diff options
| author | Jakub Kicinski <kubakici@wp.pl> | 2015-03-31 22:11:40 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-04-10 15:43:48 +0300 |
| commit | f0e381158a95a63a283be4cde64795d37e32134b (patch) | |
| tree | 5be606cfaaae79b833e7750721db08e172064784 /drivers/tty/serial/sc16is7xx.c | |
| parent | 6a8bc239a8c3e6ad34fceabb61ff8ec6222dad4e (diff) | |
| download | linux-f0e381158a95a63a283be4cde64795d37e32134b.tar.xz | |
sc16is7xx: expose RTS inversion in RS-485 mode
Hardware is capable of inverting RTS signal when working
in RS-485 mode. Expose this functionality to user space.
Relay on a matching combination of standard flags
(SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND) to
detect when user space is requesting inverted RTS mode.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Jon Ringle <jringle@gridpoint.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/sc16is7xx.c')
| -rw-r--r-- | drivers/tty/serial/sc16is7xx.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 36b3c266925d..468354ef7baa 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -829,16 +829,32 @@ static void sc16is7xx_set_termios(struct uart_port *port, } static int sc16is7xx_config_rs485(struct uart_port *port, - struct serial_rs485 *rs485) + struct serial_rs485 *rs485) { - if (port->rs485.flags & SER_RS485_ENABLED) - sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, - SC16IS7XX_EFCR_AUTO_RS485_BIT, - SC16IS7XX_EFCR_AUTO_RS485_BIT); - else - sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, - SC16IS7XX_EFCR_AUTO_RS485_BIT, - 0); + const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT | + SC16IS7XX_EFCR_RTS_INVERT_BIT; + u32 efcr = 0; + + if (rs485->flags & SER_RS485_ENABLED) { + bool rts_during_rx, rts_during_tx; + + rts_during_rx = rs485->flags & SER_RS485_RTS_AFTER_SEND; + rts_during_tx = rs485->flags & SER_RS485_RTS_ON_SEND; + + efcr |= SC16IS7XX_EFCR_AUTO_RS485_BIT; + + if (!rts_during_rx && rts_during_tx) + /* default */; + else if (rts_during_rx && !rts_during_tx) + efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT; + else + dev_err(port->dev, + "unsupported RTS signalling on_send:%d after_send:%d - exactly one of RS485 RTS flags should be set\n", + rts_during_tx, rts_during_rx); + } + + sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr); + port->rs485 = *rs485; return 0; |