154 lines
4.4 KiB
YAML
154 lines
4.4 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: "http://devicetree.org/schemas/serial/serial.yaml#"
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$schema: "http://devicetree.org/meta-schemas/core.yaml#"
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title: Serial Interface Generic DT Bindings
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maintainers:
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- Rob Herring <robh@kernel.org>
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- Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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description:
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This document lists a set of generic properties for describing UARTs in a
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device tree. Whether these properties apply to a particular device depends
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on the DT bindings for the actual device.
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Each enabled UART may have an optional "serialN" alias in the "aliases" node,
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where N is the port number (non-negative decimal integer) as printed on the
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label next to the physical port.
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properties:
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$nodename:
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pattern: "^serial(@.*)?$"
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label: true
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cts-gpios:
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maxItems: 1
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description:
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Must contain a GPIO specifier, referring to the GPIO pin to be used as
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the UART's CTS line.
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dcd-gpios:
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maxItems: 1
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description:
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Must contain a GPIO specifier, referring to the GPIO pin to be used as
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the UART's DCD line.
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dsr-gpios:
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maxItems: 1
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description:
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Must contain a GPIO specifier, referring to the GPIO pin to be used as
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the UART's DSR line.
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dtr-gpios:
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maxItems: 1
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description:
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Must contain a GPIO specifier, referring to the GPIO pin to be used as
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the UART's DTR line.
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rng-gpios:
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maxItems: 1
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description:
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Must contain a GPIO specifier, referring to the GPIO pin to be used as
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the UART's RNG line.
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rts-gpios:
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maxItems: 1
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description:
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Must contain a GPIO specifier, referring to the GPIO pin to be used as
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the UART's RTS line.
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uart-has-rtscts:
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$ref: /schemas/types.yaml#/definitions/flag
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description:
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The presence of this property indicates that the UART has dedicated lines
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for RTS/CTS hardware flow control, and that they are available for use
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(wired and enabled by pinmux configuration). This depends on both the
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UART hardware and the board wiring.
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rx-tx-swap:
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type: boolean
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description: RX and TX pins are swapped.
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cts-rts-swap:
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type: boolean
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description: CTS and RTS pins are swapped.
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rx-threshold:
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$ref: /schemas/types.yaml#/definitions/uint32
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description:
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RX FIFO threshold configuration (in bytes).
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tx-threshold:
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$ref: /schemas/types.yaml#/definitions/uint32
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description:
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TX FIFO threshold configuration (in bytes).
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if:
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required:
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- uart-has-rtscts
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then:
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properties:
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cts-gpios: false
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rts-gpios: false
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patternProperties:
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".*":
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if:
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type: object
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then:
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description:
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Serial attached devices shall be a child node of the host UART device
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the slave device is attached to. It is expected that the attached
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device is the only child node of the UART device. The slave device node
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name shall reflect the generic type of device for the node.
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properties:
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compatible:
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description:
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Compatible of the device connected to the serial port.
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max-speed:
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$ref: /schemas/types.yaml#/definitions/uint32
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description:
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The maximum baud rate the device operates at.
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This should only be present if the maximum is less than the slave
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device can support. For example, a particular board has some
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signal quality issue or the host processor can't support higher
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baud rates.
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current-speed:
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$ref: /schemas/types.yaml#/definitions/uint32
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description: |
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The current baud rate the device operates at.
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This should only be present in case a driver has no chance to know
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the baud rate of the slave device.
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Examples:
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* device supports auto-baud
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* the rate is setup by a bootloader and there is no way to reset
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the device
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* device baud rate is configured by its firmware but there is no
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way to request the actual settings
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required:
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- compatible
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additionalProperties: true
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examples:
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- |
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serial@1234 {
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compatible = "ns16550a";
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reg = <0x1234 0x20>;
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interrupts = <1>;
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bluetooth {
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compatible = "brcm,bcm4330-bt";
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interrupt-parent = <&gpio>;
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interrupts = <10>;
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};
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};
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