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: head/lib/libusb/libusb20.3 276294 2014-12-27 08:31:52Z joel $ 28.\" 29.Dd January 16, 2015 30.Dt LIBUSB20 3 31.Os 32.Sh NAME 33.Nm libusb20 34. 35.Nd "USB access library" 36. 37. 38.Sh LIBRARY 39. 40. 41.Lb libusb 42. 43. 44. 45.Sh SYNOPSIS 46.In libusb20.h 47.Ft int 48.Fn libusb20_tr_close "struct libusb20_transfer *xfer" 49.Ft int 50.Fn libusb20_tr_open "struct libusb20_transfer *xfer" "uint32_t max_buf_size" "uint32_t max_frame_count" "uint8_t ep_no" 51.Ft int 52.Fn libusb20_tr_open_stream "struct libusb20_transfer *xfer" "uint32_t max_buf_size" "uint32_t max_frame_count" "uint8_t ep_no" "uint16_t stream_id" 53.Ft struct libusb20_transfer* 54.Fn libusb20_tr_get_pointer "struct libusb20_device *pdev" "uint16_t tr_index" 55.Ft uint16_t 56.Fn libusb20_tr_get_time_complete "struct libusb20_transfer *xfer" 57.Ft uint32_t 58.Fn libusb20_tr_get_actual_frames "struct libusb20_transfer *xfer" 59.Ft uint32_t 60.Fn libusb20_tr_get_actual_length "struct libusb20_transfer *xfer" 61.Ft uint32_t 62.Fn libusb20_tr_get_max_frames "struct libusb20_transfer *xfer" 63.Ft uint32_t 64.Fn libusb20_tr_get_max_packet_length "struct libusb20_transfer *xfer" 65.Ft uint32_t 66.Fn libusb20_tr_get_max_total_length "struct libusb20_transfer *xfer" 67.Ft uint8_t 68.Fn libusb20_tr_get_status "struct libusb20_transfer *xfer" 69.Ft uint8_t 70.Fn libusb20_tr_pending "struct libusb20_transfer *xfer" 71.Ft void 72.Fn libusb20_tr_callback_wrapper "struct libusb20_transfer *xfer" 73.Ft void 74.Fn libusb20_tr_clear_stall_sync "struct libusb20_transfer *xfer" 75.Ft void 76.Fn libusb20_tr_drain "struct libusb20_transfer *xfer" 77.Ft void 78.Fn libusb20_tr_set_buffer "struct libusb20_transfer *xfer" "void *buffer" "uint16_t fr_index" 79.Ft void 80.Fn libusb20_tr_set_callback "struct libusb20_transfer *xfer" "libusb20_tr_callback_t *cb" 81.Ft void 82.Fn libusb20_tr_set_flags "struct libusb20_transfer *xfer" "uint8_t flags" 83.Ft uint32_t 84.Fn libusb20_tr_get_length "struct libusb20_transfer *xfer" "uint16_t fr_index" 85.Ft void 86.Fn libusb20_tr_set_length "struct libusb20_transfer *xfer" "uint32_t length" "uint16_t fr_index" 87.Ft void 88.Fn libusb20_tr_set_priv_sc0 "struct libusb20_transfer *xfer" "void *sc0" 89.Ft void 90.Fn libusb20_tr_set_priv_sc1 "struct libusb20_transfer *xfer" "void *sc1" 91.Ft void 92.Fn libusb20_tr_set_timeout "struct libusb20_transfer *xfer" "uint32_t timeout" 93.Ft void 94.Fn libusb20_tr_set_total_frames "struct libusb20_transfer *xfer" "uint32_t nframes" 95.Ft void 96.Fn libusb20_tr_setup_bulk "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout" 97.Ft void 98.Fn libusb20_tr_setup_control "struct libusb20_transfer *xfer" "void *psetup" "void *pbuf" "uint32_t timeout" 99.Ft void 100.Fn libusb20_tr_setup_intr "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout" 101.Ft void 102.Fn libusb20_tr_setup_isoc "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint16_t fr_index" 103.Ft uint8_t 104.Fn libusb20_tr_bulk_intr_sync "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t *pactlen" "uint32_t timeout" 105.Ft void 106.Fn libusb20_tr_start "struct libusb20_transfer *xfer" 107.Ft void 108.Fn libusb20_tr_stop "struct libusb20_transfer *xfer" 109.Ft void 110.Fn libusb20_tr_submit "struct libusb20_transfer *xfer" 111.Ft void * 112.Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer" 113.Ft void * 114.Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer" 115.Ft const char * 116.Fn libusb20_dev_get_backend_name "struct libusb20_device *" 117.Ft int 118.Fn libusb20_dev_get_port_path "struct libusb20_device *pdev" "uint8_t *buf" "uint8_t bufsize" 119.Ft int 120.Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo" 121.Ft int 122.Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len" 123.Ft const char * 124.Fn libusb20_dev_get_desc "struct libusb20_device *pdev" 125.Ft int 126.Fn libusb20_dev_close "struct libusb20_device *pdev" 127.Ft int 128.Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index" 129.Ft int 130.Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex" 131.Ft int 132.Fn libusb20_dev_get_debug "struct libusb20_device *pdev" 133.Ft int 134.Fn libusb20_dev_get_fd "struct libusb20_device *pdev" 135.Ft int 136.Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index" 137.Ft int 138.Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max" 139.Ft int 140.Fn libusb20_dev_process "struct libusb20_device *pdev" 141.Ft int 142.Fn libusb20_dev_request_sync "struct libusb20_device *pdev" "struct LIBUSB20_CONTROL_SETUP_DECODED *setup" "void *data" "uint16_t *pactlen" "uint32_t timeout" "uint8_t flags" 143.Ft int 144.Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len" 145.Ft int 146.Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len" 147.Ft int 148.Fn libusb20_dev_reset "struct libusb20_device *pdev" 149.Ft int 150.Fn libusb20_dev_check_connected "struct libusb20_device *pdev" 151.Ft int 152.Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode" 153.Ft uint8_t 154.Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev" 155.Ft uint16_t 156.Fn libusb20_dev_get_power_usage "struct libusb20_device *pdev" 157.Ft int 158.Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index" 159.Ft struct LIBUSB20_DEVICE_DESC_DECODED * 160.Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev" 161.Ft struct libusb20_config * 162.Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index" 163.Ft struct libusb20_device * 164.Fn libusb20_dev_alloc "void" 165.Ft uint8_t 166.Fn libusb20_dev_get_address "struct libusb20_device *pdev" 167.Ft uint8_t 168.Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev" 169.Ft uint8_t 170.Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev" 171.Ft uint8_t 172.Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev" 173.Ft uint8_t 174.Fn libusb20_dev_get_mode "struct libusb20_device *pdev" 175.Ft uint8_t 176.Fn libusb20_dev_get_speed "struct libusb20_device *pdev" 177.Ft uint8_t 178.Fn libusb20_dev_get_config_index "struct libusb20_device *pdev" 179.Ft void 180.Fn libusb20_dev_free "struct libusb20_device *pdev" 181.Ft void 182.Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug" 183.Ft void 184.Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout" 185.Ft int 186.Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp" 187.Ft int 188.Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp" 189.Ft int 190.Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq" 191.Ft int 192.Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq" 193.Ft int 194.Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 195.Ft int 196.Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 197.Ft struct libusb20_backend * 198.Fn libusb20_be_alloc_default "void" 199.Ft struct libusb20_backend * 200.Fn libusb20_be_alloc_freebsd "void" 201.Ft struct libusb20_backend * 202.Fn libusb20_be_alloc_linux "void" 203.Ft struct libusb20_device * 204.Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 205.Ft void 206.Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 207.Ft void 208.Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 209.Ft void 210.Fn libusb20_be_free "struct libusb20_backend *pbe" 211.Ft "const char *" 212.Fn libusb20_strerror "int code" 213.Ft "const char *" 214.Fn libusb20_error_name "int code" 215.In libusb20_desc.h 216.Ft uint8_t 217.Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off" 218.Ft uint16_t 219.Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off" 220.Ft uint16_t 221.Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded" 222.Ft uint16_t 223.Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded" 224.Ft "const uint8_t *" 225.Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc" 226. 227. 228.Sh DESCRIPTION 229. 230The 231.Nm 232library implements functions to be able to easily access and control 233USB through the USB file system interface. 234The 235.Nm 236interfaces are specific to the 237.Fx 238usb stack and are not available on other operating systems, portable 239applications should consider using 240.Xr libusb 3 . 241. 242. 243.Sh USB TRANSFER OPERATIONS 244. 245. 246.Fn libusb20_tr_close 247will release all kernel resources associated with an USB 248.Fa xfer . 249. 250This function returns zero upon success. 251. 252Non-zero return values indicate a LIBUSB20_ERROR value. 253. 254.Pp 255. 256.Fn libusb20_tr_open 257will allocate kernel buffer resources according to 258.Fa max_buf_size 259and 260.Fa max_frame_count 261associated with an USB 262.Fa pxfer 263and bind the transfer to the specified 264.Fa ep_no . 265.Fa max_buf_size 266is the minimum buffer size which the data transport layer has to support. 267If 268.Fa max_buf_size 269is zero, the 270.Nm 271library will use wMaxPacketSize to compute the buffer size. 272This can be useful for isochronous transfers. 273The actual buffer size can be greater than 274.Fa max_buf_size 275and is returned by 276.Fn libusb20_tr_get_max_total_length . 277. 278If 279.Fa max_frame_count 280is OR'ed with LIBUSB20_MAX_FRAME_PRE_SCALE the remaining part of the 281argument is converted from milliseconds into the actual number of 282frames rounded up, when this function returns. 283This flag is only valid for ISOCHRONOUS transfers and has no effect 284for other transfer types. 285The actual number of frames setup is found by calling 286.Fn libusb20_tr_get_max_frames . 287. 288This function returns zero upon success. 289. 290Non-zero return values indicate a LIBUSB20_ERROR value. 291. 292.Pp 293. 294.Fn libusb20_tr_open_stream 295is identical to 296.Fn libusb20_tr_open 297except that a stream ID can be specified for BULK endpoints having 298such a feature. 299.Fn libusb20_tr_open 300can be used to open stream ID zero. 301. 302.Pp 303. 304.Fn libusb20_tr_get_pointer 305will return a pointer to the allocated USB transfer according to the 306.Fa pdev 307and 308.Fa tr_index 309arguments. 310. 311This function returns NULL in case of failure. 312. 313.Pp 314. 315.Fn libusb20_tr_get_time_complete 316will return the completion time of an USB transfer in 317millisecond units. This function is most useful for isochronous USB 318transfers when doing echo cancelling. 319. 320.Pp 321. 322.Fn libusb20_tr_get_actual_frames 323will return the actual number of USB frames after an USB 324transfer completed. A value of zero means that no data was transferred. 325. 326.Pp 327. 328.Fn libusb20_tr_get_actual_length 329will return the sum of the actual length for all 330transferred USB frames for the given USB transfer. 331. 332.Pp 333. 334.Fn libusb20_tr_get_max_frames 335will return the maximum number of USB frames that were 336allocated when an USB transfer was setup for the given USB transfer. 337. 338.Pp 339. 340.Fn libusb20_tr_get_max_packet_length 341will return the maximum packet length in bytes 342associated with the given USB transfer. 343. 344The packet length can be used round up buffer sizes so that short USB 345packets are avoided for proxy buffers. 346. 347. 348.Pp 349. 350.Fn libusb20_tr_get_max_total_length 351will return the maximum value for the data length sum of all USB 352frames associated with an USB transfer. 353In case of control transfers the value returned does not include the 354length of the SETUP packet, 8 bytes, which is part of frame zero. 355The returned value of this function is always aligned to the maximum 356packet size, wMaxPacketSize, of the endpoint which the USB transfer is 357bound to. 358. 