From: Nicolas Ferre Date: Mon, 11 May 2015 11:00:31 +0000 (+0200) Subject: tty/serial: at91: RS485 mode: 0 is valid for delay_rts_after_send X-Git-Tag: v3.4.110~58 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9219e070a10f0bb7f7cad215803843ed5b578245;p=thirdparty%2Fkernel%2Fstable.git tty/serial: at91: RS485 mode: 0 is valid for delay_rts_after_send commit 8687634b7908c42eb700e0469e110e02833611d1 upstream. 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 Signed-off-by: Nicolas Ferre Signed-off-by: Greg Kroah-Hartman [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li --- diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index ff58d288c9c88..85c28e325c95f 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -229,8 +229,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) 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"); @@ -305,9 +304,7 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl) if (atmel_port->rs485.flags & SER_RS485_ENABLED) { dev_dbg(port->dev, "Setting UART to RS485\n"); - if ((atmel_port->rs485.delay_rts_after_send) > 0) - UART_PUT_TTGR(port, - atmel_port->rs485.delay_rts_after_send); + UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_after_send); mode |= ATMEL_US_USMODE_RS485; } else { dev_dbg(port->dev, "Setting UART to RS232\n"); @@ -1239,9 +1236,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, if (atmel_port->rs485.flags & SER_RS485_ENABLED) { dev_dbg(port->dev, "Setting UART to RS485\n"); - if ((atmel_port->rs485.delay_rts_after_send) > 0) - UART_PUT_TTGR(port, - atmel_port->rs485.delay_rts_after_send); + UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_after_send); mode |= ATMEL_US_USMODE_RS485; } else { dev_dbg(port->dev, "Setting UART to RS232\n");