb20_transfer *xfer" 71.Ft void 72.Fn libusb20_tr_clear_stall_sync "struct libusb20_transfer *xfer" 73.Ft void 74.Fn libusb20_tr_drain "struct libusb20_transfer *xfer" 75.Ft void 76.Fn libusb20_tr_set_buffer "struct libusb20_transfer *xfer" "void *buffer" "uint16_t fr_index" 77.Ft void 78.Fn libusb20_tr_set_callback "struct libusb20_transfer *xfer" "libusb20_tr_callback_t *cb" 79.Ft void 80.Fn libusb20_tr_set_flags "struct libusb20_transfer *xfer" "uint8_t flags" 81.Ft uint32_t 82.Fn libusb20_tr_get_length "struct libusb20_transfer *xfer" "uint16_t fr_index" 83.Ft void 84.Fn libusb20_tr_set_length "struct libusb20_transfer *xfer" "uint32_t length" "uint16_t fr_index" 85.Ft void 86.Fn libusb20_tr_set_priv_sc0 "struct libusb20_transfer *xfer" "void *sc0" 87.Ft void 88.Fn libusb20_tr_set_priv_sc1 "struct libusb20_transfer *xfer" "void *sc1" 89.Ft void 90.Fn libusb20_tr_set_timeout "struct libusb20_transfer *xfer" "uint32_t timeout" 91.Ft void 92.Fn libusb20_tr_set_total_frames "struct libusb20_transfer *xfer" "uint32_t nframes" 93.Ft void 94.Fn libusb20_tr_setup_bulk "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout" 95.Ft void 96.Fn libusb20_tr_setup_control "struct libusb20_transfer *xfer" "void *psetup" "void *pbuf" "uint32_t timeout" 97.Ft void 98.Fn libusb20_tr_setup_intr "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout" 99.Ft void 100.Fn libusb20_tr_setup_isoc "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint61_t fr_index" 101.Ft uint8_t 102.Fn libusb20_tr_bulk_intr_sync "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t *pactlen" "uint32_t timeout" 103.Ft void 104.Fn libusb20_tr_start "struct libusb20_transfer *xfer" 105.Ft void 106.Fn libusb20_tr_stop "struct libusb20_transfer *xfer" 107.Ft void 108.Fn libusb20_tr_submit "struct libusb20_transfer *xfer" 109.Ft void * 110.Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer" 111.Ft void * 112.Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer" 113.Ft const char * 114.Fn libusb20_dev_get_backend_name "struct libusb20_device *" 115.Ft int 116.Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo" 117.Ft int 118.Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len" 119.Ft const char * 120.Fn libusb20_dev_get_desc "struct libusb20_device *pdev" 121.Ft int 122.Fn libusb20_dev_close "struct libusb20_device *pdev" 123.Ft int 124.Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index" 125.Ft int 126.Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex" 127.Ft int 128.Fn libusb20_dev_get_debug "struct libusb20_device *pdev" 129.Ft int 130.Fn libusb20_dev_get_fd "struct libusb20_device *pdev" 131.Ft int 132.Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index" 133.Ft int 134.Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max" 135.Ft int 136.Fn libusb20_dev_process "struct libusb20_device *pdev" 137.Ft int 138.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" 139.Ft int 140.Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len" 141.Ft int 142.Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len" 143.Ft int 144.Fn libusb20_dev_reset "struct libusb20_device *pdev" 145.Ft int 146.Fn libusb20_dev_check_connected "struct libusb20_device *pdev" 147.Ft int 148.Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode" 149.Ft uint8_t 150.Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev" 151.Ft int 152.Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index" 153.Ft struct LIBUSB20_DEVICE_DESC_DECODED * 154.Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev" 155.Ft struct libusb20_config * 156.Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index" 157.Ft struct libusb20_device * 158.Fn libusb20_dev_alloc "void" 159.Ft uint8_t 160.Fn libusb20_dev_get_address "struct libusb20_device *pdev" 161.Ft uint8_t 162.Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev" 163.Ft uint8_t 164.Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev" 165.Ft uint8_t 166.Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev" 167.Ft uint8_t 168.Fn libusb20_dev_get_mode "struct libusb20_device *pdev" 169.Ft uint8_t 170.Fn libusb20_dev_get_speed "struct libusb20_device *pdev" 171.Ft uint8_t 172.Fn libusb20_dev_get_config_index "struct libusb20_device *pdev" 173.Ft void 174.Fn libusb20_dev_free "struct libusb20_device *pdev" 175.Ft void 176.Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug" 177.Ft void 178.Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout" 179.Ft int 180.Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp" 181.Ft int 182.Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp" 183.Ft int 184.Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq" 185.Ft int 186.Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq" 187.Ft int 188.Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 189.Ft int 190.Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 191.Ft struct libusb20_backend * 192.Fn libusb20_be_alloc_default "void" 193.Ft struct libusb20_backend * 194.Fn libusb20_be_alloc_freebsd "void" 195.Ft struct libusb20_backend * 196.Fn libusb20_be_alloc_linux "void" 197.Ft struct libusb20_device * 198.Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 199.Ft void 200.Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 201.Ft void 202.Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 203.Ft void 204.Fn libusb20_be_free "struct libusb20_backend *pbe" 205.Ft uint8_t 206.Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off" 207.Ft uint16_t 208.Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off" 209.Ft uint16_t 210.Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded" 211.Ft uint16_t 212.Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded" 213.Ft "const uint8_t *" 214.Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc" 215.Ft "const char *" 216.Fn libusb20_strerror "int code" 217.Ft "const char *" 218.Fn libusb20_error_name "int code" 219. 220. 221.Sh DESCRIPTION 222. 223The 224.Nm 225library implements functions to be able to easily access and control 226USB through the USB file system interface. 227The 228.Nm 229interfaces are specific to the 230.Fx 231usb stack and are not available on other operating systems, portable 232applications should consider using 233.Xr libusb 3 . 234. 235. 236.Sh USB TRANSFER OPERATIONS 237. 238.Pp 239. 240.Fn libusb20_tr_close 241will release all kernel resources associated with an USB 242.Fa xfer . 243. 244This function returns zero upon success. 245. 246Non-zero return values indicate a LIBUSB20_ERROR value. 247. 248.Pp 249. 250.Fn libusb20_tr_open 251will allocate kernel buffer resources according to 252.Fa max_buf_size 253and 254.Fa max_frame_count 255associated with an USB 256.Fa pxfer 257and bind the transfer to the specified 258.Fa ep_no . 259.Fa max_buf_size 260is the minimum buffer size which the data transport layer has to support. 261If 262.Fa max_buf_size 263is zero, the 264.Nm 265library will use wMaxPacketSize to compute the buffer size. 266This can be useful for isochronous transfers. 267The actual buffer size can be greater than 268.Fa max_buf_size 269and is returned by 270.Fn libusb20_tr_get_max_total_length . 271. 272If 273.Fa max_frame_count 274is OR'ed with LIBUSB20_MAX_FRAME_PRE_SCALE the remaining part of the 275argument is converted from milliseconds into the actual number of 276frames rounded up, when this function returns. 277This flag is only valid for ISOCHRONOUS transfers and has no effect 278for other transfer types. 279The actual number of frames setup is found by calling 280.Fn libusb20_tr_get_max_frames . 281. 282This function returns zero upon success. 283. 284Non-zero return values indicate a LIBUSB20_ERROR value. 285. 286.Pp 287. 288.Fn libusb20_tr_get_pointer 289will return a pointer to the allocated USB transfer according to the 290.Fa pdev 291and 292.Fa tr_index 293arguments. 