Earlier this year I started writing my first article with a former professor of mine. The article is almost done, but until now he hasn't written a single sentence or provided any data. It has been all my work. We have met about 10 times where each meeting lasted about 90 minutes to discuss the progress of the article, and I have to recognize that during these meetings his advice shaped some of my ideas , especially regarding the research question. I know he has spent his time in this work, but I don't think that qualifies as authorship on the article, and I'm not sure what to do about this. I appreciate any advice you can give me on how to act on this issue.
So in general:
If a professor meets with you a few times to assist you in writing a paper but does not do any actual writing, is this sufficient to justify him being an author?