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 250582 2013-05-12 22:22:12Z joel $ 28.\" 29.Dd May 3, 2013 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.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" "uint16_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_close "struct libusb20_device *pdev" 126.Ft int 127.Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index" 128.Ft int 129.Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex" 130.Ft int 131.Fn libusb20_dev_get_debug "struct libusb20_device *pdev" 132.Ft int 133.Fn libusb20_dev_get_fd "struct libusb20_device *pdev" 134.Ft int 135.Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index" 136.Ft int 137.Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max" 138.Ft int 139.Fn libusb20_dev_process "struct libusb20_device *pdev" 140.Ft int 141.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" 142.Ft int 143.Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len" 144.Ft int 145.Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len" 146.Ft int 147.Fn libusb20_dev_reset "struct libusb20_device *pdev" 148.Ft int 149.Fn libusb20_dev_check_connected "struct libusb20_device *pdev" 150.Ft int 151.Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode" 152.Ft uint8_t 153.Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev" 154.Ft uint16_t 155.Fn libusb20_dev_get_power_usage "struct libusb20_device *pdev" 156.Ft int 157.Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index" 158.Ft struct LIBUSB20_DEVICE_DESC_DECODED * 159.Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev" 160.Ft struct libusb20_config * 161.Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index" 162.Ft struct libusb20_device * 163.Fn libusb20_dev_alloc "void" 164.Ft uint8_t 165.Fn libusb20_dev_get_address "struct libusb20_device *pdev" 166.Ft uint8_t 167.Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev" 168.Ft uint8_t 169.Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev" 170.Ft uint8_t 171.Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev" 172.Ft uint8_t 173.Fn libusb20_dev_get_mode "struct libusb20_device *pdev" 174.Ft uint8_t 175.Fn libusb20_dev_get_speed "struct libusb20_device *pdev" 176.Ft uint8_t 177.Fn libusb20_dev_get_config_index "struct libusb20_device *pdev" 178.Ft void 179.Fn libusb20_dev_free "struct libusb20_device *pdev" 180.Ft void 181.Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug" 182.Ft void 183.Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout" 184.Ft int 185.Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp" 186.Ft int 187.Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp" 188.Ft int 189.Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq" 190.Ft int 191.Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq" 192.Ft int 193.Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 194.Ft int 195.Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq" 196.Ft struct libusb20_backend * 197.Fn libusb20_be_alloc_default "void" 198.Ft struct libusb20_backend * 199.Fn libusb20_be_alloc_freebsd "void" 200.Ft struct libusb20_backend * 201.Fn libusb20_be_alloc_linux "void" 202.Ft struct libusb20_device * 203.Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 204.Ft void 205.Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 206.Ft void 207.Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev" 208.Ft void 209.Fn libusb20_be_free "struct libusb20_backend *pbe" 210.Ft "const char *" 211.Fn libusb20_strerror "int code" 212.Ft "const char *" 213.Fn libusb20_error_name "int code" 214.In libusb20_desc.h 215.Ft uint8_t 216.Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off" 217.Ft uint16_t 218.Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off" 219.Ft uint16_t 220.Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded" 221.Ft uint16_t 222.Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded" 223.Ft "const uint8_t *" 224.Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc" 225. 226. 227.Sh DESCRIPTION 228. 229The 230.Nm 231library implements functions to be able to easily access and control 232USB through the USB file system interface. 233The 234.Nm 235interfaces are specific to the 236.Fx 237usb stack and are not available on other operating systems, portable 238applications should consider using 239.Xr libusb 3 . 240. 241. 242.Sh USB TRANSFER OPERATIONS 243. 244. 245.Fn libusb20_tr_close 246will release all kernel resources associated with an USB 247.Fa xfer . 