add '#define SOFT_SERIAL_PIN D0' to keyboards/iris/rev*/config.h

keyboards/iris/rev1/config.h

@@ -48,6 +48,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* Set 0 if debouncing isn't needed */
 #define DEBOUNCING_DELAY 5
 
+/* serial.c configuration for split keyboard */
+#define SOFT_SERIAL_PIN D0
+
 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */
 #define LOCKING_SUPPORT_ENABLE
 /* Locking resynchronize hack */

keyboards/iris/rev1_led/config.h

@@ -48,6 +48,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* Set 0 if debouncing isn't needed */
 #define DEBOUNCING_DELAY 5
 
+/* serial.c configuration for split keyboard */
+#define SOFT_SERIAL_PIN D0
+
 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */
 #define LOCKING_SUPPORT_ENABLE
 /* Locking resynchronize hack */

keyboards/iris/rev2/config.h

@@ -48,6 +48,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* Set 0 if debouncing isn't needed */
 #define DEBOUNCING_DELAY 5
 
+/* serial.c configuration for split keyboard */
+#define SOFT_SERIAL_PIN D0
+
 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */
 #define LOCKING_SUPPORT_ENABLE
 /* Locking resynchronize hack */

keyboards/iris/rev3/config.h

@@ -48,6 +48,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* Set 0 if debouncing isn't needed */
 #define DEBOUNCING_DELAY 5
 
+/* serial.c configuration for split keyboard */
+#define SOFT_SERIAL_PIN D0
+
 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */
 #define LOCKING_SUPPORT_ENABLE
 /* Locking resynchronize hack */

quantum/split_common/split-keyboards-list.txt

@@ -6,7 +6,7 @@ ok keyboards/foobar/rules.mk:SPLIT_KEYBOARD = yes
 ok keyboards/handwired/dactyl_manuform/rules.mk:SPLIT_KEYBOARD = yes
 ok keyboards/handwired/qc60/rules.mk:SPLIT_KEYBOARD = yes
 ok keyboards/handwired/xealous/rules.mk:SPLIT_KEYBOARD = yes        # Use shared split_common code
-keyboards/iris/rules.mk:SPLIT_KEYBOARD = yes
+ok keyboards/iris/rules.mk:SPLIT_KEYBOARD = yes
 keyboards/lets_split_eh/rules.mk:SPLIT_KEYBOARD = yes
 keyboards/levinson/rules.mk:SPLIT_KEYBOARD = yes
 keyboards/miniaxe/rules.mk:SPLIT_KEYBOARD = yes        # Use shared split_common code