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Commit f0e38115 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Greg Kroah-Hartman
Browse files

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: default avatarJakub Kicinski <kubakici@wp.pl>
Signed-off-by: default avatarJon Ringle <jringle@gridpoint.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6a8bc239

drivers/tty/serial/sc16is7xx.c

+25 −9
Original line number Diff line number Diff line
@@ -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;