294. 295This function returns NULL in case of failure. 296. 297.Pp 298. 299.Fn libusb20_tr_get_time_complete 300will return the completion time of an USB transfer in 301millisecond units. This function is most useful for isochronous USB 302transfers when doing echo cancelling. 303. 304.Pp 305. 306.Fn libusb20_tr_get_actual_frames 307will return the actual number of USB frames after an USB 308transfer completed. A value of zero means that no data was transferred. 309. 310.Pp 311. 312.Fn libusb20_tr_get_actual_length 313will return the sum of the actual length for all 314transferred USB frames for the given USB transfer. 315. 316.Pp 317. 318.Fn libusb20_tr_get_max_frames 319will return the maximum number of USB frames that were 320allocated when an USB transfer was setup for the given USB transfer. 321. 322.Pp 323. 324.Fn libusb20_tr_get_max_packet_length 325will return the maximum packet length in bytes 326associated with the given USB transfer. 327. 328The packet length can be used round up buffer sizes so that short USB 329packets are avoided for proxy buffers. 330. 331. 332.Pp 333. 334.Fn libusb20_tr_get_max_total_length 335function will return the maximum value for the data length sum of all USB 336frames associated with an USB transfer. 337In case of control transfers the value returned does not include the 338length of the SETUP packet, 8 bytes, which is part of frame zero. 339The returned value of this function is always aligned to the maximum 340packet size, wMaxPacketSize, of the endpoint which the USB transfer is 341bound to. 342. 343.Pp 344. 345.Fn libusb20_tr_get_status 346will return the status of an USB transfer. 347. 348Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums. 349. 350.Pp 351. 352.Fn libusb20_tr_pending 353will return non-zero if the given USB transfer is 354pending for completion. 355. 356Else this function returns zero. 357. 358.Pp 359. 360.Fn libusb20_tr_callback_wrapper 361This is an internal function used to wrap asynchronous USB callbacks. 362. 363.Pp 364. 365.Fn libusb20_tr_clear_stall_sync 366This is an internal function used to synchronously clear the stall on 367the given USB transfer. 368. 369Please see the USB specification for more information on stall 370clearing. 371. 372If the given USB transfer is pending when this function is called, the 373USB transfer will complete with an error after that this function has 374been called. 375. 376.Pp 377. 378.Fn libusb20_tr_drain 379will stop the given USB transfer and will not return 380until the USB transfer has been stopped in hardware. 381. 382.Pp 383. 384.Fn libusb20_tr_set_buffer 385is used to set the 386.Fa buffer 387pointer for the given USB transfer and 388.Fa fr_index . 389. 390Typically the frame index is zero. 391. 392. 393.Pp 394. 395.Fn libusb20_tr_set_callback 396is used to set the USB callback for asynchronous USB 397transfers. 398. 399The callback type is defined by libusb20_tr_callback_t. 400. 401.Pp 402. 403.Fn libusb20_tr_set_flags 404is used to set various USB flags for the given USB transfer. 405.Bl -tag 406.It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK 407Report a short frame as error. 408.It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK 409Multiple short frames are not allowed. 410.It LIBUSB20_TRANSFER_FORCE_SHORT 411All transmitted frames are short terminated. 412.It LIBUSB20_TRANSFER_DO_CLEAR_STALL 413Will do a clear-stall before starting the transfer. 414.El 415. 416.Pp 417. 418.Fn libusb20_tr_get_length 419returns the length of the given USB frame by index. 420After an USB transfer is complete the USB frame length will get updated to the actual transferred length. 421. 422.Pp 423. 424.Fn libusb20_tr_set_length 425sets the length of the given USB frame by index. 426. 427.Pp 428. 429.Fn libusb20_tr_set_priv_sc0 430sets private driver pointer number zero. 431. 432.Pp 433. 