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Commit 1e5e7cc7 authored by Enric Balletbo i Serra's avatar Enric Balletbo i Serra Committed by Lee Jones
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dt-bindings: pwm-backlight: Add a num-interpolation-steps property 



The num-interpolated-steps property specifies the number of
interpolated steps between each value of brightness-level table. This is
useful for high resolution PWMs to not have to list out every possible
value in the brightness-level array.

Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 573fe6d1

Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt

+19 −0
Original line number Diff line number Diff line
@@ -21,6 +21,11 @@ Optional properties: 
                          and enabling the backlight using GPIO.

  - pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO

                      and setting PWM value to 0.

  - num-interpolated-steps: Number of interpolated steps between each value

                            of brightness-levels table. This way a high

                            resolution pwm duty cycle can be used without

                            having to list out every possible value in the

                            brightness-level array.



[0]: Documentation/devicetree/bindings/pwm/pwm.txt

[1]: Documentation/devicetree/bindings/gpio/gpio.txt
@@ -39,3 +44,17 @@ Example: 
		post-pwm-on-delay-ms = <10>;

		pwm-off-delay-ms = <10>;

	};



Example using num-interpolation-steps:



	backlight {

		compatible = "pwm-backlight";

		pwms = <&pwm 0 5000000>;



		brightness-levels = <0 2048 4096 8192 16384 65535>;

		num-interpolated-steps = <2048>;

		default-brightness-level = <4096>;



		power-supply = <&vdd_bl_reg>;

		enable-gpios = <&gpio 58 0>;

	};