From: "Christoph Vogtländer" <Christoph.Vogtlaender@sigma-surface-science.com>
To: unlisted-recipients:; (no To-header on input)
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Jiri Slaby" <jslaby@suse.com>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Christoph Vogtländer"
<Christoph.Vogtlaender@sigma-surface-science.com>
Subject: [PATCH] serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control
Date: Fri, 30 Aug 2019 09:58:41 +0000 [thread overview]
Message-ID: <bd9fb8e75d0e45218eb110c25bb539ef@SSSDEEX.i.sigma-surface-science.com> (raw)
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
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next reply other threads:[~2019-08-30 10:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-30 9:58 Christoph Vogtländer [this message]
2019-09-04 7:30 ` [PATCH] serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control Greg Kroah-Hartman
2019-09-04 12:17 ` Christoph Vogtländer
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