Documentation/devicetree/bindings/clock/nvidia,tegra124-car.yaml

# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/clock/nvidia,tegra124-car.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: NVIDIA Tegra Clock and Reset Controller

maintainers:
  - Jon Hunter <jonathanh@nvidia.com>
  - Thierry Reding <thierry.reding@gmail.com>

description: |
  The Clock and Reset (CAR) is the HW module responsible for muxing and gating
  Tegra's clocks, and setting their rates. It comprises CLKGEN and RSTGEN units.

  CLKGEN provides the registers to program the PLLs. It controls most of
  the clock source programming and most of the clock dividers.

  CLKGEN input signals include the external clock for the reference frequency
  (12 MHz, 26 MHz) and the external clock for the Real Time Clock (32.768 KHz).

  Outputs from CLKGEN are inputs clock of the h/w blocks in the Tegra system.

  RSTGEN provides the registers needed to control resetting of each block in
  the Tegra system.

properties:
  compatible:
    const: nvidia,tegra124-car

  reg:
    maxItems: 1

  '#clock-cells':
    const: 1

  "#reset-cells":
    const: 1

  nvidia,external-memory-controller:
    $ref: /schemas/types.yaml#/definitions/phandle
    description:
      phandle of the external memory controller node

patternProperties:
  "^emc-timings-[0-9]+$":
    type: object
    properties:
      nvidia,ram-code:
        $ref: /schemas/types.yaml#/definitions/uint32
        description:
          value of the RAM_CODE field in the PMC_STRAPPING_OPT_A register that
          this timing set is used for

    patternProperties:
      "^timing-[0-9]+$":
        type: object
        properties:
          clock-frequency:
            description:
              external memory clock rate in Hz
            minimum: 1000000
            maximum: 1000000000

          nvidia,parent-clock-frequency:
            $ref: /schemas/types.yaml#/definitions/uint32
            description:
              rate of parent clock in Hz
            minimum: 1000000
            maximum: 1000000000

          clocks:
            items:
              - description: parent clock of EMC

          clock-names:
            items:
              - const: emc-parent

        required:
          - clock-frequency
          - nvidia,parent-clock-frequency
          - clocks
          - clock-names

        additionalProperties: false

    additionalProperties: false

required:
  - compatible
  - reg
  - '#clock-cells'
  - "#reset-cells"

additionalProperties: false

examples:
  - |
    #include <dt-bindings/clock/tegra124-car.h>

    car: clock-controller@60006000 {
        compatible = "nvidia,tegra124-car";
        reg = <0x60006000 0x1000>;
        #clock-cells = <1>;
        #reset-cells = <1>;
    };

    usb-controller@c5004000 {
        compatible = "nvidia,tegra20-ehci";
        reg = <0xc5004000 0x4000>;
        clocks = <&car TEGRA124_CLK_USB2>;
        resets = <&car TEGRA124_CLK_USB2>;
    };