1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 %YAML 1.2 2 %YAML 1.2
3 --- 3 ---
4 $id: http://devicetree.org/schemas/leds/backli 4 $id: http://devicetree.org/schemas/leds/backlight/pwm-backlight.yaml#
5 $schema: http://devicetree.org/meta-schemas/co 5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6 6
7 title: pwm-backlight !! 7 title: pwm-backlight bindings
8 8
9 maintainers: 9 maintainers:
10 - Lee Jones <lee@kernel.org> !! 10 - Lee Jones <lee.jones@linaro.org>
11 - Daniel Thompson <daniel.thompson@linaro.org 11 - Daniel Thompson <daniel.thompson@linaro.org>
12 - Jingoo Han <jingoohan1@gmail.com> 12 - Jingoo Han <jingoohan1@gmail.com>
13 13
14 allOf: <<
15 - $ref: common.yaml# <<
16 <<
17 properties: 14 properties:
18 compatible: 15 compatible:
19 const: pwm-backlight 16 const: pwm-backlight
20 17
21 pwms: 18 pwms:
22 maxItems: 1 19 maxItems: 1
23 20
24 pwm-names: true 21 pwm-names: true
25 22
26 power-supply: 23 power-supply:
27 description: regulator for supply voltage 24 description: regulator for supply voltage
28 25
29 enable-gpios: 26 enable-gpios:
30 description: 27 description:
31 Contains a single GPIO specifier for the 28 Contains a single GPIO specifier for the GPIO which enables and disables
32 the backlight. 29 the backlight.
33 maxItems: 1 30 maxItems: 1
34 31
35 post-pwm-on-delay-ms: 32 post-pwm-on-delay-ms:
36 description: 33 description:
37 Delay in ms between setting an initial ( 34 Delay in ms between setting an initial (non-zero) PWM and enabling the
38 backlight using GPIO. 35 backlight using GPIO.
39 36
40 pwm-off-delay-ms: 37 pwm-off-delay-ms:
41 description: 38 description:
42 Delay in ms between disabling the backli 39 Delay in ms between disabling the backlight using GPIO and setting PWM
43 value to 0. 40 value to 0.
44 41
>> 42 brightness-levels:
>> 43 description:
>> 44 Array of distinct brightness levels. Typically these are in the range
>> 45 from 0 to 255, but any range starting at 0 will do. The actual brightness
>> 46 level (PWM duty cycle) will be interpolated from these values. 0 means a
>> 47 0% duty cycle (darkest/off), while the last value in the array represents
>> 48 a 100% duty cycle (brightest).
>> 49 $ref: /schemas/types.yaml#/definitions/uint32-array
>> 50
>> 51 default-brightness-level:
>> 52 description:
>> 53 The default brightness level (index into the array defined by the
>> 54 "brightness-levels" property).
>> 55 $ref: /schemas/types.yaml#/definitions/uint32
>> 56
45 num-interpolated-steps: 57 num-interpolated-steps:
46 description: 58 description:
47 Number of interpolated steps between eac 59 Number of interpolated steps between each value of brightness-levels
48 table. This way a high resolution pwm du 60 table. This way a high resolution pwm duty cycle can be used without
49 having to list out every possible value 61 having to list out every possible value in the brightness-level array.
50 $ref: /schemas/types.yaml#/definitions/uin 62 $ref: /schemas/types.yaml#/definitions/uint32
51 63
52 dependencies: 64 dependencies:
53 default-brightness-level: [brightness-levels 65 default-brightness-level: [brightness-levels]
54 num-interpolated-steps: [brightness-levels] 66 num-interpolated-steps: [brightness-levels]
55 67
56 required: 68 required:
57 - compatible 69 - compatible
58 - pwms 70 - pwms
>> 71 - power-supply
59 72
60 unevaluatedProperties: false !! 73 additionalProperties: false
61 74
62 examples: 75 examples:
63 - | 76 - |
64 backlight { 77 backlight {
65 compatible = "pwm-backlight"; 78 compatible = "pwm-backlight";
66 pwms = <&pwm 0 5000000>; 79 pwms = <&pwm 0 5000000>;
67 80
68 brightness-levels = <0 4 8 16 32 64 12 81 brightness-levels = <0 4 8 16 32 64 128 255>;
69 default-brightness-level = <6>; 82 default-brightness-level = <6>;
70 83
71 power-supply = <&vdd_bl_reg>; 84 power-supply = <&vdd_bl_reg>;
72 enable-gpios = <&gpio 58 0>; 85 enable-gpios = <&gpio 58 0>;
73 post-pwm-on-delay-ms = <10>; 86 post-pwm-on-delay-ms = <10>;
74 pwm-off-delay-ms = <10>; 87 pwm-off-delay-ms = <10>;
75 }; 88 };
76 89
77 - | 90 - |
78 // Example using num-interpolation-steps: 91 // Example using num-interpolation-steps:
79 backlight { 92 backlight {
80 compatible = "pwm-backlight"; 93 compatible = "pwm-backlight";
81 pwms = <&pwm 0 5000000>; 94 pwms = <&pwm 0 5000000>;
82 95
83 brightness-levels = <0 2048 4096 8192 96 brightness-levels = <0 2048 4096 8192 16384 65535>;
84 num-interpolated-steps = <2048>; 97 num-interpolated-steps = <2048>;
85 default-brightness-level = <4096>; 98 default-brightness-level = <4096>;
86 99
87 power-supply = <&vdd_bl_reg>; 100 power-supply = <&vdd_bl_reg>;
88 enable-gpios = <&gpio 58 0>; 101 enable-gpios = <&gpio 58 0>;
89 }; 102 };
90 103
91 ... 104 ...
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