linux-brain/Documentation/devicetree/bindings/serial/rs485.txt
Will Deacon 806654a966 Documentation: Use "while" instead of "whilst"
Whilst making an unrelated change to some Documentation, Linus sayeth:

  | Afaik, even in Britain, "whilst" is unusual and considered more
  | formal, and "while" is the common word.
  |
  | [...]
  |
  | Can we just admit that we work with computers, and we don't need to
  | use þe eald Englisc spelling of words that most of the world never
  | uses?

dictionary.com refers to the word as "Chiefly British", which is
probably an undesirable attribute for technical documentation.

Replace all occurrences under Documentation/ with "while".

Cc: David Howells <dhowells@redhat.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-11-20 09:30:43 -07:00

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* 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
while 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
};