Documentation/devicetree/bindings/timestamp/nvidia,tegra194-hte.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/timestamp/nvidia,tegra194-hte.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Tegra194 on chip generic hardware timestamping engine (HTE)

maintainers:
  - Dipen Patel <dipenp@nvidia.com>

description:
  Tegra SoC has two instances of generic hardware timestamping engines (GTE)
  known as GTE GPIO and GTE IRQ, which can monitor subset of GPIO and on chip
  IRQ lines for the state change respectively, upon detection it will record
  timestamp (taken from system counter) in its internal hardware FIFO. It has
  a bitmap array arranged in 32bit slices where each bit represent signal/line
  to enable or disable for the hardware timestamping. The GTE GPIO monitors
  GPIO lines from the AON (always on) GPIO controller.

properties:
  compatible:
    enum:
      - nvidia,tegra194-gte-aon
      - nvidia,tegra194-gte-lic

  reg:
    maxItems: 1

  interrupts:
    maxItems: 1

  nvidia,int-threshold:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      HTE device generates its interrupt based on this u32 FIFO threshold
      value. The recommended value is 1.
    minimum: 1
    maximum: 256

  nvidia,slices:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      HTE lines are arranged in 32 bit slice where each bit represents different
      line/signal that it can enable/configure for the timestamp. It is u32
      property and depends on the HTE instance in the chip. The value 3 is for
      GPIO GTE and 11 for IRQ GTE.
    enum: [3, 11]

  '#timestamp-cells':
    description:
      This represents number of line id arguments as specified by the
      consumers. For the GTE IRQ, this is IRQ number as mentioned in the
      SoC technical reference manual. For the GTE GPIO, its value is same as
      mentioned in the nvidia GPIO device tree binding document.
    const: 1

required:
  - compatible
  - reg
  - interrupts
  - nvidia,slices
  - "#timestamp-cells"

additionalProperties: false

examples:
  - |
    tegra_hte_aon: timestamp@c1e0000 {
              compatible = "nvidia,tegra194-gte-aon";
              reg = <0xc1e0000 0x10000>;
              interrupts = <0 13 0x4>;
              nvidia,int-threshold = <1>;
              nvidia,slices = <3>;
              #timestamp-cells = <1>;
    };

  - |
    tegra_hte_lic: timestamp@3aa0000 {
              compatible = "nvidia,tegra194-gte-lic";
              reg = <0x3aa0000 0x10000>;
              interrupts = <0 11 0x4>;
              nvidia,int-threshold = <1>;
              nvidia,slices = <11>;
              #timestamp-cells = <1>;
    };

...