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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/gpio/nxp,pcf8575.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: PCF857x-compatible I/O expanders
maintainers:
- Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
description:
The PCF857x-compatible chips have "quasi-bidirectional" I/O lines that can be
driven high by a pull-up current source or driven low to ground. This
combines the direction and output level into a single bit per line, which
can't be read back. We can't actually know at initialization time whether a
line is configured (a) as output and driving the signal low/high, or (b) as
input and reporting a low/high value, without knowing the last value written
since the chip came out of reset (if any). The only reliable solution for
setting up line direction is thus to do it explicitly.
properties:
compatible:
enum:
- maxim,max7328
- maxim,max7329
- nxp,pca8574
- nxp,pca8575
- nxp,pca9670
- nxp,pca9671
- nxp,pca9672
- nxp,pca9673
- nxp,pca9674
- nxp,pca9675
- nxp,pcf8574
- nxp,pcf8574a
- nxp,pcf8575
reg:
maxItems: 1
gpio-controller: true
'#gpio-cells':
const: 2
description:
The first cell is the GPIO number and the second cell specifies GPIO
flags, as defined in <dt-bindings/gpio/gpio.h>. Only the GPIO_ACTIVE_HIGH
and GPIO_ACTIVE_LOW flags are supported.
lines-initial-states:
$ref: /schemas/types.yaml#/definitions/uint32
description:
Bitmask that specifies the initial state of each line.
When a bit is set to zero, the corresponding line will be initialized to
the input (pulled-up) state.
When the bit is set to one, the line will be initialized to the
low-level output state.
If the property is not specified all lines will be initialized to the
input state.
interrupts:
maxItems: 1
interrupt-controller: true
'#interrupt-cells':
const: 2
wakeup-source: true
patternProperties:
"^(.+-hog(-[0-9]+)?)$":
type: object
required:
- gpio-hog
required:
- compatible
- reg
- gpio-controller
- '#gpio-cells'
additionalProperties: false
examples:
- |
i2c {
#address-cells = <1>;
#size-cells = <0>;
pcf8575: gpio@20 {
compatible = "nxp,pcf8575";
reg = <0x20>;
interrupt-parent = <&irqpin2>;
interrupts = <3 0>;
gpio-controller;
#gpio-cells = <2>;
interrupt-controller;
#interrupt-cells = <2>;
};
};
|
