@@ -361,6 +361,7 @@ static void imx_stop_tx(struct uart_port *port)
imx_port_rts_inactive(sport, &temp);
else
imx_port_rts_active(sport, &temp);
+ temp |= UCR2_RXEN;
writel(temp, port->membase + UCR2);
temp = readl(port->membase + UCR4);
@@ -568,6 +569,8 @@ static void imx_start_tx(struct uart_port *port)
imx_port_rts_inactive(sport, &temp);
else
imx_port_rts_active(sport, &temp);
+ if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
+ temp &= ~UCR2_RXEN;
writel(temp, port->membase + UCR2);
/* enable transmitter and shifter empty irq */
@@ -1610,19 +1613,17 @@ static int imx_rs485_config(struct uart_port *port,
struct serial_rs485 *rs485conf)
{
struct imx_port *sport = (struct imx_port *)port;
+ unsigned long temp;
/* unimplemented */
rs485conf->delay_rts_before_send = 0;
rs485conf->delay_rts_after_send = 0;
- rs485conf->flags |= SER_RS485_RX_DURING_TX;
/* RTS is required to control the transmitter */
if (!sport->have_rtscts)
rs485conf->flags &= ~SER_RS485_ENABLED;
if (rs485conf->flags & SER_RS485_ENABLED) {
- unsigned long temp;
-
/* disable transmitter */
temp = readl(sport->port.membase + UCR2);
if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
@@ -1632,6 +1633,14 @@ static int imx_rs485_config(struct uart_port *port,
writel(temp, sport->port.membase + UCR2);
}
+ /* Make sure Rx is enabled in case Tx is active with Rx disabled */
+ if (!(rs485conf->flags & SER_RS485_ENABLED) ||
+ rs485conf->flags & SER_RS485_RX_DURING_TX) {
+ temp = readl(sport->port.membase + UCR2);
+ temp |= UCR2_RXEN;
+ writel(temp, sport->port.membase + UCR2);
+ }
+
port->rs485 = *rs485conf;
return 0;
Some RS-232 to RS-485 transceivers require Rx to be disabled on Tx to avoid echo of Tx data into the Rx buffer. Specifically, the XR3160E RS-232/RS-485/RS-422 transceiver behaves this way. This commit disables Rx on active Tx when SER_RS485_ENABLED is active and SER_RS485_RX_DURING_TX is disabled. Note that this is a change in behavior of the driver. Until now SER_RS485_RX_DURING_TX was enabled unconditionally even when disabled in the TIOCSRS485 ioctl serial_rs485 flags field. Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Baruch Siach <baruch@tkos.co.il> --- v2: * Make Rx enable more robust as Uwe Kleine-König suggested * Expand Cc list --- drivers/tty/serial/imx.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)