In the bowl of a food processor, add the whole wheat flour, oats, brown sugar, and salt. Pulse ~15 times to help combine the ingredients and to break down the oats a little. You don't want to pulverize the oats completely—just enough to create some texture variation.
½ cup whole wheat flour, 1 cup old fashioned oats, ¼ cup brown sugar, ¼ tsp kosher salt