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Date: Wed, 6 Jun 2018 11:49:39 +0200
From: Giulio Benetti <giulio.benetti@...ronovasrl.com>
To: unlisted-recipients:; (no To-header on input)
Cc: matwey.kornilov@...il.com,
Giulio Benetti <giulio.benetti@...ronovasrl.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jslaby@...e.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Matthias Brugger <mbrugger@...e.com>,
Kees Cook <keescook@...omium.org>, Sean Young <sean@...s.org>,
linux-serial@...r.kernel.org (open list:SERIAL DRIVERS),
linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 4/4] serial: core: Mask mctrl with TIOCM_RTS too if rs485 on and RTS_AFTER_SEND set.
If rs485 is enabled and RTS_AFTER_SEND is set on startup need to keep
TIOCM_RTS asserted to keep rs485 transceiver in RX when idle.
Check if rs485 is on and RTS_AFTER_SEND is set and mask port->mctrl with
TIOCM_RTS too and not only TIOCM_DTR.
Signed-off-by: Giulio Benetti <giulio.benetti@...ronovasrl.com>
---
drivers/tty/serial/serial_core.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 0466f9f08a91..06d9441f6d20 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2288,6 +2288,16 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
if (port->type != PORT_UNKNOWN) {
unsigned long flags;
+ int rs485_on = port->rs485_config &&
+ (port->rs485.flags & SER_RS485_ENABLED);
+ int RTS_after_send = !!(port->rs485.flags &
+ SER_RS485_RTS_AFTER_SEND);
+ int mctrl;
+
+ if (rs485_on && RTS_after_send)
+ mctrl = port->mctrl & (TIOCM_DTR | TIOCM_RTS);
+ else
+ mctrl = port->mctrl & TIOCM_DTR;
uart_report_port(drv, port);
@@ -2300,7 +2310,7 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
* We probably don't need a spinlock around this, but
*/
spin_lock_irqsave(&port->lock, flags);
- port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
+ port->ops->set_mctrl(port, mctrl);
spin_unlock_irqrestore(&port->lock, flags);
/*
--
2.17.1
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