dts/bindings/led_strip/worldsemi,ws2812-gpio.yaml

# Copyright (c) 2019, Nordic Semiconductor ASA
# SPDX-License-Identifier: Apache-2.0

description: |
  Worldsemi WS2812 LED strip, GPIO binding

  Driver bindings for bit-banging a WS2812 or compatible LED strip.

  The CPU driver uses inline assembly, and isn't available for all
  boards. The timing is automatically derived from the CPU clock frequency,
  or can be provided by setting the delay-txx properties in the device
  tree, or can be manually provided by the Kconfig settings DELAY_Txx.

  The four delays provided (calculated based on the clock frequency,
  provided by a dts, or Kconfig file) determine the delays as depicted
  below. The exact timings of the LED strip data line might vary on the
  type of LEDs used, consult the data-sheet for the precise timings.

  0 code
     +-------+                 +---
     |       |                 |
     |  T0H  |       T0L       |
     |       |                 |
  ---+       +-----------------+

  1 code
     +---------------+         +---
     |               |         |
     |      T1H      |   T1L   |
     |               |         |
  ---+               +---------+


  Example dts file:
  / {
        cpus {
            cpu@0 {
                clock-frequency = <64000000>;
            };
        };

        rgb_led: ws2812 {
            compatible = "worldsemi,ws2812-gpio";
            chain-length = <1>;
            color-mapping = <LED_COLOR_ID_GREEN
                             LED_COLOR_ID_RED
                             LED_COLOR_ID_BLUE>;
            gpios = <&gpio0 16 0>;
        };
  };

  Example dts file:
  / {
        chosen {
            zephyr,led-strip = &rgb_led;
        };

        rgb_led: ws2812 {
            compatible = "worldsemi,ws2812-gpio";
            chain-length = <1>;
            color-mapping = <LED_COLOR_ID_GREEN
                             LED_COLOR_ID_RED
                             LED_COLOR_ID_BLUE>;
            reset-delay = <50>;
            gpios = <&gpio0 16 0>;
            delay-t1h = <48>;
            delay-t1l = <32>;
            delay-t0h = <16>;
            delay-t0l = <32>;
        };
  };

compatible: "worldsemi,ws2812-gpio"

include: [base.yaml, ws2812-gpio.yaml]

properties:
  delay-t1h:
    type: int
    description: |
      Number of NOP assembly operations to create a delay for a 1 bit, high
      voltage period (default 700 nsec)

  delay-t1l:
    type: int
    description: |
      Number of NOP assembly operations to create a delay for a 1 bit, low
      voltage period (default 600 nsec)

  delay-t0h:
    type: int
    description: |
      Number of NOP assembly operations to create a delay for a 0 bit, high
      voltage period (default 350 nsec)

  delay-t0l:
    type: int
    description: |
      Number of NOP assembly operations to create a delay for a 0 bit, low
      voltage period (default 800 nsec)