This is a note to let you know that I've just added the patch titled
serial: pl011: Fix incorrect rs485 RTS polarity on set_mctrl
to the 5.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-pl011-fix-incorrect-rs485-rts-polarity-on-set_mctrl.patch
and it can be found in the queue-5.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 62f676ff7898f6c1bd26ce014564773a3dc00601 Mon Sep 17 00:00:00 2001
From: Jochen Mades <jochen@xxxxxxxxx>
Date: Sat, 23 Jan 2021 05:10:14 +0100
Subject: serial: pl011: Fix incorrect rs485 RTS polarity on set_mctrl
From: Jochen Mades <jochen@xxxxxxxxx>
commit 62f676ff7898f6c1bd26ce014564773a3dc00601 upstream.
Commit 8d479237727c ("serial: amba-pl011: add RS485 support") sought to
keep RTS deasserted on set_mctrl if rs485 is enabled. However it did so
only if deasserted RTS polarity is high. Fix it in case it's low.
Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support")
Cc: stable@xxxxxxxxxxxxxxx # v5.15+
Cc: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
Signed-off-by: Jochen Mades <jochen@xxxxxxxxx>
[lukas: copyedit commit message, add stable designation]
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Link: https://lore.kernel.org/r/85fa3323ba8c307943969b7343e23f34c3e652ba.1642909284.git.lukas@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/amba-pl011.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1615,8 +1615,12 @@ static void pl011_set_mctrl(struct uart_
container_of(port, struct uart_amba_port, port);
unsigned int cr;
- if (port->rs485.flags & SER_RS485_ENABLED)
- mctrl &= ~TIOCM_RTS;
+ if (port->rs485.flags & SER_RS485_ENABLED) {
+ if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
+ mctrl &= ~TIOCM_RTS;
+ else
+ mctrl |= TIOCM_RTS;
+ }
cr = pl011_read(uap, REG_CR);
Patches currently in stable-queue which might be from jochen@xxxxxxxxx are
queue-5.16/serial-pl011-fix-incorrect-rs485-rts-polarity-on-set_mctrl.patch