434.Fn libusb20_tr_set_priv_sc1 435sets private driver pointer number one. 436. 437.Pp 438. 439.Fn libusb20_tr_set_timeout 440sets the timeout for the given USB transfer. 441. 442A timeout value of zero means no timeout. 443. 444The timeout is given in milliseconds. 445. 446.Pp 447. 448.Fn libusb20_tr_set_total_frames 449sets the total number of frames that should be executed when the USB transfer is submitted. 450. 451The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer. 452. 453.Pp 454. 455.Fn libusb20_tr_setup_bulk 456is a helper function for setting up a single frame USB BULK transfer. 457. 458.Pp 459. 460.Fn libusb20_tr_setup_control 461is a helper function for setting up a single or dual 462frame USB CONTROL transfer depending on the control transfer length. 463. 464.Pp 465. 466.Fn libusb20_tr_setup_intr 467is a helper function for setting up a single frame USB INTERRUPT transfer. 468. 469.Pp 470. 471.Fn libusb20_tr_setup_isoc 472is a helper function for setting up a multi frame USB ISOCHRONOUS transfer. 473. 474.Pp 475. 476.Fn libusb20_tr_bulk_intr_sync 477will perform a synchronous BULK or INTERRUPT transfer having length given by the 478.Fa length 479argument and buffer pointer given by the 480.Fa pbuf 481argument on the USB transfer given by the 482.Fa xfer 483argument. 484. 485If the 486.Fa pactlen 487argument is non-NULL the actual transfer length will be stored at the given pointer destination. 488. 489If the 490.Fa timeout 491argument is non-zero the transfer will timeout after the given value in milliseconds. 492. 493This function does not change the transfer flags, like short packet not ok. 494. 495This function returns zero on success else a LIBUSB20_TRANSFER_XXX value is returned. 496. 497.Pp 498. 499.Fn libusb20_tr_start 500will get the USB transfer started, if not already 501started. 502. 503This function will not get the transfer queued in hardware. 504. 505This function is non-blocking. 506. 507.Pp 508. 509.Fn libusb20_tr_stop 510will get the USB transfer stopped, if not already stopped. 511. 512This function is non-blocking, which means that the actual stop can 513happen after the return of this function. 514. 515.Pp 516. 517.Fn libusb20_tr_submit 518will get the USB transfer queued in hardware. 519. 520. 521.Pp 522. 523.Fn libusb20_tr_get_priv_sc0 524returns private driver pointer number zero associated 525with an USB transfer. 526. 527. 528.Pp 529. 530.Fn libusb20_tr_get_priv_sc1 531returns private driver pointer number one associated 532with an USB transfer. 533. 534. 535.Sh USB DEVICE OPERATIONS 536. 537.Pp 538. 539.Fn libusb20_dev_get_backend_name 540returns a zero terminated string describing the backend used. 541. 542.Pp 543. 544.Fn libusb20_dev_get_info 545retrieves the BSD specific usb_device_info structure into the memory location given by 546.Fa pinfo . 547The USB device given by 548.Fa pdev 549must be opened before this function will succeed. 550This function returns zero on success else a LIBUSB20_ERROR value is returned. 551. 552.Pp 553. 554.Fn libusb20_dev_get_iface_desc 555retrieves the kernel interface description for the given USB 556.Fa iface_index . 557The format of the USB interface description is: "drivername<unit>: <description>" 558The description string is always zero terminated. 559A zero length string is written in case no driver is attached to the given interface. 560The USB device given by 561.Fa pdev 562must be opened before this function will succeed. 563This function returns zero on success else a LIBUSB20_ERROR value is returned. 564. 565.Pp 566. 567.Fn libusb20_dev_get_desc 568returns a zero terminated string describing the given USB device. 569The format of the string is: "drivername<unit>: <description>" 570. 571.Pp 572. 573.Fn libusb20_dev_close 574will close the given USB device. 575. 576This function returns zero on success else a LIBUSB20_ERROR value is 577returned. 578. 579.Pp 580. 