Commit 6f633bc9 authored by Jonathan Cameron's avatar Jonathan Cameron

dt-bindings:iio:afe:voltage-divider: txt to yaml conversion

Simple binding so straight forward conversion, though did require
adding a separate binding document for the max1027 to reflect
its abilities to provide channels to consumers.
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Cc: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20201031181242.742301-9-jic23@kernel.org
parent bd690dfa
Voltage divider
===============
When an io-channel measures the midpoint of a voltage divider, the
interesting voltage is often the voltage over the full resistance
of the divider. This binding describes the voltage divider in such
a curcuit.
Vin ----.
|
.-----.
| R |
'-----'
|
+---- Vout
|
.-----.
| Rout|
'-----'
|
GND
Required properties:
- compatible : "voltage-divider"
- io-channels : Channel node of a voltage io-channel measuring Vout.
- output-ohms : Resistance Rout over which the output voltage is measured.
See full-ohms.
- full-ohms : Resistance R + Rout for the full divider. The io-channel
is scaled by the Rout / (R + Rout) quotient.
Example:
The system voltage is circa 12V, but divided down with a 22/222
voltage divider (R = 200 Ohms, Rout = 22 Ohms) and fed to an ADC.
sysv {
compatible = "voltage-divider";
io-channels = <&maxadc 1>;
/* Scale the system voltage by 22/222 to fit the ADC range. */
output-ohms = <22>;
full-ohms = <222>; /* 200 + 22 */
};
&spi {
maxadc: adc@0 {
compatible = "maxim,max1027";
reg = <0>;
#io-channel-cells = <1>;
interrupt-parent = <&gpio5>;
interrupts = <15 IRQ_TYPE_EDGE_RISING>;
spi-max-frequency = <1000000>;
};
};
# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/afe/voltage-divider.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Voltage divider
maintainers:
- Peter Rosin <peda@axentia.se>
description: |
When an io-channel measures the midpoint of a voltage divider, the
interesting voltage is often the voltage over the full resistance
of the divider. This binding describes the voltage divider in such
a curcuit.
Vin ----.
|
.-----.
| R |
'-----'
|
+---- Vout
|
.-----.
| Rout|
'-----'
|
GND
properties:
compatible:
const: voltage-divider
io-channels:
maxItems: 1
description: |
Channel node of a voltage io-channel.
output-ohms:
description:
Resistance Rout over which the output voltage is measured. See full-ohms.
full-ohms:
description:
Resistance R + Rout for the full divider. The io-channel is scaled by
the Rout / (R + Rout) quotient.
required:
- compatible
- io-channels
- output-ohms
- full-ohms
additionalProperties: false
examples:
- |
#include <dt-bindings/interrupt-controller/irq.h>
/*
* The system voltage is circa 12V, but divided down with a 22/222
* voltage divider (R = 200 Ohms, Rout = 22 Ohms) and fed to an ADC.
*/
spi {
#address-cells = <1>;
#size-cells = <0>;
maxadc: adc@0 {
compatible = "maxim,max1027";
reg = <0>;
#io-channel-cells = <1>;
interrupt-parent = <&gpio5>;
interrupts = <15 IRQ_TYPE_EDGE_RISING>;
spi-max-frequency = <1000000>;
};
};
sysv {
compatible = "voltage-divider";
io-channels = <&maxadc 1>;
/* Scale the system voltage by 22/222 to fit the ADC range. */
output-ohms = <22>;
full-ohms = <222>; /* 200 + 22 */
};
...
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment