diff options
| author | Johan Hovold | 2021-01-25 14:48:12 +0100 |
|---|---|---|
| committer | Johan Hovold | 2021-02-01 10:03:42 +0100 |
| commit | 8cce3bbfb4cffce097c823c29ba487d5a7422d37 (patch) | |
| tree | 9c737647056996b4aefa348f21bfa41c53558d18 /drivers/usb/serial/cp210x.c | |
| parent | 5951b8508855799fbb2d6a9553ab3b7af595ea94 (diff) | |
USB: serial: cp210x: fix modem-control handling
The vendor request used to set the flow-control settings also sets the
state of the modem-control lines.
Add state variables to keep track of the modem-control lines to avoid
always asserting the lines whenever the flow-control settings are
updated.
This specifically also avoids asserting DTR/RTS when opening a port with
the line speed set to B0.
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb/serial/cp210x.c')
| -rw-r--r-- | drivers/usb/serial/cp210x.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 7e4a09b42c99..9378b4bba34b 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -269,6 +269,8 @@ struct cp210x_port_private { struct mutex mutex; bool crtscts; + bool dtr; + bool rts; }; static struct usb_serial_driver cp210x_device = { @@ -1162,7 +1164,10 @@ static void cp210x_set_flow_control(struct tty_struct *tty, ctl_hs &= ~CP210X_SERIAL_DCD_HANDSHAKE; ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY; ctl_hs &= ~CP210X_SERIAL_DTR_MASK; - ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE); + if (port_priv->dtr) + ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE); + else + ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_INACTIVE); if (C_CRTSCTS(tty)) { ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE; @@ -1172,7 +1177,10 @@ static void cp210x_set_flow_control(struct tty_struct *tty, } else { ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE; flow_repl &= ~CP210X_SERIAL_RTS_MASK; - flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE); + if (port_priv->rts) + flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE); + else + flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_INACTIVE); port_priv->crtscts = false; } @@ -1287,25 +1295,29 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port, u16 control = 0; int ret; + mutex_lock(&port_priv->mutex); + if (set & TIOCM_RTS) { + port_priv->rts = true; control |= CONTROL_RTS; control |= CONTROL_WRITE_RTS; } if (set & TIOCM_DTR) { + port_priv->dtr = true; control |= CONTROL_DTR; control |= CONTROL_WRITE_DTR; } if (clear & TIOCM_RTS) { + port_priv->rts = false; control &= ~CONTROL_RTS; control |= CONTROL_WRITE_RTS; } if (clear & TIOCM_DTR) { + port_priv->dtr = false; control &= ~CONTROL_DTR; control |= CONTROL_WRITE_DTR; } - mutex_lock(&port_priv->mutex); - /* * SET_MHS cannot be used to control RTS when auto-RTS is enabled. * Note that RTS is still deasserted when disabling the UART on close. |