248. 249This function returns zero upon success. 250. 251Non-zero return values indicate a LIBUSB20_ERROR value. 252. 253.Pp 254. 255.Fn libusb20_tr_open 256will allocate kernel buffer resources according to 257.Fa max_buf_size 258and 259.Fa max_frame_count 260associated with an USB 261.Fa pxfer 262and bind the transfer to the specified 263.Fa ep_no . 264.Fa max_buf_size 265is the minimum buffer size which the data transport layer has to support. 266If 267.Fa max_buf_size 268is zero, the 269.Nm 270library will use wMaxPacketSize to compute the buffer size. 271This can be useful for isochronous transfers. 272The actual buffer size can be greater than 273.Fa max_buf_size 274and is returned by 275.Fn libusb20_tr_get_max_total_length . 276. 277If 278.Fa max_frame_count 279is OR'ed with LIBUSB20_MAX_FRAME_PRE_SCALE the remaining part of the 280argument is converted from milliseconds into the actual number of 281frames rounded up, when this function returns. 282This flag is only valid for ISOCHRONOUS transfers and has no effect 283for other transfer types. 284The actual number of frames setup is found by calling 285.Fn libusb20_tr_get_max_frames . 286. 287This function returns zero upon success. 288. 289Non-zero return values indicate a LIBUSB20_ERROR value. 290. 291.Pp 292. 293.Fn libusb20_tr_open_stream 294is identical to 295.Fn libusb20_tr_open 296except that a stream ID can be specified for BULK endpoints having 297such a feature. 298.Fn libusb20_tr_open 299can be used to open stream ID zero. 300. 301.Pp 302. 303.Fn libusb20_tr_get_pointer 304will return a pointer to the allocated USB transfer according to the 305.Fa pdev 306and 307.Fa tr_index 308arguments. 309. 310This function returns NULL in case of failure. 311. 312.Pp 313. 314.Fn libusb20_tr_get_time_complete 315will return the completion time of an USB transfer in 316millisecond units. This function is most useful for isochronous USB 317transfers when doing echo cancelling. 318. 319.Pp 320. 321.Fn libusb20_tr_get_actual_frames 322will return the actual number of USB frames after an USB 323transfer completed. A value of zero means that no data was transferred. 324. 325.Pp 326. 327.Fn libusb20_tr_get_actual_length 328will return the sum of the actual length for all 329transferred USB frames for the given USB transfer. 330. 331.Pp 332. 333.Fn libusb20_tr_get_max_frames 334will return the maximum number of USB frames that were 335allocated when an USB transfer was setup for the given USB transfer. 336. 337.Pp 338. 339.Fn libusb20_tr_get_max_packet_length 340will return the maximum packet length in bytes 341associated with the given USB transfer. 342. 343The packet length can be used round up buffer sizes so that short USB 344packets are avoided for proxy buffers. 345. 346. 347.Pp 348. 349.Fn libusb20_tr_get_max_total_length 350will return the maximum value for the data length sum of all USB 351frames associated with an USB transfer. 352In case of control transfers the value returned does not include the 353length of the SETUP packet, 8 bytes, which is part of frame zero. 354The returned value of this function is always aligned to the maximum 355packet size, wMaxPacketSize, of the endpoint which the USB transfer is 356bound to. 357. 358.Pp 359. 360.Fn libusb20_tr_get_status 361will return the status of an USB transfer. 362. 363Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums. 364. 365.Pp 366. 367.Fn libusb20_tr_pending 368will return non-zero if the given USB transfer is 369pending for completion. 370. 371Else this function returns zero. 372. 373.Pp 374. 375.Fn libusb20_tr_callback_wrapper 376This is an internal function used to wrap asynchronous USB callbacks. 377. 378.Pp 379. 380.Fn libusb20_tr_clear_stall_sync 381This is an internal function used to synchronously clear the stall on 382the given USB transfer. 383. 384Please see the USB specification for more information on stall 385clearing. 386. 387If the given USB transfer is pending when this function is called, the 388USB transfer will complete with an error after that this function has 389been called. 390. 391.Pp 392. 393.Fn libusb20_tr_drain 394will stop the given USB transfer and will not return 395until the USB transfer has been stopped in hardware. 396. 397.Pp 398. 399.Fn libusb20_tr_set_buffer 400is used to set the 401.Fa buffer 402pointer for the given USB transfer and 403.Fa fr_index . 404. 405Typically the frame index is zero. 406. 