summaryrefslogtreecommitdiff
path: root/Documentation/devicetree
diff options
context:
space:
mode:
authorThierry Reding <thierry.reding@avionic-design.de>2011-12-16 20:25:29 (GMT)
committerThierry Reding <thierry.reding@avionic-design.de>2012-07-23 11:23:52 (GMT)
commit3e3ed6cdc49d758719c148a78c8b04c243ef74d0 (patch)
tree4898c961d49967089139c79ff222441a4495dca4 /Documentation/devicetree
parent4dce82c1e84007d38747533673c2289bfc6497d2 (diff)
downloadlinux-3e3ed6cdc49d758719c148a78c8b04c243ef74d0.tar.xz
pwm-backlight: Add rudimentary device tree support
This commit adds very basic support for device tree probing. Currently, only a PWM and a list of distinct brightness levels can be specified. Enabling or disabling backlight power via GPIOs is not yet supported. Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt28
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
new file mode 100644
index 0000000..1e4fc72
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
@@ -0,0 +1,28 @@
+pwm-backlight bindings
+
+Required properties:
+ - compatible: "pwm-backlight"
+ - pwms: OF device-tree PWM specification (see PWM binding[0])
+ - brightness-levels: Array of distinct brightness levels. Typically these
+ are in the range from 0 to 255, but any range starting at 0 will do.
+ The actual brightness level (PWM duty cycle) will be interpolated
+ from these values. 0 means a 0% duty cycle (darkest/off), while the
+ last value in the array represents a 100% duty cycle (brightest).
+ - default-brightness-level: the default brightness level (index into the
+ array defined by the "brightness-levels" property)
+
+Optional properties:
+ - pwm-names: a list of names for the PWM devices specified in the
+ "pwms" property (see PWM binding[0])
+
+[0]: Documentation/devicetree/bindings/pwm/pwm.txt
+
+Example:
+
+ backlight {
+ compatible = "pwm-backlight";
+ pwms = <&pwm 0 5000000>;
+
+ brightness-levels = <0 4 8 16 32 64 128 255>;
+ default-brightness-level = <6>;
+ };