mirror of
https://github.com/torvalds/linux.git
synced 2024-12-25 20:32:22 +00:00
e51e597d9f
The i.MX UART peripheral uses the RST_B signal as input, and CTS_B as output. This is just like the DCE role in RS-232. This is true regardless of the "DTE mode" setting of this peripheral. As a result, rs485 support hardware must use the CTS_B signal to control the RS-485 transceiver. This is in contrast to generic rs485 kernel code, documentation, and DT property names that consistently refer to the RTS as transceiver control signal. Add a note in the DT binding document about that, to reduce the confusion somewhat. Signed-off-by: Baruch Siach <baruch@tkos.co.il> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
37 lines
1.1 KiB
Plaintext
37 lines
1.1 KiB
Plaintext
* Freescale i.MX Universal Asynchronous Receiver/Transmitter (UART)
|
|
|
|
Required properties:
|
|
- compatible : Should be "fsl,<soc>-uart"
|
|
- reg : Address and length of the register set for the device
|
|
- interrupts : Should contain uart interrupt
|
|
|
|
Optional properties:
|
|
- fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
|
|
in DCE mode by default.
|
|
- rs485-rts-delay, rs485-rts-active-low, rs485-rx-during-tx,
|
|
linux,rs485-enabled-at-boot-time: see rs485.txt. Note that for RS485
|
|
you must enable either the "uart-has-rtscts" or the "rts-gpios"
|
|
properties. In case you use "uart-has-rtscts" the signal that controls
|
|
the transceiver is actually CTS_B, not RTS_B. CTS_B is always output,
|
|
and RTS_B is input, regardless of dte-mode.
|
|
|
|
Please check Documentation/devicetree/bindings/serial/serial.txt
|
|
for the complete list of generic properties.
|
|
|
|
Note: Each uart controller should have an alias correctly numbered
|
|
in "aliases" node.
|
|
|
|
Example:
|
|
|
|
aliases {
|
|
serial0 = &uart1;
|
|
};
|
|
|
|
uart1: serial@73fbc000 {
|
|
compatible = "fsl,imx51-uart", "fsl,imx21-uart";
|
|
reg = <0x73fbc000 0x4000>;
|
|
interrupts = <31>;
|
|
uart-has-rtscts;
|
|
fsl,dte-mode;
|
|
};
|