xref: /openbmc/linux/Documentation/devicetree/bindings/pwm/pwm-sifive.yaml (revision e040921c)

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
# Copyright (C) 2020 SiFive, Inc.
%YAML 1.2
---
$id: http://devicetree.org/schemas/pwm/pwm-sifive.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: SiFive PWM controller

maintainers:
  - Yash Shah <yash.shah@sifive.com>
  - Sagar Kadam <sagar.kadam@sifive.com>
  - Paul Walmsley <paul.walmsley@sifive.com>

description:
  Unlike most other PWM controllers, the SiFive PWM controller currently
  only supports one period for all channels in the PWM. All PWMs need to
  run at the same period. The period also has significant restrictions on
  the values it can achieve, which the driver rounds to the nearest
  achievable period. PWM RTL that corresponds to the IP block version
  numbers can be found here -

  https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm

allOf:
  - $ref: pwm.yaml#

properties:
  compatible:
    items:
      - enum:
          - sifive,fu540-c000-pwm
          - sifive,fu740-c000-pwm
      - const: sifive,pwm0
    description:
      Should be "sifive,<chip>-pwm" and "sifive,pwm<version>". Supported
      compatible strings are "sifive,fu540-c000-pwm" and
      "sifive,fu740-c000-pwm" for the SiFive PWM v0 as integrated onto the
      SiFive FU540 and FU740 chip respectively, and "sifive,pwm0" for the
      SiFive PWM v0 IP block with no chip integration tweaks.
      Please refer to sifive-blocks-ip-versioning.txt for details.

  reg:
    maxItems: 1

  clocks:
    maxItems: 1

  "#pwm-cells":
    const: 3

  interrupts:
    maxItems: 4
    description:
      Each PWM instance in FU540-C000 has 4 comparators. One interrupt per comparator.

required:
  - compatible
  - reg
  - clocks
  - interrupts

additionalProperties: false

examples:
  - |
    pwm:  pwm@10020000 {
      compatible = "sifive,fu540-c000-pwm", "sifive,pwm0";
      reg = <0x10020000 0x1000>;
      clocks = <&tlclk>;
      interrupt-parent = <&plic>;
      interrupts = <42>, <43>, <44>, <45>;
      #pwm-cells = <3>;
    };