359.Pp 360. 361.Fn libusb20_tr_get_status 362will return the status of an USB transfer. 363. 364Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums. 365. 366.Pp 367. 368.Fn libusb20_tr_pending 369will return non-zero if the given USB transfer is 370pending for completion. 371. 372Else this function returns zero. 373. 374.Pp 375. 376.Fn libusb20_tr_callback_wrapper 377This is an internal function used to wrap asynchronous USB callbacks. 378. 379.Pp 380. 381.Fn libusb20_tr_clear_stall_sync 382This is an internal function used to synchronously clear the stall on 383the given USB transfer. 384. 385Please see the USB specification for more information on stall 386clearing. 387. 388If the given USB transfer is pending when this function is called, the 389USB transfer will complete with an error after that this function has 390been called. 391. 392.Pp 393. 394.Fn libusb20_tr_drain 395will stop the given USB transfer and will not return 396until the USB transfer has been stopped in hardware. 397. 398.Pp 399. 400.Fn libusb20_tr_set_buffer 401is used to set the 402.Fa buffer 403pointer for the given USB transfer and 404.Fa fr_index . 405. 406Typically the frame index is zero. 407. 408. 409.Pp 410. 411.Fn libusb20_tr_set_callback 412is used to set the USB callback for asynchronous USB 413transfers. 414. 415The callback type is defined by libusb20_tr_callback_t. 416. 417.Pp 418. 419.Fn libusb20_tr_set_flags 420is used to set various USB flags for the given USB transfer. 421.Bl -tag -width "LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK" 422.It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK 423Report a short frame as error. 424.It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK 425Multiple short frames are not allowed. 426.It LIBUSB20_TRANSFER_FORCE_SHORT 427All transmitted frames are short terminated. 428.It LIBUSB20_TRANSFER_DO_CLEAR_STALL 429Will do a clear-stall before starting the transfer. 430.El 431. 432.Pp 433. 434.Fn libusb20_tr_get_length 435returns the length of the given USB frame by index. 436After an USB transfer is complete the USB frame length will get updated to the actual transferred length. 437. 438.Pp 439. 440.Fn libusb20_tr_set_length 441sets the length of the given USB frame by index. 442. 443.Pp 444. 445.Fn libusb20_tr_set_priv_sc0 446sets private driver pointer number zero. 447. 448.Pp 449. 450.Fn libusb20_tr_set_priv_sc1 451sets private driver pointer number one. 452. 453.Pp 454. 455.Fn libusb20_tr_set_timeout 456sets the timeout for the given USB transfer. 457. 458A timeout value of zero means no timeout. 459. 460The timeout is given in milliseconds. 461. 462.Pp 463. 464.Fn libusb20_tr_set_total_frames 465sets the total number of frames that should be executed when the USB transfer is submitted. 466. 467The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer. 468. 469.Pp 470. 471.Fn libusb20_tr_setup_bulk 472is a helper function for setting up a single frame USB BULK transfer. 473. 474.Pp 475. 476.Fn libusb20_tr_setup_control 477is a helper function for setting up a single or dual 478frame USB CONTROL transfer depending on the control transfer length. 479. 480.Pp 481. 482.Fn libusb20_tr_setup_intr 483is a helper function for setting up a single frame USB INTERRUPT transfer. 484. 485.Pp 486. 487.Fn libusb20_tr_setup_isoc 488is a helper function for setting up a multi frame USB ISOCHRONOUS transfer. 489. 490.Pp 491. 492.Fn libusb20_tr_bulk_intr_sync 493will perform a synchronous BULK or INTERRUPT transfer having length given by the 494.Fa length 495argument and buffer pointer given by the 496.Fa pbuf 497argument on the USB transfer given by the 498.Fa xfer 499argument. 500. 