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|
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/pwm/microchip,corepwm.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Microchip IP corePWM controller
maintainers:
- Conor Dooley <conor.dooley@microchip.com>
description: |
corePWM is an 16 channel pulse width modulator FPGA IP
https://www.microsemi.com/existing-parts/parts/152118
allOf:
- $ref: pwm.yaml#
properties:
compatible:
items:
- const: microchip,corepwm-rtl-v4
reg:
maxItems: 1
clocks:
maxItems: 1
"#pwm-cells":
enum: [2, 3]
description:
The only flag supported by the controller is PWM_POLARITY_INVERTED.
microchip,sync-update-mask:
description: |
Depending on how the IP is instantiated, there are two modes of operation.
In synchronous mode, all channels are updated at the beginning of the PWM period,
and in asynchronous mode updates happen as the control registers are written.
A 16 bit wide "SHADOW_REG_EN" parameter of the IP core controls whether synchronous
mode is possible for each channel, and is set by the bitstream programmed to the
FPGA. If the IP core is instantiated with SHADOW_REG_ENx=1, both registers that
control the duty cycle for channel x have a second "shadow"/buffer reg synthesised.
At runtime a bit wide register exposed to APB can be used to toggle on/off
synchronised mode for all channels it has been synthesised for.
Each bit of "microchip,sync-update-mask" corresponds to a PWM channel & represents
whether synchronous mode is possible for the PWM channel.
$ref: /schemas/types.yaml#/definitions/uint32
default: 0
microchip,dac-mode-mask:
description: |
Optional, per-channel Low Ripple DAC mode is possible on this IP core. It creates
a minimum period pulse train whose High/Low average is that of the chosen duty
cycle. This "DAC" will have far better bandwidth and ripple performance than the
standard PWM algorithm can achieve. A 16 bit DAC_MODE module parameter of the IP
core, set at instantiation and by the bitstream programmed to the FPGA, determines
whether a given channel operates in regular PWM or DAC mode.
Each bit corresponds to a PWM channel & represents whether DAC mode is enabled
for that channel.
$ref: /schemas/types.yaml#/definitions/uint32
default: 0
required:
- compatible
- reg
- clocks
additionalProperties: false
examples:
- |
pwm@41000000 {
compatible = "microchip,corepwm-rtl-v4";
microchip,sync-update-mask = /bits/ 32 <0>;
clocks = <&clkcfg 30>;
reg = <0x41000000 0xF0>;
#pwm-cells = <2>;
};
|
