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
70if:
71 required:
72 - uart-has-rtscts
73then:
74 properties:
75 cts-gpios: false
76 rts-gpios: false
77
78patternProperties:
79 ".*":
80 if:
81 type: object
82 then:
83 description:
84 Serial attached devices shall be a child node of the host UART device
85 the slave device is attached to. It is expected that the attached
86 device is the only child node of the UART device. The slave device node
87 name shall reflect the generic type of device for the node.
88
89 properties:
90 compatible:
91 description:
92 Compatible of the device connected to the serial port.
93
94 max-speed:
95 $ref: /schemas/types.yaml#/definitions/uint32
96 description:
97 The maximum baud rate the device operates at.
98 This should only be present if the maximum is less than the slave
99 device can support. For example, a particular board has some
100 signal quality issue or the host processor can't support higher
101 baud rates.
102
103 current-speed:
104 $ref: /schemas/types.yaml#/definitions/uint32
105 description: |
106 The current baud rate the device operates at.
107 This should only be present in case a driver has no chance to know
108 the baud rate of the slave device.
109 Examples:
110 * device supports auto-baud
111 * the rate is setup by a bootloader and there is no way to reset
112 the device
113 * device baud rate is configured by its firmware but there is no
114 way to request the actual settings
115
116 required:
117 - compatible
118
119examples:
120 - |
121 serial@1234 {
122 compatible = "ns16550a";
123 reg = <0x1234 0x20>;
124 interrupts = <1>;
125
126 bluetooth {
127 compatible = "brcm,bcm43341-bt";
128 interrupt-parent = <&gpio>;
129 interrupts = <10>;
130 };
131 };