arm,syscon-icst.yaml

  1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
  2%YAML 1.2
  3---
  4$id: http://devicetree.org/schemas/clock/arm,syscon-icst.yaml#
  5$schema: http://devicetree.org/meta-schemas/core.yaml#
  6
  7title: ARM System Controller ICST Clocks
  8
  9maintainers:
 10  - Linus Walleij <linusw@kernel.org>
 11
 12description: |
 13  The ICS525 and ICS307 oscillators are produced by Integrated
 14  Devices Technology (IDT). ARM integrated these oscillators deeply into their
 15  reference designs by adding special control registers that manage such
 16  oscillators to their system controllers.
 17
 18  The various ARM system controllers contain logic to serialize and initialize
 19  an ICST clock request after a write to the 32 bit register at an offset
 20  into the system controller. Furthermore, to even be able to alter one of
 21  these frequencies, the system controller must first be unlocked by
 22  writing a special token to another offset in the system controller.
 23
 24  Some ARM hardware contain special versions of the serial interface that only
 25  connects the low 8 bits of the VDW (missing one bit), hard-wires RDW to
 26  different values and sometimes also hard-wires the output divider. They
 27  therefore have special compatible strings as per this table (the OD value is
 28  the value on the pins, not the resulting output divider).
 29
 30  In the core modules and logic tiles, the ICST is a configurable clock fed
 31  from a 24 MHz clock on the motherboard (usually the main crystal) used for
 32  generating e.g. video clocks. It is located on the core module and there is
 33  only one of these. This clock node must be a subnode of the core module.
 34
 35  Hardware variant         RDW     OD          VDW
 36
 37  Integrator/AP            22      1           Bit 8 0, rest variable
 38  integratorap-cm
 39
 40  Integrator/AP            46      3           Bit 8 0, rest variable
 41  integratorap-sys
 42
 43  Integrator/AP            22 or   1           17 or (33 or 25 MHz)
 44  integratorap-pci         14      1           14
 45
 46  Integrator/CP            22      variable    Bit 8 0, rest variable
 47  integratorcp-cm-core
 48
 49  Integrator/CP            22      variable    Bit 8 0, rest variable
 50  integratorcp-cm-mem
 51
 52  The ICST oscillator must be provided inside a system controller node.
 53
 54properties:
 55  "#clock-cells":
 56    const: 0
 57
 58  compatible:
 59    enum:
 60      - arm,syscon-icst525
 61      - arm,syscon-icst307
 62      - arm,syscon-icst525-integratorap-cm
 63      - arm,syscon-icst525-integratorap-sys
 64      - arm,syscon-icst525-integratorap-pci
 65      - arm,syscon-icst525-integratorcp-cm-core
 66      - arm,syscon-icst525-integratorcp-cm-mem
 67      - arm,integrator-cm-auxosc
 68      - arm,versatile-cm-auxosc
 69      - arm,impd1-vco1
 70      - arm,impd1-vco2
 71
 72  reg:
 73    maxItems: 1
 74    description: The VCO register
 75
 76  clocks:
 77    description: Parent clock for the ICST VCO
 78    maxItems: 1
 79
 80  clock-output-names:
 81    maxItems: 1
 82
 83  lock-offset:
 84    $ref: /schemas/types.yaml#/definitions/uint32
 85    description: Offset to the unlocking register for the oscillator
 86
 87  vco-offset:
 88    $ref: /schemas/types.yaml#/definitions/uint32
 89    description: Offset to the VCO register for the oscillator
 90    deprecated: true
 91
 92required:
 93  - "#clock-cells"
 94  - compatible
 95  - clocks
 96
 97additionalProperties: false
 98
 99examples:
100  - |
101    vco1: clock {
102      compatible = "arm,impd1-vco1";
103      #clock-cells = <0>;
104      lock-offset = <0x08>;
105      vco-offset = <0x00>;
106      clocks = <&sysclk>;
107      clock-output-names = "IM-PD1-VCO1";
108    };
109
110...