Academy Award nominee and Rhode Island native Viola Davis is the star who keeps on giving back. Already slated to deliver the commencement address at Providence College on Sunday, Davis will take the stage May 23 for “An Evening With Viola Davis,’’ a fund-raiser for Community Preparatory School in Providence. Tickets for the event, which will fund scholarships for students, start at $250. According to Dan Corley, founder of Community Prep, most of the students live at or below the poverty level, and 90 percent receive scholarships. The cause sounds as if it’s close to Davis’s heart. The Tony-winning actress grew up poor in Central Falls, R.I., and received a scholarship to the Young People’s School for the Performing Arts in Rhode Island.