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# 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 <krzysztof.kozlowski@canonical.com>
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>;
};
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