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# 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
properties:
compatible:
items:
- const: sifive,fu540-c000-pwm
- const: sifive,pwm0
description:
Should be "sifive,<chip>-pwm" and "sifive,pwm<version>". Supported
compatible strings are "sifive,fu540-c000-pwm" for the SiFive PWM v0
as integrated onto the SiFive FU540 chip, 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
- "#pwm-cells"
- 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>;
};
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