1.\" 2.\" Copyright (c) 2009 Sylvestre Gallon 3.\" 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd June 22, 2009 30.Dt LIBUSB 3 31.Os 32.Sh NAME 33.Nm libusb 34. 35.Nd "USB access library" 36. 37. 38.Sh LIBRARY 39. 40. 41USB access library (libusb -lusb) 42. 43. 44.Sh SYNOPSIS 45. 46. 47.In libusb.h 48. 49. 50.Sh DESCRIPTION 51The 52.Nm 53library contains interfaces for directly managing a usb device. 54The current implementation supports v1.0 of the libusb API. 55. 56. 57.Sh LIBRARY INITIALISATION / DEINITIALISATION 58. 59.Pp 60. 61.Ft int 62.Fn libusb_init libusb_context **ctx 63This function initialises libusb. Must be called at the beginning 64of the program. This function returns 0 on success or LIBUSB_ERROR on 65failure. 66. 67.Pp 68. 69.Ft void 70.Fn libusb_exit "libusb_context *ctx" 71Deinitialise libusb. Must be called at the end of the application. 72. 73.Pp 74. 75.Ft void 76.Fn libusb_set_debug "libusb_context *ctx" "int level" 77Set debug to the 78.Fa level 79level. 80. 81.Pp 82. 83.Ft ssize_t 84.Fn libusb_get_device_list "libusb_context *ctx" "libusb_device ***list" 85Fill into 86.Fa list 87the list of usb device available. All the device created by this 88function must be unref and free when you are done with them. This 89function returns the number of devices in list or a LIBUSB_ERROR code. 90. 91.Pp 92. 93.Ft void 94.Fn libusb_free_device_list "libusb_device **list" "int unref_devices" 95Free the list of devices discovered by libusb_get_device_list. If 96.Fa unref_device 97is set to 1 all devices are unref one time. 98. 99.Pp 100. 101.Ft uint8_t 102.Fn libusb_get_bus_number "libusb_device *dev" 103Returns the number of the bus contained by the device 104.Fa dev. 105. 106.Pp 107. 108.Ft uint8_t 109.Fn libusb_get_device_address "libusb_device *dev" 110Return the device_address contained by the device 111.Fa dev. 112. 113.Pp 114. 115.Ft int 116.Fn libusb_get_max_packet_size "libusb_device *dev" "unsigned char endpoint" 117Return the wMaxPacketSize value on success, LIBUSB_ERROR_NOT_FOUND if the 118endpoint does not exist and LIBUSB_ERROR_OTHERS on other failure. 119. 120.Pp 121. 122.Ft libusb_device * 123.Fn libusb_ref_device "libusb_device *dev" 124Increment the reference counter of the device 125.Fa dev. 126. 127.Pp 128. 129.Ft void 130.Fn libusb_unref_device "libusb_device *dev" 131Decrement the reference counter of the device 132.Fa dev. 133. 134.Pp 135. 136.Ft int 137.Fn libusb_open "libusb_device *dev" "libusb_device_handle **devh" 138Open a device and obtain a device_handle. Return 0 on success, 139LIBUSB_ERROR_NO_MEM on memory allocation problem, LIBUSB_ERROR_ACCESS 140on permission problem, LIBUSB_ERROR_NO_DEVICE if the device has been 141disconnected and a LIBUSB_ERROR code on error. 142. 143.Pp 144. 145.Ft libusb_device_handle * 146.Fn libusb_open_device_with_vid_pid "libusb_context *ctx" "uint16_t vid" "uint16_t pid" 147Conveniance function to open a device with is 148.Fa vid 149and 150.Fa pid. 151Return NULL on error. 152. 153.Pp 154. 155.Ft void 156.Fn libusb_close "libusb_device_handle *devh" 157Close a device handle. 158. 159.Pp 160. 161.Ft libusb_device * 162.Fn libusb_get_device(libusb_device_handle *devh) 163Get the device contained by devh. Return NULL on error. 164. 165.Pp 166. 167.Ft int 168.Fn libusb_get_configuration "libusb_device_handle *devh" "int *config" 169Return the bConfiguration value of the current configuration. return 0 170on success, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected 171and a LIBUSB_ERROR code on error. 172. 173.Pp 174. 175.Ft int 176.Fn libusb_set_configuration "libusb_device_handle *devh" "int config" 177Set the active configuration 178.Fa config 179for the device contained by 180.Fa devh. 181This function return 0 on success, LIBUSB_ERROR_NOT_FOUND if the requested 182configuration does not exist, LIBUSB_ERROR_BUSY if the interfaces are currently 183claimed, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and a 184LIBUSB_ERROR code on failure. 185. 186.Pp 187. 188.Ft int 189.Fn libusb_claim_interface "libusb_device_handle *devh" "int interface_number" 190Claim an interface in a given libusb_handle 191.Fa devh. 192This is a non-blocking function. It return 0 success, LIBUSB_ERROR_NOT_FOUND 193if the requested interface does not exist, LIBUSB_ERROR_BUSY if a program or 194driver has claimed the interface, LIBUSB_ERROR_NO_DEVICE if the device has 195been disconnected and a LIBUSB_ERROR code on failure. 196. 197.Pp 198. 199.Ft int 200.Fn libusb_release_interface "libusb_device_handle *devh" "int interface_number" 201This function release an interface. All the claimed interface must be released 202before closing a device. Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the 203interafce was not claimed, LIBUSB_ERROR_NO_DEVICE if the device has been 204disconnected and LIBUSB_ERROR on failure. 205. 206.Pp 207. 208.Ft int 209.Fn libusb_set_interface_alt_setting "libusb_device_handle *dev" "int interface_number" "int alternate_setting" 210Activate an alternate setting for an interface. Returns 0 on success, 211LIBUSB_ERROR_NOT_FOUND if the interface was not claimed or the requested 212setting does not exist, LIBUSB_ERROR_NO_DEVICE if the device has been 213disconnected and LIBUSB_ERROR code on failure. 214. 215.Pp 216. 217.Ft int 218.Fn libusb_clear_halt "libusb_device_handle *devh" "unsigned char endpoint" 219Clear an halt/stall for a endpoint. Returns 0 on success, LIBUSB_ERROR_NOT_FOUND 220if the endpoint does not exist, LIBUSB_ERROR_NO_DEVICE if the device has been 221disconnected and a LIBUSB_ERROR code on failure. 222. 223.Pp 224. 225.Ft int 226.Fn libusb_reset_device "libusb_device_handle *devh" 227Perform an USB port reset for an usb device. Returns 0 on success, 228LIBUSB_ERROR_NOT_FOUND if re-enumeration is required or if the device has 229been disconnected and a LIBUSB_ERROR code on failure. 230. 231.Pp 232. 233.Ft int 234.Fn libusb_kernel_driver_active "libusb_device_handle *devh" "int interface" 235Determine if a driver is active on a interface. Returns 0 if no kernel driver 236is active, returns 1 if a kernel driver is active, returns LIBUSB_ERROR_NO_DEVICE 237if the device has been disconnected and return a LIBUSB_ERROR code on failure. 238. 239.Pp 240. 241.Ft int 242.Fn libusb_detach_kernel_driver "libusb_device_handle *devh" "int interface" 243Detach a kernel driver from an interface. This is needed to claim an interface 244required by a kernel driver. Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if 245no kernel driver was active, LIBUSB_ERROR_INVALID_PARAM if the interface does not 246exist, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and a 247LIBUSB_ERROR code on failure. 248. 249.Pp 250. 251.Ft int 252.Fn libusb_attach_kernel_driver "libusb_device_handle *devh" "int interface" 253Re-attach an interface kernel driver previously detached. Returns 0 on success, 254LIBUSB_ERROR_INVALID_PARAM if the interface does not exist, LIBUSB_ERROR_NO_DEVICE 255if the device has been disconnect, LIBUSB_ERROR_BUSY if the driver cannot be 256attached because the interface is claimed by a program or driver and a 257LIBUSB_ERROR code on failure. 258. 259.Pp 260. 261.Sh USB DESCRIPTORS 262. 263.Pp 264. 265.Ft int 266.Fn libusb_get_device_descriptor "libusb_device *dev" "libusb_device_descriptor *desc" 267Get the USB device descriptor for the device 268.Fa dev. 269This is a non-blocking function. Returns 0 on success and a LIBUSB_ERROR code on 270failure. 271. 272.Pp 273.Ft int 274.Fn libsub_get_active_config_descriptor "libusb_device *dev" "libusb_device_descriptor **config" 275Get the USB configuration descriptor for the active configuration. Returns 0 on 276success, returns LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state 277and return another LIBUSB_ERROR code on error. 278. 279.Pp 280.Ft int 281.Fn libusb_get_config_descriptor "libusb_device *dev" "uint8_t config_index" "libusb_config_descriptor **config" 282Get USB configuration descriptor based on its index 283.Fa idx. 284Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the configuration does not exist 285and returns another LIBUSB_ERROR code on error. 286. 287.Pp 288.Ft int 289.Fn libusb_get_config_descriptor_by_value "libusb_device *dev" "uint8 bConfigurationValue" "libusb_config_descriptor **config" 290Get a USB configuration descriptor with a specific bConfigurationValue. This is 291a non-blocking function which does not send request through the device. Returns 0 292on success, LIBUSB_ERROR_NOT_FOUND if the configuration does not exist and another 293LIBUSB_ERROR code on failure. 294. 295.Pp 296.Ft void 297.Fn libusb_free_config_descriptor "libusb_config_descriptor *config`" 298Free a configuration descriptor. 299. 300.Pp 301.Ft int 302.Fn libusb_get_string_descriptor_ascii "libusb_device_handle *devh" "uint8_t desc_idx" "unsigned char *data" "int length" 303Retrieve a string descriptor in C style ascii. Returns a number of byte on success 304and a LIBUSB_ERROR code on failure. 305. 306.Pp 307. 308.Sh USB ASYNCHRONOUS I/O 309. 310.Pp 311.Ft struct libusb_transfer * 312.Fn libusb_alloc_transfer "int iso_packets" 313Allocate a transfer with 314.Fa iso_packets 315numbers of isochronous packet descriptors. Returns NULL on error. 316. 317.Pp 318.Ft void 319.Fn libusb_free_transfer "struct libusb_transfer *tr" 320Free a transfer. 321. 322.Pp 323.Ft int 324.Fn libusb_submit_transfer "struct libusb_transfer *tr" 325This function will submit a transfer and returns immediately. Returns 0 on 326success, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and 327LIBUSB_ERROR code on other failure. 328. 329.Pp 330.Ft int 331.Fn libusb_cancel_transfer "struct libusb_transfer *tr" 332This function asynchronously cancel a transfer. Returns 0 on success and 333LIBUSB_ERROR code on failure. 334. 335.Pp 336.Sh USB SYNCHRONOUS I/O 337. 338.Pp 339.Ft int 340.Fn libusb_control_transfer "libusb_device_handle *devh" "uint8_t bmRequestType" "uint16_t wIndex" "unsigned char *data" "uint16_t wLength" "unsigned int timeout" 341Perform a USB control transfer. Returns 0 on success, LIBUSB_ERROR_TIMEOUT 342if the transfer timeout, LIBUSB_ERROR_PIPE if the control request was not 343supported, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and 344LIBUSB_ERROR code on other failure. 345. 346.Pp 347.Ft int 348.Fn libusb_bulk_transfer "struct libusb_device_handle *devh" "unsigned char endpoint" "unsigned char *data" "int length" "int *transferred" "unsigned int timeout" 349Perform an USB bulk transfer. Returns 0 on success, LIBUSB_ERROR_TIMEOUT 350if the transfer timeout, LIBUSB_ERROR_PIPE if the control request was not 351supported, LIBUSB_ERROR_OVERFLOW if the device offered more data, 352LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and 353LIBUSB_ERROR code on other failure. 354. 355.Pp 356.Ft int 357.Fn libusb_interrupt_transfer "struct libusb_device_handle *devh" "unsigned char endpoint" "unsigned char *data" "int length" "int *transferred" "unsigned int timeout" 358Perform an USB Interrupt transfer. Returns 0 on success, LIBUSB_ERROR_TIMEOUT 359if the transfer timeout, LIBUSB_ERROR_PIPE if the control request was not 360supported, LIBUSB_ERROR_OVERFLOW if the device offered more data, 361LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and 362LIBUSB_ERROR code on other failure. 363. 364.Pp 365.Sh USB EVENTS 366. 367.Pp 368.Ft int 369.Fn libusb_try_lock_events "libusb_context *ctx" 370Try to acquire the event handling lock. Returns 0 if the lock was obtained and 1 371if not. 372. 373.Pp 374.Ft void 375.Fn libusb_lock_events "libusb_context *ctx" 376Acquire the event handling lock. This function is blocking. 377. 378.Pp 379.Ft void 380.Fn libusb_unlock_events "libusb_context *ctx" 381Release the event handling lock. This will wake up any thread blocked 382on libusb_wait_for_event(). 383. 384.Pp 385.Ft int 386.Fn libusb_event_handling_ok "libusb_context *ctx" 387Determine if it still OK for this thread to be doing event handling. Returns 1 388if event handling can start or continue. Returns 0 if this thread must give up 389the events lock. 390. 391.Pp 392.Ft int 393.Fn libusb_event_handler_active "libusb_context *ctx" 394Determine if an active thread is handling events. Returns 1 if yes and 0 if there 395are no threads currently handling events. 396. 397.Pp 398.Ft void 399.Fn libusb_lock_event_waiters "libusb_context *ctx" 400Acquire the event_waiters lock. This lock is designed to be obtained under the 401situation where you want to be aware when events are completed, but some other 402thread is event handling so calling libusb_handle_events() is not allowed. 403. 404.Pp 405.Ft void 406.Fn libusb_unlock_event_waiters "libusb_context *ctx" 407Release the event_waiters lock. 408. 409.Pp 410.Ft int 411.Fn libusb_wait_for_event "libusb_context *ctx" "struct timeval *tv" 412Wait for another thread to signal completion of an event. Must be called 413with the event waiters lock held, see libusb_lock_event_waiters(). This will 414block until the timeout expires or a transfer completes or a thread releases 415the event handling lock through libusb_unlock_events(). Returns 0 after a 416transfer completes or another thread stops event handling, returns 1 if the 417timeout expired. 418. 419.Pp 420.Ft int 421.Fn libusb_handle_events_timeout "libusb_context *ctx" "struct timeval *tv" 422Handle any pending events by checking if timeouts have expired and by 423checking the set of file descriptors for activity. Returns 0 on success, or a 424LIBUSB_ERROR code on failure. 425. 426.Pp 427.Ft int 428.Fn libusb_handle_events "libusb_context *ctx" 429Handle any pending events in blocking mode with a sensible timeout. Returns 0 430on success, returns a LIBUSB_ERROR code on failure. 431. 432.Pp 433.Ft int 434.Fn libusb_handle_events_locked "libusb_context *ctx" "struct timeval *tv" 435Handle any pending events by polling file desciptors, without checking if 436another threads are already doing so. Must be called with the event lock held. 437. 438.Pp 439.Ft int 440.Fn libusb_get_next_timeout "libusb_context *ctx" "struct timeval *tv" 441Determine the next internal timeout that libusb needs to handle. Returns 0 442if there are no pending timeouts, 1 if a timeout was returned, or LIBUSB_ERROR 443code on failure. 444. 445.Pp 446.Ft void 447.Fn libusb_set_pollfd_notifiers "libusb_context *ctx" "libusb_pollfd_added_cb added_cb" "libusb_pollfd_removed_cb remove_cb" "void *user_data" 448Register notification functions for file descriptor additions/removals. 449These functions will be invoked for every new or removed file descriptor 450that libusb uses as an event source. 451. 452.Pp 453.Ft const struct libusb_pollfd ** 454.Fn libusb_get_pollfds "libusb_context *ctx" 455Retrive a list of file descriptors that should be polled by your main loop as 456libusb event sources. Returns a NULL-terminated list on success or NULL on failure. 457. 458.Sh LIBUSB VERSION 0.1 COMPATIBILITY 459.Pp 460The library is also compliant with LibUSB version 0.1.12. 461.Pp 462.Fn usb_open 463.Fn usb_close 464.Fn usb_get_string 465.Fn usb_get_string_simple 466.Fn usb_get_descriptor_by_endpoint 467.Fn usb_get_descriptor 468.Fn usb_parse_descriptor 469.Fn usb_parse_configuration 470.Fn usb_destroy_configuration 471.Fn usb_fetch_and_parse_descriptors 472.Fn usb_bulk_write 473.Fn usb_bulk_read 474.Fn usb_interrupt_write 475.Fn usb_interrupt_read 476.Fn usb_control_msg 477.Fn usb_set_configuration 478.Fn usb_claim_interface 479.Fn usb_release_interface 480.Fn usb_set_altinterface 481.Fn usb_resetep 482.Fn usb_clear_halt 483.Fn usb_reset 484.Fn usb_strerror 485.Fn usb_init 486.Fn usb_set_debug 487.Fn usb_find_busses 488.Fn usb_find_devices 489.Fn usb_device 490.Fn usb_get_busses 491. 492.Sh SEE ALSO 493.Xr libusb20 3 , 494.Xr usb 4 , 495.Xr usbconfig 8 496.Pp 497.Pa http://libusb.sourceforge.net/ 498. 499.Sh HISTORY 500. 501.Nm 502support first appeared in 503.Fx 8.0 . 504