V4L/DVB (8234): uvcvideo: Make input device support optional

UVC devices can report button events. The uvcvideo driver depends on
CONFIG_INPUT to report events to the input layer. This patch removes the hard
dependency by introducing a new CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV option.
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/uvc/Kconfig

+config USB_VIDEO_CLASS
+	tristate "USB Video Class (UVC)"
+	---help---
+	  Support for the USB Video Class (UVC).  Currently only video
+	  input devices, such as webcams, are supported.
+
+	  For more information see: <http://linux-uvc.berlios.de/>
+
+config USB_VIDEO_CLASS_INPUT_EVDEV
+	bool "UVC input events device support"
+	default y
+	depends on USB_VIDEO_CLASS && INPUT
+	---help---
+	  This option makes USB Video Class devices register an input device
+	  to report button events.
+
+	  If you are in doubt, say Y.

drivers/media/video/uvc/uvc_status.c

@@ -22,6 +22,7 @@
 /* --------------------------------------------------------------------------
  * Input device
  */
+#ifdef CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV
 static int uvc_input_init(struct uvc_device *dev)
 {
 	struct usb_device *udev = dev->udev;
@@ -67,6 +68,19 @@ static void uvc_input_cleanup(struct uvc_device *dev)
 		input_unregister_device(dev->input);
 }
 
+static void uvc_input_report_key(struct uvc_device *dev, unsigned int code,
+	int value)
+{
+	if (dev->input)
+		input_report_key(dev->input, code, value);
+}
+
+#else
+#define uvc_input_init(dev)
+#define uvc_input_cleanup(dev)
+#define uvc_input_report_key(dev, code, value)
+#endif /* CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV */
+
 /* --------------------------------------------------------------------------
  * Status interrupt endpoint
  */
@@ -83,8 +97,7 @@ static void uvc_event_streaming(struct uvc_device *dev, __u8 *data, int len)
 			return;
 		uvc_trace(UVC_TRACE_STATUS, "Button (intf %u) %s len %d\n",
 			data[1], data[3] ? "pressed" : "released", len);
-		if (dev->input)
-			input_report_key(dev->input, BTN_0, data[3]);
+		uvc_input_report_key(dev, BTN_0, data[3]);
 	} else {
 		uvc_trace(UVC_TRACE_STATUS, "Stream %u error event %02x %02x "
 			"len %d.\n", data[1], data[2], data[3], len);