xref: /linux/Documentation/devicetree/bindings/gpio/nxp,pcf8575.yaml (revision 1ac731c529cd4d6adbce134754b51ff7d822b145) 
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/gpio/nxp,pcf8575.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: PCF857x-compatible I/O expanders
8
9maintainers:
10  - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
11
12description:
13  The PCF857x-compatible chips have "quasi-bidirectional" I/O lines that can be
14  driven high by a pull-up current source or driven low to ground. This
15  combines the direction and output level into a single bit per line, which
16  can't be read back. We can't actually know at initialization time whether a
17  line is configured (a) as output and driving the signal low/high, or (b) as
18  input and reporting a low/high value, without knowing the last value written
19  since the chip came out of reset (if any). The only reliable solution for
20  setting up line direction is thus to do it explicitly.
21
22properties:
23  compatible:
24    enum:
25      - maxim,max7328
26      - maxim,max7329
27      - nxp,pca8574
28      - nxp,pca8575
29      - nxp,pca9670
30      - nxp,pca9671
31      - nxp,pca9672
32      - nxp,pca9673
33      - nxp,pca9674
34      - nxp,pca9675
35      - nxp,pcf8574
36      - nxp,pcf8574a
37      - nxp,pcf8575
38
39  reg:
40    maxItems: 1
41
42  gpio-line-names:
43    minItems: 1
44    maxItems: 16
45
46  gpio-controller: true
47
48  '#gpio-cells':
49    const: 2
50    description:
51      The first cell is the GPIO number and the second cell specifies GPIO
52      flags, as defined in <dt-bindings/gpio/gpio.h>. Only the GPIO_ACTIVE_HIGH
53      and GPIO_ACTIVE_LOW flags are supported.
54
55  lines-initial-states:
56    $ref: /schemas/types.yaml#/definitions/uint32
57    description:
58      Bitmask that specifies the initial state of each line.
59      When a bit is set to zero, the corresponding line will be initialized to
60      the input (pulled-up) state.
61      When the  bit is set to one, the line will be initialized to the
62      low-level output state.
63      If the property is not specified all lines will be initialized to the
64      input state.
65
66  interrupts:
67    maxItems: 1
68
69  interrupt-controller: true
70
71  '#interrupt-cells':
72    const: 2
73
74  wakeup-source: true
75
76patternProperties:
77  "^(.+-hog(-[0-9]+)?)$":
78    type: object
79
80    required:
81      - gpio-hog
82
83required:
84  - compatible
85  - reg
86  - gpio-controller
87  - '#gpio-cells'
88
89additionalProperties: false
90
91examples:
92  - |
93    i2c {
94            #address-cells = <1>;
95            #size-cells = <0>;
96
97            pcf8575: gpio@20 {
98                    compatible = "nxp,pcf8575";
99                    reg = <0x20>;
100                    interrupt-parent = <&irqpin2>;
101                    interrupts = <3 0>;
102                    gpio-controller;
103                    #gpio-cells = <2>;
104                    interrupt-controller;
105                    #interrupt-cells = <2>;
106            };
107    };
108