From 2a71de2f7366fb1aec632116d0549ec56d6a3940 Mon Sep 17 00:00:00 2001
From: Lukas Wunner <lukas@wunner.de>
Date: Sat, 21 Oct 2017 10:50:18 +0200
Subject: [PATCH] serial: omap: Fix EFR write on RTS deassertion
Git-commit: 2a71de2f7366fb1aec632116d0549ec56d6a3940
Patch-mainline: v4.15-rc1
References: bsc#1051510

Commit 348f9bb31c56 ("serial: omap: Fix RTS handling") sought to enable
auto RTS upon manual RTS assertion and disable it on deassertion.
However it seems the latter was done incorrectly, it clears all bits in
the Extended Features Register *except* auto RTS.

Fixes: 348f9bb31c56 ("serial: omap: Fix RTS handling")
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/tty/serial/omap-serial.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -693,7 +693,7 @@ static void serial_omap_set_mctrl(struct
 	if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
 		up->efr |= UART_EFR_RTS;
 	else
-		up->efr &= UART_EFR_RTS;
+		up->efr &= ~UART_EFR_RTS;
 	serial_out(up, UART_EFR, up->efr);
 	serial_out(up, UART_LCR, lcr);