Documentation/devicetree/bindings/gpio/sprd,gpio-eic.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
# Copyright 2022 Unisoc Inc.
%YAML 1.2
---
$id: http://devicetree.org/schemas/gpio/sprd,gpio-eic.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Unisoc EIC controller

maintainers:
  - Orson Zhai <orsonzhai@gmail.com>
  - Baolin Wang <baolin.wang7@gmail.com>
  - Chunyan Zhang <zhang.lyra@gmail.com>

description: |
  The EIC is the abbreviation of external interrupt controller, which can
  be used only in input mode. The Spreadtrum platform has 2 EIC controllers,
  one is in digital chip, and another one is in PMIC. The digital chip EIC
  controller contains 4 sub-modules, i.e. EIC-debounce, EIC-latch, EIC-async and
  EIC-sync. But the PMIC EIC controller contains only one EIC-debounce sub-
  module.

  The EIC-debounce sub-module provides up to 8 source input signal
  connections. A debounce mechanism is used to capture the input signals'
  stable status (millisecond resolution) and a single-trigger mechanism
  is introduced into this sub-module to enhance the input event detection
  reliability. In addition, this sub-module's clock can be shut off
  automatically to reduce power dissipation. Moreover the debounce range
  is from 1ms to 4s with a step size of 1ms. The input signal will be
  ignored if it is asserted for less than 1 ms.

  The EIC-latch sub-module is used to latch some special power down signals
  and generate interrupts, since the EIC-latch does not depend on the APB
  clock to capture signals.

  The EIC-async sub-module uses a 32kHz clock to capture the short signals
  (microsecond resolution) to generate interrupts by level or edge trigger.

  The EIC-sync is similar with GPIO's input function, which is a synchronized
  signal input register. It can generate interrupts by level or edge trigger
  when detecting input signals.

properties:
  compatible:
    oneOf:
      - enum:
          - sprd,sc9860-eic-debounce
          - sprd,sc9860-eic-latch
          - sprd,sc9860-eic-async
          - sprd,sc9860-eic-sync
          - sprd,sc2731-eic
      - items:
          - enum:
              - sprd,ums512-eic-debounce
          - const: sprd,sc9860-eic-debounce
      - items:
          - enum:
              - sprd,ums512-eic-latch
          - const: sprd,sc9860-eic-latch
      - items:
          - enum:
              - sprd,ums512-eic-async
          - const: sprd,sc9860-eic-async
      - items:
          - enum:
              - sprd,ums512-eic-sync
          - const: sprd,sc9860-eic-sync
      - items:
          - enum:
              - sprd,sc2730-eic
          - const: sprd,sc2731-eic

  reg:
    minItems: 1
    maxItems: 3
    description:
      EIC controller can support maximum 3 banks which has its own
      address base.

  gpio-controller: true

  "#gpio-cells":
    const: 2

  interrupt-controller: true

  "#interrupt-cells":
    const: 2

  interrupts:
    maxItems: 1
    description:
      The interrupt shared by all GPIO lines for this controller.

required:
  - compatible
  - reg
  - gpio-controller
  - "#gpio-cells"
  - interrupt-controller
  - "#interrupt-cells"
  - interrupts

additionalProperties: false

examples:
  - |
    #include <dt-bindings/interrupt-controller/arm-gic.h>

    soc {
        #address-cells = <2>;
        #size-cells = <2>;

        eic_debounce: gpio@40210000 {
            compatible = "sprd,sc9860-eic-debounce";
            reg = <0 0x40210000 0 0x80>;
            gpio-controller;
            #gpio-cells = <2>;
            interrupt-controller;
            #interrupt-cells = <2>;
            interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>;
        };
    };
...