501If the 502.Fa pactlen 503argument is non-NULL the actual transfer length will be stored at the given pointer destination. 504. 505If the 506.Fa timeout 507argument is non-zero the transfer will timeout after the given value in milliseconds. 508. 509This function does not change the transfer flags, like short packet not ok. 510. 511This function returns zero on success else a LIBUSB20_TRANSFER_XXX value is returned. 512. 513.Pp 514. 515.Fn libusb20_tr_start 516will get the USB transfer started, if not already 517started. 518. 519This function will not get the transfer queued in hardware. 520. 521This function is non-blocking. 522. 523.Pp 524. 525.Fn libusb20_tr_stop 526will get the USB transfer stopped, if not already stopped. 527. 528This function is non-blocking, which means that the actual stop can 529happen after the return of this function. 530. 531.Pp 532. 533.Fn libusb20_tr_submit 534will get the USB transfer queued in hardware. 535. 536. 537.Pp 538. 539.Fn libusb20_tr_get_priv_sc0 540returns private driver pointer number zero associated 541with an USB transfer. 542. 543. 544.Pp 545. 546.Fn libusb20_tr_get_priv_sc1 547returns private driver pointer number one associated 548with an USB transfer. 549. 550. 551.Sh USB DEVICE OPERATIONS 552. 553. 554.Fn libusb20_dev_get_backend_name 555returns a zero terminated string describing the backend used. 556. 557.Pp 558. 559.Fn libusb20_dev_get_port_path 560retrieves the list of USB port numbers which the datastream for a given USB device follows. 561The first port number is the Root HUB port number. 562Then children port numbers follow. 563The Root HUB device itself has a port path length of zero. 564Valid port numbers start at one and range until and including 255. 565Typically there should not be more than 16 levels, due to electrical and protocol limitations. 566This functions returns the number of actual port levels upon success 567else a LIBUSB20_ERROR value is returned which are always negative. 568If the actual number of port levels is greater than the maximum 569specified, a LIBUSB20_ERROR value is returned. 570. 571.Pp 572. 573.Fn libusb20_dev_get_info 574retrieves the BSD specific usb_device_info structure into the memory location given by 575.Fa pinfo . 576The USB device given by 577.Fa pdev 578must be opened before this function will succeed. 579This function returns zero on success else a LIBUSB20_ERROR value is returned. 580. 581.Pp 582. 583.Fn libusb20_dev_get_iface_desc 584retrieves the kernel interface description for the given USB 585.Fa iface_index . 586The format of the USB interface description is: "drivername<unit>: <description>" 587The description string is always zero terminated. 588A zero length string is written in case no driver is attached to the given interface. 589The USB device given by 590.Fa pdev 591must be opened before this function will succeed. 592This function returns zero on success else a LIBUSB20_ERROR value is returned. 593. 594.Pp 595. 596.Fn libusb20_dev_get_desc 597returns a zero terminated string describing the given USB device. 598The format of the string is: "drivername<unit>: <description>" 599. 600.Pp 601. 602.Fn libusb20_dev_close 603will close the given USB device. 604. 605This function returns zero on success else a LIBUSB20_ERROR value is 606returned. 607. 608.Pp 609. 610.Fn libusb20_dev_detach_kernel_driver 611will try to detach the kernel driver for the USB interface given by 612.Fa iface_index . 613. 614This function returns zero on success else a LIBUSB20_ERROR value is 615returned. 616. 617.Pp 618. 619.Fn libusb20_dev_set_config_index 620will try to set the configuration index on an USB 621device. 622. 623The first configuration index is zero. 624. 625The un-configure index is 255. 626. 627This function returns zero on success else a LIBUSB20_ERROR value is returned. 