581.Fn libusb20_dev_detach_kernel_driver 582will try to detach the kernel driver for the USB interface given by 583.Fa iface_index . 584. 585This function returns zero on success else a LIBUSB20_ERROR value is 586returned. 587. 588.Pp 589. 590.Fn libusb20_dev_set_config_index 591will try to set the configuration index on an USB 592device. 593. 594The first configuration index is zero. 595. 596The un-configure index is 255. 597. 598This function returns zero on success else a LIBUSB20_ERROR value is returned. 599. 600.Pp 601. 602.Fn libusb20_dev_get_debug 603returns the debug level of an USB device. 604. 605.Pp 606. 607.Fn libusb20_dev_get_fd 608returns the file descriptor of the given USB device. 609. 610A negative value is returned when no file descriptor is present. 611. 612The file descriptor can be used for polling purposes. 613. 614.Pp 615. 616.Fn libusb20_dev_kernel_driver_active 617returns zero if a kernel driver is active on the given USB interface. 618. 619Else a LIBUSB20_ERROR value is returned. 620. 621.Pp 622. 623.Fn libusb20_dev_open 624opens an USB device so that setting up USB transfers 625becomes possible. 626. 627The number of USB transfers can be zero which means only control 628transfers are allowed. 629. 630This function returns zero on success else a LIBUSB20_ERROR value is 631returned. 632. 633A return value of LIBUSB20_ERROR_BUSY means that the device is already 634opened. 635. 636.Pp 637. 638.Fn libusb20_dev_process 639is called to sync kernel USB transfers with userland USB 640transfers. 641. 642This function returns zero on success else a LIBUSB20_ERROR value is 643returned typically indicating that the given USB device has been 644detached. 645. 646.Pp 647. 648.Fn libusb20_dev_request_sync 649will perform a synchronous control request on the given 650USB device. 651. 652Before this call will succeed the USB device must be opened. 653. 654.Fa setup 655is a pointer to a decoded and host endian SETUP packet. 656.Fa data 657is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL. 658.Fa pactlen 659is a pointer to a variable that will hold the actual transfer length after the control transaction is complete. 660.Fa timeout 661is the transaction timeout given in milliseconds. 662A timeout of zero means no timeout. 663.Fa flags 664is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK. 665. 666This function returns zero on success else a LIBUSB20_ERROR value is 667returned. 668. 669.Pp 670. 671.Fn libusb20_dev_req_string_sync 672will synchronously request an USB string by language ID 673and string index into the given buffer limited by a maximum length. 674. 675This function returns zero on success else a LIBUSB20_ERROR value is 676returned. 677. 678.Pp 679. 680.Fn libusb20_dev_req_string_simple_sync 681will synchronously request an USB string using the 682default language ID and convert the string into ASCII before storing 683the string into the given buffer limited by a maximum length which 684includes the terminating zero. 685. 686This function returns zero on success else a LIBUSB20_ERROR value is 687returned. 688. 689. 690.Pp 691. 692.Fn libusb20_dev_reset 693will try to BUS reset the given USB device and restore 694the last set USB configuration. 695. 696This function returns zero on success else a LIBUSB20_ERROR value is 697returned. 698. 699. 700.Pp 701. 702.Fn libusb20_dev_check_connected 703will check if an opened USB device is still connected. 704. 705This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned. 706. 707. 708.Pp 709. 710.Fn libusb20_dev_set_power_mode 711sets the power mode of the USB device. 712. 713Valid power modes: 714.Bl -tag 715.It LIBUSB20_POWER_OFF 716.It LIBUSB20_POWER_ON 717.It LIBUSB20_POWER_SAVE 718.It LIBUSB20_POWER_SUSPEND 719.It LIBUSB20_POWER_RESUME 720.El 721. 722This function returns zero on success else a LIBUSB20_ERROR value is 723returned. 724. 725.Pp 726. 