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Diffstat (limited to 'drivers/tty/serial/imx.c')
-rw-r--r--drivers/tty/serial/imx.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index f8962a3d4..573bf7e9b 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -496,8 +496,7 @@ static void imx_uart_stop_tx(struct uart_port *port)
}
}
-/* called with port.lock taken and irqs off */
-static void imx_uart_stop_rx(struct uart_port *port)
+static void imx_uart_stop_rx_with_loopback_ctrl(struct uart_port *port, bool loopback)
{
struct imx_port *sport = (struct imx_port *)port;
u32 ucr1, ucr2, ucr4, uts;
@@ -519,7 +518,7 @@ static void imx_uart_stop_rx(struct uart_port *port)
/* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
if (port->rs485.flags & SER_RS485_ENABLED &&
port->rs485.flags & SER_RS485_RTS_ON_SEND &&
- sport->have_rtscts && !sport->have_rtsgpio) {
+ sport->have_rtscts && !sport->have_rtsgpio && loopback) {
uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
uts |= UTS_LOOP;
imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
@@ -532,6 +531,16 @@ static void imx_uart_stop_rx(struct uart_port *port)
}
/* called with port.lock taken and irqs off */
+static void imx_uart_stop_rx(struct uart_port *port)
+{
+ /*
+ * Stop RX and enable loopback in order to make sure RS485 bus
+ * is not blocked. Se comment in imx_uart_probe().
+ */
+ imx_uart_stop_rx_with_loopback_ctrl(port, true);
+}
+
+/* called with port.lock taken and irqs off */
static void imx_uart_enable_ms(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
@@ -719,8 +728,13 @@ static void imx_uart_start_tx(struct uart_port *port)
imx_uart_rts_inactive(sport, &ucr2);
imx_uart_writel(sport, ucr2, UCR2);
+ /*
+ * Since we are about to transmit we can not stop RX
+ * with loopback enabled because that will make our
+ * transmitted data being just looped to RX.
+ */
if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
- imx_uart_stop_rx(port);
+ imx_uart_stop_rx_with_loopback_ctrl(port, false);
sport->tx_state = WAIT_AFTER_RTS;