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1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)2%YAML 1.23---4$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr2-timings.yaml#5$schema: http://devicetree.org/meta-schemas/core.yaml#6 7title: LPDDR2 SDRAM AC timing parameters for a given speed-bin8 9maintainers:10 - Krzysztof Kozlowski <krzk@kernel.org>11 12properties:13 compatible:14 const: jedec,lpddr2-timings15 16 max-freq:17 $ref: /schemas/types.yaml#/definitions/uint3218 description: |19 Maximum DDR clock frequency for the speed-bin, in Hz.20 21 min-freq:22 $ref: /schemas/types.yaml#/definitions/uint3223 description: |24 Minimum DDR clock frequency for the speed-bin, in Hz.25 26 tCKESR:27 $ref: /schemas/types.yaml#/definitions/uint3228 description: |29 CKE minimum pulse width during SELF REFRESH (low pulse width during30 SELF REFRESH) in pico seconds.31 32 tDQSCK-max:33 $ref: /schemas/types.yaml#/definitions/uint3234 description: |35 DQS output data access time from CK_t/CK_c in pico seconds.36 37 tDQSCK-max-derated:38 $ref: /schemas/types.yaml#/definitions/uint3239 description: |40 DQS output data access time from CK_t/CK_c, temperature de-rated, in pico41 seconds.42 43 tFAW:44 $ref: /schemas/types.yaml#/definitions/uint3245 description: |46 Four-bank activate window in pico seconds.47 48 tRAS-max-ns:49 description: |50 Row active time in nano seconds.51 52 tRAS-min:53 $ref: /schemas/types.yaml#/definitions/uint3254 description: |55 Row active time in pico seconds.56 57 tRCD:58 $ref: /schemas/types.yaml#/definitions/uint3259 description: |60 RAS-to-CAS delay in pico seconds.61 62 tRPab:63 $ref: /schemas/types.yaml#/definitions/uint3264 description: |65 Row precharge time (all banks) in pico seconds.66 67 tRRD:68 $ref: /schemas/types.yaml#/definitions/uint3269 description: |70 Active bank A to active bank B in pico seconds.71 72 tRTP:73 $ref: /schemas/types.yaml#/definitions/uint3274 description: |75 Internal READ to PRECHARGE command delay in pico seconds.76 77 tWR:78 $ref: /schemas/types.yaml#/definitions/uint3279 description: |80 WRITE recovery time in pico seconds.81 82 tWTR:83 $ref: /schemas/types.yaml#/definitions/uint3284 description: |85 Internal WRITE-to-READ command delay in pico seconds.86 87 tXP:88 $ref: /schemas/types.yaml#/definitions/uint3289 description: |90 Exit power-down to next valid command delay in pico seconds.91 92 tZQCL:93 $ref: /schemas/types.yaml#/definitions/uint3294 description: |95 Long calibration time in pico seconds.96 97 tZQCS:98 $ref: /schemas/types.yaml#/definitions/uint3299 description: |100 Short calibration time in pico seconds.101 102 tZQinit:103 $ref: /schemas/types.yaml#/definitions/uint32104 description: |105 Initialization calibration time in pico seconds.106 107required:108 - compatible109 - min-freq110 - max-freq111 112additionalProperties: false113 114examples:115 - |116 timings {117 compatible = "jedec,lpddr2-timings";118 min-freq = <10000000>;119 max-freq = <400000000>;120 tCKESR = <15000>;121 tDQSCK-max = <5500>;122 tFAW = <50000>;123 tRAS-max-ns = <70000>;124 tRAS-min = <42000>;125 tRPab = <21000>;126 tRCD = <18000>;127 tRRD = <10000>;128 tRTP = <7500>;129 tWR = <15000>;130 tWTR = <7500>;131 tXP = <7500>;132 tZQCL = <360000>;133 tZQCS = <90000>;134 tZQinit = <1000000>;135 };136