diff --git a/src/simtrace2-discovery.c b/src/simtrace2-discovery.c
new file mode 100644
index 0000000..a7306ce
--- /dev/null
+++ b/src/simtrace2-discovery.c
@@ -0,0 +1,94 @@
+/* simtrace2-discovery - host PC library to scan for matching USB
+ * devices
+ *
+ * (C) 2016 by Harald Welte <hwelte@hmw-consulting.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include <stdint.h>
+
+#include <libusb.h>
+
+/*! \brief obtain the endpoint addresses for a given USB interface */
+int get_usb_ep_addrs(libusb_device_handle *devh, unsigned int if_num,
+		     uint8_t *out, uint8_t *in, uint8_t *irq)
+{
+	libusb_device *dev = libusb_get_device(devh);
+	struct libusb_config_descriptor *cdesc;
+	const struct libusb_interface_descriptor *idesc;
+	const struct libusb_interface *iface;
+	int rc, l;
+
+	rc = libusb_get_active_config_descriptor(dev, &cdesc);
+	if (rc < 0)
+		return rc;
+
+	iface = &cdesc->interface[if_num];
+	/* FIXME: we assume there's no altsetting */
+	idesc = &iface->altsetting[0];
+
+	for (l = 0; l < idesc->bNumEndpoints; l++) {
+		const struct libusb_endpoint_descriptor *edesc = &idesc->endpoint[l];
+		switch (edesc->bmAttributes & 3) {
+		case LIBUSB_TRANSFER_TYPE_BULK:
+			if (edesc->bEndpointAddress & 0x80) {
+				if (in)
+					*in = edesc->bEndpointAddress;
+			} else {
+				if (out)
+					*out = edesc->bEndpointAddress;
+			}
+			break;
+		case LIBUSB_TRANSFER_TYPE_INTERRUPT:
+			if (irq)
+				*irq = edesc->bEndpointAddress;
+			break;
+		default:
+			break;
+		}
+	}
+	return 0;
+}
+
+#if 0
+	struct libusb_device_descriptor ddesc;
+	int rc, i, j, k;
+
+	rc = libusb_get_device_descriptor(devh, &ddesc);
+	if (rc < 0)
+		return;
+
+	for (i = 0; i < ddesc.bNumConfigurations; i++) {
+		struct libusb_config_descriptor *cdesc;
+		rc = libusb_get_config_descriptor(devh, i, &cdesc);
+		if (rc < 0)
+			return;
+
+		for (j = 0; j < cdesc->bNumInterfaces; j++) {
+			const struct libusb_interface *iface = cdesc->interface[j];
+			for (k = 0; k < iface->num_altsetting; k++) {
+				const struct libusb_interface_descriptor *idesc = iface->altsetting[k];
+				/* make sure this is the interface we're looking for */
+				if (idesc->bInterfaceClass != 0xFF ||
+				    idesc->bInterfaceSubClass != if_class ||
+				    idsec->bInterfaceProtocol != if_proto)
+					continue;
+				/* FIXME */
+			}
+		}
+
+		libusb_free_config_descriptor(cdesc);
+	}
+#endif