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 ...
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