407. 408.Pp 409. 410.Fn libusb20_tr_set_callback 411is used to set the USB callback for asynchronous USB 412transfers. 413. 414The callback type is defined by libusb20_tr_callback_t. 415. 416.Pp 417. 418.Fn libusb20_tr_set_flags 419is used to set various USB flags for the given USB transfer. 420.Bl -tag -width "LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK" 421.It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK 422Report a short frame as error. 423.It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK 424Multiple short frames are not allowed. 425.It LIBUSB20_TRANSFER_FORCE_SHORT 426All transmitted frames are short terminated. 427.It LIBUSB20_TRANSFER_DO_CLEAR_STALL 428Will do a clear-stall before starting the transfer. 429.El 430. 431.Pp 432. 433.Fn libusb20_tr_get_length 434returns the length of the given USB frame by index. 435After an USB transfer is complete the USB frame length will get updated to the actual transferred length. 436. 437.Pp 438. 439.Fn libusb20_tr_set_length 440sets the length of the given USB frame by index. 441. 442.Pp 443. 444.Fn libusb20_tr_set_priv_sc0 445sets private driver pointer number zero. 446. 447.Pp 448. 449.Fn libusb20_tr_set_priv_sc1 450sets private driver pointer number one. 451. 452.Pp 453. 454.Fn libusb20_tr_set_timeout 455sets the timeout for the given USB transfer. 456. 457A timeout value of zero means no timeout. 458. 459The timeout is given in milliseconds. 460. 461.Pp 462. 463.Fn libusb20_tr_set_total_frames 464sets the total number of frames that should be executed when the USB transfer is submitted. 465. 466The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer. 467. 468.Pp 469. 470.Fn libusb20_tr_setup_bulk 471is a helper function for setting up a single frame USB BULK transfer. 472. 473.Pp 474. 475.Fn libusb20_tr_setup_control 476is a helper function for setting up a single or dual 477frame USB CONTROL transfer depending on the control transfer length. 478. 479.Pp 480. 481.Fn libusb20_tr_setup_intr 482is a helper function for setting up a single frame USB INTERRUPT transfer. 483. 484.Pp 485. 486.Fn libusb20_tr_setup_isoc 487is a helper function for setting up a multi frame USB ISOCHRONOUS transfer. 488. 489.Pp 490. 491.Fn libusb20_tr_bulk_intr_sync 492will perform a synchronous BULK or INTERRUPT transfer having length given by the 493.Fa length 494argument and buffer pointer given by the 495.Fa pbuf 496argument on the USB transfer given by the 497.Fa xfer 498argument. 499. 500If the 501.Fa pactlen 502argument is non-NULL the actual transfer length will be stored at the given pointer destination. 503. 504If the 505.Fa timeout 506argument is non-zero the transfer will timeout after the given value in milliseconds. 507. 508This function does not change the transfer flags, like short packet not ok. 509. 510This function returns zero on success else a LIBUSB20_TRANSFER_XXX value is returned. 511. 512.Pp 513. 514.Fn libusb20_tr_start 515will get the USB transfer started, if not already 516started. 517. 518This function will not get the transfer queued in hardware. 519. 520This function is non-blocking. 521. 522.Pp 523. 524.Fn libusb20_tr_stop 525will get the USB transfer stopped, if not already stopped. 526. 527This function is non-blocking, which means that the actual stop can 528happen after the return of this function. 529. 530.Pp 531. 532.Fn libusb20_tr_submit 533will get the USB transfer queued in hardware. 534. 535. 536.Pp 537. 538.Fn libusb20_tr_get_priv_sc0 539returns private driver pointer number zero associated 540with an USB transfer. 541. 542. 543.Pp 544. 545.Fn libusb20_tr_get_priv_sc1 546returns private driver pointer number one associated 547with an USB transfer. 548. 549. 550.Sh USB DEVICE OPERATIONS 551. 552. 553.Fn libusb20_dev_get_backend_name 554returns a zero terminated string describing the backend used. 555. 556.Pp 557. 558.Fn libusb20_dev_get_port_path 559retrieves the list of USB port numbers which the datastream for a given USB device follows. 560The first port number is the Root HUB port number. 561Then children port numbers follow. 562The Root HUB device itself has a port path length of zero. 563Valid port numbers start at one and range until and including 255. 564Typically there should not be more than 16 levels, due to electrical and protocol limitations. 565This functions returns the number of actual port levels upon success 566else a LIBUSB20_ERROR value is returned which are always negative. 