mirror of
https://github.com/torvalds/linux.git
synced 2024-12-27 13:22:23 +00:00
32 lines
1.1 KiB
Plaintext
32 lines
1.1 KiB
Plaintext
|
* 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.
|
||
|
|
|
||
|
|
Required properties:
|
||
|
|
- rs485-rts-delay: prop-encoded-array <a b> where:
|
||
|
|
* a is the delay beteween 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.
|
||
|
|
|
||
|
|
Optional properties:
|
||
|
|
- 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
|
||
|
|
};
|
||
|
|
|