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 June 22, 2009 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 void 102.Fn libusb20_tr_start "struct libusb20_transfer *xfer" 103.Ft void 104.Fn libusb20_tr_stop "struct libusb20_transfer *xfer" 105.Ft void 106.Fn libusb20_tr_submit "struct libusb20_transfer *xfer" 107.Ft void * 108.Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer" 109.Ft void * 110.Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer" 111.Ft const char * 112.Fn libusb20_dev_get_backend_name "struct libusb20_device *" 113.Ft int 114.Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo" 115.Ft int 116.Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len" 117.Ft const char * 118.Fn libusb20_dev_get_desc "struct libusb20_device *pdev" 119.Ft int 120.Fn libusb20_dev_close "struct libusb20_device *pdev" 121.Ft int 122.Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index" 123.Ft int 124.Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex" 125.Ft int 126.Fn libusb20_dev_get_debug "struct libusb20_device *pdev" 127.Ft int 128.Fn libusb20_dev_get_fd "struct libusb20_device *pdev" 129.Ft int 130.Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index" 131.Ft int 132.Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max" 133.Ft int 134.Fn libusb20_dev_process "struct libusb20_device *pdev" 135.Ft int 136.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" 137.Ft int 138.Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len" 139.Ft int 140.Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len" 141.Ft int 142.Fn libusb20_dev_reset "struct libusb20_device *pdev" 143.Ft int 144.Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode" 145.Ft uint8_t 146.Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev" 147.Ft int 148.Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index" 149.Ft struct LIBUSB20_DEVICE_DESC_DECODED * 150.Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev" 151.Ft struct libusb20_config * 152.Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index" 153.Ft struct libusb20_device * 154.Fn libusb20_dev_alloc "void" 155.Ft uint8_t 156.Fn libusb20_dev_get_address "struct libusb20_device *pdev" 157.Ft uint8_t 158.Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev" 159.Ft uint8_t 160.Fn libusb20_dev_get_mode "struct libusb20_device *pdev" 161.Ft uint8_t 162.Fn libusb20_dev_get_speed "struct libusb20_device *pdev" 163.Ft uint8_t 164.Fn libusb20_dev_get_config_index "struct libusb20_device *pdev" 165.Ft void 166.Fn libusb20_dev_free "struct libusb20_device *pdev" 167.Ft void 168.Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug" 169.Ft void 170.Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout" 171.Ft int 172.Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp" 173.Ft int 174.Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp" 175.Ft int 176.Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber", "uint16_t index" "struct libusb20_quirk *pq" 177.Ft int 178.Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq" 179.Ft int 180.Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 181.Ft int 182.Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 183.Ft struct libusb20_backend * 184.Fn libusb20_be_alloc_default "void" 185.Ft struct libusb20_backend * 186.Fn libusb20_be_alloc_freebsd "void" 187.Ft struct libusb20_backend * 188.Fn libusb20_be_alloc_linux "void" 189.Ft struct libusb20_device * 190.Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 191.Ft void 192.Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 193.Ft void 194.Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 195.Ft void 196.Fn libusb20_be_free "struct libusb20_backend *pbe" 197.Ft uint8_t 198.Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off" 199.Ft uint16_t 200.Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off" 201.Ft uint16_t 202.Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded" 203.Ft uint16_t 204.Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded" 205.Ft "const uint8_t *" 206.Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc" 207. 208. 209.Sh DESCRIPTION 210. 211The 212.Nm 213library implements functions to be able to easily access and control 214USB through the USB file system interface. 215The 216.Nm 217interfaces are specific to the 218.Fx 219usb stack and are not available on other operating systems, portable 220applications should consider using 221.Xr libusb 3 . 222. 223. 224.Sh USB TRANSFER OPERATIONS 225. 226.Pp 227. 228.Fn libusb20_tr_close 229will release all kernel resources associated with an USB 230.Fa xfer . 231. 