dt-bindings: leds: Add Qualcomm Light Pulse Generator binding

This adds the binding document describing the three hardware blocks
related to the Light Pulse Generator found in a wide range of Qualcomm
PMICs.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

Documentation/devicetree/bindings/leds/leds-qcom-lpg.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/leds-qcom-lpg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Light Pulse Generator
+
+maintainers:
+  - Bjorn Andersson <bjorn.andersson@linaro.org>
+
+description: >
+  The Qualcomm Light Pulse Generator consists of three different hardware blocks;
+  a ramp generator with lookup table, the light pulse generator and a three
+  channel current sink. These blocks are found in a wide range of Qualcomm PMICs.
+
+properties:
+  compatible:
+    enum:
+      - qcom,pm8150b-lpg
+      - qcom,pm8150l-lpg
+      - qcom,pm8916-pwm
+      - qcom,pm8941-lpg
+      - qcom,pm8994-lpg
+      - qcom,pmc8180c-lpg
+      - qcom,pmi8994-lpg
+      - qcom,pmi8998-lpg
+
+  "#pwm-cells":
+    const: 2
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  qcom,power-source:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      power-source used to drive the output, as defined in the datasheet.
+      Should be specified if the TRILED block is present
+    enum: [0, 1, 3]
+
+  qcom,dtest:
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    description: >
+      A list of integer pairs, where each pair represent the dtest line the
+      particular channel should be connected to and the flags denoting how the
+      value should be outputed, as defined in the datasheet. The number of
+      pairs should be the same as the number of channels.
+    items:
+      items:
+        - description: dtest line to attach
+        - description: flags for the attachment
+
+  multi-led:
+    type: object
+    $ref: leds-class-multicolor.yaml#
+    properties:
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+    patternProperties:
+      "^led@[0-9a-f]$":
+        type: object
+        $ref: common.yaml#
+
+patternProperties:
+  "^led@[0-9a-f]$":
+    type: object
+    $ref: common.yaml#
+
+    properties:
+      reg: true
+
+    required:
+      - reg
+
+required:
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    led-controller {
+      compatible = "qcom,pmi8994-lpg";
+
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      qcom,power-source = <1>;
+
+      qcom,dtest = <0 0>,
+                   <0 0>,
+                   <0 0>,
+                   <4 1>;
+
+      led@1 {
+        reg = <1>;
+        color = <LED_COLOR_ID_GREEN>;
+        function = LED_FUNCTION_INDICATOR;
+        function-enumerator = <1>;
+      };
+
+      led@2 {
+        reg = <2>;
+        color = <LED_COLOR_ID_GREEN>;
+        function = LED_FUNCTION_INDICATOR;
+        function-enumerator = <0>;
+        default-state = "on";
+      };
+
+      led@3 {
+        reg = <3>;
+        color = <LED_COLOR_ID_GREEN>;
+        function = LED_FUNCTION_INDICATOR;
+        function-enumerator = <2>;
+      };
+
+      led@4 {
+        reg = <4>;
+        color = <LED_COLOR_ID_GREEN>;
+        function = LED_FUNCTION_INDICATOR;
+        function-enumerator = <3>;
+      };
+    };
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    led-controller {
+      compatible = "qcom,pmi8994-lpg";
+
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      qcom,power-source = <1>;
+
+      multi-led {
+        color = <LED_COLOR_ID_RGB>;
+        function = LED_FUNCTION_STATUS;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led@1 {
+          reg = <1>;
+          color = <LED_COLOR_ID_RED>;
+        };
+
+        led@2 {
+          reg = <2>;
+          color = <LED_COLOR_ID_GREEN>;
+        };
+
+        led@3 {
+          reg = <3>;
+          color = <LED_COLOR_ID_BLUE>;
+        };
+      };
+    };
+  - |
+    pwm-controller {
+      compatible = "qcom,pm8916-pwm";
+      #pwm-cells = <2>;
+    };
+...