dt-bindings: leds: Add Allwinner A100 LED controller

The Allwinner A100, R329, and D1 SoCs contain an LED controller designed
to drive a series of RGB LED pixels. It supports PIO and DMA transfers,
and has configurable timing and pixel format. All three implementations
appear to be identical, so use the oldest as the fallback compatible.

Acked-by: Guo Ren <[e-mail]>
Acked-by: Maxime Ripard <[e-mail]>
Acked-by: Palmer Dabbelt <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Tested-by: Trevor Woerner <[e-mail]>
Signed-off-by: Samuel Holland <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

Documentation/devicetree/bindings/leds/allwinner,sun50i-a100-ledc.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/allwinner,sun50i-a100-ledc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner A100 LED Controller
+
+maintainers:
+  - Samuel Holland <[e-mail]>
+
+description:
+  The LED controller found in Allwinner sunxi SoCs uses a one-wire serial
+  interface to drive up to 1024 RGB LEDs.
+
+properties:
+  compatible:
+    oneOf:
+      - const: allwinner,sun50i-a100-ledc
+      - items:
+          - enum:
+              - allwinner,sun20i-d1-ledc
+              - allwinner,sun50i-r329-ledc
+          - const: allwinner,sun50i-a100-ledc
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Bus clock
+      - description: Module clock
+
+  clock-names:
+    items:
+      - const: bus
+      - const: mod
+
+  resets:
+    maxItems: 1
+
+  dmas:
+    maxItems: 1
+    description: TX DMA channel
+
+  dma-names:
+    const: tx
+
+  allwinner,pixel-format:
+    description: Pixel format (subpixel transmission order), default is "grb"
+    enum:
+      - bgr
+      - brg
+      - gbr
+      - grb
+      - rbg
+      - rgb
+
+  allwinner,t0h-ns:
+    default: 336
+    description: Length of high pulse when transmitting a "0" bit
+
+  allwinner,t0l-ns:
+    default: 840
+    description: Length of low pulse when transmitting a "0" bit
+
+  allwinner,t1h-ns:
+    default: 882
+    description: Length of high pulse when transmitting a "1" bit
+
+  allwinner,t1l-ns:
+    default: 294
+    description: Length of low pulse when transmitting a "1" bit
+
+  allwinner,treset-ns:
+    default: 300000
+    description: Minimum delay between transmission frames
+
+patternProperties:
+  "^multi-led@[0-9a-f]+$":
+    type: object
+    $ref: leds-class-multicolor.yaml#
+    unevaluatedProperties: false
+    properties:
+      reg:
+        minimum: 0
+        maximum: 1023
+        description: Index of the LED in the series (must be contiguous)
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/leds/common.h>
+
+    ledc: led-controller@2008000 {
+      compatible = "allwinner,sun20i-d1-ledc",
+                   "allwinner,sun50i-a100-ledc";
+      reg = <0x2008000 0x400>;
+      interrupts = <36 IRQ_TYPE_LEVEL_HIGH>;
+      clocks = <&ccu 12>, <&ccu 34>;
+      clock-names = "bus", "mod";
+      resets = <&ccu 12>;
+      dmas = <&dma 42>;
+      dma-names = "tx";
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      multi-led@0 {
+        reg = <0x0>;
+        color = <LED_COLOR_ID_RGB>;
+        function = LED_FUNCTION_INDICATOR;
+      };
+    };
+
+...