727.Fn libusb20_dev_get_power_mode 728returns the currently selected power mode for the given 729USB device. 730. 731.Pp 732. 733.Fn libusb20_dev_set_alt_index 734will try to set the given alternate index for the given 735USB interface index. 736. 737This function returns zero on success else a LIBUSB20_ERROR value is 738returned. 739. 740.Pp 741. 742.Fn libusb20_dev_get_device_desc 743returns a pointer to the decoded and host endian version 744of the device descriptor. 745. 746The USB device need not be opened when calling this function. 747. 748.Pp 749. 750.Fn libusb20_dev_alloc_config 751will read out and decode the USB config descriptor for 752the given USB device and config index. This function returns a pointer 753to the decoded configuration which must eventually be passed to 754free(). NULL is returned in case of failure. 755. 756.Pp 757. 758.Fn libusb20_dev_alloc 759is an internal function to allocate a new USB device. 760. 761.Pp 762. 763.Fn libusb20_dev_get_address 764returns the internal and not necessarily the real 765hardware address of the given USB device. 766Valid addresses start at one. 767. 768.Pp 769. 770.Fn libusb20_dev_get_parent_address 771returns the internal and not necessarily the real hardware address of 772the given parent USB HUB device. 773This value is zero for the root HUB which usually has a device address 774equal to one. 775Valid addresses start at one. 776. 777.Pp 778. 779.Fn libusb20_dev_get_parent_port 780returns the port number on the parent USB HUB device. 781This value is zero for the root HUB which usually has a device address 782equal to one. 783Valid port numbers start at one. 784. 785.Pp 786. 787.Fn libusb20_dev_get_bus_number 788returns the internal bus number which the given USB 789device belongs to. 790Valid bus numbers start at zero. 791. 792.Pp 793. 794.Fn libusb20_dev_get_mode 795returns the current operation mode of the USB entity. 796. 797Valid return values are: 798.Bl -tag 799.It LIBUSB20_MODE_HOST 800.It LIBUSB20_MODE_DEVICE 801.El 802. 803.Pp 804. 805.Fn libusb20_dev_get_speed 806returns the current speed of the given USB device. 807. 808.Bl -tag 809.It LIBUSB20_SPEED_UNKNOWN 810.It LIBUSB20_SPEED_LOW 811.It LIBUSB20_SPEED_FULL 812.It LIBUSB20_SPEED_HIGH 813.It LIBUSB20_SPEED_VARIABLE 814.It LIBUSB20_SPEED_SUPER 815.El 816. 817.Pp 818. 819.Fn libusb20_dev_get_config_index 820This function returns the currently select config index for the given 821USB device. 822. 823.Pp 824. 825.Fn libusb20_dev_free 826will free the given USB device and all associated USB 827transfers. 828. 829.Pp 830. 831.Fn libusb20_dev_set_debug 832will set the debug level for the given USB device. 833. 834.Pp 835. 836.Fn libusb20_dev_wait_process 837function will wait until a pending USB transfer has completed on 838the given USB device. 839. 840A timeout value can be specified which is passed on to the 841.Xr poll 2 842function. 843. 844.Sh USB BACKEND OPERATIONS 845. 846.Fn libusb20_be_get_template 847will return the currently selected global USB device 848side mode template into the integer pointer 849.Fa ptemp . 850This function returns zero on success else a LIBUSB20_ERROR value is 851returned. 852. 853.Pp 854. 855.Fn libusb20_be_set_template 856will set the global USB device side mode template to 857.Fa temp . 858The new template is not activated until after the next USB 859enumeration. 860The template number decides how the USB device will present itself to 861the USB Host, like Mass Storage Device, USB Ethernet Device. Also see 862the 863.Xr usb2_template 4 864module. 865This function returns zero on success else a LIBUSB20_ERROR value is 866returned. 867. 868.Pp 869. 870.Fn libusb20_be_get_dev_quirk 871This function will return the device quirk according to 872.Fa index 873into the libusb20_quirk structure pointed to by 874.Fa pq . 875This function returns zero on success else a LIBUSB20_ERROR value is 876returned. 