Index: sys/dev/iicbus/iic.c
===================================================================
--- sys/dev/iicbus/iic.c
+++ sys/dev/iicbus/iic.c
@@ -231,6 +231,7 @@
 			error = iicbus_read(parent, buffer,
 			    num_bytes, &transferred_bytes,
 			    ((uio->uio_resid <= sizeof(buffer)) ? last : 0), 0);
+			error = iic2errno(error);
 			if (error == 0)
 				error = uiomove(buffer, transferred_bytes, uio);
 		}
@@ -263,6 +264,7 @@
 
 	error = iicbus_request_bus(parent, priv->sc->sc_dev,
 	    (ioflag & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
+	error = iic2errno(error);
 	if (error != 0) {
 		IIC_UNLOCK(priv);
 		return (error);
@@ -274,6 +276,7 @@
 		addr = priv->addr & ~LSB;
 
 	error = iicbus_start(parent, addr, 0);
+	error = iic2errno(error);
 	if (error != 0)
 	{
 		iicbus_release_bus(parent, priv->sc->sc_dev);
@@ -334,12 +337,15 @@
 			error = copyin(usrbufs[i], m->buf, m->len);
 	}
 
-	if (error == 0)
+	if (error == 0) {
 		error = iicbus_request_bus(parent, iicdev,
 		    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
+		error = iic2errno(error);
+	}
 
 	if (error == 0) {
 		error = iicbus_transfer(iicdev, buf, d->nmsgs);
+		error = iic2errno(error);
 		iicbus_release_bus(parent, iicdev);
 	}
 
@@ -386,10 +392,12 @@
 		}
 		error = iicbus_request_bus(parent, iicdev,
 		    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
+		error = iic2errno(error);
 
-		if (error == 0)
+		if (error == 0) {
 			error = iicbus_start(parent, s->slave, 0);
-
+			error = iic2errno(error);
+		}
 		if (error == 0) {
 			priv->addr = s->slave;
 			priv->started = true;
@@ -401,6 +409,7 @@
 	case I2CSTOP:
 		if (priv->started) {
 			error = iicbus_stop(parent);
+			error = iic2errno(error);
 			iicbus_release_bus(parent, iicdev);
 			priv->started = false;
 		}
@@ -413,9 +422,11 @@
 		 * We allow the bus to be already owned as the result of an in-progress
 		 * sequence; however, bus reset will always be followed by release
 		 * (a new start is presumably needed for I/O anyway). */ 
-		if (!priv->started)	
+		if (!priv->started) {
 			error = iicbus_request_bus(parent, iicdev,
 			    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
+			error = iic2errno(error);
+		}
 
 		if (error == 0) {
 			error = iicbus_reset(parent, IIC_UNKNOWN, 0, NULL);
@@ -485,6 +496,7 @@
 			break;
 		}
 		error = iicbus_repeated_start(parent, s->slave, 0);
+		error = iic2errno(error);
 		break;
 
 	case I2CSADDR: