Death Penalty Focus is working to put an initiative to do that on the ballot in November 2016. They call their measure the Justice that Works Act.
Meanwhile prosecutors and others who want the state of California to kill more prisoners are collecting signatures for a measure to make executions easier to accomplish. More here. This group starts out ahead among whites, Republicans and Protestant Christians.
The electorate in November 2016 is likely to look more like the former group than the latter, but the campaign is sure to be hard fought and emotional on both sides.