dt-bindings: leds: Add 'active-high' property

Other than described in commit c94d1783136e ("dt-bindings: net: phy:
Make LED active-low property common") the absence of the 'active-low'
property means not to touch the polarity settings which are inherited
from reset defaults, the bootloader or bootstrap configuration. Hence,
in order to override a LED pin being active-high in case of the default,
bootloader or bootstrap setting being active-low an additional property
'active-high' is required. Document that property and make it mutually
exclusive to the existing 'active-low' property.

Signed-off-by: Daniel Golle <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

Documentation/devicetree/bindings/leds/common.yaml

···
       #trigger-source-cells property in the source node.
     $ref: /schemas/types.yaml#/definitions/phandle-array
 
+  active-high:
+    type: boolean
+    description:
+      Makes LED active high. To turn the LED ON, line needs to be
+      set to high voltage instead of low.
+
   active-low:
     type: boolean
     description:
···
     description:
       Maximum timeout in microseconds after which the flash LED is turned off.
       Required for flash LED nodes with configurable timeout.
+
+allOf:
+  - if:
+      required:
+        - active-low
+    then:
+      properties:
+        active-high: false
 
 additionalProperties: true