Index: sys/dev/iicbus/iic.c
===================================================================
--- sys/dev/iicbus/iic.c
+++ sys/dev/iicbus/iic.c
@@ -265,7 +265,7 @@
 	    (ioflag & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
 	if (error != 0) {
 		IIC_UNLOCK(priv);
-		return (error);
+		return (iic2errno(error));
 	}
 
 	if (uio->uio_rw == UIO_READ)
@@ -278,7 +278,7 @@
 	{
 		iicbus_release_bus(parent, priv->sc->sc_dev);
 		IIC_UNLOCK(priv);
-		return (error);
+		return (iic2errno(error));
 	}
 
 	error = iicuio_move(priv, uio, IIC_LAST_READ);
@@ -286,7 +286,7 @@
 	iicbus_stop(parent);
 	iicbus_release_bus(parent, priv->sc->sc_dev);
 	IIC_UNLOCK(priv);
-	return (error);
+	return (iic2errno(error));
 }
 
 static int
@@ -303,7 +303,7 @@
 	error = 0;
 
 	if (d->nmsgs > IIC_RDRW_MAX_MSGS)
-		return (EINVAL);
+		return (errno2iic(EINVAL));
 
 	buf = malloc(sizeof(*d->msgs) * d->nmsgs, M_IIC, M_WAITOK);
 
@@ -381,7 +381,7 @@
 	switch (cmd) {
 	case I2CSTART:
 		if (priv->started) {
-			error = EINVAL;
+			error = errno2iic(EINVAL);
 			break;
 		}
 		error = iicbus_request_bus(parent, iicdev,
@@ -433,7 +433,7 @@
 
 	case I2CWRITE:
 		if (!priv->started) {
-			error = EINVAL;
+			error = errno2iic(EINVAL);
 			break;
 		}
 		uvec.iov_base = s->buf;
@@ -450,7 +450,7 @@
 
 	case I2CREAD:
 		if (!priv->started) {
-			error = EINVAL;
+			error = errno2iic(EINVAL);
 			break;
 		}
 		uvec.iov_base = s->buf;
@@ -471,7 +471,7 @@
 		 * transactions.  Fail if another transaction is in progress.
                  */
 		if (priv->started) {
-			error = EINVAL;
+			error = errno2iic(EINVAL);
 			break;
 		}
 
@@ -481,7 +481,7 @@
 
 	case I2CRPTSTART:
 		if (!priv->started) {
-			error = EINVAL;
+			error = errno2iic(EINVAL);
 			break;
 		}
 		error = iicbus_repeated_start(parent, s->slave, 0);
@@ -492,11 +492,11 @@
 		break;
 
 	default:
-		error = ENOTTY;
+		error = errno2iic(ENOTTY);
 	}
 
 	IIC_UNLOCK(priv);
-	return (error);
+	return (iic2errno(error));
 }
 
 DRIVER_MODULE(iic, iicbus, iic_driver, iic_devclass, 0, 0);