Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a6845e1e authored by Rafael Gago's avatar Rafael Gago Committed by Greg Kroah-Hartman
Browse files

serial: core: Consider rs485 settings to drive RTS 



Previously the rs485 settings weren't considered when setting the RTS
line, so e.g. closing and reopening a port made serial_core to drive
the line as if rs485 was disabled.

This patch fixes those issues.

Signed-off-by: default avatarRafael Gago Castano <rgc@hms.se>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d77dc47f

drivers/tty/serial/serial_core.c

+25 −9
Original line number Diff line number Diff line
@@ -165,6 +165,27 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear) 
#define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)

#define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)



static void uart_port_dtr_rts(struct uart_port *uport, int raise)

{

	int rs485_on = uport->rs485_config &&

		(uport->rs485.flags & SER_RS485_ENABLED);

	int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);



	if (raise) {

		if (rs485_on && !RTS_after_send) {

			uart_set_mctrl(uport, TIOCM_DTR);

			uart_clear_mctrl(uport, TIOCM_RTS);

		} else {

			uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);

		}

	} else {

		unsigned int clear = TIOCM_DTR;



		clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;

		uart_clear_mctrl(uport, clear);

	}

}



/*

 * Startup the port.  This will be called once per open.  All calls

 * will be serialised by the per-port mutex.
@@ -214,7 +235,7 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, 
		 * port is open and ready to respond.

		 */

		if (init_hw && C_BAUD(tty))

			uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);

			uart_port_dtr_rts(uport, 1);

	}



	/*
@@ -272,7 +293,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) 
			uport->cons->cflag = tty->termios.c_cflag;



		if (!tty || C_HUPCL(tty))

			uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);

			uart_port_dtr_rts(uport, 0);



		uart_port_shutdown(port);

	}
@@ -1658,7 +1679,7 @@ static int uart_carrier_raised(struct tty_port *port) 
	return 0;

}



static void uart_dtr_rts(struct tty_port *port, int onoff)

static void uart_dtr_rts(struct tty_port *port, int raise)

{

	struct uart_state *state = container_of(port, struct uart_state, port);

	struct uart_port *uport;
@@ -1666,12 +1687,7 @@ static void uart_dtr_rts(struct tty_port *port, int onoff) 
	uport = uart_port_ref(state);

	if (!uport)

		return;



	if (onoff)

		uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);

	else

		uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);



	uart_port_dtr_rts(uport, raise);

	uart_port_deref(uport);

}