567If the actual number of port levels is greater than the maximum 568specified, a LIBUSB20_ERROR value is returned. 569. 570.Pp 571. 572.Fn libusb20_dev_get_info 573retrieves the BSD specific usb_device_info structure into the memory location given by 574.Fa pinfo . 575The USB device given by 576.Fa pdev 577must be opened before this function will succeed. 578This function returns zero on success else a LIBUSB20_ERROR value is returned. 579. 580.Pp 581. 582.Fn libusb20_dev_get_iface_desc 583retrieves the kernel interface description for the given USB 584.Fa iface_index . 585The format of the USB interface description is: "drivername<unit>: <description>" 586The description string is always zero terminated. 587A zero length string is written in case no driver is attached to the given interface. 588The USB device given by 589.Fa pdev 590must be opened before this function will succeed. 591This function returns zero on success else a LIBUSB20_ERROR value is returned. 592. 593.Pp 594. 595.Fn libusb20_dev_get_desc 596returns a zero terminated string describing the given USB device. 597The format of the string is: "drivername<unit>: <description>" 598. 599.Pp 600. 601.Fn libusb20_dev_close 602will close the given USB device. 603. 604This function returns zero on success else a LIBUSB20_ERROR value is 605returned. 606. 607.Pp 608. 609.Fn libusb20_dev_detach_kernel_driver 610will try to detach the kernel driver for the USB interface given by 611.Fa iface_index . 612. 613This function returns zero on success else a LIBUSB20_ERROR value is 614returned. 615. 616.Pp 617. 618.Fn libusb20_dev_set_config_index 619will try to set the configuration index on an USB 620device. 621. 622The first configuration index is zero. 623. 624The un-configure index is 255. 625. 626This function returns zero on success else a LIBUSB20_ERROR value is returned. 627. 628.Pp 629. 630.Fn libusb20_dev_get_debug 631returns the debug level of an USB device. 632. 633.Pp 634. 635.Fn libusb20_dev_get_fd 636returns the file descriptor of the given USB device. 637. 638A negative value is returned when no file descriptor is present. 639. 640The file descriptor can be used for polling purposes. 641. 642.Pp 643. 644.Fn libusb20_dev_kernel_driver_active 645returns zero if a kernel driver is active on the given USB interface. 646. 647Else a LIBUSB20_ERROR value is returned. 648. 649.Pp 650. 651.Fn libusb20_dev_open 652opens an USB device so that setting up USB transfers 653becomes possible. 654. 655The number of USB transfers can be zero which means only control 656transfers are allowed. 657. 658This function returns zero on success else a LIBUSB20_ERROR value is 659returned. 660. 661A return value of LIBUSB20_ERROR_BUSY means that the device is already 662opened. 663. 664.Pp 665. 666.Fn libusb20_dev_process 667is called to sync kernel USB transfers with userland USB 668transfers. 669. 670This function returns zero on success else a LIBUSB20_ERROR value is 671returned typically indicating that the given USB device has been 672detached. 673. 674.Pp 675. 676.Fn libusb20_dev_request_sync 677will perform a synchronous control request on the given 678USB device. 679. 680Before this call will succeed the USB device must be opened. 681. 682.Fa setup 683is a pointer to a decoded and host endian SETUP packet. 684.Fa data 685is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL. 686.Fa pactlen 687is a pointer to a variable that will hold the actual transfer length after the control transaction is complete. 688.Fa timeout 689is the transaction timeout given in milliseconds. 690A timeout of zero means no timeout. 691.Fa flags 692is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK. 693. 694This function returns zero on success else a LIBUSB20_ERROR value is 695returned. 696. 697.Pp 698. 699.Fn libusb20_dev_req_string_sync 700will synchronously request an USB string by language ID 701and string index into the given buffer limited by a maximum length. 702. 703This function returns zero on success else a LIBUSB20_ERROR value is 704returned. 705. 706.Pp 707. 708.Fn libusb20_dev_req_string_simple_sync 709will synchronously request an USB string using the 710default language ID and convert the string into ASCII before storing 711the string into the given buffer limited by a maximum length which 712includes the terminating zero. 713. 714This function returns zero on success else a LIBUSB20_ERROR value is 715returned. 716. 717. 718.Pp 719. 