[PATCH 4.9 05/91] tty/serial: atmel: Add is_half_duplex helper

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Razvan Stefanescu <razvan.stefane...@microchip.com>

commit f3040983132bf3477acd45d2452a906e67c2fec9 upstream.

Use a helper function to check that a port needs to use half duplex
communication, replacing several occurrences of multi-line bit checking.

Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX 
after TX is done")
Cc: stable <sta...@vger.kernel.org>
Signed-off-by: Razvan Stefanescu <razvan.stefane...@microchip.com>
Acked-by: Richard Genoud <richard.gen...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>


---
 drivers/tty/serial/atmel_serial.c |   19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -241,6 +241,12 @@ static inline void atmel_uart_write_char
 
 #endif
 
+static inline int atmel_uart_is_half_duplex(struct uart_port *port)
+{
+       return (port->rs485.flags & SER_RS485_ENABLED) &&
+               !(port->rs485.flags & SER_RS485_RX_DURING_TX);
+}
+
 #ifdef CONFIG_SERIAL_ATMEL_PDC
 static bool atmel_use_pdc_rx(struct uart_port *port)
 {
@@ -492,9 +498,9 @@ static void atmel_stop_tx(struct uart_po
        /* Disable interrupts */
        atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
 
-       if ((port->rs485.flags & SER_RS485_ENABLED) &&
-           !(port->rs485.flags & SER_RS485_RX_DURING_TX))
+       if (atmel_uart_is_half_duplex(port))
                atmel_start_rx(port);
+
 }
 
 /*
@@ -511,8 +517,7 @@ static void atmel_start_tx(struct uart_p
                return;
 
        if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
-               if ((port->rs485.flags & SER_RS485_ENABLED) &&
-                   !(port->rs485.flags & SER_RS485_RX_DURING_TX))
+               if (atmel_uart_is_half_duplex(port))
                        atmel_stop_rx(port);
 
        if (atmel_use_pdc_tx(port))
@@ -809,8 +814,7 @@ static void atmel_complete_tx_dma(void *
         */
        if (!uart_circ_empty(xmit))
                atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
-       else if ((port->rs485.flags & SER_RS485_ENABLED) &&
-                !(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
+       else if (atmel_uart_is_half_duplex(port)) {
                /* DMA done, stop TX, start RX for RS485 */
                atmel_start_rx(port);
        }
@@ -1386,8 +1390,7 @@ static void atmel_tx_pdc(struct uart_por
                atmel_uart_writel(port, ATMEL_US_IER,
                                  atmel_port->tx_done_mask);
        } else {
-               if ((port->rs485.flags & SER_RS485_ENABLED) &&
-                   !(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
+               if (atmel_uart_is_half_duplex(port)) {
                        /* DMA done, stop TX, start RX for RS485 */
                        atmel_start_rx(port);
                }