dt-bindings: interrupt-controller: riscv,cpu-intc: convert to dtschema

Convert the RISC-V Hart-Level Interrupt Controller (HLIC) to newer
DT schema, Created DT schema based on the .txt file which had
`compatible`, `#interrupt-cells` and `interrupt-controller` as
required properties.
Changes made with respect to original file:
- Changed the example to just use interrupt-controller instead of
using the whole cpu block
- Changed the example compatible string.

Reviewed-by: Conor Dooley <[email protected]>
Signed-off-by: Kanak Shilledar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

Author: kanakshilledar

Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt

@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/riscv,cpu-intc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V Hart-Level Interrupt Controller (HLIC)
+
+description:
+  RISC-V cores include Control Status Registers (CSRs) which are local to
+  each CPU core (HART in RISC-V terminology) and can be read or written by
+  software. Some of these CSRs are used to control local interrupts connected
+  to the core. Every interrupt is ultimately routed through a hart's HLIC
+  before it interrupts that hart.
+
+  The RISC-V supervisor ISA manual specifies three interrupt sources that are
+  attached to every HLIC namely software interrupts, the timer interrupt, and
+  external interrupts. Software interrupts are used to send IPIs between
+  cores.  The timer interrupt comes from an architecturally mandated real-
+  time timer that is controlled via Supervisor Binary Interface (SBI) calls
+  and CSR reads. External interrupts connect all other device interrupts to
+  the HLIC, which are routed via the platform-level interrupt controller
+  (PLIC).
+
+  All RISC-V systems that conform to the supervisor ISA specification are
+  required to have a HLIC with these three interrupt sources present.  Since
+  the interrupt map is defined by the ISA it's not listed in the HLIC's device
+  tree entry, though external interrupt controllers (like the PLIC, for
+  example) will need to define how their interrupts map to the relevant HLICs.
+  This means a PLIC interrupt property will typically list the HLICs for all
+  present HARTs in the system.
+
+maintainers:
+  - Palmer Dabbelt <[email protected]>
+  - Paul Walmsley <[email protected]>
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: andestech,cpu-intc
+          - const: riscv,cpu-intc
+      - const: riscv,cpu-intc
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 1
+    description: |
+      The interrupt sources are defined by the RISC-V supervisor ISA manual,
+      with only the following three interrupts being defined for
+      supervisor mode:
+        - Source 1 is the supervisor software interrupt, which can be sent by
+          an SBI call and is reserved for use by software.
+        - Source 5 is the supervisor timer interrupt, which can be configured
+          by SBI calls and implements a one-shot timer.
+        - Source 9 is the supervisor external interrupt, which chains to all
+          other device interrupts.
+
+required:
+  - compatible
+  - '#interrupt-cells'
+  - interrupt-controller
+
+additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller {
+        #interrupt-cells = <1>;
+        compatible = "riscv,cpu-intc";
+        interrupt-controller;
+    };