apply dwt2 function into blkproc

I want to apply dwt2 functon into blkproc function(for sub divided images).How to do this? dwt2 function is this type,

[cA cH cV cD]=dwt2(B,wavename)
block processing function is this type,

B=blkproc(I,[m n],fun),how to apply dwt2 as the fun