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@xxxxxxxxxxxxxx> Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx> --- drivers/tty/serial/imx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 9362f54c816c..333d34ff358c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -361,6 +361,8 @@ static void imx_stop_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); temp = readl(port->membase + UCR4); @@ -568,6 +570,8 @@ 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 */ @@ -1614,7 +1618,6 @@ static int imx_rs485_config(struct uart_port *port, /* 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) -- 2.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
