xref: /freebsd/sys/contrib/device-tree/Bindings/memory-controllers/ddr/jedec,lpddr2-timings.yaml (revision c9ccf3a3)

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr2-timings.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: LPDDR2 SDRAM AC timing parameters for a given speed-bin

maintainers:
  - Krzysztof Kozlowski <krzk@kernel.org>

properties:
  compatible:
    const: jedec,lpddr2-timings

  max-freq:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Maximum DDR clock frequency for the speed-bin, in Hz.

  min-freq:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Minimum DDR clock frequency for the speed-bin, in Hz.

  tCKESR:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      CKE minimum pulse width during SELF REFRESH (low pulse width during
      SELF REFRESH) in pico seconds.

  tDQSCK-max:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      DQS output data access time from CK_t/CK_c in pico seconds.

  tDQSCK-max-derated:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      DQS output data access time from CK_t/CK_c, temperature de-rated, in pico
      seconds.

  tFAW:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Four-bank activate window in pico seconds.

  tRAS-max-ns:
    description: |
      Row active time in nano seconds.

  tRAS-min:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Row active time in pico seconds.

  tRCD:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      RAS-to-CAS delay in pico seconds.

  tRPab:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Row precharge time (all banks) in pico seconds.

  tRRD:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Active bank A to active bank B in pico seconds.

  tRTP:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Internal READ to PRECHARGE command delay in pico seconds.

  tWR:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      WRITE recovery time in pico seconds.

  tWTR:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Internal WRITE-to-READ command delay in pico seconds.

  tXP:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Exit power-down to next valid command delay in pico seconds.

  tZQCL:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Long calibration time in pico seconds.

  tZQCS:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Short calibration time in pico seconds.

  tZQinit:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: |
      Initialization calibration time in pico seconds.

required:
  - compatible
  - min-freq
  - max-freq

additionalProperties: false

examples:
  - |
    timings {
        compatible = "jedec,lpddr2-timings";
        min-freq = <10000000>;
        max-freq = <400000000>;
        tCKESR = <15000>;
        tDQSCK-max = <5500>;
        tFAW = <50000>;
        tRAS-max-ns = <70000>;
        tRAS-min = <42000>;
        tRPab = <21000>;
        tRCD = <18000>;
        tRRD = <10000>;
        tRTP = <7500>;
        tWR = <15000>;
        tWTR = <7500>;
        tXP = <7500>;
        tZQCL = <360000>;
        tZQCS = <90000>;
        tZQinit = <1000000>;
    };