Bindings/clock/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
   7 title: ARM System Controller ICST Clocks
   8
   9 maintainers:
  10   - Linus Walleij <linusw@kernel.org>
  11
  12 description: |
  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
  54 properties:
  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
  92 required:
  93   - "#clock-cells"
  94   - compatible
  95   - clocks
  96
  97 additionalProperties: false
  98
  99 examples:
 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 ...