Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/leds/backlight/qcom-wled.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Binding for Qualcomm Technologies, Inc. WLED driver

maintainers:
  - Bjorn Andersson <bjorn.andersson@linaro.org>
  - Kiran Gunda <kgunda@codeaurora.org>

description: |
  WLED (White Light Emitting Diode) driver is used for controlling display
  backlight that is part of PMIC on Qualcomm Technologies, Inc. reference
  platforms. The PMIC is connected to the host processor via SPMI bus.

properties:
  compatible:
    enum:
      - qcom,pm8941-wled
      - qcom,pmi8994-wled
      - qcom,pmi8998-wled
      - qcom,pm660l-wled
      - qcom,pm8150l-wled

  reg:
    maxItems: 1

  default-brightness:
    description: |
      brightness value on boot.

  label: true

  max-brightness:
    description: |
      Maximum brightness level.

  qcom,cs-out:
    description: |
      enable current sink output.
      This property is supported only for WLED3.
    type: boolean

  qcom,cabc:
    description: |
      enable content adaptive backlight control.
    type: boolean

  qcom,ext-gen:
    description: |
      use externally generated modulator signal to dim.
      This property is supported only for WLED3.
    type: boolean

  qcom,current-limit:
    description: |
      mA; per-string current limit.
      This property is supported only for WLED3.
    $ref: /schemas/types.yaml#/definitions/uint32
    default: 20
    minimum: 0
    maximum: 25

  qcom,current-limit-microamp:
    description: |
      uA; per-string current limit.
    default: 25
    minimum: 0
    maximum: 30000
    multipleOf: 25

  qcom,current-boost-limit:
    description: |
      mA; boost current limit.
    $ref: /schemas/types.yaml#/definitions/uint32

  qcom,switching-freq:
    description: |
      kHz; switching frequency.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 600, 640, 685, 738, 800, 872, 960, 1066, 1200, 1371, 1600, 1920, 
            2400, 3200, 4800, 9600 ]

  qcom,ovp:
    description: |
      V; Over-voltage protection limit.
      This property is supported only for WLED3.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 27, 29, 32, 35 ]
    default: 29

  qcom,ovp-millivolt:
    description: |
      Over-voltage protection limit. This property is for WLED4 only.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 18100, 19600, 29600, 31100 ]
    default: 29600

  qcom,num-strings:
    description: |
      number of led strings attached.
    $ref: /schemas/types.yaml#/definitions/uint32

  qcom,enabled-strings:
    description: |
      Array of the WLED strings numbered from 0 to 3. Each
      string of leds are operated individually. Specify the
      list of strings used by the device. Any combination of
      led strings can be used.
    $ref: /schemas/types.yaml#/definitions/uint32-array
    minItems: 1
    maxItems: 4

  qcom,external-pfet:
    description: |
      Specify if external PFET control for short circuit
      protection is used. This property is supported only
      for WLED4.
    type: boolean

  qcom,auto-string-detection:
    description: |
      Enables auto-detection of the WLED string configuration.
      This feature is not supported for WLED3.
    type: boolean

  interrupts:
    minItems: 1
    items:
      - description: over voltage protection interrupt.
      - description: short circuit interrupt.

  interrupt-names:
    minItems: 1
    items:
      - const: ovp
      - const: short

  qcom,modulator-sel:
    description: |
      Selects the modulator used for brightness modulation.
      Allowed values are,
           0 - Modulator A
           1 - Modulator B
      This property is applicable only to WLED5 peripheral.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1 ]
    default: 0

  qcom,cabc-sel:
    description: |
      Selects the CABC pin signal used for brightness modulation.
      Allowed values are,
           0 - CABC disabled
           1 - CABC 1
           2 - CABC 2
           3 - External signal (e.g. LPG) is used for dimming
      This property is applicable only to WLED5 peripheral.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 0, 1, 2, 3 ]

allOf:
  - if:
      properties:
        compatible:
          contains:
            const: qcom,pm8941-wled

    then:
      properties:
        qcom,current-boost-limit:
          enum: [ 105, 385, 525, 805, 980, 1260, 1400, 1680 ]
          default: 805

        qcom,switching-freq:
          default: 1600

        qcom,num-strings:
          enum: [ 1, 2, 3 ]

        interrupts:
          maxItems: 1

        interrupt-names:
          maxItems: 1

    else:
      properties:
        qcom,current-boost-limit:
          enum: [ 105, 280, 450, 620, 970, 1150, 1300, 1500 ]
          default: 970

        qcom,switching-freq:
          default: 800

        qcom,num-strings:
          enum: [ 1, 2, 3, 4 ]

        interrupts:
          minItems: 2

        interrupt-names:
          minItems: 2
  - if:
      properties:
        compatible:
          contains:
            enum:
              - qcom,pm8150l-wled

    then:
      properties:
        default-brightness:
          minimum: 0
          maximum: 32767

        max-brightness:
          minimum: 0
          maximum: 32767

    else:
      properties:
        default-brightness:
          minimum: 0
          maximum: 4095

        max-brightness:
          minimum: 0
          maximum: 4095

required:
  - compatible
  - reg
  - label

additionalProperties: false

examples:
  - |
    backlight@d800 {
        compatible = "qcom,pm8941-wled";
        reg = <0xd800 0x100>;
        label = "backlight";

        qcom,cs-out;
        qcom,current-limit = <20>;
        qcom,current-boost-limit = <805>;
        qcom,switching-freq = <1600>;
        qcom,ovp = <29>;
        qcom,num-strings = <2>;
        qcom,enabled-strings = <0 1>;
     };