diff mbox series

[5.15,046/171] serial: pl011: Fix incorrect rs485 RTS polarity on set_mctrl

Message ID 20220131105231.578810721@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Jan. 31, 2022, 10:55 a.m. UTC 
From: Jochen Mades <jochen@mades.net>

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@vger.kernel.org # v5.15+
Cc: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Jochen Mades <jochen@mades.net>
[lukas: copyedit commit message, add stable designation]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/85fa3323ba8c307943969b7343e23f34c3e652ba.1642909284.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/amba-pl011.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

--- 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);