From: Konstantin Shkolnyy <konstantin.shkolnyy@gmail.com>
Date: Wed, 4 May 2016 21:56:52 +0000 (-0500)
Subject: USB: serial: cp210x: fix hardware flow-control disable
X-Git-Tag: v4.7-rc1~93^2^2~11
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a377f9e906af4df9071ba8ddba60188cb4013d93;p=karo-tx-linux.git

USB: serial: cp210x: fix hardware flow-control disable

A bug in the CRTSCTS handling caused RTS to alternate between

CRTSCTS=0 => "RTS is transmit active signal" and
CRTSCTS=1 => "RTS is used for receive flow control"

instead of

CRTSCTS=0 => "RTS is statically active" and
CRTSCTS=1 => "RTS is used for receive flow control"

This only happened after first having enabled CRTSCTS.

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@gmail.com>
Fixes: 39a66b8d22a3 ("[PATCH] USB: CP2101 Add support for flow control")
Cc: stable <stable@vger.kernel.org>
[johan: reword commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>
---

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index dd47823bb014..fef7a512bff4 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -967,8 +967,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
 		} else {
 			modem_ctl[0] &= ~0x7B;
 			modem_ctl[0] |= 0x01;
-			/* FIXME - OR here instead of assignment looks wrong */
-			modem_ctl[4] |= 0x40;
+			modem_ctl[4] = 0x40;
 			dev_dbg(dev, "%s - flow control = NONE\n", __func__);
 		}