1.\" 2.\" Copyright (c) 2008-2019 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 December 27, 2019 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.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" 52.Ft struct libusb20_transfer* 53.Fn libusb20_tr_get_pointer "struct libusb20_device *pdev" "uint16_t tr_index" 54.Ft uint16_t 55.Fn libusb20_tr_get_time_complete "struct libusb20_transfer *xfer" 56.Ft uint32_t 57.Fn libusb20_tr_get_actual_frames "struct libusb20_transfer *xfer" 58.Ft uint32_t 59.Fn libusb20_tr_get_actual_length "struct libusb20_transfer *xfer" 60.Ft uint32_t 61.Fn libusb20_tr_get_max_frames "struct libusb20_transfer *xfer" 62.Ft uint32_t 63.Fn libusb20_tr_get_max_packet_length "struct libusb20_transfer *xfer" 64.Ft uint32_t 65.Fn libusb20_tr_get_max_total_length "struct libusb20_transfer *xfer" 66.Ft uint8_t 67.Fn libusb20_tr_get_status "struct libusb20_transfer *xfer" 68.Ft uint8_t 69.Fn libusb20_tr_pending "struct libusb20_transfer *xfer" 70.Ft void 71.Fn libusb20_tr_callback_wrapper "struct libusb20_transfer *xfer" 72.Ft void 73.Fn libusb20_tr_clear_stall_sync "struct libusb20_transfer *xfer" 74.Ft void 75.Fn libusb20_tr_drain "struct libusb20_transfer *xfer" 76.Ft void 77.Fn libusb20_tr_set_buffer "struct libusb20_transfer *xfer" "void *buffer" "uint16_t fr_index" 78.Ft void 79.Fn libusb20_tr_set_callback "struct libusb20_transfer *xfer" "libusb20_tr_callback_t *cb" 80.Ft void 81.Fn libusb20_tr_set_flags "struct libusb20_transfer *xfer" "uint8_t flags" 82.Ft uint32_t 83.Fn libusb20_tr_get_length "struct libusb20_transfer *xfer" "uint16_t fr_index" 84.Ft void 85.Fn libusb20_tr_set_length "struct libusb20_transfer *xfer" "uint32_t length" "uint16_t fr_index" 86.Ft void 87.Fn libusb20_tr_set_priv_sc0 "struct libusb20_transfer *xfer" "void *sc0" 88.Ft void 89.Fn libusb20_tr_set_priv_sc1 "struct libusb20_transfer *xfer" "void *sc1" 90.Ft void 91.Fn libusb20_tr_set_timeout "struct libusb20_transfer *xfer" "uint32_t timeout" 92.Ft void 93.Fn libusb20_tr_set_total_frames "struct libusb20_transfer *xfer" "uint32_t nframes" 94.Ft void 95.Fn libusb20_tr_setup_bulk "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout" 96.Ft void 97.Fn libusb20_tr_setup_control "struct libusb20_transfer *xfer" "void *psetup" "void *pbuf" "uint32_t timeout" 98.Ft void 99.Fn libusb20_tr_setup_intr "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout" 100.Ft void 101.Fn libusb20_tr_setup_isoc "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint61_t fr_index" 102.Ft uint8_t 103.Fn libusb20_tr_bulk_intr_sync "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t *pactlen" "uint32_t timeout" 104.Ft void 105.Fn libusb20_tr_start "struct libusb20_transfer *xfer" 106.Ft void 107.Fn libusb20_tr_stop "struct libusb20_transfer *xfer" 108.Ft void 109.Fn libusb20_tr_submit "struct libusb20_transfer *xfer" 110.Ft void * 111.Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer" 112.Ft void * 113.Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer" 114.Ft const char * 115.Fn libusb20_dev_get_backend_name "struct libusb20_device *" 116.Ft int 117.Fn libusb20_dev_get_port_path "struct libusb20_device *pdev" "uint8_t *buf" "uint8_t bufsize" 118.Ft int 119.Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo" 120.Ft int 121.Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len" 122.Ft const char * 123.Fn libusb20_dev_get_desc "struct libusb20_device *pdev" 124.Ft int 125.Fn libusb20_dev_get_stats "struct libusb20_device *pdev" "struct libusb20_device_stats *pstats" 126.Ft int 127.Fn libusb20_dev_close "struct libusb20_device *pdev" 128.Ft int 129.Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index" 130.Ft int 131.Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex" 132.Ft int 133.Fn libusb20_dev_get_debug "struct libusb20_device *pdev" 134.Ft int 135.Fn libusb20_dev_get_fd "struct libusb20_device *pdev" 136.Ft int 137.Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index" 138.Ft int 139.Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max" 140.Ft int 141.Fn libusb20_dev_process "struct libusb20_device *pdev" 142.Ft int 143.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" 144.Ft int 145.Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len" 146.Ft int 147.Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len" 148.Ft int 149.Fn libusb20_dev_reset "struct libusb20_device *pdev" 150.Ft int 151.Fn libusb20_dev_check_connected "struct libusb20_device *pdev" 152.Ft int 153.Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode" 154.Ft uint8_t 155.Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev" 156.Ft uint16_t 157.Fn libusb20_dev_get_power_usage "struct libusb20_device *pdev" 158.Ft int 159.Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index" 160.Ft struct LIBUSB20_DEVICE_DESC_DECODED * 161.Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev" 162.Ft struct libusb20_config * 163.Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index" 164.Ft struct libusb20_device * 165.Fn libusb20_dev_alloc "void" 166.Ft uint8_t 167.Fn libusb20_dev_get_address "struct libusb20_device *pdev" 168.Ft uint8_t 169.Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev" 170.Ft uint8_t 171.Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev" 172.Ft uint8_t 173.Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev" 174.Ft uint8_t 175.Fn libusb20_dev_get_mode "struct libusb20_device *pdev" 176.Ft uint8_t 177.Fn libusb20_dev_get_speed "struct libusb20_device *pdev" 178.Ft uint8_t 179.Fn libusb20_dev_get_config_index "struct libusb20_device *pdev" 180.Ft void 181.Fn libusb20_dev_free "struct libusb20_device *pdev" 182.Ft void 183.Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug" 184.Ft void 185.Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout" 186.Ft int 187.Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp" 188.Ft int 189.Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp" 190.Ft int 191.Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq" 192.Ft int 193.Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq" 194.Ft int 195.Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 196.Ft int 197.Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 198.Ft struct libusb20_backend * 199.Fn libusb20_be_alloc_default "void" 200.Ft struct libusb20_backend * 201.Fn libusb20_be_alloc_freebsd "void" 202.Ft struct libusb20_backend * 203.Fn libusb20_be_alloc_linux "void" 204.Ft struct libusb20_device * 205.Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 206.Ft void 207.Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 208.Ft void 209.Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 210.Ft void 211.Fn libusb20_be_free "struct libusb20_backend *pbe" 212.Ft uint8_t 213.Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off" 214.Ft uint16_t 215.Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off" 216.Ft uint16_t 217.Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded" 218.Ft uint16_t 219.Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded" 220.Ft "const uint8_t *" 221.Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc" 222.Ft "const char *" 223.Fn libusb20_strerror "int code" 224.Ft "const char *" 225.Fn libusb20_error_name "int code" 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_get_stats 603retrieves the device statistics into the structure pointed to by the 604.Fa pstats 605argument. 606This function returns zero on success else a LIBUSB20_ERROR value is returned. 607. 608.Pp 609. 610.Fn libusb20_dev_close 611will close the given USB device. 612. 613This function returns zero on success else a LIBUSB20_ERROR value is 614returned. 615. 616.Pp 617. 618.Fn libusb20_dev_detach_kernel_driver 619will try to detach the kernel driver for the USB interface given by 620.Fa iface_index . 621. 