[PATCH 4.15 48/55] serial: imx: Only wakeup via RTSDEN bit if the system has RTS/CTS

From: Greg Kroah-Hartman
Date: Fri Feb 02 2018 - 12:37:08 EST


4.15-stable review patch. If anyone has any objections, please let me know.

------------------

From: Fabio Estevam <fabio.estevam@xxxxxxx>

commit 38b1f0fb42f772b8c9aac53593883a18ff5eb9d7 upstream.

The wakeup mechanism via RTSDEN bit relies on the system using the RTS/CTS
lines, so only allow such wakeup method when the system actually has
RTS/CTS support.

Fixes: bc85734b126f ("serial: imx: allow waking up on RTSD")
Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
Reviewed-by: Martin Kaiser <martin@xxxxxxxxx>
Acked-by: Fugang Duan <fugang.duan@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/tty/serial/imx.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2238,12 +2238,14 @@ static void serial_imx_enable_wakeup(str
val &= ~UCR3_AWAKEN;
writel(val, sport->port.membase + UCR3);

- val = readl(sport->port.membase + UCR1);
- if (on)
- val |= UCR1_RTSDEN;
- else
- val &= ~UCR1_RTSDEN;
- writel(val, sport->port.membase + UCR1);
+ if (sport->have_rtscts) {
+ val = readl(sport->port.membase + UCR1);
+ if (on)
+ val |= UCR1_RTSDEN;
+ else
+ val &= ~UCR1_RTSDEN;
+ writel(val, sport->port.membase + UCR1);
+ }
}

static int imx_serial_port_suspend_noirq(struct device *dev)