feat: Add physical layout to BDN9 rev2.

Author: petejohanson

app/boards/arm/bdn9/bdn9_rev2.dts

@@ -9,6 +9,10 @@
 #include <st/f0/stm32f072c(8-b)tx-pinctrl.dtsi>
 #include <dt-bindings/led/led.h>
 
+#include <dt-bindings/zmk/matrix_transform.h>
+
+#include <physical_layouts.dtsi>
+
 / {
     model = "Keeb.io BDN9 rev2";
     compatible = "keebio,bdn9", "st,stm32f072";
@@ -20,6 +24,38 @@
         zmk,underglow = &led_strip;
     };
 
+    matrix_transform: matrix_transform {
+        compatible = "zmk,matrix-transform";
+
+        compatible = "zmk,matrix-transform";
+        columns = <3>;
+        rows = <3>;
+        map = <
+            RC(0,0) RC(0,1) RC(0,2)
+            RC(0,3) RC(0,4) RC(0,5)
+            RC(0,6) RC(0,7) RC(0,8)
+        >;
+    };
+
+    physical_layout {
+        compatible = "zmk,physical-layout";
+
+        display-name = "BDN9";
+        transform = <&matrix_transform>;
+
+        keys  //                     w   h    x    y     rot    rx    ry
+            = <&key_physical_attrs 100 100    0    0       0     0     0>
+            , <&key_physical_attrs 100 100  100    0       0     0     0>
+            , <&key_physical_attrs 100 100  200    0       0     0     0>
+            , <&key_physical_attrs 100 100    0  100       0     0     0>
+            , <&key_physical_attrs 100 100  100  100       0     0     0>
+            , <&key_physical_attrs 100 100  200  100       0     0     0>
+            , <&key_physical_attrs 100 100    0  200       0     0     0>
+            , <&key_physical_attrs 100 100  100  200       0     0     0>
+            , <&key_physical_attrs 100 100  200  200       0     0     0>
+            ;
+    };
+
     kscan: kscan {
         compatible = "zmk,kscan-gpio-direct";