622This function returns zero on success else a LIBUSB20_ERROR value is 623returned. 624. 625.Pp 626. 627.Fn libusb20_dev_set_config_index 628will try to set the configuration index on an USB 629device. 630. 631The first configuration index is zero. 632. 633The un-configure index is 255. 634. 635This function returns zero on success else a LIBUSB20_ERROR value is returned. 636. 637.Pp 638. 639.Fn libusb20_dev_get_debug 640returns the debug level of an USB device. 641. 642.Pp 643. 644.Fn libusb20_dev_get_fd 645returns the file descriptor of the given USB device. 646. 647A negative value is returned when no file descriptor is present. 648. 649The file descriptor can be used for polling purposes. 650. 651.Pp 652. 653.Fn libusb20_dev_kernel_driver_active 654returns zero if a kernel driver is active on the given USB interface. 655. 656Else a LIBUSB20_ERROR value is returned. 657. 658.Pp 659. 660.Fn libusb20_dev_open 661opens an USB device so that setting up USB transfers 662becomes possible. 663. 664The number of USB transfers can be zero which means only control 665transfers are allowed. 666. 667This function returns zero on success else a LIBUSB20_ERROR value is 668returned. 669. 670A return value of LIBUSB20_ERROR_BUSY means that the device is already 671opened. 672. 673.Pp 674. 675.Fn libusb20_dev_process 676is called to sync kernel USB transfers with userland USB 677transfers. 678. 679This function returns zero on success else a LIBUSB20_ERROR value is 680returned typically indicating that the given USB device has been 681detached. 682. 683.Pp 684. 685.Fn libusb20_dev_request_sync 686will perform a synchronous control request on the given 687USB device. 688. 689Before this call will succeed the USB device must be opened. 690. 691.Fa setup 692is a pointer to a decoded and host endian SETUP packet. 693.Fa data 694is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL. 695.Fa pactlen 696is a pointer to a variable that will hold the actual transfer length after the control transaction is complete. 697.Fa timeout 698is the transaction timeout given in milliseconds. 699A timeout of zero means no timeout. 700.Fa flags 701is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK. 702. 703This function returns zero on success else a LIBUSB20_ERROR value is 704returned. 705. 706.Pp 707. 708.Fn libusb20_dev_req_string_sync 709will synchronously request an USB string by language ID 710and string index into the given buffer limited by a maximum length. 711. 712This function returns zero on success else a LIBUSB20_ERROR value is 713returned. 714. 715.Pp 716. 717.Fn libusb20_dev_req_string_simple_sync 718will synchronously request an USB string using the 719default language ID and convert the string into ASCII before storing 720the string into the given buffer limited by a maximum length which 721includes the terminating zero. 722. 723This function returns zero on success else a LIBUSB20_ERROR value is 724returned. 725. 726. 727.Pp 728. 729.Fn libusb20_dev_reset 730will try to BUS reset the given USB device and restore 731the last set USB configuration. 732. 733This function returns zero on success else a LIBUSB20_ERROR value is 734returned. 735. 736. 737.Pp 738. 739.Fn libusb20_dev_check_connected 740will check if an opened USB device is still connected. 741. 742This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned. 743. 744. 745.Pp 746. 747.Fn libusb20_dev_set_power_mode 748sets the power mode of the USB device. 749. 750Valid power modes: 751.Bl -tag -width "LIBUSB20_POWER_OFF" 752.It LIBUSB20_POWER_OFF 753.It LIBUSB20_POWER_ON 754.It LIBUSB20_POWER_SAVE 755.It LIBUSB20_POWER_SUSPEND 756.It LIBUSB20_POWER_RESUME 757.El 758.Pp 759. 760This function returns zero on success else a LIBUSB20_ERROR value is 761returned. 762. 763.Pp 764. 765.Fn libusb20_dev_get_power_mode 766returns the currently selected power mode for the given 767USB device. 768. 769.Pp 770. 