628. 629.Pp 630. 631.Fn libusb20_dev_get_debug 632returns the debug level of an USB device. 633. 634.Pp 635. 636.Fn libusb20_dev_get_fd 637returns the file descriptor of the given USB device. 638. 639A negative value is returned when no file descriptor is present. 640. 641The file descriptor can be used for polling purposes. 642. 643.Pp 644. 645.Fn libusb20_dev_kernel_driver_active 646returns zero if a kernel driver is active on the given USB interface. 647. 648Else a LIBUSB20_ERROR value is returned. 649. 650.Pp 651. 652.Fn libusb20_dev_open 653opens an USB device so that setting up USB transfers 654becomes possible. 655. 656The number of USB transfers can be zero which means only control 657transfers are allowed. 658. 659This function returns zero on success else a LIBUSB20_ERROR value is 660returned. 661. 662A return value of LIBUSB20_ERROR_BUSY means that the device is already 663opened. 664. 665.Pp 666. 667.Fn libusb20_dev_process 668is called to sync kernel USB transfers with userland USB 669transfers. 670. 671This function returns zero on success else a LIBUSB20_ERROR value is 672returned typically indicating that the given USB device has been 673detached. 674. 675.Pp 676. 677.Fn libusb20_dev_request_sync 678will perform a synchronous control request on the given 679USB device. 680. 681Before this call will succeed the USB device must be opened. 682. 683.Fa setup 684is a pointer to a decoded and host endian SETUP packet. 685.Fa data 686is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL. 687.Fa pactlen 688is a pointer to a variable that will hold the actual transfer length after the control transaction is complete. 689.Fa timeout 690is the transaction timeout given in milliseconds. 691A timeout of zero means no timeout. 692.Fa flags 693is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK. 694. 695This function returns zero on success else a LIBUSB20_ERROR value is 696returned. 697. 698.Pp 699. 700.Fn libusb20_dev_req_string_sync 701will synchronously request an USB string by language ID 702and string index into the given buffer limited by a maximum length. 703. 704This function returns zero on success else a LIBUSB20_ERROR value is 705returned. 706. 707.Pp 708. 709.Fn libusb20_dev_req_string_simple_sync 710will synchronously request an USB string using the 711default language ID and convert the string into ASCII before storing 712the string into the given buffer limited by a maximum length which 713includes the terminating zero. 714. 715This function returns zero on success else a LIBUSB20_ERROR value is 716returned. 717. 718. 719.Pp 720. 721.Fn libusb20_dev_reset 722will try to BUS reset the given USB device and restore 723the last set USB configuration. 724. 725This function returns zero on success else a LIBUSB20_ERROR value is 726returned. 727. 728. 729.Pp 730. 731.Fn libusb20_dev_check_connected 732will check if an opened USB device is still connected. 733. 734This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned. 735. 736. 737.Pp 738. 739.Fn libusb20_dev_set_power_mode 740sets the power mode of the USB device. 741. 742Valid power modes: 743.Bl -tag -width "LIBUSB20_POWER_OFF" 744.It LIBUSB20_POWER_OFF 745.It LIBUSB20_POWER_ON 746.It LIBUSB20_POWER_SAVE 747.It LIBUSB20_POWER_SUSPEND 748.It LIBUSB20_POWER_RESUME 749.El 750.Pp 751. 752This function returns zero on success else a LIBUSB20_ERROR value is 753returned. 754. 755.Pp 756. 757.Fn libusb20_dev_get_power_mode 758returns the currently selected power mode for the given 759USB device. 760. 761.Pp 762. 763.Fn libusb20_dev_get_power_usage 764returns the reported power usage in milliamps for the given USB device. 765A power usage of zero typically means that the device is self powered. 766. 767.Pp 768. 