Yes, that should be pretty simple to implement. I took a stab at it here: https://chromium-review.googlesource.com/#/c/352820/

I don't have hardware to test it with. Try adding serial=<serial_num> to your programmer arguments, ie "-p raiden_spi:serial=<serial num>" and let me know how it goes.

Souvik might also be able to help.

This looks like it will require a refactor of the usb init code to remove a bunch of hardcoded assumptions. Maybe better if dhendrix@ does it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/flashrom/+/5c79a49c0fe6fec3474678c4846e74532cf7a1f1

commit 5c79a49c0fe6fec3474678c4846e74532cf7a1f1
Author: David Hendricks <dhendrix@chromium.org>
Date: Wed Jun 15 03:56:36 2016

usb_device: Add serial number to command-line parameters

This adds support for specifying serial number for programmers
which use the usb_device library, such as raiden_spi.

BUG= chromium:620106 
BRANCH=none
TEST=needs testing

Change-Id: I895bc08a3e2c14ba1c1e1a81f8dbf2073d0d8f3a
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/352820
Tested-by: Nick Sanders <nsanders@chromium.org>
Reviewed-by: Nick Sanders <nsanders@chromium.org>
Reviewed-by: Kevin Cheng <kevcheng@chromium.org>

[modify] https://crrev.com/5c79a49c0fe6fec3474678c4846e74532cf7a1f1/raiden_debug_spi.c
[modify] https://crrev.com/5c79a49c0fe6fec3474678c4846e74532cf7a1f1/usb_device.h