serial: amba-pl011: drive the bus during break in RS485 mode

In RS485 mode the transceiver is enabled only while data is sent. A
break set with TIOCSBRK therefore never reaches the bus, and protocols
that start each frame with a break, like DMX512, do not work.

Handle an active break like a transmission. Enable the transceiver
before setting the break, after delay_rts_before_send if one is
configured. When the break ends, stop transmitting unless the TX path
is still sending data.

Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>
Link: https://patch.msgid.link/20261013-devel-pl011-rs485-break-v2-1-31c9f80d3e3d@tipi-net.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions