API.md

API Mapping

below includes a direct mapping of Libusb functions to usb concepts.

Device Handling

Libusb	usb equiv	Done?
struct libusb_device	usb.Device	✔
libusb_get_device_list()	usb.List()	✔
libusb_get_bus_number()	usb.Device.Bus	✔
libusb_get_port_number()	usb.Device.Port	✔
libusb_get_port_numbers()	usb.Device.Ports	✔
libusb_get_parent()	usb.Device.Parent	✔
libusb_get_device_address()	usb.Device.Device	✔
libusb_get_device_speed()	usb.Device.Speed	✔
libusb_get_max_packet_size()	usb.Endpoint.MaxPacketSize	✔
libusb_get_max_iso_packet_size()	usb.Endpoint.MaxISOPacketSize	✔
libusb_open()	usb.Open()	✔
libusb_open_device_with_vid_pid()	usb.VidPid().Open()	✔
libusb_close()	usb.Device.Close()	✔
libusb_get_configuration()	usb.Device.ActiveConfig	✔
libusb_set_configuration()	usb.Device.SetConfiguration()	✔
libusb_claim_interface()	usb.Interface.Claim()	✔
libusb_release_interface()	usb.Interface.Release()	✔
libusb_set_interface_alt_setting()	usb.Interface.SetAlt()	✔
libusb_clear_halt()	-
libusb_reset_device()	usb.Device.Reset()	✔
libusb_kernel_driver_active()	-
enum libusb_speed	usb.Speed	✔
enum libusb_supported_speed	(reuse usb.Speed?)
enum libusb_2_0_extension_attributes	-
enum libusb_ss_usb_device_capability_attributes	-
enum libusb_bos_type	-

Details

This is the equivalent pattern for enumerating devices, choosing your device, and opening it

var found *usb.Device

devs, err := usb.List()
if err != nil {
    panic(err)
}

for _, d := range devs {
    if isMyDevice(d) {
        found = d
        break
    }
}

if found == nil {
    panic("device not found")
}

err = found.Open()
if err != nil {
    panic(err)
}
defer found.Close()

The concept of needing a handle separately from a device object is not carried over to this library. The device is the object from which you may obtain descriptor data, and it is the device you use for I/O operations.

Similarly, the list obtained from usb.List() does not need to be freed. And devices are not reference counted.

Descriptors

These are implemented in the gusb subpackage

Libusb	gusb equiv	Done?
struct libusb_device_descriptor	gusb.DeviceDescriptor
struct libusb_endpoint_descriptor	gusb.EndpointDescriptor
struct libusb_interface_descriptor	gusb.InterfaceDescriptor
struct libusb_interface
struct libusb_config_descriptor	gusb.ConfigDescriptor
struct libusb_ss_endpoint_companion_descriptor
struct libusb_bos_dev_capability_descriptor
struct libusb_bos_descriptor
struct libusb_2_0_extension_descriptor
struct libusb_ss_usb_device_capability_descriptor
struct libusb_container_id_descriptor
enum libusb_class_code	gusb.USBClass
enum libusb_descriptor_type	gusb.DT
enum libusb_endpoint_direction	gusb.EndpointDirection
enum libusb_transfer_type	gusb.TransferType
enum libusb_iso_sync_type	gusb.ISOSyncType
enum libusb_iso_usage_type	gusb.ISOSyncMode
libusb_get_device_descriptor()	``
libusb_get_active_config_descriptor()	``
libusb_get_config_descriptor()	``
libusb_get_config_descriptor_by_value()	``
libusb_get_ss_endpoint_companion_descriptor()	``
libusb_get_bos_descriptor()	``
libusb_get_usb_2_0_extension_descriptor()	``
libusb_get_ss_usb_device_capability_descriptor()	``
libusb_get_container_id_descriptor()	``
libusb_get_string_descriptor_ascii()	``
libusb_get_descriptor()	``
libusb_get_string_descriptor()	``

Hotplug

Libusb	usb equiv	Done?
libusb_hotplug_register_callback()	-
libusb_hotplug_deregister_callback()	-

Async IO

TODO

Polling, Timing

TODO

Synchronous IO

Libusb	usb equiv	Done?
libusb_control_transfer()	-
libusb_bulk_transfer()	-
libusb_interrupt_transfer()	-

Not Included

These pieces are not being ported to usb

Libusb	reason
libusb_version
libusb_context	this is not a shared library
libusb_option	not planned
libusb_set_option	not planned
libusb_init
libusb_exit
libusb_device_handle	handles not used
libusb_get_device	handles not used
libusb_set_auto_detach_kernel_driver	this feature is always enabled
libusb_detach_kernel_driver	automatically detached with claim
libusb_attach_kernel_driver	automatically reattached with release
libusb_free_device_list	not manually memory managed
libusb_free_config_descriptor	not manually memory managed
libusb_free_ss_endpoint_companion_descriptor	not manually memory managed
libusb_free_bos_descriptor	not manually memory managed
libusb_free_usb_2_0_extension_descriptor	not manually memory managed
libusb_free_ss_usb_device_capability_descriptor	not manually memory managed
libusb_free_container_id_descriptor	not manually memory managed
libusb_ref_device	not reference counted
libusb_unref_device	not reference counted
libusb_get_port_path	deprecated in libusb
libusb_set_debug	deprecated in libusb