I used to have this game on Xbox and I'm coming back to it on pc,
on Xbox I had already unlocked blood mage and I would like to use it also in this playthrough on my companio,
I'm looking for a way to unlock blood mage spec, without unlocking every other specialization as well,
anyone know of a way to do this?

During the Arl of Redcliffe quest line, a mage Warden can unlock the specialization
to avoid spoilers for hose not wanting in depth spoilification. i will merely provide the below link
http://dragonage.wikia.com/wiki/The_Arl_of_Redcliffe

in Awakening you can buy a manual for it. (tavern in Amaranthine) as well as get it during the "Shadows of the Blackmarsh" quest
http://dragonage.wikia.com/wiki/Shadows_of_the_Blackmarsh

i hope this helps you out

If you don't mind cheating, you could just use the console.
With you mage companion selected. runscript addtalent 4017

I thought the Awakening unlocks all specializations. Do you play without it?

I wanted to keep awakenings for after origins that's why :)
thanks for the tips guys! this topic is solved