diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 357a2e0f637a1d7270e247d146c00131d4374f62..258defdb2efd1cb82d242be2024ab49029a70e58 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -100,7 +100,8 @@ int w1_add_master_device(struct w1_bus_master *master)
 
         /* validate minimum functionality */
         if (!(master->touch_bit && master->reset_bus) &&
-            !(master->write_bit && master->read_bit)) {
+            !(master->write_bit && master->read_bit) &&
+	    !(master->write_byte && master->read_byte && master->reset_bus)) {
 		printk(KERN_ERR "w1_add_master_device: invalid function set\n");
 		return(-EINVAL);
         }