diff --git a/hal/sm_io/sm_io.h b/hal/sm_io/sm_io.h
index 639fd9721fcc5e7c966522c61d1110fae35aa682..0d592d37aa52c82f819337ec0227a277ff2c78b1 100644
--- a/hal/sm_io/sm_io.h
+++ b/hal/sm_io/sm_io.h
@@ -37,6 +37,9 @@ struct _smio_t {
     /* int verbose; */                  /* Print activity to stdout */
     mdp_worker_t *worker;               /* zeroMQ Majordomo worker */
     struct _devio_t *parent;            /* Pointer back to parent dev_io */
+    void *smio_handler;                 /* Generic pointer to a device handler. This
+                                            must be cast to a specific type by the
+                                            devices functions */
     zctx_t *ctx;                        /* Our context */
     void *pipe;                         /* Pipe back to parent to exchange messages */
 
diff --git a/hal/sm_io/sm_io_bootstrap.c b/hal/sm_io/sm_io_bootstrap.c
index 1e6b2fd6dd468a551ee07fce7fa6ed06d491b32f..9976214b9cd9d588d0a544a6326023705698327a 100644
--- a/hal/sm_io/sm_io_bootstrap.c
+++ b/hal/sm_io/sm_io_bootstrap.c
@@ -165,6 +165,7 @@ static struct _smio_t *_smio_new (struct _devio_t *parent, struct _zctx_t *ctx,
     self->exp_ops_dtable = disp_table_new ();
     ASSERT_ALLOC(self->exp_ops_dtable, err_exp_ops_dtable_alloc);
 
+    self->smio_handler = NULL;      /* This is set by the device functions */
     self->ctx = ctx;
     self->pipe = pipe;