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

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/leds/backlight/pwm-backlight.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: pwm-backlight
   8
   9 maintainers:
  10   - Lee Jones <lee@kernel.org>
  11   - Daniel Thompson <daniel.thompson@linaro.org>
  12   - Jingoo Han <jingoohan1@gmail.com>
  13
  14 allOf:
  15   - $ref: common.yaml#
  16
  17 properties:
  18   compatible:
  19     const: pwm-backlight
  20
  21   pwms:
  22     maxItems: 1
  23
  24   pwm-names: true
  25
  26   power-supply:
  27     description: regulator for supply voltage
  28
  29   enable-gpios:
  30     description:
  31       Contains a single GPIO specifier for the GPIO which enables and disables
  32       the backlight.
  33     maxItems: 1
  34
  35   post-pwm-on-delay-ms:
  36     description:
  37       Delay in ms between setting an initial (non-zero) PWM and enabling the
  38       backlight using GPIO.
  39
  40   pwm-off-delay-ms:
  41     description:
  42       Delay in ms between disabling the backlight using GPIO and setting PWM
  43       value to 0.
  44
  45   num-interpolated-steps:
  46     description:
  47       Number of interpolated steps between each value of brightness-levels
  48       table. This way a high resolution pwm duty cycle can be used without
  49       having to list out every possible value in the brightness-level array.
  50     $ref: /schemas/types.yaml#/definitions/uint32
  51
  52 dependencies:
  53   default-brightness-level: [brightness-levels]
  54   num-interpolated-steps: [brightness-levels]
  55
  56 required:
  57   - compatible
  58   - pwms
  59
  60 unevaluatedProperties: false
  61
  62 examples:
  63   - |
  64     backlight {
  65         compatible = "pwm-backlight";
  66         pwms = <&pwm 0 5000000>;
  67
  68         brightness-levels = <0 4 8 16 32 64 128 255>;
  69         default-brightness-level = <6>;
  70
  71         power-supply = <&vdd_bl_reg>;
  72         enable-gpios = <&gpio 58 0>;
  73         post-pwm-on-delay-ms = <10>;
  74         pwm-off-delay-ms = <10>;
  75     };
  76
  77   - |
  78     // Example using num-interpolation-steps:
  79     backlight {
  80         compatible = "pwm-backlight";
  81         pwms = <&pwm 0 5000000>;
  82
  83         brightness-levels = <0 2048 4096 8192 16384 65535>;
  84         num-interpolated-steps = <2048>;
  85         default-brightness-level = <4096>;
  86
  87         power-supply = <&vdd_bl_reg>;
  88         enable-gpios = <&gpio 58 0>;
  89     };
  90
  91 ...