769.Fn libusb20_dev_set_alt_index 770will try to set the given alternate index for the given 771USB interface index. 772. 773This function returns zero on success else a LIBUSB20_ERROR value is 774returned. 775. 776.Pp 777. 778.Fn libusb20_dev_get_device_desc 779returns a pointer to the decoded and host endian version 780of the device descriptor. 781. 782The USB device need not be opened when calling this function. 783. 784.Pp 785. 786.Fn libusb20_dev_alloc_config 787will read out and decode the USB config descriptor for 788the given USB device and config index. This function returns a pointer 789to the decoded configuration which must eventually be passed to 790free(). NULL is returned in case of failure. 791. 792.Pp 793. 794.Fn libusb20_dev_alloc 795is an internal function to allocate a new USB device. 796. 797.Pp 798. 799.Fn libusb20_dev_get_address 800returns the internal and not necessarily the real 801hardware address of the given USB device. 802Valid addresses start at one. 803. 804.Pp 805. 806.Fn libusb20_dev_get_parent_address 807returns the internal and not necessarily the real hardware address of 808the given parent USB HUB device. 809This value is zero for the root HUB which usually has a device address 810equal to one. 811Valid addresses start at one. 812. 813.Pp 814. 815.Fn libusb20_dev_get_parent_port 816returns the port number on the parent USB HUB device. 817This value is zero for the root HUB which usually has a device address 818equal to one. 819Valid port numbers start at one. 820. 821.Pp 822. 823.Fn libusb20_dev_get_bus_number 824returns the internal bus number which the given USB 825device belongs to. 826Valid bus numbers start at zero. 827. 828.Pp 829. 830.Fn libusb20_dev_get_mode 831returns the current operation mode of the USB entity. 832. 833Valid return values are: 834.Bl -tag -width "LIBUSB20_MODE_DEVICE" 835.It LIBUSB20_MODE_HOST 836.It LIBUSB20_MODE_DEVICE 837.El 838. 839.Pp 840. 841.Fn libusb20_dev_get_speed 842returns the current speed of the given USB device. 843. 844.Bl -tag -width "LIBUSB20_SPEED_VARIABLE" 845.It LIBUSB20_SPEED_UNKNOWN 846.It LIBUSB20_SPEED_LOW 847.It LIBUSB20_SPEED_FULL 848.It LIBUSB20_SPEED_HIGH 849.It LIBUSB20_SPEED_VARIABLE 850.It LIBUSB20_SPEED_SUPER 851.El 852. 853.Pp 854. 855.Fn libusb20_dev_get_config_index 856returns the currently selected config index for the given 857USB device. 858. 859.Pp 860. 861.Fn libusb20_dev_free 862will free the given USB device and all associated USB 863transfers. 864. 865.Pp 866. 867.Fn libusb20_dev_set_debug 868will set the debug level for the given USB device. 869. 870.Pp 871. 872.Fn libusb20_dev_wait_process 873will wait until a pending USB transfer has completed on 874the given USB device. 875. 876A timeout value can be specified which is passed on to the 877.Xr poll 2 878function. 879. 880.Sh USB BACKEND OPERATIONS 881. 882.Fn libusb20_be_get_template 883will return the currently selected global USB device 884side mode template into the integer pointer 885.Fa ptemp . 886This function returns zero on success else a LIBUSB20_ERROR value is 887returned. 888. 889.Pp 890. 891.Fn libusb20_be_set_template 892will set the global USB device side mode template to 893.Fa temp . 894The new template is not activated until after the next USB 895enumeration. 896The template number decides how the USB device will present itself to 897the USB Host, like Mass Storage Device, USB Ethernet Device. 898.\"Also see the 899.\".Xr usb2_template 4 900.\"module. 901This function returns zero on success else a LIBUSB20_ERROR value is 902returned. 903. 904.Pp 905. 906.Fn libusb20_be_get_dev_quirk 907will return the device quirk according to 908.Fa index 909into the libusb20_quirk structure pointed to by 910.Fa pq . 