xref: /linux/Documentation/devicetree/bindings/serial/rs485.yaml (revision 7f71507851fc7764b36a3221839607d3a45c2025) 
1# SPDX-License-Identifier: GPL-2.0
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/serial/rs485.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: RS485 serial communications
8
9description: The RTS signal is capable of automatically controlling line
10  direction for the built-in half-duplex mode. The properties described
11  hereafter shall be given to a half-duplex capable UART node.
12
13maintainers:
14  - Rob Herring <robh@kernel.org>
15
16properties:
17  rs485-rts-delay:
18    description: prop-encoded-array <a b>
19    $ref: /schemas/types.yaml#/definitions/uint32-array
20    items:
21      - description: Delay between rts signal and beginning of data sent in
22          milliseconds. It corresponds to the delay before sending data.
23        default: 0
24        maximum: 100
25      - description: Delay between end of data sent and rts signal in milliseconds.
26          It corresponds to the delay after sending data and actual release
27          of the line.
28        default: 0
29        maximum: 100
30
31  rs485-rts-active-high:
32    description: drive RTS high when sending (this is the default).
33    $ref: /schemas/types.yaml#/definitions/flag
34
35  rs485-rts-active-low:
36    description: drive RTS low when sending (default is high).
37    $ref: /schemas/types.yaml#/definitions/flag
38
39  rs485-rx-active-high:
40    description: Polarity of receiver enable signal (when separate from RTS).
41      True indicates active high (default is low).
42    $ref: /schemas/types.yaml#/definitions/flag
43
44  linux,rs485-enabled-at-boot-time:
45    description: enables the rs485 feature at boot time. It can be disabled
46      later with proper ioctl.
47    $ref: /schemas/types.yaml#/definitions/flag
48
49  rs485-rx-during-tx:
50    description: enables the receiving of data even while sending data.
51    $ref: /schemas/types.yaml#/definitions/flag
52
53  rs485-term-gpios:
54    description: GPIO pin to enable RS485 bus termination.
55    maxItems: 1
56
57  rs485-rx-during-tx-gpios:
58    description: Output GPIO pin that sets the state of rs485-rx-during-tx. This
59      signal can be used to control the RX part of an RS485 transceiver. Thereby
60      the active state enables RX during TX.
61    maxItems: 1
62
63additionalProperties: true
64
65...
66