Documentation/devicetree/bindings/ptp/fsl,ptp.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/ptp/fsl,ptp.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Freescale QorIQ 1588 timer based PTP clock

maintainers:
  - Frank Li <Frank.Li@nxp.com>

properties:
  compatible:
    oneOf:
      - enum:
          - fsl,etsec-ptp
          - fsl,fman-ptp-timer
          - fsl,dpaa2-ptp
      - items:
          - const: pci1957,ee02
          - const: fsl,enetc-ptp

  reg:
    maxItems: 1

  interrupts:
    maxItems: 1

  clocks:
    maxItems: 1

  fsl,cksel:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Timer reference clock source.

      Reference clock source is determined by the value, which is holded
      in CKSEL bits in TMR_CTRL register. "fsl,cksel" property keeps the
      value, which will be directly written in those bits, that is why,
      according to reference manual, the next clock sources can be used:

      For eTSEC,
      <0> - external high precision timer reference clock (TSEC_TMR_CLK
            input is used for this purpose);
      <1> - eTSEC system clock;
      <2> - eTSEC1 transmit clock;
      <3> - RTC clock input.

      For DPAA FMan,
      <0> - external high precision timer reference clock (TMR_1588_CLK)
      <1> - MAC system clock (1/2 FMan clock)
      <2> - reserved
      <3> - RTC clock oscillator

  fsl,tclk-period:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: Timer reference clock period in nanoseconds.

  fsl,tmr-prsc:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: Prescaler, divides the output clock.

  fsl,tmr-add:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: Frequency compensation value.

  fsl,tmr-fiper1:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: Fixed interval period pulse generator.

  fsl,tmr-fiper2:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: Fixed interval period pulse generator.

  fsl,tmr-fiper3:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      Fixed interval period pulse generator.
      Supported only on DPAA2 and ENETC hardware.

  fsl,max-adj:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Maximum frequency adjustment in parts per billion.

      These properties set the operational parameters for the PTP
      clock. You must choose these carefully for the clock to work right.
      Here is how to figure good values:

      TimerOsc     = selected reference clock   MHz
      tclk_period  = desired clock period       nanoseconds
      NominalFreq  = 1000 / tclk_period         MHz
      FreqDivRatio = TimerOsc / NominalFreq     (must be greater that 1.0)
      tmr_add      = ceil(2^32 / FreqDivRatio)
      OutputClock  = NominalFreq / tmr_prsc     MHz
      PulseWidth   = 1 / OutputClock            microseconds
      FiperFreq1   = desired frequency in Hz
      FiperDiv1    = 1000000 * OutputClock / FiperFreq1
      tmr_fiper1   = tmr_prsc * tclk_period * FiperDiv1 - tclk_period
      max_adj      = 1000000000 * (FreqDivRatio - 1.0) - 1

      The calculation for tmr_fiper2 is the same as for tmr_fiper1. The
      driver expects that tmr_fiper1 will be correctly set to produce a 1
      Pulse Per Second (PPS) signal, since this will be offered to the PPS
      subsystem to synchronize the Linux clock.

      When this attribute is not used, the IEEE 1588 timer reference clock
      will use the eTSEC system clock (for Gianfar) or the MAC system
      clock (for DPAA).

  fsl,extts-fifo:
    $ref: /schemas/types.yaml#/definitions/flag
    description:
      The presence of this property indicates hardware
      support for the external trigger stamp FIFO

  little-endian:
    $ref: /schemas/types.yaml#/definitions/flag
    description:
      The presence of this property indicates the 1588 timer
      support for the external trigger stamp FIFO.
      IP block is little-endian mode. The default endian mode
      is big-endian.

required:
  - compatible
  - reg

allOf:
  - if:
      properties:
        compatible:
          contains:
            const: fsl,enetc-ptp
    then:
      $ref: /schemas/pci/pci-device.yaml

additionalProperties: false

examples:
  - |
    #include <dt-bindings/interrupt-controller/irq.h>

    phc@24e00 {
        compatible = "fsl,etsec-ptp";
        reg = <0x24e00 0xb0>;
        interrupts = <12 IRQ_TYPE_LEVEL_LOW>;
        interrupt-parent = <&ipic>;
        fsl,cksel       = <1>;
        fsl,tclk-period = <10>;
        fsl,tmr-prsc    = <100>;
        fsl,tmr-add     = <0x999999a4>;
        fsl,tmr-fiper1  = <0x3b9ac9f6>;
        fsl,tmr-fiper2  = <0x00018696>;
        fsl,max-adj     = <659999998>;
    };