dts/bindings/pwm/nordic,nrf-sw-pwm.yaml

description: nRFx S/W PWM

compatible: "nordic,nrf-sw-pwm"

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

properties:
    generator:
      type: phandle
      required: true
      description: |
        Reference to TIMER or RTC instance for generating PWM output signals

    clock-prescaler:
      type: int
      required: true
      description: |
        Clock prescaler for RTC or TIMER used for generating PWM output signals.

        RTC: needs to be set to 0, which gives 32768 Hz base clock for PWM
        generation.

        TIMER: 16 MHz / 2^prescaler base clock is used for PWM generation.

    channel-gpios:
      type: phandle-array
      required: true
      description: |
        An array of GPIOs assigned as outputs for the PWM channels. The number
        of items in this array determines the number of channels that this PWM
        will provide. This value is limited by the number of compare registers
        in the used RTC/TIMER instance minus 1.

        Example:

          sw_pwm: sw-pwm {
            compatible = "nordic,nrf-sw-pwm";
            ...
            channel-gpios = <&gpio0 20 GPIO_ACTIVE_HIGH>,
                            <&gpio1 12 GPIO_ACTIVE_HIGH>;
            ...
          };

        The above will assign P0.20 as the output for channel 0 and P1.12 as
        the output for channel 1. Both outputs will be initially configured as
        active high.

        Please note that in the flags cell (the last component of each item
        of the array) only the GPIO flags that specify the active level are
        taken into account (any others are ignored), and they are used only
        when the initial (inactive) state of the outputs is set.
        After any PWM signal generation is requested for a given channel,
        the polarity of its output is determined by the flag specified
        in the request, i.e. PWM_POLARITY_INVERTED or PWM_POLARITY_NORMAL.

    "#pwm-cells":
      const: 3

pwm-cells:
  - channel
  - period
  - flags