771.Fn libusb20_dev_get_power_usage 772returns the reported power usage in milliamps for the given USB device. 773A power usage of zero typically means that the device is self powered. 774. 775.Pp 776. 777.Fn libusb20_dev_set_alt_index 778will try to set the given alternate index for the given 779USB interface index. 780. 781This function returns zero on success else a LIBUSB20_ERROR value is 782returned. 783. 784.Pp 785. 786.Fn libusb20_dev_get_device_desc 787returns a pointer to the decoded and host endian version 788of the device descriptor. 789. 790The USB device need not be opened when calling this function. 791. 792.Pp 793. 794.Fn libusb20_dev_alloc_config 795will read out and decode the USB config descriptor for 796the given USB device and config index. This function returns a pointer 797to the decoded configuration which must eventually be passed to 798free(). NULL is returned in case of failure. 799. 800.Pp 801. 802.Fn libusb20_dev_alloc 803is an internal function to allocate a new USB device. 804. 805.Pp 806. 807.Fn libusb20_dev_get_address 808returns the internal and not necessarily the real 809hardware address of the given USB device. 810Valid addresses start at one. 811. 812.Pp 813. 814.Fn libusb20_dev_get_parent_address 815returns the internal and not necessarily the real hardware address of 816the given parent USB HUB device. 817This value is zero for the root HUB which usually has a device address 818equal to one. 819Valid addresses start at one. 820. 821.Pp 822. 823.Fn libusb20_dev_get_parent_port 824returns the port number on the parent USB HUB device. 825This value is zero for the root HUB which usually has a device address 826equal to one. 827Valid port numbers start at one. 828. 829.Pp 830. 831.Fn libusb20_dev_get_bus_number 832returns the internal bus number which the given USB 833device belongs to. 834Valid bus numbers start at zero. 835. 836.Pp 837. 838.Fn libusb20_dev_get_mode 839returns the current operation mode of the USB entity. 840. 841Valid return values are: 842.Bl -tag -width "LIBUSB20_MODE_DEVICE" 843.It LIBUSB20_MODE_HOST 844.It LIBUSB20_MODE_DEVICE 845.El 846. 847.Pp 848. 849.Fn libusb20_dev_get_speed 850returns the current speed of the given USB device. 851. 852.Bl -tag -width "LIBUSB20_SPEED_VARIABLE" 853.It LIBUSB20_SPEED_UNKNOWN 854.It LIBUSB20_SPEED_LOW 855.It LIBUSB20_SPEED_FULL 856.It LIBUSB20_SPEED_HIGH 857.It LIBUSB20_SPEED_VARIABLE 858.It LIBUSB20_SPEED_SUPER 859.El 860. 861.Pp 862. 863.Fn libusb20_dev_get_config_index 864returns the currently selected config index for the given 865USB device. 866. 867.Pp 868. 869.Fn libusb20_dev_free 870will free the given USB device and all associated USB 871transfers. 872. 873.Pp 874. 875.Fn libusb20_dev_set_debug 876will set the debug level for the given USB device. 877. 878.Pp 879. 880.Fn libusb20_dev_wait_process 881will wait until a pending USB transfer has completed on 882the given USB device. 883. 884A timeout value can be specified which is passed on to the 885.Xr poll 2 886function. 887. 888.Sh USB BACKEND OPERATIONS 889. 890.Fn libusb20_be_get_template 891will return the currently selected global USB device 892side mode template into the integer pointer 893.Fa ptemp . 894This function returns zero on success else a LIBUSB20_ERROR value is 895returned. 896. 897.Pp 898. 899.Fn libusb20_be_set_template 900will set the global USB device side mode template to 901.Fa temp . 902The new template is not activated until after the next USB 903enumeration. 904The template number decides how the USB device will present itself to 905the USB Host, like Mass Storage Device, USB Ethernet Device. Also see 906the 907.Xr usb2_template 4 908module. 909This function returns zero on success else a LIBUSB20_ERROR value is 910returned. 911. 912.Pp 913. 914.Fn libusb20_be_get_dev_quirk 915will return the device quirk according to 916.Fa index 917into the libusb20_quirk structure pointed to by 918.Fa pq . 