HID: uhid: add UHID_START and UHID_STOP events

We send UHID_START and UHID_STOP events to user-space when the HID core
starts/stops the device. This notifies user-space about driver readiness
and data-I/O can start now.

This directly forwards the callbacks from hid-core to user-space.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/uhid.c

@@ -82,11 +82,17 @@ static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
 
 static int uhid_hid_start(struct hid_device *hid)
 {
-	return 0;
+	struct uhid_device *uhid = hid->driver_data;
+
+	return uhid_queue_event(uhid, UHID_START);
 }
 
 static void uhid_hid_stop(struct hid_device *hid)
 {
+	struct uhid_device *uhid = hid->driver_data;
+
+	hid->claimed = 0;
+	uhid_queue_event(uhid, UHID_STOP);
 }
 
 static int uhid_hid_open(struct hid_device *hid)

include/linux/uhid.h

@@ -25,6 +25,8 @@
 enum uhid_event_type {
 	UHID_CREATE,
 	UHID_DESTROY,
+	UHID_START,
+	UHID_STOP,
 	UHID_INPUT,
 };