720.Fn libusb20_dev_reset 721will try to BUS reset the given USB device and restore 722the last set USB configuration. 723. 724This function returns zero on success else a LIBUSB20_ERROR value is 725returned. 726. 727. 728.Pp 729. 730.Fn libusb20_dev_check_connected 731will check if an opened USB device is still connected. 732. 733This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned. 734. 735. 736.Pp 737. 738.Fn libusb20_dev_set_power_mode 739sets the power mode of the USB device. 740. 741Valid power modes: 742.Bl -tag -width "LIBUSB20_POWER_OFF" 743.It LIBUSB20_POWER_OFF 744.It LIBUSB20_POWER_ON 745.It LIBUSB20_POWER_SAVE 746.It LIBUSB20_POWER_SUSPEND 747.It LIBUSB20_POWER_RESUME 748.El 749.Pp 750. 751This function returns zero on success else a LIBUSB20_ERROR value is 752returned. 753. 754.Pp 755. 756.Fn libusb20_dev_get_power_mode 757returns the currently selected power mode for the given 758USB device. 759. 760.Pp 761. 762.Fn libusb20_dev_get_power_usage 763returns the reported power usage in milliamps for the given USB device. 764A power usage of zero typically means that the device is self powered. 765. 766.Pp 767. 768.Fn libusb20_dev_set_alt_index 769will try to set the given alternate index for the given 770USB interface index. 771. 772This function returns zero on success else a LIBUSB20_ERROR value is 773returned. 774. 775.Pp 776. 777.Fn libusb20_dev_get_device_desc 778returns a pointer to the decoded and host endian version 779of the device descriptor. 780. 781The USB device need not be opened when calling this function. 782. 783.Pp 784. 785.Fn libusb20_dev_alloc_config 786will read out and decode the USB config descriptor for 787the given USB device and config index. This function returns a pointer 788to the decoded configuration which must eventually be passed to 789free(). NULL is returned in case of failure. 790. 791.Pp 792. 793.Fn libusb20_dev_alloc 794is an internal function to allocate a new USB device. 795. 796.Pp 797. 798.Fn libusb20_dev_get_address 799returns the internal and not necessarily the real 800hardware address of the given USB device. 801Valid addresses start at one. 802. 803.Pp 804. 805.Fn libusb20_dev_get_parent_address 806returns the internal and not necessarily the real hardware address of 807the given parent USB HUB device. 808This value is zero for the root HUB which usually has a device address 809equal to one. 810Valid addresses start at one. 811. 812.Pp 813. 814.Fn libusb20_dev_get_parent_port 815returns the port number on the parent USB HUB device. 816This value is zero for the root HUB which usually has a device address 817equal to one. 818Valid port numbers start at one. 819. 820.Pp 821. 822.Fn libusb20_dev_get_bus_number 823returns the internal bus number which the given USB 824device belongs to. 825Valid bus numbers start at zero. 826. 827.Pp 828. 829.Fn libusb20_dev_get_mode 830returns the current operation mode of the USB entity. 831. 832Valid return values are: 833.Bl -tag -width "LIBUSB20_MODE_DEVICE" 834.It LIBUSB20_MODE_HOST 835.It LIBUSB20_MODE_DEVICE 836.El 837. 838.Pp 839. 840.Fn libusb20_dev_get_speed 841returns the current speed of the given USB device. 842. 843.Bl -tag -width "LIBUSB20_SPEED_VARIABLE" 844.It LIBUSB20_SPEED_UNKNOWN 845.It LIBUSB20_SPEED_LOW 846.It LIBUSB20_SPEED_FULL 847.It LIBUSB20_SPEED_HIGH 848.It LIBUSB20_SPEED_VARIABLE 849.It LIBUSB20_SPEED_SUPER 850.El 851. 852.Pp 853. 854.Fn libusb20_dev_get_config_index 855returns the currently selected config index for the given 856USB device. 857. 858.Pp 859. 860.Fn libusb20_dev_free 861will free the given USB device and all associated USB 862transfers. 863. 864.Pp 865. 866.Fn libusb20_dev_set_debug 867will set the debug level for the given USB device. 868. 869.Pp 870. 871.Fn libusb20_dev_wait_process 872will wait until a pending USB transfer has completed on 873the given USB device. 874. 875A timeout value can be specified which is passed on to the 876.Xr poll 2 877function. 878. 879.Sh USB BACKEND OPERATIONS 880. 881.Fn libusb20_be_get_template 882will return the currently selected global USB device 883side mode template into the integer pointer 884.Fa ptemp . 885This function returns zero on success else a LIBUSB20_ERROR value is 886returned. 887. 888.Pp 889. 890.Fn libusb20_be_set_template 891will set the global USB device side mode template to 892.Fa temp . 893The new template is not activated until after the next USB 894enumeration. 