232This function returns zero upon success. 233. 234Non-zero return values indicate a LIBUSB20_ERROR value. 235. 236.Pp 237. 238.Fn libusb20_tr_open 239will allocate kernel buffer resources according to 240.Fa max_buf_size 241and 242.Fa max_frame_count 243associated with an USB 244.Fa pxfer 245and bind the transfer to the specified 246.Fa ep_no . 247.Fa max_buf_size 248is the minimum buffer size which the data transport layer has to support. 249If 250.Fa max_buf_size 251is zero, the 252.Nm 253library will use wMaxPacketSize to compute the buffer size. 254This can be useful for isochronous transfers. 255The actual buffer size can be greater than 256.Fa max_buf_size 257and is returned by 258.Fn libusb20_tr_get_max_total_length . 259. 260This function returns zero upon success. 261. 262Non-zero return values indicate a LIBUSB20_ERROR value. 263. 264.Pp 265. 266.Fn libusb20_tr_get_pointer 267will return a pointer to the allocated USB transfer according to the 268.Fa pdev 269and 270.Fa tr_index 271arguments. 272. 273This function returns NULL in case of failure. 274. 275.Pp 276. 277.Fn libusb20_tr_get_time_complete 278will return the completion time of an USB transfer in 279millisecond units. This function is most useful for isochronous USB 280transfers when doing echo cancelling. 281. 282.Pp 283. 284.Fn libusb20_tr_get_actual_frames 285will return the actual number of USB frames after an USB 286transfer completed. A value of zero means that no data was transferred. 287. 288.Pp 289. 290.Fn libusb20_tr_get_actual_length 291will return the sum of the actual length for all 292transferred USB frames for the given USB transfer. 293. 294.Pp 295. 296.Fn libusb20_tr_get_max_frames 297will return the maximum number of USB frames that were 298allocated when an USB transfer was setup for the given USB transfer. 299. 300.Pp 301. 302.Fn libusb20_tr_get_max_packet_length 303will return the maximum packet length in bytes 304associated with the given USB transfer. 305. 306The packet length can be used round up buffer sizes so that short USB 307packets are avoided for proxy buffers. 308. 309. 310.Pp 311. 312.Fn libusb20_tr_get_max_total_length 313function will return the maximum value for the data length sum of all USB 314frames associated with an USB transfer. 315In case of control transfers the value returned does not include the 316length of the SETUP packet, 8 bytes, which is part of frame zero. 317The returned value of this function is always aligned to the maximum 318packet size, wMaxPacketSize, of the endpoint which the USB transfer is 319bound to. 320. 321.Pp 322. 323.Fn libusb20_tr_get_status 324will return the status of an USB transfer. 325. 326Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums. 327. 328.Pp 329. 330.Fn libusb20_tr_pending 331will return non-zero if the given USB transfer is 332pending for completion. 333. 334Else this function returns zero. 335. 336.Pp 337. 338.Fn libusb20_tr_callback_wrapper 339This is an internal function used to wrap asynchronous USB callbacks. 340. 341.Pp 342. 343.Fn libusb20_tr_clear_stall_sync 344This is an internal function used to synchronously clear the stall on 345the given USB transfer. 346. 347Please see the USB specification for more information on stall 348clearing. 349. 350If the given USB transfer is pending when this function is called, the 351USB transfer will complete with an error after that this function has 352been called. 353. 354.Pp 355. 356.Fn libusb20_tr_drain 357will stop the given USB transfer and will not return 358until the USB transfer has been stopped in hardware. 359. 360.Pp 361. 362.Fn libusb20_tr_set_buffer 363is used to set the 364.Fa buffer 365pointer for the given USB transfer and 366.Fa fr_index . 367. 368Typically the frame index is zero. 369. 370. 371.Pp 372. 373.Fn libusb20_tr_set_callback 374is used to set the USB callback for asynchronous USB 375transfers. 376. 377The callback type is defined by libusb20_tr_callback_t. 378. 379.Pp 380. 381.Fn libusb20_tr_set_flags 382is used to set various USB flags for the given USB transfer. 383.Bl -tag 384.It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK 385Report a short frame as error. 386.It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK 387Multiple short frames are not allowed. 388.It LIBUSB20_TRANSFER_FORCE_SHORT 389All transmitted frames are short terminated. 390.It LIBUSB20_TRANSFER_DO_CLEAR_STALL 391Will do a clear-stall before starting the transfer. 392.El 393. 394.Pp 395. 396.Fn libusb20_tr_get_length 397returns the length of the given USB frame by index. 398After an USB transfer is complete the USB frame length will get updated to the actual transferred length. 