atmel_serial: RS485: receiving enabled when sending data

By default the atmel_serial driver in RS485 mode disables receiving data until
all data in the send buffer has been sent. This flag allows to receive data
even whilst sending data.

Signed-off-by: Bernhard Roth <br@pwrnet.de>
Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt
index a493238..c8878f8 100644 (file)
--- a/Documentation/serial/serial-rs485.txt
+++ b/Documentation/serial/serial-rs485.txt
@@ -104,6 +104,9 @@
        rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
        rs485conf.delay_rts_after_send = ...;
 
+       /* Set this flag if you want to receive data even whilst sending data */
+       rs485conf.flags |= SER_RS485_RX_DURING_TX;
+
        if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) {
                /* Error handling. See errno. */
        }

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index af9b781..c7232a9 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -339,7 +339,8 @@ static void atmel_stop_tx(struct uart_port *port)
        /* Disable interrupts */
        UART_PUT_IDR(port, atmel_port->tx_done_mask);
 
-       if (atmel_port->rs485.flags & SER_RS485_ENABLED)
+       if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
+           !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX))
                atmel_start_rx(port);
 }
 
@@ -356,7 +357,8 @@ static void atmel_start_tx(struct uart_port *port)
                           really need this.*/
                        return;
 
-               if (atmel_port->rs485.flags & SER_RS485_ENABLED)
+               if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
+                   !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX))
                        atmel_stop_rx(port);
 
                /* re-enable PDC transmit */
@@ -680,7 +682,8 @@ static void atmel_tx_dma(struct uart_port *port)
                /* Enable interrupts */
                UART_PUT_IER(port, atmel_port->tx_done_mask);
        } else {
-               if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
+               if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
+                   !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) {
                        /* DMA done, stop TX, start RX for RS485 */
                        atmel_start_rx(port);
                }

diff --git a/include/linux/serial.h b/include/linux/serial.h
index ef91406..97ff8e2 100644 (file)
--- a/include/linux/serial.h
+++ b/include/linux/serial.h
@@ -211,6 +211,7 @@ struct serial_rs485 {
 #define SER_RS485_RTS_ON_SEND          (1 << 1)
 #define SER_RS485_RTS_AFTER_SEND       (1 << 2)
 #define SER_RS485_RTS_BEFORE_SEND      (1 << 3)
+#define SER_RS485_RX_DURING_TX         (1 << 4)
        __u32   delay_rts_before_send;  /* Milliseconds */
        __u32   delay_rts_after_send;   /* Milliseconds */
        __u32   padding[5];             /* Memory is cheap, new structs