dt-bindings: interrupt-controller: Convert mti,gic to DT schema

Modern device tree bindings are supposed to be created as YAML-files
in accordance with DT schema. This commit replaces MIPS GIC legacy bare
text binding with YAML file. As before the binding file states that the
corresponding dts node is supposed to be compatible with MIPS Global
Interrupt Controller indicated by the "mti,gic" compatible string and
to provide a mandatory interrupt-controller and '#interrupt-cells'
properties. There might be optional registers memory range,
"mti,reserved-cpu-vectors" and "mti,reserved-ipi-vectors" properties
specified.

MIPS GIC also includes a free-running global timer, per-CPU count/compare
timers, and a watchdog. Since currently the GIC Timer is only supported the
DT schema expects an IRQ and clock-phandler charged timer sub-node with
"mti,mips-gic-timer" compatible string.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Documentation/devicetree/bindings/interrupt-controller/mti,gic.yaml

@@ -0,0 +1,148 @@
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/mti,gic.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MIPS Global Interrupt Controller
+
+maintainers:
+  - Paul Burton <paulburton@kernel.org>
+  - Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+
+description: |
+  The MIPS GIC routes external interrupts to individual VPEs and IRQ pins.
+  It also supports local (per-processor) interrupts and software-generated
+  interrupts which can be used as IPIs. The GIC also includes a free-running
+  global timer, per-CPU count/compare timers, and a watchdog.
+
+properties:
+  compatible:
+    const: mti,gic
+
+  "#interrupt-cells":
+    const: 3
+    description: |
+      The 1st cell is the type of interrupt: local or shared defined in the
+      file 'dt-bindings/interrupt-controller/mips-gic.h'. The 2nd cell is the
+      GIC interrupt number. The 3d cell encodes the interrupt flags setting up
+      the IRQ trigger modes, which are defined in the file
+      'dt-bindings/interrupt-controller/irq.h'.
+
+  reg:
+    description: |
+      Base address and length of the GIC registers space. If not present,
+      the base address reported by the hardware GCR_GIC_BASE will be used.
+    maxItems: 1
+
+  interrupt-controller: true
+
+  mti,reserved-cpu-vectors:
+    description: |
+      Specifies the list of CPU interrupt vectors to which the GIC may not
+      route interrupts. This property is ignored if the CPU is started in EIC
+      mode.
+    allOf:
+      - $ref: /schemas/types.yaml#definitions/uint32-array
+      - minItems: 1
+        maxItems: 6
+        uniqueItems: true
+        items:
+          minimum: 2
+          maximum: 7
+
+  mti,reserved-ipi-vectors:
+    description: |
+      Specifies the range of GIC interrupts that are reserved for IPIs.
+      It accepts two values: the 1st is the starting interrupt and the 2nd is
+      the size of the reserved range. If not specified, the driver will
+      allocate the last (2 * number of VPEs in the system).
+    allOf:
+      - $ref: /schemas/types.yaml#definitions/uint32-array
+      - items:
+          - minimum: 0
+            maximum: 254
+          - minimum: 2
+            maximum: 254
+
+  timer:
+    type: object
+    description: |
+      MIPS GIC includes a free-running global timer, per-CPU count/compare
+      timers, and a watchdog. Currently only the GIC Timer is supported.
+    properties:
+      compatible:
+        const: mti,gic-timer
+
+      interrupts:
+        description: |
+          Interrupt for the GIC local timer, so normally it's suppose to be of
+          <GIC_LOCAL X IRQ_TYPE_NONE> format.
+        maxItems: 1
+
+      clocks:
+        maxItems: 1
+
+      clock-frequency: true
+
+    required:
+      - compatible
+      - interrupts
+
+    oneOf:
+      - required:
+          - clocks
+      - required:
+          - clock-frequency
+
+    additionalProperties: false
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - "#interrupt-cells"
+  - interrupt-controller
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/mips-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    interrupt-controller@1bdc0000 {
+      compatible = "mti,gic";
+      reg = <0x1bdc0000 0x20000>;
+      interrupt-controller;
+      #interrupt-cells = <3>;
+      mti,reserved-cpu-vectors = <7>;
+      mti,reserved-ipi-vectors = <40 8>;
+
+      timer {
+        compatible = "mti,gic-timer";
+        interrupts = <GIC_LOCAL 1 IRQ_TYPE_NONE>;
+        clock-frequency = <50000000>;
+      };
+    };
+  - |
+    #include <dt-bindings/interrupt-controller/mips-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    interrupt-controller@1bdc0000 {
+      compatible = "mti,gic";
+      reg = <0x1bdc0000 0x20000>;
+      interrupt-controller;
+      #interrupt-cells = <3>;
+
+      timer {
+        compatible = "mti,gic-timer";
+        interrupts = <GIC_LOCAL 1 IRQ_TYPE_NONE>;
+        clocks = <&cpu_pll>;
+      };
+    };
+  - |
+    interrupt-controller {
+      compatible = "mti,gic";
+      interrupt-controller;
+      #interrupt-cells = <3>;
+    };
+...