1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
# 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-line-names:
minItems: 1
maxItems: 16
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:
$ref: /schemas/types.yaml#/definitions/uint32
description:
Bitmask that specifies the initial state of each line.
When a bit is set to zero, the corresponding line will be initialized to
the input (pulled-up) state.
When the bit is set to one, the line will be initialized to the
low-level output state.
If the property is not specified all lines will be initialized to the
input state.
interrupts:
maxItems: 1
interrupt-controller: true
'#interrupt-cells':
const: 2
wakeup-source: true
reset-gpios:
maxItems: 1
description:
GPIO controlling the (reset active LOW) RESET# pin.
The active polarity of the GPIO must translate to the low state of the
RESET# pin on the IC, i.e. if a GPIO is directly routed to the RESET# pin
without any inverter, GPIO_ACTIVE_LOW is expected.
Performing a reset makes all lines initialized to their input (pulled-up)
state.
allOf:
- if:
properties:
compatible:
not:
contains:
enum:
- nxp,pca9670
- nxp,pca9671
- nxp,pca9672
- nxp,pca9673
then:
properties:
reset-gpios: false
# lines-initial-states XOR reset-gpios
# Performing a reset reinitializes all lines to a known state which
# may not match passed lines-initial-states
- if:
required:
- lines-initial-states
then:
properties:
reset-gpios: false
patternProperties:
"^(.+-hog(-[0-9]+)?)$":
type: object
required:
- gpio-hog
required:
- compatible
- reg
- gpio-controller
- '#gpio-cells'
additionalProperties: false
examples:
- |
i2c {
#address-cells = <1>;
#size-cells = <0>;
gpio@20 {
compatible = "nxp,pcf8575";
reg = <0x20>;
interrupt-parent = <&irqpin2>;
interrupts = <3 0>;
gpio-controller;
#gpio-cells = <2>;
interrupt-controller;
#interrupt-cells = <2>;
};
};
|