895The template number decides how the USB device will present itself to 896the USB Host, like Mass Storage Device, USB Ethernet Device. 897.\"Also see the 898.\".Xr usb2_template 4 899.\"module. 900This function returns zero on success else a LIBUSB20_ERROR value is 901returned. 902. 903.Pp 904. 905.Fn libusb20_be_get_dev_quirk 906will return the device quirk according to 907.Fa index 908into the libusb20_quirk structure pointed to by 909.Fa pq . 910This function returns zero on success else a LIBUSB20_ERROR value is 911returned. 912. 913If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 914returned. 915. 916.Pp 917. 918.Fn libusb20_be_get_quirk_name 919will return the quirk name according to 920.Fa index 921into the libusb20_quirk structure pointed to by 922.Fa pq . 923This function returns zero on success else a LIBUSB20_ERROR value is 924returned. 925. 926If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 927returned. 928. 929.Pp 930. 931.Fn libusb20_be_add_dev_quirk 932will add the libusb20_quirk structure pointed to by the 933.Fa pq 934argument into the device quirk list. 935. 936This function returns zero on success else a LIBUSB20_ERROR value is 937returned. 938. 939If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is 940returned. 941. 942.Pp 943. 944.Fn libusb20_be_remove_dev_quirk 945will remove the quirk matching the libusb20_quirk structure pointed to by the 946.Fa pq 947argument from the device quirk list. 948. 949This function returns zero on success else a LIBUSB20_ERROR value is 950returned. 951. 952If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is 953returned. 954. 955.Pp 956. 957.Fn libusb20_be_alloc_default 958.Fn libusb20_be_alloc_freebsd 959.Fn libusb20_be_alloc_linux 960These functions are used to allocate a specific USB backend or the 961operating system default USB backend. Allocating a backend is a way to 962scan for currently present USB devices. 963. 964.Pp 965. 966.Fn libusb20_be_device_foreach 967is used to iterate USB devices present in a USB backend. 968. 969The starting value of 970.Fa pdev 971is NULL. 972. 973This function returns the next USB device in the list. 974. 975If NULL is returned the end of the USB device list has been reached. 976. 977.Pp 978. 979.Fn libusb20_be_dequeue_device 980will dequeue the given USB device pointer from the 981backend USB device list. 982. 983Dequeued USB devices will not be freed when the backend is freed. 984. 985.Pp 986. 987.Fn libusb20_be_enqueue_device 988will enqueue the given USB device pointer in the backend USB device list. 989. 990Enqueued USB devices will get freed when the backend is freed. 991. 992.Pp 993. 994.Fn libusb20_be_free 995will free the given backend and all USB devices in its device list. 996. 997. 998.Sh USB DESCRIPTOR PARSING 999. 1000.Fn libusb20_me_get_1 pie offset 1001This function will return a byte at the given byte offset of a message 1002entity. 1003. 1004This function is safe against invalid offsets. 1005. 1006.Pp 1007. 1008.Fn libusb20_me_get_2 pie offset 1009This function will return a little endian 16-bit value at the given byte offset of a message 1010entity. 1011. 1012This function is safe against invalid offsets. 1013. 1014.Pp 1015. 1016.Fn libusb20_me_encode pbuf len pdecoded 1017This function will encode a so-called *DECODED structure into binary 1018format. 1019. 1020The total encoded length that will fit in the given buffer is 1021returned. 1022. 1023If the buffer pointer is NULL no data will be written to the buffer 1024location. 1025. 1026.Pp 1027. 1028.Fn libusb20_me_decode pbuf len pdecoded 1029This function will decode a binary structure into a so-called *DECODED 1030structure. 1031. 1032The total decoded length is returned. 1033. 1034The buffer pointer cannot be NULL. 1035. 1036. 1037.Sh USB DEBUGGING 1038.Ft const char * 1039.Fn libusb20_strerror "int code" 1040Get the ASCII representation of the error given by the 1041.Fa code 1042argument. 1043This function does not return NULL. 1044.Pp 1045.Ft const char * 1046.Fn libusb20_error_name "int code" 1047Get the ASCII representation of the error enum given by the 1048.Fa code 1049argument. 1050This function does not return NULL. 1051. 1052.Sh FILES 1053.Bl -tag -width Pa 1054.It Pa /dev/usb 1055.El 1056.Sh SEE ALSO 1057.Xr libusb 3 , 1058.Xr usb 4 , 1059.Xr usbconfig 8 , 1060.Xr usbdump 8 1061. 1062. 1063.Sh HISTORY 1064. 1065. 1066Some parts of the 1067.Nm 1068API derives from the libusb project at sourceforge. 1069