Declare the shared buffer with zero input ports. The third argument specifies the number of output ports (consuming kernels).
// '0' input ports: buffer is populated by the host via g.update()
wts = adf::shared_buffer<int32>::create({2*SAMPLES}, 0, 2);
adf::connect(wts.out[0], k1.in[1]);
adf::connect(wts.out[1], k2.in[1]);