From 8687634b7908c42eb700e0469e110e02833611d1 Mon Sep 17 00:00:00 2001
From: Nicolas Ferre <nicolas.ferre@atmel.com>
Date: Mon, 11 May 2015 13:00:31 +0200
Subject: [PATCH] tty/serial: at91: RS485 mode: 0 is valid for
delay_rts_after_send
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In RS485 mode, we may want to set the delay_rts_after_send value to 0.
In the datasheet, the 0 value is said to "disable" the Transmitter Timeguard but
this is exactly the expected behavior if we want no delay...
Moreover, if the value was set to non-zero value by device-tree or earlier
ioctl command, it was impossible to change it back to zero.
Reported-by: Sami Pietikäinen <Sami.Pietikainen@wapice.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable@vger.kernel.org # 3.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/atmel_serial.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index b1fcddd6652acc..2a8f528153e7cf 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -316,8 +316,7 @@ static int atmel_config_rs485(struct uart_port *port,
if (rs485conf->flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
- if ((rs485conf->delay_rts_after_send) > 0)
- UART_PUT_TTGR(port, rs485conf->delay_rts_after_send);
+ UART_PUT_TTGR(port, rs485conf->delay_rts_after_send);
mode |= ATMEL_US_USMODE_RS485;
} else {
dev_dbg(port->dev, "Setting UART to RS232\n");
@@ -355,8 +354,7 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
/* override mode to RS485 if needed, otherwise keep the current mode */
if (port->rs485.flags & SER_RS485_ENABLED) {
- if ((port->rs485.delay_rts_after_send) > 0)
- UART_PUT_TTGR(port, port->rs485.delay_rts_after_send);
+ UART_PUT_TTGR(port, port->rs485.delay_rts_after_send);
mode &= ~ATMEL_US_USMODE;
mode |= ATMEL_US_USMODE_RS485;
}
@@ -2062,8 +2060,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
/* mode */
if (port->rs485.flags & SER_RS485_ENABLED) {
- if ((port->rs485.delay_rts_after_send) > 0)
- UART_PUT_TTGR(port, port->rs485.delay_rts_after_send);
+ UART_PUT_TTGR(port, port->rs485.delay_rts_after_send);
mode |= ATMEL_US_USMODE_RS485;
} else if (termios->c_cflag & CRTSCTS) {
/* RS232 with hardware handshake (RTS/CTS) */
--
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