dt-bindings: memory: lpddr3-timings: convert to dtschema

Convert the LPDDR3 memory timings bindings to DT schema format.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220206135807.211767-3-krzysztof.kozlowski@canonical.com
This commit is contained in:
Krzysztof Kozlowski 2022-02-06 14:58:01 +01:00
parent 425fd283e4
commit 180a276c99
2 changed files with 153 additions and 58 deletions

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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,lpddr3-timings.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: LPDDR3 SDRAM AC timing parameters for a given speed-bin
maintainers:
- Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
properties:
compatible:
const: jedec,lpddr3-timings
reg:
maxItems: 1
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.
tCKE:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
CKE minimum pulse width (HIGH and LOW pulse width) in pico seconds.
tCKESR:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
CKE minimum pulse width during SELF REFRESH (low pulse width during
SELF REFRESH) in pico seconds.
tFAW:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Four-bank activate window in pico seconds.
tMRD:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Mode register set command delay in pico seconds.
tR2R-C2C:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Additional READ-to-READ delay in chip-to-chip cases in pico seconds.
tRAS:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Row active time in pico seconds.
tRC:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
ACTIVATE-to-ACTIVATE command period in pico seconds.
tRCD:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
RAS-to-CAS delay in pico seconds.
tRFC:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Refresh Cycle time in pico seconds.
tRPab:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Row precharge time (all banks) in pico seconds.
tRPpb:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Row precharge time (single 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.
tW2W-C2C:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Additional WRITE-to-WRITE delay in chip-to-chip cases 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.
tXSR:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
SELF REFRESH exit to next valid command delay in pico seconds.
required:
- compatible
- min-freq
- reg
additionalProperties: false
examples:
- |
lpddr3 {
#address-cells = <1>;
#size-cells = <0>;
timings@800000000 {
compatible = "jedec,lpddr3-timings";
reg = <800000000>;
min-freq = <100000000>;
tCKE = <3750>;
tCKESR = <3750>;
tFAW = <25000>;
tMRD = <7000>;
tR2R-C2C = <0>;
tRAS = <23000>;
tRC = <33750>;
tRCD = <10000>;
tRFC = <65000>;
tRPab = <12000>;
tRPpb = <12000>;
tRRD = <6000>;
tRTP = <3750>;
tW2W-C2C = <0>;
tWR = <7500>;
tWTR = <3750>;
tXP = <3750>;
tXSR = <70000>;
};
};

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* AC timing parameters of LPDDR3 memories for a given speed-bin.
The structures are based on LPDDR2 and extended where needed.
Required properties:
- compatible : Should be "jedec,lpddr3-timings"
- min-freq : minimum DDR clock frequency for the speed-bin. Type is <u32>
- reg : maximum DDR clock frequency for the speed-bin. Type is <u32>
Optional properties:
The following properties represent AC timing parameters from the memory
data-sheet of the device for a given speed-bin. All these properties are
of type <u32> and the default unit is ps (pico seconds).
- tRFC
- tRRD
- tRPab
- tRPpb
- tRCD
- tRC
- tRAS
- tWTR
- tWR
- tRTP
- tW2W-C2C
- tR2R-C2C
- tFAW
- tXSR
- tXP
- tCKE
- tCKESR
- tMRD
Example:
timings_samsung_K3QF2F20DB_800mhz: lpddr3-timings@800000000 {
compatible = "jedec,lpddr3-timings";
reg = <800000000>; /* workaround: it shows max-freq */
min-freq = <100000000>;
tRFC = <65000>;
tRRD = <6000>;
tRPab = <12000>;
tRPpb = <12000>;
tRCD = <10000>;
tRC = <33750>;
tRAS = <23000>;
tWTR = <3750>;
tWR = <7500>;
tRTP = <3750>;
tW2W-C2C = <0>;
tR2R-C2C = <0>;
tFAW = <25000>;
tXSR = <70000>;
tXP = <3750>;
tCKE = <3750>;
tCKESR = <3750>;
tMRD = <7000>;
};