[media] v4l2-ctrls: add a filter function to v4l2_ctrl_add_handler
With a filter function you can control more precisely which controls
are added. This is useful in particular for radio device nodes for
combined TV/Radio cards where you want to show just the radio-specific
controls and not controls like brightness.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 6890f5e..801adb4 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -384,14 +384,28 @@
* @hdl: The control handler.
* @add: The control handler whose controls you want to add to
* the @hdl control handler.
+ * @filter: This function will filter which controls should be added.
*
- * Does nothing if either of the two is a NULL pointer.
+ * Does nothing if either of the two handlers is a NULL pointer.
+ * If @filter is NULL, then all controls are added. Otherwise only those
+ * controls for which @filter returns true will be added.
* In case of an error @hdl->error will be set to the error code (if it
* wasn't set already).
*/
int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
- struct v4l2_ctrl_handler *add);
+ struct v4l2_ctrl_handler *add,
+ bool (*filter)(const struct v4l2_ctrl *ctrl));
+/** v4l2_ctrl_radio_filter() - Standard filter for radio controls.
+ * @ctrl: The control that is filtered.
+ *
+ * This will return true for any controls that are valid for radio device
+ * nodes. Those are all of the V4L2_CID_AUDIO_* user controls and all FM
+ * transmitter class controls.
+ *
+ * This function is to be used with v4l2_ctrl_add_handler().
+ */
+bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);
/** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
* @ncontrols: The number of controls in this cluster.