399. 400.Pp 401. 402.Fn libusb20_tr_set_length 403sets the length of the given USB frame by index. 404. 405.Pp 406. 407.Fn libusb20_tr_set_priv_sc0 408sets private driver pointer number zero. 409. 410.Pp 411. 412.Fn libusb20_tr_set_priv_sc1 413sets private driver pointer number one. 414. 415.Pp 416. 417.Fn libusb20_tr_set_timeout 418sets the timeout for the given USB transfer. 419. 420A timeout value of zero means no timeout. 421. 422The timeout is given in milliseconds. 423. 424.Pp 425. 426.Fn libusb20_tr_set_total_frames 427sets the total number of frames that should be executed when the USB transfer is submitted. 428. 429The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer. 430. 431.Pp 432. 433.Fn libusb20_tr_setup_bulk 434is a helper function for setting up a single frame USB BULK transfer. 435. 436.Pp 437. 438.Fn libusb20_tr_setup_control 439is a helper function for setting up a single or dual 440frame USB CONTROL transfer depending on the control transfer length. 441. 442.Pp 443. 444.Fn libusb20_tr_setup_intr 445is a helper function for setting up a single frame USB INTERRUPT transfer. 446. 447.Pp 448. 449.Fn libusb20_tr_setup_isoc 450is a helper function for setting up a multi frame USB ISOCHRONOUS transfer. 451. 452.Pp 453. 454.Fn libusb20_tr_start 455will get the USB transfer started, if not already 456started. 457. 458This function will not get the transfer queued in hardware. 459. 460This function is non-blocking. 461. 462.Pp 463. 464.Fn libusb20_tr_stop 465will get the USB transfer stopped, if not already stopped. 466. 467This function is non-blocking, which means that the actual stop can 468happen after the return of this function. 469. 470.Pp 471. 472.Fn libusb20_tr_submit 473will get the USB transfer queued in hardware. 474. 475. 476.Pp 477. 478.Fn libusb20_tr_get_priv_sc0 479returns private driver pointer number zero associated 480with an USB transfer. 481. 482. 483.Pp 484. 485.Fn libusb20_tr_get_priv_sc1 486returns private driver pointer number one associated 487with an USB transfer. 488. 489. 490.Sh USB DEVICE OPERATIONS 491. 492.Pp 493. 494.Fn libusb20_dev_get_backend_name 495returns a zero terminated string describing the backend used. 496. 497.Pp 498. 499.Fn libusb20_dev_get_info 500retrives the BSD specific usb_device_info structure into the memory location given by 501.Fa pinfo . 502The USB device given by 503.Fa pdev 504must be opened before this function will succeed. 505This function returns zero on success else a LIBUSB20_ERROR value is returned. 506. 507.Pp 508. 509.Fn libusb20_dev_get_iface_desc 510retrieves the kernel interface description for the given USB 511.Fa iface_index . 512The format of the USB interface description is: "drivername<unit>: <description>" 513The description string is always zero terminated. 514A zero length string is written in case no driver is attached to the given interface. 515The USB device given by 516.Fa pdev 517must be opened before this function will succeed. 518This function returns zero on success else a LIBUSB20_ERROR value is returned. 519. 520.Pp 521. 522.Fn libusb20_dev_get_desc 523returns a zero terminated string describing the given USB device. 524The format of the string is: "drivername<unit>: <description>" 525. 526.Pp 527. 528.Fn libusb20_dev_close 529will close the given USB device. 530. 531This function returns zero on success else a LIBUSB20_ERROR value is 532returned. 533. 534.Pp 535. 536.Fn libusb20_dev_detach_kernel_driver 537will try to detach the kernel driver for the USB interface given by 538.Fa iface_index . 539. 540This function returns zero on success else a LIBUSB20_ERROR value is 541returned. 542. 543.Pp 544. 545.Fn libusb20_dev_set_config_index 546will try to set the configuration index on an USB 547device. 548. 549The first configuration index is zero. 550. 551The un-configure index is 255. 552. 553This function returns zero on success else a LIBUSB20_ERROR value is returned. 554. 555.Pp 556. 557.Fn libusb20_dev_get_debug 558returns the debug level of an USB device. 559. 560.Pp 561. 562.Fn libusb20_dev_get_fd 563returns the file descriptor of the given USB device. 564. 565A negative value is returned when no file descriptor is present. 566. 567The file descriptor can be used for polling purposes. 568. 569.Pp 570. 571.Fn libusb20_dev_kernel_driver_active 572returns a non-zero value if a kernel driver is active on 573the given USB interface. 574. 575Else zero is returned. 576. 577.Pp 578. 579.Fn libusb20_dev_open 580opens an USB device so that setting up USB transfers 581becomes possible. 582. 583The number of USB transfers can be zero which means only control 584transfers are allowed. 585. 586This function returns zero on success else a LIBUSB20_ERROR value is 587returned. 588. 589A return value of LIBUSB20_ERROR_BUSY means that the device is already 590opened. 591. 592.Pp 593. 594.Fn libusb20_dev_process 595is called to sync kernel USB transfers with userland USB 596transfers. 597. 598This function returns zero on success else a LIBUSB20_ERROR value is 599returned typically indicating that the given USB device has been 600detached. 601. 602.Pp 603. 604.Fn libusb20_dev_request_sync 605will perform a synchronous control request on the given 606USB device. 607. 608Before this call will succeed the USB device must be opened. 609. 610.Fa setup 611is a pointer to a decoded and host endian SETUP packet. 612.Fa data 613is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL. 614.Fa pactlen 615is a pointer to a variable that will hold the actual transfer length after the control transaction is complete. 616.Fa timeout 617is the transaction timeout given in milliseconds. 618A timeout of zero means no timeout. 619.Fa flags 620is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK. 621. 622This function returns zero on success else a LIBUSB20_ERROR value is 623returned. 624. 625.Pp 626. 627.Fn libusb20_dev_req_string_sync 628will synchronously request an USB string by language ID 629and string index into the given buffer limited by a maximum length. 630. 631This function returns zero on success else a LIBUSB20_ERROR value is 632returned. 633. 634.Pp 635. 636.Fn libusb20_dev_req_string_simple_sync 637will synchronously request an USB string using the 638default language ID and convert the string into ASCII before storing 639the string into the given buffer limited by a maximum length which 640includes the terminating zero. 641. 642This function returns zero on success else a LIBUSB20_ERROR value is 643returned. 644. 645. 646.Pp 647. 648.Fn libusb20_dev_reset 649will try to BUS reset the given USB device and restore 650the last set USB configuration. 651. 652This function returns zero on success else a LIBUSB20_ERROR value is 653returned. 654. 655.Pp 656. 657.Fn libusb20_dev_set_power_mode 658sets the power mode of the USB device. 659. 660Valid power modes: 661.Bl -tag 662.It LIBUSB20_POWER_OFF 663.It LIBUSB20_POWER_ON 664.It LIBUSB20_POWER_SAVE 665.It LIBUSB20_POWER_SUSPEND 666.It LIBUSB20_POWER_RESUME 667.El 668. 669This function returns zero on success else a LIBUSB20_ERROR value is 670returned. 671. 672.Pp 673. 674.Fn libusb20_dev_get_power_mode 675returns the currently selected power mode for the given 676USB device. 677. 678.Pp 679. 680.Fn libusb20_dev_set_alt_index 681will try to set the given alternate index for the given 682USB interface index. 683. 684This function returns zero on success else a LIBUSB20_ERROR value is 685returned. 686. 687.Pp 688. 689.Fn libusb20_dev_get_device_desc 690returns a pointer to the decoded and host endian version 691of the device descriptor. 692. 693The USB device need not be opened when calling this function. 694. 695.Pp 696. 697.Fn libusb20_dev_alloc_config 698will read out and decode the USB config descriptor for 699the given USB device and config index. This function returns a pointer 700to the decoded configuration which must eventually be passed to 701free(). NULL is returned in case of failure. 702. 703.Pp 704. 705.Fn libusb20_dev_alloc 706is an internal function to allocate a new USB device. 707. 708.Pp 709. 710.Fn libusb20_dev_get_address 711returns the internal and not necessarily the real 712hardware address of the given USB device. 713. 714.Pp 715. 716.Fn libusb20_dev_get_bus_number 717returns the internal bus number which the given USB 718device belongs to. 719. 720.Pp 721. 722.Fn libusb20_dev_get_mode 723returns the current operation mode of the USB entity. 724. 725Valid return values are: 726.Bl -tag 727.It LIBUSB20_MODE_HOST 728.It LIBUSB20_MODE_DEVICE 729.El 730. 731.Pp 732. 733.Fn libusb20_dev_get_speed 734returns the current speed of the given USB device. 735. 736.Bl -tag 737.It LIBUSB20_SPEED_UNKNOWN 738.It LIBUSB20_SPEED_LOW 739.It LIBUSB20_SPEED_FULL 740.It LIBUSB20_SPEED_HIGH 741.It LIBUSB20_SPEED_VARIABLE 742.It LIBUSB20_SPEED_SUPER 743.El 744. 745.Pp 746. 747.Fn libusb20_dev_get_config_index 748This function returns the currently select config index for the given 749USB device. 750. 751.Pp 752. 753.Fn libusb20_dev_free 754will free the given USB device and all associated USB 755transfers. 756. 757.Pp 758. 759.Fn libusb20_dev_set_debug 760will set the debug level for the given USB device. 761. 762.Pp 763. 764.Fn libusb20_dev_wait_process 765function will wait until a pending USB transfer has completed on 766the given USB device. 767. 768A timeout value can be specified which is passed on to the 769.Xr poll 2 770function. 771. 772.Sh USB BACKEND OPERATIONS 773. 774.Fn libusb20_be_get_template 775will return the currently selected global USB device 776side mode template into the integer pointer 777.Fa ptemp . 778This function returns zero on success else a LIBUSB20_ERROR value is 779returned. 780. 781.Pp 782. 783.Fn libusb20_be_set_template 784will set the global USB device side mode template to 785.Fa temp . 786The new template is not activated until after the next USB 787enumeration. 788The template number decides how the USB device will present itself to 789the USB Host, like Mass Storage Device, USB Ethernet Device. Also see 790the 791.Xr usb2_template 4 792module. 793This function returns zero on success else a LIBUSB20_ERROR value is 794returned. 795. 796.Pp 797. 798.Fn libusb20_be_get_dev_quirk 799This function will return the device quirk according to 800.Fa index 801into the libusb20_quirk structure pointed to by 802.Fa pq . 803This function returns zero on success else a LIBUSB20_ERROR value is 804returned. 805. 806If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 807returned. 808. 809.Pp 810. 811.Fn libusb20_be_get_quirk_name 812will return the quirk name according to 813.Fa index 814into the libusb20_quirk structure pointed to by 815.Fa pq . 816This function returns zero on success else a LIBUSB20_ERROR value is 817returned. 818. 819If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 820returned. 821. 822.Pp 823. 824.Fn libusb20_be_add_dev_quirk 825will add the libusb20_quirk structure pointed to by the 826.Fa pq 827argument into the device quirk list. 828. 829This function returns zero on success else a LIBUSB20_ERROR value is 830returned. 831. 832If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is 833returned. 834. 835.Pp 836. 837.Fn libusb20_be_remove_dev_quirk 838will remove the quirk matching the libusb20_quirk structure pointed to by the 839.Fa pq 840argument from the device quirk list. 841. 842This function returns zero on success else a LIBUSB20_ERROR value is 843returned. 844. 845If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 846returned. 847. 848.Pp 849. 850.Fn libusb20_be_alloc_default 851.Fn libusb20_be_alloc_freebsd 852.Fn libusb20_be_alloc_linux 853These functions are used to allocate a specific USB backend or the 854operating system default USB backend. Allocating a backend is a way to 855scan for currently present USB devices. 856. 857.Pp 858. 859.Fn libusb20_be_device_foreach 860is used to iterate USB devices present in a USB backend. 861. 862The starting value of 863.Fa pdev 864is NULL. 865. 866This function returns the next USB device in the list. 867. 868If NULL is returned the end of the USB device list has been reached. 869. 870.Pp 871. 872.Fn libusb20_be_dequeue_device 873will dequeue the given USB device pointer from the 874backend USB device list. 875. 876Dequeued USB devices will not be freed when the backend is freed. 877. 878.Pp 879. 880.Fn libusb20_be_enqueue_device 881This function will enqueue the given USB device pointer in the backend USB device list. 882. 883Enqueued USB devices will get freed when the backend is freed. 884. 885.Pp 886. 887.Fn libusb20_be_free 888will free the given backend and all USB devices in its device list. 889. 890. 891.Sh USB DESCRIPTOR PARSING 892. 893.Fn libusb20_me_get_1 pie offset 894This function will return a byte at the given byte offset of a message 895entity. 896. 897This function is safe against invalid offsets. 898. 899.Pp 900. 901.Fn libusb20_me_get_2 pie offset 902This function will return a little endian 16-bit value at the given byte offset of a message 903entity. 904. 905This function is safe against invalid offsets. 906. 907.Pp 908. 909.Fn libusb20_me_encode pbuf len pdecoded 910This function will encode a so-called *DECODED structure into binary 911format. 912. 913The total encoded length that will fit in the given buffer is 914returned. 915. 916If the buffer pointer is NULL no data will be written to the buffer 917location. 918. 919.Pp 920. 921.Fn libusb20_me_decode pbuf len pdecoded 922This function will decode a binary structure into a so-called *DECODED 923structure. 924. 925The total decoded length is returned. 926. 927The buffer pointer cannot be NULL. 928. 929. 930.Sh FILES 931. 932. 933/dev/usb 934.Sh SEE ALSO 935.Xr usb 4 , 936.Xr libusb 3 , 937.Xr usbconfig 8 938. 939. 940.Sh HISTORY 941. 942. 943Some parts of the 944.Nm 945API derives from the libusb project at sourceforge. 946