@@ -18,11 +18,34 @@
* Input device
*/
#ifdef CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV
+
+static bool uvc_input_has_button(struct uvc_device *dev)
+{
+ struct uvc_streaming *stream;
+
+ /*
+ * The device has button events if both bTriggerSupport and
+ * bTriggerUsage are one. Otherwise the camera button does not
+ * exist or is handled automatically by the camera without host
+ * driver or client application intervention.
+ */
+ list_for_each_entry(stream, &dev->streams, list) {
+ if (stream->header.bTriggerSupport == 1 &&
+ stream->header.bTriggerUsage == 1)
+ return true;
+ }
+
+ return false;
+}
+
static int uvc_input_init(struct uvc_device *dev)
{
struct input_dev *input;
int ret;
+ if (!uvc_input_has_button(dev))
+ return 0;
+
input = input_allocate_device();
if (input == NULL)
return -ENOMEM;