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