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sc16is7xx: expose RTS inversion in RS-485 mode

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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>
This commit is contained in:
Jakub Kicinski 2015-03-31 21:11:40 +02:00 committed by Greg Kroah-Hartman
parent 6a8bc239a8
commit f0e381158a
1 changed files with 25 additions and 9 deletions
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30
drivers/tty/serial/sc16is7xx.c
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@ -831,14 +831,30 @@ static void sc16is7xx_set_termios(struct uart_port *port,
static int sc16is7xx_config_rs485(struct uart_port *port,
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);
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
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_AUTO_RS485_BIT,
0);
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;