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105 lines
3.3 KiB
105 lines
3.3 KiB
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) |
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%YAML 1.2 |
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--- |
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$id: http://devicetree.org/schemas/clock/arm,syscon-icst.yaml# |
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$schema: http://devicetree.org/meta-schemas/core.yaml# |
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title: ARM System Controller ICST Clocks |
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maintainers: |
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- Linus Walleij <[email protected]> |
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description: | |
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The ICS525 and ICS307 oscillators are produced by Integrated |
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Devices Technology (IDT). ARM integrated these oscillators deeply into their |
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reference designs by adding special control registers that manage such |
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oscillators to their system controllers. |
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The various ARM system controllers contain logic to serialize and initialize |
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an ICST clock request after a write to the 32 bit register at an offset |
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into the system controller. Furthermore, to even be able to alter one of |
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these frequencies, the system controller must first be unlocked by |
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writing a special token to another offset in the system controller. |
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Some ARM hardware contain special versions of the serial interface that only |
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connects the low 8 bits of the VDW (missing one bit), hard-wires RDW to |
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different values and sometimes also hard-wires the output divider. They |
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therefore have special compatible strings as per this table (the OD value is |
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the value on the pins, not the resulting output divider). |
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In the core modules and logic tiles, the ICST is a configurable clock fed |
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from a 24 MHz clock on the motherboard (usually the main crystal) used for |
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generating e.g. video clocks. It is located on the core module and there is |
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only one of these. This clock node must be a subnode of the core module. |
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Hardware variant RDW OD VDW |
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Integrator/AP 22 1 Bit 8 0, rest variable |
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integratorap-cm |
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Integrator/AP 46 3 Bit 8 0, rest variable |
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integratorap-sys |
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Integrator/AP 22 or 1 17 or (33 or 25 MHz) |
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integratorap-pci 14 1 14 |
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Integrator/CP 22 variable Bit 8 0, rest variable |
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integratorcp-cm-core |
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Integrator/CP 22 variable Bit 8 0, rest variable |
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integratorcp-cm-mem |
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The ICST oscillator must be provided inside a system controller node. |
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properties: |
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"#clock-cells": |
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const: 0 |
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compatible: |
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enum: |
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- arm,syscon-icst525 |
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- arm,syscon-icst307 |
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- arm,syscon-icst525-integratorap-cm |
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- arm,syscon-icst525-integratorap-sys |
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- arm,syscon-icst525-integratorap-pci |
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- arm,syscon-icst525-integratorcp-cm-core |
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- arm,syscon-icst525-integratorcp-cm-mem |
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- arm,integrator-cm-auxosc |
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- arm,versatile-cm-auxosc |
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- arm,impd1-vco1 |
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- arm,impd1-vco2 |
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clocks: |
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description: Parent clock for the ICST VCO |
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maxItems: 1 |
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clock-output-names: |
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maxItems: 1 |
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lock-offset: |
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$ref: '/schemas/types.yaml#/definitions/uint32' |
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description: Offset to the unlocking register for the oscillator |
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vco-offset: |
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$ref: '/schemas/types.yaml#/definitions/uint32' |
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description: Offset to the VCO register for the oscillator |
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required: |
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- "#clock-cells" |
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- compatible |
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- clocks |
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additionalProperties: false |
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examples: |
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- | |
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vco1: clock { |
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compatible = "arm,impd1-vco1"; |
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#clock-cells = <0>; |
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lock-offset = <0x08>; |
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vco-offset = <0x00>; |
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clocks = <&sysclk>; |
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clock-output-names = "IM-PD1-VCO1"; |
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}; |
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...
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