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_get_quirk_name 920will return the quirk name according to 921.Fa index 922into the libusb20_quirk structure pointed to by 923.Fa pq . 924This function returns zero on success else a LIBUSB20_ERROR value is 925returned. 926. 927If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 928returned. 929. 930.Pp 931. 932.Fn libusb20_be_add_dev_quirk 933will add the libusb20_quirk structure pointed to by the 934.Fa pq 935argument into the device quirk list. 936. 937This function returns zero on success else a LIBUSB20_ERROR value is 938returned. 939. 940If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is 941returned. 942. 943.Pp 944. 945.Fn libusb20_be_remove_dev_quirk 946will remove the quirk matching the libusb20_quirk structure pointed to by the 947.Fa pq 948argument from the device quirk list. 949. 950This function returns zero on success else a LIBUSB20_ERROR value is 951returned. 952. 953If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 954returned. 955. 956.Pp 957. 958.Fn libusb20_be_alloc_default 959.Fn libusb20_be_alloc_freebsd 960.Fn libusb20_be_alloc_linux 961These functions are used to allocate a specific USB backend or the 962operating system default USB backend. Allocating a backend is a way to 963scan for currently present USB devices. 964. 965.Pp 966. 967.Fn libusb20_be_device_foreach 968is used to iterate USB devices present in a USB backend. 969. 970The starting value of 971.Fa pdev 972is NULL. 973. 974This function returns the next USB device in the list. 975. 976If NULL is returned the end of the USB device list has been reached. 977. 978.Pp 979. 980.Fn libusb20_be_dequeue_device 981will dequeue the given USB device pointer from the 982backend USB device list. 983. 984Dequeued USB devices will not be freed when the backend is freed. 985. 986.Pp 987. 988.Fn libusb20_be_enqueue_device 989will enqueue the given USB device pointer in the backend USB device list. 990. 991Enqueued USB devices will get freed when the backend is freed. 992. 993.Pp 994. 995.Fn libusb20_be_free 996will free the given backend and all USB devices in its device list. 997. 998. 999.Sh USB DESCRIPTOR PARSING 1000. 1001.Fn libusb20_me_get_1 pie offset 1002This function will return a byte at the given byte offset of a message 1003entity. 1004. 1005This function is safe against invalid offsets. 1006. 1007.Pp 1008. 1009.Fn libusb20_me_get_2 pie offset 1010This function will return a little endian 16-bit value at the given byte offset of a message 1011entity. 1012. 1013This function is safe against invalid offsets. 1014. 1015.Pp 1016. 1017.Fn libusb20_me_encode pbuf len pdecoded 1018This function will encode a so-called *DECODED structure into binary 1019format. 1020. 1021The total encoded length that will fit in the given buffer is 1022returned. 1023. 1024If the buffer pointer is NULL no data will be written to the buffer 1025location. 1026. 1027.Pp 1028. 1029.Fn libusb20_me_decode pbuf len pdecoded 1030This function will decode a binary structure into a so-called *DECODED 1031structure. 1032. 1033The total decoded length is returned. 1034. 1035The buffer pointer cannot be NULL. 1036. 1037. 1038.Sh USB DEBUGGING 1039.Ft const char * 1040.Fn libusb20_strerror "int code" 1041Get the ASCII representation of the error given by the 1042.Fa code 1043argument. 1044This function does not return NULL. 1045.Pp 1046.Ft const char * 1047.Fn libusb20_error_name "int code" 1048Get the ASCII representation of the error enum given by the 1049.Fa code 1050argument. 1051This function does not return NULL. 1052. 1053.Sh FILES 1054.Bl -tag -width Pa 1055.It Pa /dev/usb 1056.El 1057.Sh SEE ALSO 1058.Xr libusb 3 , 1059.Xr usb 4 , 1060.Xr usbconfig 8 , 1061.Xr usbdump 8 1062. 1063. 1064.Sh HISTORY 1065. 1066. 1067Some parts of the 1068.Nm 1069API derives from the libusb project at sourceforge. 1070