dt-bindings: leds: Add QCOM flash LED controller

Add binding document for flash LED module inside Qualcomm Technologies,
Inc. PMICs.
Signed-off-by: Fenglin Wu <quic_fenglinw@quicinc.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230303095023.538917-3-quic_fenglinw@quicinc.com

Documentation/devicetree/bindings/leds/qcom,spmi-flash-led.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/qcom,spmi-flash-led.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Flash LED device inside Qualcomm Technologies, Inc. PMICs
+
+maintainers:
+  - Fenglin Wu <quic_fenglinw@quicinc.com>
+
+description: |
+  Flash LED controller is present inside some Qualcomm Technologies, Inc. PMICs.
+  The flash LED module can have different number of LED channels supported
+  e.g. 3 or 4. There are some different registers between them but they can
+  both support maximum current up to 1.5 A per channel and they can also support
+  ganging 2 channels together to supply maximum current up to 2 A. The current
+  will be split symmetrically on each channel and they will be enabled and
+  disabled at the same time.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - qcom,pm8150c-flash-led
+          - qcom,pm8150l-flash-led
+          - qcom,pm8350c-flash-led
+      - const: qcom,spmi-flash-led
+
+  reg:
+    maxItems: 1
+
+patternProperties:
+  "^led-[0-3]$":
+    type: object
+    $ref: common.yaml#
+    unevaluatedProperties: false
+    description:
+      Represents the physical LED components which are connected to the
+      flash LED channels' output.
+
+    properties:
+      led-sources:
+        description:
+          The HW indices of the flash LED channels that connect to the
+          physical LED
+        allOf:
+          - minItems: 1
+            maxItems: 2
+            items:
+              enum: [1, 2, 3, 4]
+
+      led-max-microamp:
+        anyOf:
+          - minimum: 5000
+            maximum: 500000
+            multipleOf: 5000
+          - minimum: 10000
+            maximum: 1000000
+            multipleOf: 10000
+
+      flash-max-microamp:
+        anyOf:
+          - minimum: 12500
+            maximum: 1500000
+            multipleOf: 12500
+          - minimum: 25000
+            maximum: 2000000
+            multipleOf: 25000
+
+      flash-max-timeout-us:
+        minimum: 10000
+        maximum: 1280000
+        multipleOf: 10000
+
+    required:
+      - led-sources
+      - led-max-microamp
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+    spmi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        led-controller@ee00 {
+            compatible = "qcom,pm8350c-flash-led", "qcom,spmi-flash-led";
+            reg = <0xee00>;
+
+            led-0 {
+                function = LED_FUNCTION_FLASH;
+                color = <LED_COLOR_ID_WHITE>;
+                led-sources = <1>, <4>;
+                led-max-microamp = <300000>;
+                flash-max-microamp = <2000000>;
+                flash-max-timeout-us = <1280000>;
+                function-enumerator = <0>;
+            };
+
+            led-1 {
+                function = LED_FUNCTION_FLASH;
+                color = <LED_COLOR_ID_YELLOW>;
+                led-sources = <2>, <3>;
+                led-max-microamp = <300000>;
+                flash-max-microamp = <2000000>;
+                flash-max-timeout-us = <1280000>;
+                function-enumerator = <1>;
+            };
+        };
+    };