xref: /linux/Documentation/devicetree/bindings/serial/rs485.yaml (revision a23e1966932464e1c5226cb9ac4ce1d5fc10ba22) 
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      items:
22        - description: Delay between rts signal and beginning of data sent in
23            milliseconds. It corresponds to the delay before sending data.
24          default: 0
25          maximum: 100
26        - description: Delay between end of data sent and rts signal in milliseconds.
27            It corresponds to the delay after sending data and actual release
28            of the line.
29          default: 0
30          maximum: 100
31
32  rs485-rts-active-high:
33    description: drive RTS high when sending (this is the default).
34    $ref: /schemas/types.yaml#/definitions/flag
35
36  rs485-rts-active-low:
37    description: drive RTS low when sending (default is high).
38    $ref: /schemas/types.yaml#/definitions/flag
39
40  rs485-rx-active-high:
41    description: Polarity of receiver enable signal (when separate from RTS).
42      True indicates active high (default is low).
43    $ref: /schemas/types.yaml#/definitions/flag
44
45  linux,rs485-enabled-at-boot-time:
46    description: enables the rs485 feature at boot time. It can be disabled
47      later with proper ioctl.
48    $ref: /schemas/types.yaml#/definitions/flag
49
50  rs485-rx-during-tx:
51    description: enables the receiving of data even while sending data.
52    $ref: /schemas/types.yaml#/definitions/flag
53
54  rs485-term-gpios:
55    description: GPIO pin to enable RS485 bus termination.
56    maxItems: 1
57
58  rs485-rx-during-tx-gpios:
59    description: Output GPIO pin that sets the state of rs485-rx-during-tx. This
60      signal can be used to control the RX part of an RS485 transceiver. Thereby
61      the active state enables RX during TX.
62    maxItems: 1
63
64additionalProperties: true
65
66...
67