dt-bindings: clock: Create YAML schema for ICST clocks

The ICST clocks used in the ARM Integrator, Versatile and
RealView platforms are updated to use YAML schema, and two
new ICST clocks used by the Integrator IM-PD1 logical module
are added in the process.

Cc: [email protected]
Reviewed-by: Rob Herring <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: Fix some typos]
Signed-off-by: Stephen Boyd <[email protected]>

Author: linusw

Documentation/devicetree/bindings/clock/arm,syscon-icst.yaml

@@ -0,0 +1,103 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/arm,syscon-icst.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM System Controller ICST Clocks
+
+maintainers:
+  - Linus Walleij <[email protected]>
+
+description: |
+  The ICS525 and ICS307 oscillators are produced by Integrated
+  Devices Technology (IDT). ARM integrated these oscillators deeply into their
+  reference designs by adding special control registers that manage such
+  oscillators to their system controllers.
+
+  The various ARM system controllers contain logic to serialize and initialize
+  an ICST clock request after a write to the 32 bit register at an offset
+  into the system controller. Furthermore, to even be able to alter one of
+  these frequencies, the system controller must first be unlocked by
+  writing a special token to another offset in the system controller.
+
+  Some ARM hardware contain special versions of the serial interface that only
+  connects the low 8 bits of the VDW (missing one bit), hard-wires RDW to
+  different values and sometimes also hard-wires the output divider. They
+  therefore have special compatible strings as per this table (the OD value is
+  the value on the pins, not the resulting output divider).
+
+  In the core modules and logic tiles, the ICST is a configurable clock fed
+  from a 24 MHz clock on the motherboard (usually the main crystal) used for
+  generating e.g. video clocks. It is located on the core module and there is
+  only one of these. This clock node must be a subnode of the core module.
+
+  Hardware variant         RDW     OD          VDW
+
+  Integrator/AP            22      1           Bit 8 0, rest variable
+  integratorap-cm
+
+  Integrator/AP            46      3           Bit 8 0, rest variable
+  integratorap-sys
+
+  Integrator/AP            22 or   1           17 or (33 or 25 MHz)
+  integratorap-pci         14      1           14
+
+  Integrator/CP            22      variable    Bit 8 0, rest variable
+  integratorcp-cm-core
+
+  Integrator/CP            22      variable    Bit 8 0, rest variable
+  integratorcp-cm-mem
+
+  The ICST oscillator must be provided inside a system controller node.
+
+properties:
+  "#clock-cells":
+    const: 0
+
+  compatible:
+    enum:
+      - arm,syscon-icst525
+      - arm,syscon-icst307
+      - arm,syscon-icst525-integratorap-cm
+      - arm,syscon-icst525-integratorap-sys
+      - arm,syscon-icst525-integratorap-pci
+      - arm,syscon-icst525-integratorcp-cm-core
+      - arm,syscon-icst525-integratorcp-cm-mem
+      - arm,integrator-cm-auxosc
+      - arm,versatile-cm-auxosc
+      - arm,impd-vco1
+      - arm,impd-vco2
+
+  clocks:
+    description: Parent clock for the ICST VCO
+    maxItems: 1
+
+  clock-output-names:
+    maxItems: 1
+
+  lock-offset:
+    $ref: '/schemas/types.yaml#/definitions/uint32'
+    description: Offset to the unlocking register for the oscillator
+
+  vco-offset:
+    $ref: '/schemas/types.yaml#/definitions/uint32'
+    description: Offset to the VCO register for the oscillator
+
+required:
+  - "#clock-cells"
+  - compatible
+  - clocks
+
+examples:
+  - |
+    vco1: clock@00 {
+      compatible = "arm,impd1-vco1";
+      #clock-cells = <0>;
+      lock-offset = <0x08>;
+      vco-offset = <0x00>;
+      clocks = <&sysclk>;
+      clock-output-names = "IM-PD1-VCO1";
+    };
+
+...