From 62f676ff7898f6c1bd26ce014564773a3dc00601 Mon Sep 17 00:00:00 2001 From: Jochen Mades Date: Sat, 23 Jan 2021 05:10:14 +0100 Subject: serial: pl011: Fix incorrect rs485 RTS polarity on set_mctrl Commit 8d479237727c ("serial: amba-pl011: add RS485 support") sought to keep RTS deasserted on set_mctrl if rs485 is enabled. However it did so only if deasserted RTS polarity is high. Fix it in case it's low. Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support") Cc: stable@vger.kernel.org # v5.15+ Cc: Lino Sanfilippo Signed-off-by: Jochen Mades [lukas: copyedit commit message, add stable designation] Signed-off-by: Lukas Wunner Link: https://lore.kernel.org/r/85fa3323ba8c307943969b7343e23f34c3e652ba.1642909284.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/amba-pl011.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 1f1df46242f9..f64c475a1379 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1582,8 +1582,12 @@ static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) container_of(port, struct uart_amba_port, port); unsigned int cr; - if (port->rs485.flags & SER_RS485_ENABLED) - mctrl &= ~TIOCM_RTS; + if (port->rs485.flags & SER_RS485_ENABLED) { + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + mctrl &= ~TIOCM_RTS; + else + mctrl |= TIOCM_RTS; + } cr = pl011_read(uap, REG_CR); -- cgit