linux-kernel - [PATCH v3 03/11] serial: sh-sci: Always set TIOCM_CTS in .get

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Message-Id: <1464948011-377-4-git-send-email-geert+renesas@glider.be>
Date:	Fri,  3 Jun 2016 12:00:03 +0200
From:	Geert Uytterhoeven <geert+renesas@...der.be>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>,
	Peter Hurley <peter@...leysoftware.com>
Cc:	Magnus Damm <magnus.damm@...il.com>,
	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
	Yoshinori Sato <ysato@...rs.sourceforge.jp>,
	linux-serial@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
	linux-sh@...r.kernel.org, linux-kernel@...r.kernel.org,
	Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH v3 03/11] serial: sh-sci: Always set TIOCM_CTS in .get_mctrl() callback

Documentation/serial/driver clearly states:

    If the port does not support CTS, DCD or DSR, the driver should
    indicate that the signal is permanently active.

Hence always set TIOCM_CTS, as we currently don't look at the CTS
hardware line state at all.

FWIW, this fixes the transmit path when hardware-assisted flow control
is enabled, and userspace enables CRTSCTS.
The receive path is still broken, as RTS is never asserted.

Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
Reviewed-by: Peter Hurley <peter@...leysoftware.com>
---
v3:
  - Add Reviewed-by,

v2:
  - Drop RFC status.
---
 drivers/tty/serial/sh-sci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 0130feb069aee02f..135f836642ab1c5a 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1835,9 +1835,9 @@ static unsigned int sci_get_mctrl(struct uart_port *port)
 {
 	/*
 	 * CTS/RTS is handled in hardware when supported, while nothing
-	 * else is wired up. Keep it simple and simply assert DSR/CAR.
+	 * else is wired up. Keep it simple and simply assert CTS/DSR/CAR.
 	 */
-	return TIOCM_DSR | TIOCM_CAR;
+	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 }
 
 static void sci_break_ctl(struct uart_port *port, int break_state)
-- 
1.9.1