func (d *Device) OpenEndpoint(conf, iface, setup, epoint uint8) (Endpoint, error) {
end := &endpoint{
Device: d,
}
var setAlternate bool
for _, c := range d.Configs {
if c.Config != conf {
continue
}
debug.Printf("found conf: %#v\n", c)
for _, i := range c.Interfaces {
if i.Number != iface {
continue
}
debug.Printf("found iface: %#v\n", i)
for i, s := range i.Setups {
if s.Alternate != setup {
continue
}
setAlternate = i != 0
debug.Printf("found setup: %#v [default: %v]\n", s, !setAlternate)
for _, e := range s.Endpoints {
debug.Printf("ep %02x search: %#v\n", epoint, s)
if e.Address != epoint {
continue
}
end.InterfaceSetup = s
end.EndpointInfo = e
switch tt := TransferType(e.Attributes) & TRANSFER_TYPE_MASK; tt {
case TRANSFER_TYPE_BULK:
end.xfer = bulk_xfer
case TRANSFER_TYPE_INTERRUPT:
end.xfer = interrupt_xfer
case TRANSFER_TYPE_ISOCHRONOUS:
end.xfer = isochronous_xfer
default:
return nil, fmt.Errorf("usb: %s transfer is unsupported", tt)
}
goto found
}
return nil, fmt.Errorf("usb: unknown endpoint %02x", epoint)
}
return nil, fmt.Errorf("usb: unknown setup %02x", setup)
}
return nil, fmt.Errorf("usb: unknown interface %02x", iface)
}
return nil, fmt.Errorf("usb: unknown configuration %02x", conf)
found:
// Set the configuration
var activeConf C.int
if errno := C.libusb_get_configuration(d.handle, &activeConf); errno < 0 {
return nil, fmt.Errorf("usb: getcfg: %s", usbError(errno))
}
if int(activeConf) != int(conf) {
if errno := C.libusb_set_configuration(d.handle, C.int(conf)); errno < 0 {
return nil, fmt.Errorf("usb: setcfg: %s", usbError(errno))
}
}
// Claim the interface
if errno := C.libusb_claim_interface(d.handle, C.int(iface)); errno < 0 {
return nil, fmt.Errorf("usb: claim: %s", usbError(errno))
}
// Increment the claim count
d.lock.Lock()
d.claimed[iface]++
d.lock.Unlock() // unlock immediately because the next calls may block
// Choose the alternate
if setAlternate {
if errno := C.libusb_set_interface_alt_setting(d.handle, C.int(iface), C.int(setup)); errno < 0 {
debug.Printf("altsetting error: %s", usbError(errno))
return nil, fmt.Errorf("usb: setalt: %s", usbError(errno))
}
}
return end, nil
}
// Activate an alternate setting for an interface.
func (h *DeviceHandle) SetInterfaceAltSetting(num int, alternate int) error {
return toErr(C.libusb_set_interface_alt_setting(h.me(), C.int(num), C.int(alternate)))
}
func (i *Interface) SetAlternate(alt int) *UsbError {
return returnUsbError(C.libusb_set_interface_alt_setting(i.handle.handle, i.num, C.int(alt)))
}