56 lines
2.0 KiB
Plaintext
56 lines
2.0 KiB
Plaintext
pwm-backlight bindings
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Required properties:
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- compatible: "pwm-backlight"
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- pwms: OF device-tree PWM specification (see PWM binding[0])
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- brightness-levels: Array of distinct brightness levels. Typically these
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are in the range from 0 to 255, but any range starting at 0 will do.
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The actual brightness level (PWM duty cycle) will be interpolated
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from these values. 0 means a 0% duty cycle (darkest/off), while the
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last value in the array represents a 100% duty cycle (brightest).
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- default-brightness-level: the default brightness level (index into the
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array defined by the "brightness-levels" property)
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Optional properties:
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- pwm-names: a list of names for the PWM devices specified in the
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"pwms" property (see PWM binding[0])
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- enable-gpio: a GPIO used to enable the backlight.
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Child device nodes describe alternate brightness-levels tables for different
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display/backlight configurations.
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[0]: Documentation/devicetree/bindings/pwm/pwm.txt
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Example:
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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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enable-gpio = <&gpx3 0 0>;
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};
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Alternate brightness-levels tables
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Child device nodes can specify multiple alternate brightness-levels tables,
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identified by a generic string, and is selected upon calling the backlight
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device's brightness_choose().
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Properties:
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- compatible: "pwm-backlight-alt-brightness-levels"
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- identifier: A string that is used during backlight_choose() to select the
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particular alternate brightness-levels table.
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- brightness-levels: See the brightness-levels property of the parent node,
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described earlier in this documentation. Note that the length of these
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alternate brightness-level tables must be the same as the original
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brightness-levels table from the parent node.
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Example:
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panel@0 {
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compatible = "pwm-backlight-alt-brightness-levels";
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identifier = "CMN-1132-1"
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brightness-levels = <0 16 32 40 80 120 160 255>;
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};
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