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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/serial/serial.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Serial Interface Generic DT Bindings
+
+maintainers:
+ - Rob Herring <robh@kernel.org>
+ - Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+description:
+ This document lists a set of generic properties for describing UARTs in a
+ device tree. Whether these properties apply to a particular device depends
+ on the DT bindings for the actual device.
+
+ Each enabled UART may have an optional "serialN" alias in the "aliases" node,
+ where N is the port number (non-negative decimal integer) as printed on the
+ label next to the physical port.
+
+properties:
+ $nodename:
+ pattern: "^serial(@.*)?$"
+
+ cts-gpios:
+ maxItems: 1
+ description:
+ Must contain a GPIO specifier, referring to the GPIO pin to be used as
+ the UART's CTS line.
+
+ dcd-gpios:
+ maxItems: 1
+ description:
+ Must contain a GPIO specifier, referring to the GPIO pin to be used as
+ the UART's DCD line.
+
+ dsr-gpios:
+ maxItems: 1
+ description:
+ Must contain a GPIO specifier, referring to the GPIO pin to be used as
+ the UART's DSR line.
+
+ dtr-gpios:
+ maxItems: 1
+ description:
+ Must contain a GPIO specifier, referring to the GPIO pin to be used as
+ the UART's DTR line.
+
+ rng-gpios:
+ maxItems: 1
+ description:
+ Must contain a GPIO specifier, referring to the GPIO pin to be used as
+ the UART's RNG line.
+
+ rts-gpios:
+ maxItems: 1
+ description:
+ Must contain a GPIO specifier, referring to the GPIO pin to be used as
+ the UART's RTS line.
+
+ uart-has-rtscts:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description:
+ The presence of this property indicates that the UART has dedicated lines
+ for RTS/CTS hardware flow control, and that they are available for use
+ (wired and enabled by pinmux configuration). This depends on both the
+ UART hardware and the board wiring.
+
+ rx-tx-swap:
+ type: boolean
+ description: RX and TX pins are swapped.
+
+ cts-rts-swap:
+ type: boolean
+ description: CTS and RTS pins are swapped.
+
+if:
+ required:
+ - uart-has-rtscts
+then:
+ properties:
+ cts-gpios: false
+ rts-gpios: false
+
+patternProperties:
+ ".*":
+ if:
+ type: object
+ then:
+ description:
+ Serial attached devices shall be a child node of the host UART device
+ the slave device is attached to. It is expected that the attached
+ device is the only child node of the UART device. The slave device node
+ name shall reflect the generic type of device for the node.
+
+ properties:
+ compatible:
+ description:
+ Compatible of the device connected to the serial port.
+
+ max-speed:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description:
+ The maximum baud rate the device operates at.
+ This should only be present if the maximum is less than the slave
+ device can support. For example, a particular board has some
+ signal quality issue or the host processor can't support higher
+ baud rates.
+
+ current-speed:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ The current baud rate the device operates at.
+ This should only be present in case a driver has no chance to know
+ the baud rate of the slave device.
+ Examples:
+ * device supports auto-baud
+ * the rate is setup by a bootloader and there is no way to reset
+ the device
+ * device baud rate is configured by its firmware but there is no
+ way to request the actual settings
+
+ required:
+ - compatible
+
+additionalProperties: true
+
+examples:
+ - |
+ serial@1234 {
+ compatible = "ns16550a";
+ reg = <0x1234 0x20>;
+ interrupts = <1>;
+
+ bluetooth {
+ compatible = "brcm,bcm43341-bt";
+ interrupt-parent = <&gpio>;
+ interrupts = <10>;
+ };
+ };