USB: cdc-acm: use tty-port dtr_rts

Add dtr_rts tty-port operation which implements proper DTR/RTS handling
(e.g. only lower DTR/RTS during shutdown if HUPCL is set).

Note that modem-control locking still needs to be added throughout the
driver.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 8f654ce52570677732364164f17dc5c65ea04e3f..e934e19f49f57e3e463c31c65caa76cca3fee905 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -504,6 +504,25 @@ static int acm_tty_open(struct tty_struct *tty, struct file *filp)
        return tty_port_open(&acm->port, tty, filp);
 }
 
+static void acm_port_dtr_rts(struct tty_port *port, int raise)
+{
+       struct acm *acm = container_of(port, struct acm, port);
+       int val;
+       int res;
+
+       if (raise)
+               val = ACM_CTRL_DTR | ACM_CTRL_RTS;
+       else
+               val = 0;
+
+       /* FIXME: add missing ctrlout locking throughout driver */
+       acm->ctrlout = val;
+
+       res = acm_set_control(acm, val);
+       if (res && (acm->ctrl_caps & USB_CDC_CAP_LINE))
+               dev_err(&acm->control->dev, "failed to set dtr/rts\n");
+}
+
 static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
 {
        struct acm *acm = container_of(port, struct acm, port);
@@ -535,11 +554,6 @@ static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
                goto error_submit_urb;
        }
 
-       acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS;
-       retval = acm_set_control(acm, acm->ctrlout);
-       if (retval < 0 && (acm->ctrl_caps & USB_CDC_CAP_LINE))
-               goto error_set_control;
-
        /*
         * Unthrottle device in case the TTY was closed while throttled.
         */
@@ -561,9 +575,6 @@ static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
 error_submit_read_urbs:
        for (i = 0; i < acm->rx_buflimit; i++)
                usb_kill_urb(acm->read_urbs[i]);
-       acm->ctrlout = 0;
-       acm_set_control(acm, acm->ctrlout);
-error_set_control:
        usb_kill_urb(acm->ctrlurb);
 error_submit_urb:
        usb_autopm_put_interface(acm->control);
@@ -595,8 +606,6 @@ static void acm_port_shutdown(struct tty_port *port)
 
        dev_dbg(&acm->control->dev, "%s\n", __func__);
 
-       acm_set_control(acm, acm->ctrlout = 0);
-
        /*
         * Need to grab write_lock to prevent race with resume, but no need to
         * hold it due to the tty-port initialised flag.
@@ -992,6 +1001,7 @@ static void acm_tty_set_termios(struct tty_struct *tty,
 }
 
 static const struct tty_port_operations acm_port_ops = {
+       .dtr_rts = acm_port_dtr_rts,
        .shutdown = acm_port_shutdown,
        .activate = acm_port_activate,
        .destruct = acm_port_destruct,
@@ -1429,8 +1439,6 @@ skip_countries:
 
        dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
 
-       acm_set_control(acm, acm->ctrlout);
-
        acm->line.dwDTERate = cpu_to_le32(9600);
        acm->line.bDataBits = 8;
        acm_set_line(acm, &acm->line);