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: Enric Balletbo i Serra <enric.balletbo@collabora.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Documentation/devicetree/bindings/leds/backlight
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@ -21,6 +21,11 @@ Optional properties:
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and enabling the backlight using GPIO.
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- pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO
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and setting PWM value to 0.
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- num-interpolated-steps: Number of interpolated steps between each value
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of brightness-levels table. This way a high
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resolution pwm duty cycle can be used without
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having to list out every possible value in the
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brightness-level array.
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[0]: Documentation/devicetree/bindings/pwm/pwm.txt
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[1]: Documentation/devicetree/bindings/gpio/gpio.txt
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@ -39,3 +44,17 @@ Example:
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post-pwm-on-delay-ms = <10>;
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pwm-off-delay-ms = <10>;
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};
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Example using num-interpolation-steps:
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backlight {
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compatible = "pwm-backlight";
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pwms = <&pwm 0 5000000>;
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brightness-levels = <0 2048 4096 8192 16384 65535>;
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num-interpolated-steps = <2048>;
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default-brightness-level = <4096>;
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power-supply = <&vdd_bl_reg>;
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enable-gpios = <&gpio 58 0>;
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};
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