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# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/proximity/devantech-srf04.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Devantech SRF04 and Maxbotix mb1000 ultrasonic range finder
maintainers:
- Andreas Klinger <ak@it-klinger.de>
description: |
Bit-banging driver using two GPIOs:
- trigger-gpio is raised by the driver to start sending out an ultrasonic
burst
- echo-gpio is held high by the sensor after sending ultrasonic burst
until it is received once again
Specifications about the devices can be found at:
https://www.robot-electronics.co.uk/htm/srf04tech.htm
https://www.maxbotix.com/documents/LV-MaxSonar-EZ_Datasheet.pdf
properties:
compatible:
enum:
- devantech,srf04
- maxbotix,mb1000
- maxbotix,mb1010
- maxbotix,mb1020
- maxbotix,mb1030
- maxbotix,mb1040
trig-gpios:
description:
Definition of the GPIO for the triggering (output)
This GPIO is set for about 10 us by the driver to tell the device it
should initiate the measurement cycle.
See Documentation/devicetree/bindings/gpio/gpio.txt for information
on how to specify a consumer gpio.
maxItems: 1
echo-gpios:
description:
Definition of the GPIO for the echo (input)
This GPIO is set by the device as soon as an ultrasonic burst is sent
out and reset when the first echo is received.
Thus this GPIO is set while the ultrasonic waves are doing one round
trip.
It needs to be an GPIO which is able to deliver an interrupt because
the time between two interrupts is measured in the driver.
maxItems: 1
power-gpios:
description:
Definition of the GPIO for power management of connected peripheral
(output).
This GPIO can be used by the external hardware for power management.
When the device gets suspended it's switched off and when it resumes
it's switched on again. After some period of inactivity the driver
get suspended automatically (autosuspend feature).
maxItems: 1
startup-time-ms:
description:
This is the startup time the device needs after a resume to be up and
running.
minimum: 0
maximum: 1000
default: 100
required:
- compatible
- trig-gpios
- echo-gpios
additionalProperties: false
examples:
- |
#include <dt-bindings/gpio/gpio.h>
proximity {
compatible = "devantech,srf04";
trig-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH>;
echo-gpios = <&gpio2 6 GPIO_ACTIVE_HIGH>;
};
|
