From: Jochen Mades jochen@mades.net
commit 62f676ff7898f6c1bd26ce014564773a3dc00601 upstream.
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 LinoSanfilippo@gmx.de Signed-off-by: Jochen Mades jochen@mades.net [lukas: copyedit commit message, add stable designation] Signed-off-by: Lukas Wunner lukas@wunner.de Link: https://lore.kernel.org/r/85fa3323ba8c307943969b7343e23f34c3e652ba.164290928... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/amba-pl011.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1615,8 +1615,12 @@ static void pl011_set_mctrl(struct uart_ 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);