dts/bindings/pwm/nxp,s32-emios-pwm.yaml

description: |
  NXP S32 eMIOS PWM node for S32 SoCs. Each channel in eMIOS can be configured
  to use for PWM operation. There are several PWM modes supported by this module,
  some modes only support on channels that have internal counter, some modes
  require to use a reference timebase from a master bus.

  For example to configuring eMIOS instance 0 with channel 0 for mode OPWFMB, channel 1
  for mode OPWMB and channel 2 for mode OPWMCB with deadtime inserted at leading edge:
    emios0_pwm: pwm {
      pwm_0 {
        channel = <0>;
        pwm-mode = "MODE_OPWFMB";
        prescaler = <8>;
        period = <65534>;
        duty-cycle = <32768>;
        polarity = "ACTIVE_HIGH";
      };

      pwm_1 {
        channel = <1>;
        master-bus = <&emios1_bus_a>;
        pwm-mode = "MODE_OPWMB";
        duty-cycle = <32768>;
        phase-shift = <100>;
        polarity = "ACTIVE_LOW";
      };

      pwm_2 {
        channel = <2>;
        master-bus = <&emios1_bus_b>;
        pwm-mode = "MODE_OPWMCB_LEAD_EDGE";
        duty-cycle = <32768>;
        dead-time = <100>;
        polarity = "ACTIVE_LOW";
      };
    };

  OPWMB and OPWMCB modes use reference timebase, the master bus is chosen over
  phandle 'master-bus'. For OPWMB mode, PWM's period is master bus's period and
  is 2 * master bus's period - 2 for OPWMCB mode. Please notice that the devicetree
  node for master bus should be enabled and configured for using, please see
  'nxp,s32-emios' bindings.

compatible: "nxp,s32-emios-pwm"

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

properties:
  pinctrl-0:
    required: true

  pinctrl-names:
    required: true

  "#pwm-cells":
    const: 2

pwm-cells:
  - channel
  # Period in terms of nanoseconds
  - period

child-binding:
  description: |
    eMIOS PWM channel configuration.

  properties:
    channel:
      type: int
      required: true
      description: eMIOS PWM channel

    master-bus:
      type: phandle
      description: |
        A phandle to master-bus node that will be used as external timebase
        for current channel, this can be bypassed if internal counter is used
        for PWM operation.

    pwm-mode:
      type: string
      required: true
      description: |
        Select PWM mode:
        - OPWFMB: provides waveforms with variable duty cycle and frequency,
                  this mode uses internal counter.

        - OPWMB:  generate pulses with programmable leading and trailing
                  edge placement. The period is determined by period of
                  an external counter driven in MCB Up Mode. Changing PWM period
                  at runtime will impact to all channels share the same timebase.
                  The new period and cycle take effect in next period boundary.

        - OPWMCB: generates a center aligned PWM with dead time insertion to the
                  leading or trailing edge. The period is determined by period of
                  an external counter driven in MCB Up Down Mode. Changing PWM period
                  at runtime will impact to all channels share the same timebase,
                  The new period and cycle take effect in next period boundary.
      enum:
        - "MODE_OPWFMB"
        - "MODE_OPWMB"
        - "MODE_OPWMCB_TRAIL_EDGE"
        - "MODE_OPWMCB_LEAD_EDGE"

    polarity:
      type: string
      required: true
      description: |
        Output polarity for PWM channel.
      enum:
        - "ACTIVE_LOW"
        - "ACTIVE_HIGH"

    duty-cycle:
      type: int
      required: true
      description: |
        Duty-cycle (in ticks) for PWM channel at boot time.

    period:
      type: int
      description: |
        Period (in ticks) for OPWFMB at boot time. Period for the rest
        of PWM mode depends on period's master bus. Must be in range [2 ... 65535].

    freeze:
      type: boolean
      description: Freeze individual internal counter when the chip enters Debug mode.

    prescaler-src:
      type: string
      default: "PRESCALED_CLOCK"
      description: |
        Select clock source for internal counter prescaler.
      enum:
        - "PRESCALED_CLOCK" # Clock source = eMIOS clock / (global prescaler)
        - "MODULE_CLOCK"    # Clock source = eMIOS clock

    prescaler:
      type: int
      description: |
        The clock divider for internal counter prescaler.
      enum: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]

    dead-time:
      type: int
      default: 0
      description: |
        Dead time (in ticks) for PWM channel in OPWMCB mode.

    phase-shift:
      type: int
      default: 0
      description: |
        Phase Shift (in ticks) for PWM channel in OPWMB mode.