diff options
Diffstat (limited to 'drivers/tty/serial/serial_core.c')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 220e1d088c9b..3a14cccbd7ff 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -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); } |