Commit 885dcb08 authored Jul 10, 2022 by Lino Sanfilippo Committed by Greg Kroah-Hartman Jul 14, 2022

dt_bindings: rs485: Correct delay values



Currently the documentation claims that a maximum of 1000 msecs is allowed
for RTS delays. However nothing actually checks the values read from device
tree/ACPI and so it is possible to set much higher values.

There is already a maximum of 100 ms enforced for RTS delays that are set
via the UART TIOCSRS485 ioctl. To be consistent with that use the same
limit for DT/ACPI values.

Although this change is visible to userspace the risk of breaking anything
when reducing the max delays from 1000 to 100 ms should be very low, since
100 ms is already a very high maximum for delays that are usually rather in
the usecs range.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20220710164442.2958979-7-LinoSanfilippo@gmx.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 4dfd1035

Documentation/devicetree/bindings/serial/rs485.yaml

+2 −2

Original line number	Diff line number	Diff line
		@@ -22,12 +22,12 @@ properties:
		- description: Delay between rts signal and beginning of data sent in
		milliseconds. It corresponds to the delay before sending data.
		default: 0
		maximum: 1000
		maximum: 100
		- description: 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.
		default: 0
		maximum: 1000
		maximum: 100

		rs485-rts-active-low:
		description: drive RTS low when sending (default is high).