[PATCH v2 2/3] USB: serial: cp210x: disable break signalling on CP2105 SCI

Johan Hovold
2023-06-04T12:35:05Z

Only the first UART interface (ECI) on CP2105 supports break signalling.

Return an error on requests for break state changes for the second
interface (SCI) to avoid transmitting a garbage character and waiting
when break is not supported.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/serial/cp210x.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 81e49ed9d147..1e61fe043171 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1437,8 +1437,14 @@ static int cp210x_tiocmget(struct tty_struct *tty)
static int cp210x_break_ctl(struct tty_struct *tty, int break_state)
{
struct usb_serial_port *port = tty->driver_data;
+ struct cp210x_serial_private *priv = usb_get_serial_data(port->serial);
u16 state;

+ if (priv->partnum == CP210X_PARTNUM_CP2105) {
+ if (cp210x_interface_num(port->serial) == 1)
+ return -ENOTTY;
+ }
+
if (break_state == 0)
state = BREAK_OFF;
else
--
2.39.3