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