usb: gadget: f_acm: add support for USB_CDC_REQ_SEND_BREAK

Currently the usb side setting of the USB_CDC_REQ_SEND_BREAK control
is not supported. This patch adds the support.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20220406192914.3302636-1-m.grzeschik@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/f_acm.c

@@ -333,6 +333,8 @@ static void acm_complete_set_line_coding(struct usb_ep *ep,
 	}
 }
 
+static int acm_send_break(struct gserial *port, int duration);
+
 static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 {
 	struct f_acm		*acm = func_to_acm(f);
@@ -391,6 +393,14 @@ static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 		acm->port_handshake_bits = w_value;
 		break;
 
+	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
+			| USB_CDC_REQ_SEND_BREAK:
+		if (w_index != acm->ctrl_id)
+			goto invalid;
+
+		acm_send_break(&acm->port, w_value);
+		break;
+
 	default:
 invalid:
 		dev_vdbg(&cdev->gadget->dev,