Hi,

It's great to hear that you're interested in developing a cinder driver.

You can find the Cinder developer reference at http://docs.openstack.org/developer/cinder/devref/index.html and the cloud-user-facing API reference at http://api.openstack.org/api-ref.html#volumes-api

I would recommend that you introduce yourself on the Development mailing list https://wiki.openstack.org/wiki/MailingLists#Future_Development - this should get you in touch with the cinder developers so you can get the help you need.