[PATCH v2 1/2] dt-bindings: backlight: document new property default-brightness-level

[Alexandru Ardelean]

From: Yannick Fertre <yannick.fertre at foss.st.com>

Add documentation for new default-brightness-level property.

Signed-off-by: Yannick Fertre <yannick.fertre at foss.st.com>
Signed-off-by: Alexandru Ardelean <alex at shruggie.ro>
---

Link to original patch:
  https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98

Changelog v1 -> v2:
* https://lore.kernel.org/dri-devel/20230519200520.10657-2-alex@shruggie.ro/
* removed 'brightness-levels' reference
* updated doc-text for 'default-brightness-level'
* updated doc-text for 'default-on'
* added 'minimum' & 'maximum' to 'default-brightness-level' property
* removed 'Reviewed-by: Philippe CORNU <philippe.cornu at foss.st.com>' as
  requested
* patch is first in series of 2 patches (was second patch)

 .../bindings/leds/backlight/gpio-backlight.yaml    | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
index 584030b6b0b9..2da6552a207c 100644
--- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
+++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
@@ -20,9 +20,21 @@ properties:
     maxItems: 1
 
   default-on:
-    description: enable the backlight at boot.
+    description:
+      The default power state of the backlight at boot.
     type: boolean
 
+  default-brightness-level:
+    description:
+      The default brightness level on device init. The value can be 0 or 1.
+      If omitted, the value is 1. In the context of the "gpio-backlight" driver
+      the effect of this setting will be that the backlight is on/off.
+      The difference between this setting and "default-on" is that this handles
+      brightness, while "default-on" handles the power setting of the device.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 1
+
 required:
   - compatible
   - gpios
-- 
2.40.1