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 ...
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