serial: 8250: Make em485_rts_after_send() set mctrl
From: Giulio Benetti <giulio.benetti@...> Date: Fri, 1 Jun 2018 14:40:20 +0200
Commit-Message
When rs485 enabled and RTS_AFTER_SEND set on startup, need to preserve mctrl status, because later functions will call set_mctrl passing port->mctrl=0 overriding rts status, resulting in rts pin in transmission when idle. Make mctrl reflect rts pin state. Signed-off-by: Giulio Benetti <giulio.benetti@...> Signed-off-by: Heiko Stuebner <heiko.stuebner@...>
Patch-Comment
drivers/tty/serial/8250/8250_port.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
Statistics
- 5 lines added
- 2 lines removed
Changes
--------------------- drivers/tty/serial/8250/8250_port.c ----------------------
index 8407166610ce..67aa3a2a9afa 100644
@@ -565,10 +565,13 @@ static inline void serial8250_em485_rts_after_send(struct uart_8250_port *p)
{
unsigned char mcr = serial8250_in_MCR(p);
+ if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND) {
mcr |= UART_MCR_RTS;
+ p->port.mctrl |= TIOCM_RTS;
+ } else {
mcr &= ~UART_MCR_RTS;
+ p->port.mctrl &= ~TIOCM_RTS;
+ }
serial8250_out_MCR(p, mcr);
}