dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays

The Holtek HT16K33 LED controller is not only used for driving
dot-matrix displays, but also for driving segment displays.

Document compatible values for the Adafruit 7-segment[1] and
14-segment[2] FeatherWing expansion boards with red displays.  According
to the schematics, all other Adafruit 7-segment and 14-segment display
backpack and FeatherWing expansion boards (including bare boards and
boards fitted with displays) are compatible with these two boards.

[1] https://www.adafruit.com/product/3108
[2] https://www.adafruit.com/product/3130

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml

@@ -14,14 +14,21 @@ allOf:
 
 properties:
   compatible:
-    const: holtek,ht16k33
+    oneOf:
+      - items:
+          - enum:
+              - adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)
+              - adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing Display (Red)
+          - const: holtek,ht16k33
+
+      - const: holtek,ht16k33     # Generic 16*8 LED controller with dot-matrix display
 
   reg:
     maxItems: 1
 
   refresh-rate-hz:
     maxItems: 1
-    description: Display update interval in Hertz
+    description: Display update interval in Hertz for dot-matrix displays
 
   interrupts:
     maxItems: 1
@@ -44,6 +51,13 @@ properties:
 required:
   - compatible
   - reg
+
+if:
+  properties:
+    compatible:
+      const: holtek,ht16k33
+then:
+  required:
     - refresh-rate-hz
 
 additionalProperties: false