877. 878If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 879returned. 880. 881.Pp 882. 883.Fn libusb20_be_get_quirk_name 884will return the quirk name according to 885.Fa index 886into the libusb20_quirk structure pointed to by 887.Fa pq . 888This function returns zero on success else a LIBUSB20_ERROR value is 889returned. 890. 891If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 892returned. 893. 894.Pp 895. 896.Fn libusb20_be_add_dev_quirk 897will add the libusb20_quirk structure pointed to by the 898.Fa pq 899argument into the device quirk list. 900. 901This function returns zero on success else a LIBUSB20_ERROR value is 902returned. 903. 904If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is 905returned. 906. 907.Pp 908. 909.Fn libusb20_be_remove_dev_quirk 910will remove the quirk matching the libusb20_quirk structure pointed to by the 911.Fa pq 912argument from the device quirk list. 913. 914This function returns zero on success else a LIBUSB20_ERROR value is 915returned. 916. 917If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 918returned. 919. 920.Pp 921. 922.Fn libusb20_be_alloc_default 923.Fn libusb20_be_alloc_freebsd 924.Fn libusb20_be_alloc_linux 925These functions are used to allocate a specific USB backend or the 926operating system default USB backend. Allocating a backend is a way to 927scan for currently present USB devices. 928. 929.Pp 930. 931.Fn libusb20_be_device_foreach 932is used to iterate USB devices present in a USB backend. 933. 934The starting value of 935.Fa pdev 936is NULL. 937. 938This function returns the next USB device in the list. 939. 940If NULL is returned the end of the USB device list has been reached. 941. 942.Pp 943. 944.Fn libusb20_be_dequeue_device 945will dequeue the given USB device pointer from the 946backend USB device list. 947. 948Dequeued USB devices will not be freed when the backend is freed. 949. 950.Pp 951. 952.Fn libusb20_be_enqueue_device 953This function will enqueue the given USB device pointer in the backend USB device list. 954. 955Enqueued USB devices will get freed when the backend is freed. 956. 957.Pp 958. 959.Fn libusb20_be_free 960will free the given backend and all USB devices in its device list. 961. 962. 963.Sh USB DESCRIPTOR PARSING 964. 965.Fn libusb20_me_get_1 pie offset 966This function will return a byte at the given byte offset of a message 967entity. 968. 969This function is safe against invalid offsets. 970. 971.Pp 972. 973.Fn libusb20_me_get_2 pie offset 974This function will return a little endian 16-bit value at the given byte offset of a message 975entity. 976. 977This function is safe against invalid offsets. 978. 979.Pp 980. 981.Fn libusb20_me_encode pbuf len pdecoded 982This function will encode a so-called *DECODED structure into binary 983format. 984. 985The total encoded length that will fit in the given buffer is 986returned. 987. 988If the buffer pointer is NULL no data will be written to the buffer 989location. 990. 991.Pp 992. 993.Fn libusb20_me_decode pbuf len pdecoded 994This function will decode a binary structure into a so-called *DECODED 995structure. 996. 997The total decoded length is returned. 998. 999The buffer pointer cannot be NULL. 1000. 1001. 1002.Sh USB DEBUGGING 1003.Pp 1004.Ft const char * 1005.Fn libusb20_strerror "int code" 1006Get the ASCII representation of the error given by the 1007.Fa code 1008argument. 1009This function does not return NULL. 1010.Pp 1011.Ft const char * 1012.Fn libusb20_error_name "int code" 1013Get the ASCII representation of the error enum given by the 1014.Fa code 1015argument. 1016This function does not return NULL. 1017. 1018.Sh FILES 1019. 1020. 1021/dev/usb 1022.Sh SEE ALSO 1023.Xr usb 4 , 1024.Xr libusb 3 , 1025.Xr usbconfig 8 , 1026.Xr usbdump 8 1027. 1028. 1029.Sh HISTORY 1030. 1031. 1032Some parts of the 1033.Nm 1034API derives from the libusb project at sourceforge. 1035