104 lines
2.7 KiB
YAML
104 lines
2.7 KiB
YAML
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# SPDX-License-Identifier: GPL-2.0-only
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/leds/backlight/pwm-backlight.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: pwm-backlight
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maintainers:
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- Lee Jones <lee@kernel.org>
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- Daniel Thompson <daniel.thompson@linaro.org>
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- Jingoo Han <jingoohan1@gmail.com>
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properties:
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compatible:
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const: pwm-backlight
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pwms:
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maxItems: 1
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pwm-names: true
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power-supply:
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description: regulator for supply voltage
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enable-gpios:
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description:
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Contains a single GPIO specifier for the GPIO which enables and disables
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the backlight.
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maxItems: 1
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post-pwm-on-delay-ms:
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description:
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Delay in ms between setting an initial (non-zero) PWM and enabling the
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backlight using GPIO.
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pwm-off-delay-ms:
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description:
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Delay in ms between disabling the backlight using GPIO and setting PWM
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value to 0.
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brightness-levels:
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description:
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Array of distinct brightness levels. Typically these are in the range
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from 0 to 255, but any range starting at 0 will do. The actual brightness
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level (PWM duty cycle) will be interpolated from these values. 0 means a
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0% duty cycle (darkest/off), while the last value in the array represents
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a 100% duty cycle (brightest).
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$ref: /schemas/types.yaml#/definitions/uint32-array
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default-brightness-level:
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description:
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The default brightness level (index into the array defined by the
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"brightness-levels" property).
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$ref: /schemas/types.yaml#/definitions/uint32
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num-interpolated-steps:
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description:
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Number of interpolated steps between each value of brightness-levels
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table. This way a high resolution pwm duty cycle can be used without
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having to list out every possible value in the brightness-level array.
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$ref: /schemas/types.yaml#/definitions/uint32
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dependencies:
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default-brightness-level: [brightness-levels]
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num-interpolated-steps: [brightness-levels]
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required:
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- compatible
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- pwms
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additionalProperties: false
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examples:
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- |
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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 4 8 16 32 64 128 255>;
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default-brightness-level = <6>;
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power-supply = <&vdd_bl_reg>;
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enable-gpios = <&gpio 58 0>;
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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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- |
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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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...
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