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From: "Christoph Vogtländer" <c.vogtlaender@sigma-surface-science.com>
To: unlisted-recipients:; (no To-header on input)
Cc: "Christoph Vogtländer" <c.vogtlaender@sigma-surface-science.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jiri Slaby" <jslaby@suse.com>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control
Date: Wed,  4 Sep 2019 14:17:46 +0200	[thread overview]
Message-ID: <20190904121746.4641-1-c.vogtlaender@sigma-surface-science.com> (raw)
In-Reply-To: <20190904073022.GB9729@kroah.com>

As documented in the data-sheet, the transmitter must be disabled before
activating AutoCTS or auto transmitter flow control. Accordingly, the
transmitter must be enabled after AutoCTS or auto transmitter flow
control gets deactivated.

Signed-off-by: Christoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
---
 drivers/tty/serial/max310x.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index fb5a7e0e58e9..adfef6dae4a7 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -860,6 +860,15 @@ static void max310x_set_termios(struct uart_port *port,
 	max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
 	max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
 
+	/* Disable transmitter before enabling AutoCTS or auto transmitter
+	 * flow control
+	 */
+	if (termios->c_cflag & CRTSCTS || termios->c_iflag & IXOFF) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TXDIS_BIT,
+				    MAX310X_MODE1_TXDIS_BIT);
+	}
+
 	port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
 
 	if (termios->c_cflag & CRTSCTS) {
@@ -878,6 +887,15 @@ static void max310x_set_termios(struct uart_port *port,
 	}
 	max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
 
+	/* Enable transmitter after disabling AutoCTS and auto transmitter
+	 * flow control
+	 */
+	if (!(termios->c_cflag & CRTSCTS) && !(termios->c_iflag & IXOFF)) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TXDIS_BIT,
+				    0);
+	}
+
 	/* Get baud rate generator configuration */
 	baud = uart_get_baud_rate(port, termios, old,
 				  port->uartclk / 16 / 0xffff,
-- 
2.22.1


WARNING: multiple messages have this Message-ID (diff)
From: "Christoph Vogtländer" <c.vogtlaender@sigma-surface-science.com>
Cc: "Christoph Vogtländer" <c.vogtlaender@sigma-surface-science.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jiri Slaby" <jslaby@suse.com>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control
Date: Wed,  4 Sep 2019 14:17:46 +0200	[thread overview]
Message-ID: <20190904121746.4641-1-c.vogtlaender@sigma-surface-science.com> (raw)
In-Reply-To: <20190904073022.GB9729@kroah.com>

As documented in the data-sheet, the transmitter must be disabled before
activating AutoCTS or auto transmitter flow control. Accordingly, the
transmitter must be enabled after AutoCTS or auto transmitter flow
control gets deactivated.

Signed-off-by: Christoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
---
 drivers/tty/serial/max310x.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index fb5a7e0e58e9..adfef6dae4a7 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -860,6 +860,15 @@ static void max310x_set_termios(struct uart_port *port,
 	max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
 	max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
 
+	/* Disable transmitter before enabling AutoCTS or auto transmitter
+	 * flow control
+	 */
+	if (termios->c_cflag & CRTSCTS || termios->c_iflag & IXOFF) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TXDIS_BIT,
+				    MAX310X_MODE1_TXDIS_BIT);
+	}
+
 	port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
 
 	if (termios->c_cflag & CRTSCTS) {
@@ -878,6 +887,15 @@ static void max310x_set_termios(struct uart_port *port,
 	}
 	max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
 
+	/* Enable transmitter after disabling AutoCTS and auto transmitter
+	 * flow control
+	 */
+	if (!(termios->c_cflag & CRTSCTS) && !(termios->c_iflag & IXOFF)) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TXDIS_BIT,
+				    0);
+	}
+
 	/* Get baud rate generator configuration */
 	baud = uart_get_baud_rate(port, termios, old,
 				  port->uartclk / 16 / 0xffff,
-- 
2.22.1

  reply	other threads:[~2019-09-04 12:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-30  9:58 [PATCH] serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control Christoph Vogtländer
2019-08-30  9:58 ` Christoph Vogtländer
2019-09-04  7:30 ` Greg Kroah-Hartman
2019-09-04 12:17   ` Christoph Vogtländer [this message]
2019-09-04 12:17     ` Christoph Vogtländer

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