[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/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index f400035..631cdc0 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1687,7 +1687,8 @@
/* Add the controls from another handler to our own. */
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))
{
struct v4l2_ctrl_ref *ref;
int ret = 0;
@@ -1707,6 +1708,9 @@
/* And control classes */
if (ctrl->type == V4L2_CTRL_TYPE_CTRL_CLASS)
continue;
+ /* Filter any unwanted controls */
+ if (filter && !filter(ctrl))
+ continue;
ret = handler_new_ref(hdl, ctrl);
if (ret)
break;
@@ -1716,6 +1720,25 @@
}
EXPORT_SYMBOL(v4l2_ctrl_add_handler);
+bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl)
+{
+ if (V4L2_CTRL_ID2CLASS(ctrl->id) == V4L2_CTRL_CLASS_FM_TX)
+ return true;
+ switch (ctrl->id) {
+ case V4L2_CID_AUDIO_MUTE:
+ case V4L2_CID_AUDIO_VOLUME:
+ case V4L2_CID_AUDIO_BALANCE:
+ case V4L2_CID_AUDIO_BASS:
+ case V4L2_CID_AUDIO_TREBLE:
+ case V4L2_CID_AUDIO_LOUDNESS:
+ return true;
+ default:
+ break;
+ }
+ return false;
+}
+EXPORT_SYMBOL(v4l2_ctrl_radio_filter);
+
/* Cluster controls */
void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls)
{