diff --git a/drivers/i2c/busses/i2c-powermac.c b/drivers/i2c/busses/i2c-powermac.c
index 3c9d71f..a74f3ba 100644
--- a/drivers/i2c/busses/i2c-powermac.c
+++ b/drivers/i2c/busses/i2c-powermac.c
@@ -146,6 +146,12 @@
 	int			read;
 	int			addrdir;
 
+	if (num != 1) {
+		dev_err(&adap->dev,
+			"Multi-message I2C transactions not supported\n");
+		return -EOPNOTSUPP;
+	}
+
 	if (msgs->flags & I2C_M_TEN)
 		return -EINVAL;
 	read = (msgs->flags & I2C_M_RD) != 0;