USB: RTS/DTR signal patch for airprime driver
I encountered some problems with the airprime driver in use with a Novatel
Merlin XU870:
Closing an open Connection to e.g. /dev/ttyUSB0 doesn't reset the
RTS/DTR lines of the Modem. Consequently, when I use minicom to
establish a connection by "ATD*99#" the modem doesn't hang up even if i
exit minicom and so I cannot reuse the modem unless I remove it and plug
it in again.
With the attached patch, the RTS/DTR lines are resetted on a close. The
code was mainly taken from the option.c driver.
diff --git a/drivers/usb/serial/airprime.c b/drivers/usb/serial/airprime.c
index 18816bf..310a8b5 100644
--- a/drivers/usb/serial/airprime.c
+++ b/drivers/usb/serial/airprime.c
@@ -44,8 +44,43 @@
int outstanding_urbs;
int throttled;
struct urb *read_urbp[NUM_READ_URBS];
+
+ /* Settings for the port */
+ int rts_state; /* Handshaking pins (outputs) */
+ int dtr_state;
+ int cts_state; /* Handshaking pins (inputs) */
+ int dsr_state;
+ int dcd_state;
+ int ri_state;
};
+static int airprime_send_setup(struct usb_serial_port *port)
+{
+ struct usb_serial *serial = port->serial;
+ struct airprime_private *priv;
+
+ dbg("%s", __FUNCTION__);
+
+ if (port->number != 0)
+ return 0;
+
+ priv = usb_get_serial_port_data(port);
+
+ if (port->tty) {
+ int val = 0;
+ if (priv->dtr_state)
+ val |= 0x01;
+ if (priv->rts_state)
+ val |= 0x02;
+
+ return usb_control_msg(serial->dev,
+ usb_rcvctrlpipe(serial->dev, 0),
+ 0x22,0x21,val,0,NULL,0,USB_CTRL_SET_TIMEOUT);
+ }
+
+ return 0;
+}
+
static void airprime_read_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
@@ -118,6 +153,10 @@
usb_set_serial_port_data(port, priv);
}
+ /* Set some sane defaults */
+ priv->rts_state = 1;
+ priv->dtr_state = 1;
+
for (i = 0; i < NUM_READ_URBS; ++i) {
buffer = kmalloc(buffer_size, GFP_KERNEL);
if (!buffer) {
@@ -151,6 +190,9 @@
/* remember this urb so we can kill it when the port is closed */
priv->read_urbp[i] = urb;
}
+
+ airprime_send_setup(port);
+
goto out;
errout:
@@ -176,6 +218,11 @@
dbg("%s - port %d", __FUNCTION__, port->number);
+ priv->rts_state = 0;
+ priv->dtr_state = 0;
+
+ airprime_send_setup(port);
+
for (i = 0; i < NUM_READ_URBS; ++i) {
usb_kill_urb (priv->read_urbp[i]);
kfree (priv->read_urbp[i]->transfer_buffer);
