From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Kicinski Subject: [PATCH 3/4] sc16is7xx: expose RTS inversion in RS-485 mode Date: Tue, 17 Mar 2015 00:28:48 +0100 Message-ID: <1426548529-21738-4-git-send-email-moorray3@wp.pl> References: <1426548529-21738-1-git-send-email-moorray3@wp.pl> Return-path: In-Reply-To: <1426548529-21738-1-git-send-email-moorray3-5tc4TXWwyLM@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Greg Kroah-Hartman Cc: Jon Ringle , linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, =?UTF-8?q?Karol=20D=C4=99bog=C3=B3rski?= , Jakub Kicinski List-Id: linux-serial@vger.kernel.org From: Jakub Kicinski 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 --- drivers/tty/serial/sc16is7xx.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index e6b396e584f3..24902d589b07 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -829,16 +829,30 @@ 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 + return -EINVAL; + } + + sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr); + port->rs485 = *rs485; return 0; -- 2.1.0