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Subject[PATCH 4.14 004/121] tty/serial: atmel: Add is_half_duplex helper
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Razvan Stefanescu <razvan.stefanescu@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 <stable@vger.kernel.org>
Signed-off-by: Razvan Stefanescu <razvan.stefanescu@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@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
@@ -238,6 +238,12 @@ static inline void atmel_uart_write_char
__raw_writeb(value, port->membase + ATMEL_US_THR);
}

+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)
{
@@ -489,9 +495,9 @@ 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);
+
}

/*
@@ -508,8 +514,7 @@ 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))
@@ -806,8 +811,7 @@ 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);
}
@@ -1383,8 +1387,7 @@ 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);
}

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