tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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
7title: Serial Interface Generic DT Bindings
8
9maintainers:
10 - Rob Herring <robh@kernel.org>
11 - Greg Kroah-Hartman <gregkh@linuxfoundation.org>
12
13description:
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
22properties:
23 $nodename:
24 pattern: "^serial(@.*)?$"
25
26 cts-gpios:
27 maxItems: 1
28 description:
29 Must contain a GPIO specifier, referring to the GPIO pin to be used as
30 the UART's CTS line.
31
32 dcd-gpios:
33 maxItems: 1
34 description:
35 Must contain a GPIO specifier, referring to the GPIO pin to be used as
36 the UART's DCD line.
37
38 dsr-gpios:
39 maxItems: 1
40 description:
41 Must contain a GPIO specifier, referring to the GPIO pin to be used as
42 the UART's DSR line.
43
44 dtr-gpios:
45 maxItems: 1
46 description:
47 Must contain a GPIO specifier, referring to the GPIO pin to be used as
48 the UART's DTR line.
49
50 rng-gpios:
51 maxItems: 1
52 description:
53 Must contain a GPIO specifier, referring to the GPIO pin to be used as
54 the UART's RNG line.
55
56 rts-gpios:
57 maxItems: 1
58 description:
59 Must contain a GPIO specifier, referring to the GPIO pin to be used as
60 the UART's RTS line.
61
62 uart-has-rtscts:
63 $ref: /schemas/types.yaml#/definitions/flag
64 description:
65 The presence of this property indicates that the UART has dedicated lines
66 for RTS/CTS hardware flow control, and that they are available for use
67 (wired and enabled by pinmux configuration). This depends on both the
68 UART hardware and the board wiring.
69
70 rx-tx-swap:
71 type: boolean
72 description: RX and TX pins are swapped.
73
74 cts-rts-swap:
75 type: boolean
76 description: CTS and RTS pins are swapped.
77
78if:
79 required:
80 - uart-has-rtscts
81then:
82 properties:
83 cts-gpios: false
84 rts-gpios: false
85
86patternProperties:
87 ".*":
88 if:
89 type: object
90 then:
91 description:
92 Serial attached devices shall be a child node of the host UART device
93 the slave device is attached to. It is expected that the attached
94 device is the only child node of the UART device. The slave device node
95 name shall reflect the generic type of device for the node.
96
97 properties:
98 compatible:
99 description:
100 Compatible of the device connected to the serial port.
101
102 max-speed:
103 $ref: /schemas/types.yaml#/definitions/uint32
104 description:
105 The maximum baud rate the device operates at.
106 This should only be present if the maximum is less than the slave
107 device can support. For example, a particular board has some
108 signal quality issue or the host processor can't support higher
109 baud rates.
110
111 current-speed:
112 $ref: /schemas/types.yaml#/definitions/uint32
113 description: |
114 The current baud rate the device operates at.
115 This should only be present in case a driver has no chance to know
116 the baud rate of the slave device.
117 Examples:
118 * device supports auto-baud
119 * the rate is setup by a bootloader and there is no way to reset
120 the device
121 * device baud rate is configured by its firmware but there is no
122 way to request the actual settings
123
124 required:
125 - compatible
126
127examples:
128 - |
129 serial@1234 {
130 compatible = "ns16550a";
131 reg = <0x1234 0x20>;
132 interrupts = <1>;
133
134 bluetooth {
135 compatible = "brcm,bcm43341-bt";
136 interrupt-parent = <&gpio>;
137 interrupts = <10>;
138 };
139 };