1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr2-timings.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: LPDDR2 SDRAM AC timing parameters for a given speed-bin
8
9 maintainers:
10 - Krzysztof Kozlowski <krzk@kernel.org>
11
12 properties:
13 compatible:
14 const: jedec,lpddr2-timings
15
16 max-freq:
17 $ref: /schemas/types.yaml#/definitions/uint32
18 description: |
19 Maximum DDR clock frequency for the speed-bin, in Hz.
20
21 min-freq:
22 $ref: /schemas/types.yaml#/definitions/uint32
23 description: |
24 Minimum DDR clock frequency for the speed-bin, in Hz.
25
26 tCKESR:
27 $ref: /schemas/types.yaml#/definitions/uint32
28 description: |
29 CKE minimum pulse width during SELF REFRESH (low pulse width during
30 SELF REFRESH) in pico seconds.
31
32 tDQSCK-max:
33 $ref: /schemas/types.yaml#/definitions/uint32
34 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/uint32
39 description: |
40 DQS output data access time from CK_t/CK_c, temperature de-rated, in pico
41 seconds.
42
43 tFAW:
44 $ref: /schemas/types.yaml#/definitions/uint32
45 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/uint32
54 description: |
55 Row active time in pico seconds.
56
57 tRCD:
58 $ref: /schemas/types.yaml#/definitions/uint32
59 description: |
60 RAS-to-CAS delay in pico seconds.
61
62 tRPab:
63 $ref: /schemas/types.yaml#/definitions/uint32
64 description: |
65 Row precharge time (all banks) in pico seconds.
66
67 tRRD:
68 $ref: /schemas/types.yaml#/definitions/uint32
69 description: |
70 Active bank A to active bank B in pico seconds.
71
72 tRTP:
73 $ref: /schemas/types.yaml#/definitions/uint32
74 description: |
75 Internal READ to PRECHARGE command delay in pico seconds.
76
77 tWR:
78 $ref: /schemas/types.yaml#/definitions/uint32
79 description: |
80 WRITE recovery time in pico seconds.
81
82 tWTR:
83 $ref: /schemas/types.yaml#/definitions/uint32
84 description: |
85 Internal WRITE-to-READ command delay in pico seconds.
86
87 tXP:
88 $ref: /schemas/types.yaml#/definitions/uint32
89 description: |
90 Exit power-down to next valid command delay in pico seconds.
91
92 tZQCL:
93 $ref: /schemas/types.yaml#/definitions/uint32
94 description: |
95 Long calibration time in pico seconds.
96
97 tZQCS:
98 $ref: /schemas/types.yaml#/definitions/uint32
99 description: |
100 Short calibration time in pico seconds.
101
102 tZQinit:
103 $ref: /schemas/types.yaml#/definitions/uint32
104 description: |
105 Initialization calibration time in pico seconds.
106
107 required:
108 - compatible
109 - min-freq
110 - max-freq
111
112 additionalProperties: false
113
114 examples:
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 };
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