919This function returns zero on success else a LIBUSB20_ERROR value is 920returned. 921. 922If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 923returned. 924. 925.Pp 926. 927.Fn libusb20_be_get_quirk_name 928will return the quirk name according to 929.Fa index 930into the libusb20_quirk structure pointed to by 931.Fa pq . 932This function returns zero on success else a LIBUSB20_ERROR value is 933returned. 934. 935If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 936returned. 937. 938.Pp 939. 940.Fn libusb20_be_add_dev_quirk 941will add the libusb20_quirk structure pointed to by the 942.Fa pq 943argument into the device quirk list. 944. 945This function returns zero on success else a LIBUSB20_ERROR value is 946returned. 947. 948If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is 949returned. 950. 951.Pp 952. 953.Fn libusb20_be_remove_dev_quirk 954will remove the quirk matching the libusb20_quirk structure pointed to by the 955.Fa pq 956argument from the device quirk list. 957. 958This function returns zero on success else a LIBUSB20_ERROR value is 959returned. 960. 961If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 962returned. 963. 964.Pp 965. 966.Fn libusb20_be_alloc_default 967.Fn libusb20_be_alloc_freebsd 968.Fn libusb20_be_alloc_linux 969These functions are used to allocate a specific USB backend or the 970operating system default USB backend. Allocating a backend is a way to 971scan for currently present USB devices. 972. 973.Pp 974. 975.Fn libusb20_be_device_foreach 976is used to iterate USB devices present in a USB backend. 977. 978The starting value of 979.Fa pdev 980is NULL. 981. 982This function returns the next USB device in the list. 983. 984If NULL is returned the end of the USB device list has been reached. 985. 986.Pp 987. 988.Fn libusb20_be_dequeue_device 989will dequeue the given USB device pointer from the 990backend USB device list. 991. 992Dequeued USB devices will not be freed when the backend is freed. 993. 994.Pp 995. 996.Fn libusb20_be_enqueue_device 997will enqueue the given USB device pointer in the backend USB device list. 998. 999Enqueued USB devices will get freed when the backend is freed. 1000. 1001.Pp 1002. 1003.Fn libusb20_be_free 1004will free the given backend and all USB devices in its device list. 1005. 1006. 1007.Sh USB DESCRIPTOR PARSING 1008. 1009.Fn libusb20_me_get_1 pie offset 1010This function will return a byte 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_get_2 pie offset 1018This function will return a little endian 16-bit value at the given byte offset of a message 1019entity. 1020. 1021This function is safe against invalid offsets. 1022. 1023.Pp 1024. 1025.Fn libusb20_me_encode pbuf len pdecoded 1026This function will encode a so-called *DECODED structure into binary 1027format. 1028. 1029The total encoded length that will fit in the given buffer is 1030returned. 1031. 1032If the buffer pointer is NULL no data will be written to the buffer 1033location. 1034. 1035.Pp 1036. 1037.Fn libusb20_me_decode pbuf len pdecoded 1038This function will decode a binary structure into a so-called *DECODED 1039structure. 1040. 1041The total decoded length is returned. 1042. 1043The buffer pointer cannot be NULL. 1044. 1045. 1046.Sh USB DEBUGGING 1047.Ft const char * 1048.Fn libusb20_strerror "int code" 1049Get the ASCII representation of the error given by the 1050.Fa code 1051argument. 1052This function does not return NULL. 1053.Pp 1054.Ft const char * 1055.Fn libusb20_error_name "int code" 1056Get the ASCII representation of the error enum given by the 1057.Fa code 1058argument. 1059This function does not return NULL. 1060. 1061.Sh FILES 1062.Bl -tag -width Pa 1063.It Pa /dev/usb 1064.El 1065.Sh SEE ALSO 1066.Xr libusb 3 , 1067.Xr usb 4 , 1068.Xr usbconfig 8 , 1069.Xr usbdump 8 1070. 1071. 1072.Sh HISTORY 1073. 1074. 1075Some parts of the 1076.Nm 1077API derives from the libusb project at sourceforge. 1078