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Diffstat (limited to 'Documentation/devicetree/bindings/serial/rs485.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/serial/rs485.txt | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/serial/rs485.txt b/Documentation/devicetree/bindings/serial/rs485.txt new file mode 100644 index 000000000..b7c29f74e --- /dev/null +++ b/Documentation/devicetree/bindings/serial/rs485.txt @@ -0,0 +1,31 @@ +* RS485 serial communications + +The RTS signal is capable of automatically controlling line direction for +the built-in half-duplex mode. +The properties described hereafter shall be given to a half-duplex capable +UART node. + +Optional properties: +- rs485-rts-delay: prop-encoded-array <a b> where: + * a is the delay between rts signal and beginning of data sent in milliseconds. + it corresponds to the delay before sending data. + * b is the delay between end of data sent and rts signal in milliseconds + it corresponds to the delay after sending data and actual release of the line. + If this property is not specified, <0 0> is assumed. +- rs485-rts-active-low: drive RTS low when sending (default is high). +- linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485 + feature at boot time. It can be disabled later with proper ioctl. +- rs485-rx-during-tx: empty property that enables the receiving of data even + whilst sending data. + +RS485 example for Atmel USART: + usart0: serial@fff8c000 { + compatible = "atmel,at91sam9260-usart"; + reg = <0xfff8c000 0x4000>; + interrupts = <7>; + atmel,use-dma-rx; + atmel,use-dma-tx; + linux,rs485-enabled-at-boot-time; + rs485-rts-delay = <0 200>; // in milliseconds + }; + |