From 8ca8d14cd1c6bf9c1eb33040b9b899b245326d04 Mon Sep 17 00:00:00 2001 From: Giulio Benetti Date: Fri, 1 Jun 2018 14:40:20 +0200 Subject: [PATCH 1/7] serial: 8250: Make em485_rts_after_send() set mctrl according to rts state. 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 Signed-off-by: Heiko Stuebner --- drivers/tty/serial/8250/8250_port.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 8407166610ce..67aa3a2a9afa 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -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) + if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND) { mcr |= UART_MCR_RTS; - else + p->port.mctrl |= TIOCM_RTS; + } else { mcr &= ~UART_MCR_RTS; + p->port.mctrl &= ~TIOCM_RTS; + } serial8250_out_MCR(p, mcr); } -- 2.24.1