This patch adds documentation for device tree bindings for keys support
as the subnode of MT6397/MT6323 PMIC.
Signed-off-by: Chen Zhong <chen.zhong@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
 - GPIO
 - Clock
 - LED
+- Keys
 
 It is interfaced to host controller using SPI interface by a proprietary hardware
 called PMIC wrapper or pwrap. MT6397/MT6323 MFD is a child device of pwrap.
                - compatible: "mediatek,mt6323-led"
        see Documentation/devicetree/bindings/leds/leds-mt6323.txt
 
+- keys
+       Required properties:
+               - compatible: "mediatek,mt6397-keys" or "mediatek,mt6323-keys"
+       see Documentation/devicetree/bindings/input/mtk-pmic-keys.txt
+
 Example:
        pwrap: pwrap@1000f000 {
                compatible = "mediatek,mt8135-pwrap";