[PATCH 1/5] USB: serial: cp210x: Fixed RTS mode setting by the CRTSCTS flag.

From: Konstantin Shkolnyy
Date: Mon Mar 21 2016 - 19:35:29 EST


A bug in the CRTSCT handling caused RTS to alternate between
CRTSCTS=0 => "RTS transmits active signal" and
CRTSCTS=1 => "RTS receives flow control"
instead of
CRTSCTS=0 => "RTS is statically active" and
CRTSCTS=1 => "RTS receives flow control"

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@xxxxxxxxx>
---
drivers/usb/serial/cp210x.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index c740592..de1606f 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -955,16 +955,12 @@ static void cp210x_set_termios(struct tty_struct *tty,
modem_ctl[0] &= ~0x7B;
modem_ctl[0] |= 0x09;
modem_ctl[4] = 0x80;
- /* FIXME - why clear reserved bits just read? */
- modem_ctl[5] = 0;
- modem_ctl[6] = 0;
modem_ctl[7] = 0;
dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
} else {
modem_ctl[0] &= ~0x7B;
modem_ctl[0] |= 0x01;
- /* FIXME - OR here instead of assignment looks wrong */
- modem_ctl[4] |= 0x40;
+ modem_ctl[4] = 0x40;
dev_dbg(dev, "%s - flow control = NONE\n", __func__);
}

--
1.8.4.5