xref: /linux/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2-timings.yaml (revision 0a94608f0f7de9b1135ffea3546afe68eafef57f) 
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
7title: LPDDR2 SDRAM AC timing parameters for a given speed-bin
8
9maintainers:
10  - Krzysztof Kozlowski <krzk@kernel.org>
11
12properties:
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
107required:
108  - compatible
109  - min-freq
110  - max-freq
111
112additionalProperties: false
113
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