linux-kernel - [PATCH v2 1/3] tty: serial: lpuart: Remove unnecessary code from set

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Message-ID: <20191017141428.10330-1-philippe.schenker@toradex.com>
Date:   Thu, 17 Oct 2019 14:14:38 +0000
From:   Philippe Schenker <philippe.schenker@...adex.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>
CC:     Max Krummenacher <max.krummenacher@...adex.com>,
        Jiri Slaby <jslaby@...e.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Fugang Duan <fugang.duan@....com>,
        Stefan Agner <stefan@...er.ch>,
        "linux-imx@....com" <linux-imx@....com>,
        Andrey Smirnov <andrew.smirnov@...il.com>,
        Philippe Schenker <philippe.schenker@...adex.com>
Subject: [PATCH v2 1/3] tty: serial: lpuart: Remove unnecessary code from
 set_mctrl

Currently flow control is not working due to lpuart32_set_mctrl that is
clearing TXCTSE bit in all cases. This bit gets earlier setup by
lpuart32_set_termios.

As I read in Documentation set_mctrl is also not meant for hardware
flow control rather than gpio setting and clearing a RTS signal.
Therefore I guess it is safe to remove the whole code in
lpuart32_set_mctrl.

This was tested with console on a i.MX8QXP SoC.

Signed-off-by: Philippe Schenker <philippe.schenker@...adex.com>
Reviewed-by: Fugang Duan <fugang.duan@....com>

---

Changes in v2:
- Added Fugang Duan's review

 drivers/tty/serial/fsl_lpuart.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 537896c4d887..f3271857621c 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1333,18 +1333,7 @@ static void lpuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 
 static void lpuart32_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
-	unsigned long temp;
-
-	temp = lpuart32_read(port, UARTMODIR) &
-			~(UARTMODIR_RXRTSE | UARTMODIR_TXCTSE);
-
-	if (mctrl & TIOCM_RTS)
-		temp |= UARTMODIR_RXRTSE;
-
-	if (mctrl & TIOCM_CTS)
-		temp |= UARTMODIR_TXCTSE;
 
-	lpuart32_write(port, temp, UARTMODIR);
 }
 
 static void lpuart_break_ctl(struct uart_port *port, int break_state)
-- 
2.23.0