1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/serial/serial.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: Serial Interface Generic
8
9 maintainers:
10 - Rob Herring <robh@kernel.org>
11 - Greg Kroah-Hartman <gregkh@linuxfoundation.org>
12
13 description:
14 This document lists a set of generic properties for describing UARTs in a
15 device tree. Whether these properties apply to a particular device depends
16 on the DT bindings for the actual device.
17
18 Each enabled UART may have an optional "serialN" alias in the "aliases" node,
19 where N is the port number (non-negative decimal integer) as printed on the
20 label next to the physical port.
21
22 properties:
23 $nodename:
24 pattern: "^serial(@.*)?$"
25
26 label: true
27
28 cts-gpios:
29 maxItems: 1
30 description:
31 Must contain a GPIO specifier, referring to the GPIO pin to be used as
32 the UART's CTS line.
33
34 dcd-gpios:
35 maxItems: 1
36 description:
37 Must contain a GPIO specifier, referring to the GPIO pin to be used as
38 the UART's DCD line.
39
40 dsr-gpios:
41 maxItems: 1
42 description:
43 Must contain a GPIO specifier, referring to the GPIO pin to be used as
44 the UART's DSR line.
45
46 dtr-gpios:
47 maxItems: 1
48 description:
49 Must contain a GPIO specifier, referring to the GPIO pin to be used as
50 the UART's DTR line.
51
52 rng-gpios:
53 maxItems: 1
54 description:
55 Must contain a GPIO specifier, referring to the GPIO pin to be used as
56 the UART's RNG line.
57
58 rts-gpios:
59 maxItems: 1
60 description:
61 Must contain a GPIO specifier, referring to the GPIO pin to be used as
62 the UART's RTS line.
63
64 uart-has-rtscts:
65 $ref: /schemas/types.yaml#/definitions/flag
66 description:
67 The presence of this property indicates that the UART has dedicated lines
68 for RTS/CTS hardware flow control, and that they are available for use
69 (wired and enabled by pinmux configuration). This depends on both the
70 UART hardware and the board wiring.
71
72 rx-tx-swap:
73 type: boolean
74 description: RX and TX pins are swapped.
75
76 cts-rts-swap:
77 type: boolean
78 description: CTS and RTS pins are swapped.
79
80 rx-threshold:
81 $ref: /schemas/types.yaml#/definitions/uint32
82 description:
83 RX FIFO threshold configuration (in bytes).
84
85 tx-threshold:
86 $ref: /schemas/types.yaml#/definitions/uint32
87 description:
88 TX FIFO threshold configuration (in bytes).
89
90 patternProperties:
91 "^(bluetooth|bluetooth-gnss|embedded-controller|gnss|gps|mcu|onewire)$":
92 if:
93 type: object
94 then:
95 additionalProperties: true
96 $ref: serial-peripheral-props.yaml#
97 description:
98 Serial attached devices shall be a child node of the host UART device
99 the slave device is attached to. It is expected that the attached
100 device is the only child node of the UART device. The slave device node
101 name shall reflect the generic type of device for the node.
102
103 properties:
104 compatible:
105 description:
106 Compatible of the device connected to the serial port.
107
108 required:
109 - compatible
110
111 if:
112 required:
113 - uart-has-rtscts
114 then:
115 properties:
116 cts-gpios: false
117 rts-gpios: false
118
119 additionalProperties: true
120
121 examples:
122 - |
123 serial@1234 {
124 compatible = "ns16550a";
125 reg = <0x1234 0x20>;
126 interrupts = <1>;
127
128 bluetooth {
129 compatible = "brcm,bcm4330-bt";
130 interrupt-parent = <&gpio>;
131 interrupts = <10>;
132 };
133 };
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