+       if (ctx == NULL) {
+               fatal("context must not be NULL!\n");
+               return -EINVAL;
+       }
+       if (op == SCAN_OP_BUILD_DEVLIST && ctx->devices_list != NULL) {
+               error(ctx, "device scan done already? Abort!\n");
+               return -EINVAL;
+       }
+
+       num_devices = libusb_get_device_list(ctx->usb_context, &list);
+       if (num_devices < 0) {
+               ret = -ENODEV;
+               goto out;
+       }
+
+       current_index = 0;
+       for (i = 0; i < num_devices; i++) {
+               struct libusb_device_descriptor desc;
+               unsigned int j;
+
+               ret = libusb_get_device_descriptor(list[i], &desc);
+               if (ret < 0)
+                       continue;
+
+               for (j = 0; j < ARRAY_SIZE(supported_devices); j++) {
+                       if (desc.idVendor == supported_devices[j].vendor_id
+                           && desc.idProduct == supported_devices[j].product_id) {
+
+                               if (op == SCAN_OP_BUILD_DEVLIST) {
+                                       am7xxx_device *new_device;
+                                       info(ctx, "am7xxx device found, index: %d, name: %s\n",
+                                            current_index,
+                                            supported_devices[j].name);
+                                       new_device = add_new_device(ctx);
+                                       if (new_device == NULL) {
+                                               /* XXX, the caller may want
+                                                * to call am7xxx_shutdown() if
+                                                * we fail here, as we may have
+                                                * added some devices already
+                                                */
+                                               debug(ctx, "Cannot create a new device\n");
+                                               ret = -ENODEV;
+                                               goto out;
+                                       }
+                               } else if (op == SCAN_OP_OPEN_DEVICE &&
+                                          current_index == open_device_index) {
+
+                                       *dev = find_device(ctx, open_device_index);
+                                       if (*dev == NULL) {
+                                               ret = -ENODEV;
+                                               goto out;
+                                       }
+
+                                       /* the usb device has already been opened */
+                                       if ((*dev)->usb_device) {
+                                               debug(ctx, "(*dev)->usb_device already set\n");
+                                               ret = 1;
+                                               goto out;
+                                       }
+
+                                       ret = libusb_open(list[i], &((*dev)->usb_device));
+                                       if (ret < 0) {
+                                               debug(ctx, "libusb_open failed\n");
+                                               goto out;
+                                       }
+
+                                       libusb_set_configuration((*dev)->usb_device, 1);
+                                       libusb_claim_interface((*dev)->usb_device, 0);
+                                       goto out;
+                               }
+                               current_index++;
+                       }
+               }
+       }
+
+       /* if we made it up to here we didn't find any device to open */
+       if (op == SCAN_OP_OPEN_DEVICE) {
+               error(ctx, "Cannot find any device to open\n");
+               ret = -ENODEV;
+               goto out;
+       }
+
+       /* everything went fine when building the device list */
+       ret = 0;
+out:
+       libusb_free_device_list(list, 1);
+       return ret;
+}
+
+/* Public API */
+
+AM7XXX_PUBLIC int am7xxx_init(am7xxx_context **ctx)
+{
+       int ret = 0;
+
+       *ctx = malloc(sizeof(**ctx));
+       if (*ctx == NULL) {
+               fatal("cannot allocate the context (%s)\n", strerror(errno));
+               ret = -ENOMEM;
+               goto out;
+       }
+       memset(*ctx, 0, sizeof(**ctx));
+
+       /* Set the highest log level during initialization */
+       (*ctx)->log_level = AM7XXX_LOG_TRACE;
+
+       ret = libusb_init(&((*ctx)->usb_context));