[PATCH 1/3 v2] dt-bindings: backlight: Add some common backlight properties

[Linus Walleij]

Let's use a common.yaml include for the backlight like we do with
the LEDs. The LEDs are inherently incompatible so their bindings
cannot be reused for backlight.

Cc: devicetree at vger.kernel.org
Suggested-by: Sam Ravnborg <sam at ravnborg.org>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v1->v2:
- New patch as suggested by Sam.
---
 .../bindings/leds/backlight/common.yaml       | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/common.yaml

diff --git a/Documentation/devicetree/bindings/leds/backlight/common.yaml b/Documentation/devicetree/bindings/leds/backlight/common.yaml
new file mode 100644
index 000000000000..8ae7e3818b0d
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/common.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/common.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Common backlight properties
+
+maintainers:
+  - Lee Jones <lee.jones at linaro.org>
+  - Daniel Thompson <daniel.thompson at linaro.org>
+  - Jingoo Han <jingoohan1 at gmail.com>
+
+description: |
+  Backlight devices provide backlight for different types of graphical
+  displays. They are typically but not necessarilt implemented using a white
+  LED powered by a boost converter.
+
+properties:
+  default-on:
+    description:
+      The initial state of the backlight can be set to be on with this
+      property. This is a state applied by the operating system so that the
+      backlight is always turned on at boot.
+
+  default-brightness:
+    description:
+      The default brightness that should be applied to the LED by the operating
+      system on start-up. The brightness should not exceed the brightness the
+      LED can provide.
+    $ref: /schemas/types.yaml#definitions/uint32
+    minimum: 0
+
+  max-brightness:
+    description:
+      Normally the maximum brightness is determined by the hardware and this
+      property is not required. This property is used to put a software limit
+      on the brightness apart from what the driver says, as it could happen
+      that a LED can be made so bright that it gets damaged or causes damage
+      due to restrictions in a specific system, such as mounting conditions.
+    $ref: /schemas/types.yaml#definitions/uint32
+    minimum: 0
-- 
2.26.2