# Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
# SPDX-License-Identifier: Apache-2.0

description: |

  Espressif's LEDC controller Node

  The LEDC controller is primarily designed to control the intensity of LEDs, although it can be used to generate
  PWM signals for other purposes as well.

  The mapping between the channel and GPIO is done through pinctrl

    &ledc0 {
      pinctrl-0 = <&ledc0_default>;
      pinctrl-names = "default";
    }

  The 'ledc0_default' node state is defined in <board>-pinctrl.dtsi.

    ledc0_default: ledc0_default {
            group1 {
                    pinmux = <LEDC_CH0_GPIO0>,
                             <LEDC_CH1_GPIO2>,
                             <LEDC_CH2_GPIO4>;
                    output-enable;
            };
    };

  If another GPIO mapping is desired, check if <board>-pinctrl.dtsi already have it defined, otherwise, define the
  required mapping at your own application folder into a custom <board>.overlay file.
  The 'pinmux' property uses a macro defined in https://github.com/zephyrproject-rtos/hal_espressif/tree/zephyr/include/dt-bindings/pinctrl
  Before including a new node, check if the desired mapping is available according to the SoC.

  As an example, the 'ledc0_custom' state below illustrates an alternate mapping using another set of channels and
  pins in a custom overlay file.

    &pinctrl {

            ledc0_custom:  ledc0_custom {
                    group1 {
                            pinmux = <LEDC_CH0_GPIO0>,
                                     <LEDC_CH9_GPIO2>,
                                     <LEDC_CH10_GPIO4>;
                            output-enable;
                    };
             };

    };

  Use the child bindings to configure the desired channel:

    &ledc0 {
      pinctrl-0 = <&ledc0_custom>;
      pinctrl-names = "default";
      status = "okay";
      #address-cells = <1>;
      #size-cells = <0>;
      channel0@0 {
        reg = <0x0>;
        timer = <0>;
      };
      channel9@9 {
        reg = <0x9>;
        timer = <0>;
      };
      channel10@a {
        reg = <0xa>;
        timer = <1>;
      };
    };

    Note: The channel's 'reg' property defines the ID of the channel. It must match the channel used in the 'pinmux'.


compatible: "espressif,esp32-ledc"

include: [pwm-controller.yaml, pinctrl-device.yaml, base.yaml]

properties:
  label:
    required: true

  "#pwm-cells":
    const: 3

child-binding:
  description: Channel configuration.

  properties:
    reg:
      type: int
      required: true
      enum:
      - 0
      - 1
      - 2
      - 3
      - 4
      - 5
      - 6
      - 7
      - 8
      - 9
      - 10
      - 11
      - 12
      - 13
      - 14
      - 15

      description: |
        The esp32 has 8 low speed channel and 8 high speed channels.
        The low speed channel are mapped from channel 0 to 7, and the high speed are mapped from channel 8 to 15.

        High speed channels are only available in the esp32 SoC. Esp32s2 has only 8 available channels, and esp32c3
        has 6. In these SoCs there is no differentiation between low or high speed.

    timer:
      type: int
      required: true
      enum:
      - 0
      - 1
      - 2
      - 3
      description: |
        Timer selection.
        For maximum flexibility, the high-speed as well as the low-speed channels can be driven from one of four high-speed/low-speed timers.

pwm-cells:
  - channel
  - period
  - flags