0001 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
0002 %YAML 1.2
0003 ---
0004 $id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr2-timings.yaml#
0005 $schema: http://devicetree.org/meta-schemas/core.yaml#
0006
0007 title: LPDDR2 SDRAM AC timing parameters for a given speed-bin
0008
0009 maintainers:
0010 - Krzysztof Kozlowski <krzk@kernel.org>
0011
0012 properties:
0013 compatible:
0014 const: jedec,lpddr2-timings
0015
0016 max-freq:
0017 $ref: /schemas/types.yaml#/definitions/uint32
0018 description: |
0019 Maximum DDR clock frequency for the speed-bin, in Hz.
0020
0021 min-freq:
0022 $ref: /schemas/types.yaml#/definitions/uint32
0023 description: |
0024 Minimum DDR clock frequency for the speed-bin, in Hz.
0025
0026 tCKESR:
0027 $ref: /schemas/types.yaml#/definitions/uint32
0028 description: |
0029 CKE minimum pulse width during SELF REFRESH (low pulse width during
0030 SELF REFRESH) in pico seconds.
0031
0032 tDQSCK-max:
0033 $ref: /schemas/types.yaml#/definitions/uint32
0034 description: |
0035 DQS output data access time from CK_t/CK_c in pico seconds.
0036
0037 tDQSCK-max-derated:
0038 $ref: /schemas/types.yaml#/definitions/uint32
0039 description: |
0040 DQS output data access time from CK_t/CK_c, temperature de-rated, in pico
0041 seconds.
0042
0043 tFAW:
0044 $ref: /schemas/types.yaml#/definitions/uint32
0045 description: |
0046 Four-bank activate window in pico seconds.
0047
0048 tRAS-max-ns:
0049 description: |
0050 Row active time in nano seconds.
0051
0052 tRAS-min:
0053 $ref: /schemas/types.yaml#/definitions/uint32
0054 description: |
0055 Row active time in pico seconds.
0056
0057 tRCD:
0058 $ref: /schemas/types.yaml#/definitions/uint32
0059 description: |
0060 RAS-to-CAS delay in pico seconds.
0061
0062 tRPab:
0063 $ref: /schemas/types.yaml#/definitions/uint32
0064 description: |
0065 Row precharge time (all banks) in pico seconds.
0066
0067 tRRD:
0068 $ref: /schemas/types.yaml#/definitions/uint32
0069 description: |
0070 Active bank A to active bank B in pico seconds.
0071
0072 tRTP:
0073 $ref: /schemas/types.yaml#/definitions/uint32
0074 description: |
0075 Internal READ to PRECHARGE command delay in pico seconds.
0076
0077 tWR:
0078 $ref: /schemas/types.yaml#/definitions/uint32
0079 description: |
0080 WRITE recovery time in pico seconds.
0081
0082 tWTR:
0083 $ref: /schemas/types.yaml#/definitions/uint32
0084 description: |
0085 Internal WRITE-to-READ command delay in pico seconds.
0086
0087 tXP:
0088 $ref: /schemas/types.yaml#/definitions/uint32
0089 description: |
0090 Exit power-down to next valid command delay in pico seconds.
0091
0092 tZQCL:
0093 $ref: /schemas/types.yaml#/definitions/uint32
0094 description: |
0095 Long calibration time in pico seconds.
0096
0097 tZQCS:
0098 $ref: /schemas/types.yaml#/definitions/uint32
0099 description: |
0100 Short calibration time in pico seconds.
0101
0102 tZQinit:
0103 $ref: /schemas/types.yaml#/definitions/uint32
0104 description: |
0105 Initialization calibration time in pico seconds.
0106
0107 required:
0108 - compatible
0109 - min-freq
0110 - max-freq
0111
0112 additionalProperties: false
0113
0114 examples:
0115 - |
0116 timings {
0117 compatible = "jedec,lpddr2-timings";
0118 min-freq = <10000000>;
0119 max-freq = <400000000>;
0120 tCKESR = <15000>;
0121 tDQSCK-max = <5500>;
0122 tFAW = <50000>;
0123 tRAS-max-ns = <70000>;
0124 tRAS-min = <42000>;
0125 tRPab = <21000>;
0126 tRCD = <18000>;
0127 tRRD = <10000>;
0128 tRTP = <7500>;
0129 tWR = <15000>;
0130 tWTR = <7500>;
0131 tXP = <7500>;
0132 tZQCL = <360000>;
0133 tZQCS = <90000>;
0134 tZQinit = <1000000>;
0135 };
