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| author |   Rafael Gago <rafael.gago@gmail.com> | 2017-07-31 10:46:42 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-28 20:51:20 +0200 |
| commit | a6845e1e1b781933ed7f54919f5ea4a108d1b9f2 (patch) | |
| tree | ee9aeb8d87596db4032ec82f35f112ce6d64a8e0 /drivers/tty | |
| parent | tty: serial: 8250_mtk: Use PTR_ERR_OR_ZERO (diff) | |
| download | linux-dev-a6845e1e1b781933ed7f54919f5ea4a108d1b9f2.tar.xz linux-dev-a6845e1e1b781933ed7f54919f5ea4a108d1b9f2.zip | |
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: Rafael Gago Castano <rgc@hms.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -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); } |