dt-bindings: bus: Add Baikal-T1 APB-bus binding

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC

%YAML 1.2

---

$id: http://devicetree.org/schemas/bus/baikal,bt1-apb.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Baikal-T1 APB-bus

maintainers:

  - Serge Semin <fancer.lancer@gmail.com>

description: |

  Baikal-T1 CPU or DMAC MMIO requests are handled by the AMBA 3 AXI Interconnect

  which routes them to the AXI-APB bridge. This interface is a single master

  multiple slaves bus in turn serializing IO accesses and routing them to the

  addressed APB slave devices. In case of any APB protocol collisions, slave

  device not responding on timeout an IRQ is raised with an erroneous address

  reported to the APB terminator (APB Errors Handler Block).

allOf:

 - $ref: /schemas/simple-bus.yaml#

properties:

  compatible:

    contains:

      const: baikal,bt1-apb

  reg:

    items:

      - description: APB EHB MMIO registers

      - description: APB MMIO region with no any device mapped

  reg-names:

    items:

      - const: ehb

      - const: nodev

  interrupts:

    maxItems: 1

  clocks:

    items:

      - description: APB reference clock

  clock-names:

    items:

      - const: pclk

  resets:

    items:

      - description: APB domain reset line

  reset-names:

    items:

      - const: prst

unevaluatedProperties: false

required:

  - compatible

  - reg

  - reg-names

  - interrupts

  - clocks

  - clock-names

examples:

  - |

    #include <dt-bindings/interrupt-controller/mips-gic.h>

    bus@1f059000 {

      compatible = "baikal,bt1-apb", "simple-bus";

      reg = <0 0x1f059000 0 0x1000>,

            <0 0x1d000000 0 0x2040000>;

      reg-names = "ehb", "nodev";

      #address-cells = <1>;

      #size-cells = <1>;

      ranges;

      interrupts = <GIC_SHARED 16 IRQ_TYPE_LEVEL_HIGH>;

      clocks = <&ccu_sys 1>;

      clock-names = "pclk";

      resets = <&ccu_sys 1>;

      reset-names = "prst";

    };

...