dt-bindings: mediatek,mt6779-keypad: add mediatek,keys-per-group

The MediaTek keypad has 2 modes of detecting key events:
* single key: each (row, column) can detect one key
* double key: each (row, column) is a group of 2 keys

With double key, two keys are physically wired to one (row, column) pin.
These keys are in the same "group".

Multiple keys in the same group reduces the number of pins which
minimizes cost.

Add a keys-per-group property to describe this.

Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220720-mt8183-keypad-v2-3-6d42c357cb76@baylibre.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/Documentation/devicetree/bindings/input/mediatek,mt6779-keypad.yaml b/Documentation/devicetree/bindings/input/mediatek,mt6779-keypad.yaml
index ca8ae40a73f7d91d1de745d65f02dcd714516984..387d0448ff771856b98e186d7e408356d0812142 100644 (file)
--- a/Documentation/devicetree/bindings/input/mediatek,mt6779-keypad.yaml
+++ b/Documentation/devicetree/bindings/input/mediatek,mt6779-keypad.yaml
@@ -49,6 +49,12 @@ properties:
     maximum: 256
     default: 16
 
+  mediatek,keys-per-group:
+    description: each (row, column) group has multiple keys
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 1
+    maximum: 2
+
 required:
   - compatible
   - reg