8 files changed, 50 insertions, 9 deletions

diff --git a/Documentation/video4linux/v4l2-controls.txt b/Documentation/video4linux/v4l2-controls.txt
index 43da22b89728..54270df99d5c 100644
--- a/Documentation/video4linux/v4l2-controls.txt
+++ b/Documentation/video4linux/v4l2-controls.txt
@@ -594,7 +594,11 @@ handler and finally add the first handler to the second. For example:
         v4l2_ctrl_new_std(&radio_ctrl_handler, &radio_ops, V4L2_CID_AUDIO_MUTE, ...);
         v4l2_ctrl_new_std(&video_ctrl_handler, &video_ops, V4L2_CID_BRIGHTNESS, ...);
         v4l2_ctrl_new_std(&video_ctrl_handler, &video_ops, V4L2_CID_CONTRAST, ...);
-        v4l2_ctrl_add_handler(&video_ctrl_handler, &radio_ctrl_handler);
+        v4l2_ctrl_add_handler(&video_ctrl_handler, &radio_ctrl_handler, NULL);
+
+The last argument to v4l2_ctrl_add_handler() is a filter function that allows
+you to filter which controls will be added. Set it to NULL if you want to add
+all controls.
 
 Or you can add specific controls to a handler:
 
diff --git a/drivers/media/pci/cx88/cx88-blackbird.c b/drivers/media/pci/cx88/cx88-blackbird.c
index 843ffd9e533b..def363fb71c0 100644
--- a/drivers/media/pci/cx88/cx88-blackbird.c
+++ b/drivers/media/pci/cx88/cx88-blackbird.c
@@ -1236,7 +1236,7 @@ static int cx8802_blackbird_probe(struct cx8802_driver *drv)
         err = cx2341x_handler_init(&dev->cxhdl, 36);
         if (err)
                 goto fail_core;
-        v4l2_ctrl_add_handler(&dev->cxhdl.hdl, &core->video_hdl);
+        v4l2_ctrl_add_handler(&dev->cxhdl.hdl, &core->video_hdl, NULL);
 
         /* blackbird stuff */
         printk("%s/2: cx23416 based mpeg encoder (blackbird reference design)\n",
diff --git a/drivers/media/pci/cx88/cx88-video.c b/drivers/media/pci/cx88/cx88-video.c
index f6fcc7e763ab..a146d50d7795 100644
--- a/drivers/media/pci/cx88/cx88-video.c
+++ b/drivers/media/pci/cx88/cx88-video.c
@@ -1795,7 +1795,7 @@ static int __devinit cx8800_initdev(struct pci_dev *pci_dev,
                 if (vc->id == V4L2_CID_CHROMA_AGC)
                         core->chroma_agc = vc;
         }
-        v4l2_ctrl_add_handler(&core->video_hdl, &core->audio_hdl);
+        v4l2_ctrl_add_handler(&core->video_hdl, &core->audio_hdl, NULL);
 
         /* load and configure helper modules */
 
diff --git a/drivers/media/platform/s5p-fimc/fimc-capture.c b/drivers/media/platform/s5p-fimc/fimc-capture.c
index 40923885977a..ac2ca36039e4 100644
--- a/drivers/media/platform/s5p-fimc/fimc-capture.c
+++ b/drivers/media/platform/s5p-fimc/fimc-capture.c
@@ -472,7 +472,7 @@ int fimc_capture_ctrls_create(struct fimc_dev *fimc)
                 return ret;
 
         return v4l2_ctrl_add_handler(&vid_cap->ctx->ctrls.handler,
-                    fimc->pipeline.subdevs[IDX_SENSOR]->ctrl_handler);
+                    fimc->pipeline.subdevs[IDX_SENSOR]->ctrl_handler, NULL);
 }
 
 static int fimc_capture_set_default_format(struct fimc_dev *fimc);
diff --git a/drivers/media/platform/soc_camera/soc_camera.c b/drivers/media/platform/soc_camera/soc_camera.c
index f6b1c1f87761..3be92944f8e7 100644
--- a/drivers/media/platform/soc_camera/soc_camera.c
+++ b/drivers/media/platform/soc_camera/soc_camera.c
@@ -1184,7 +1184,7 @@ static int soc_camera_probe(struct soc_camera_device *icd)
         sd->grp_id = soc_camera_grp_id(icd);
         v4l2_set_subdev_hostdata(sd, icd);
 
-        if (v4l2_ctrl_add_handler(&icd->ctrl_handler, sd->ctrl_handler))
+        if (v4l2_ctrl_add_handler(&icd->ctrl_handler, sd->ctrl_handler, NULL))
                 goto ectrl;
 
         /* At this point client .probe() should have run already */
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index f40003550b60..631cdc0e0bda 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1687,7 +1687,8 @@ EXPORT_SYMBOL(v4l2_ctrl_add_ctrl);
 
 /* 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 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
                 /* 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 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
 }
 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)
 {
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 1f203b85a637..513969fa695d 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -166,7 +166,7 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
         }
 
         /* This just returns 0 if either of the two args is NULL */
-        err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
+        err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL);
         if (err) {
                 if (sd->internal_ops && sd->internal_ops->unregistered)
                         sd->internal_ops->unregistered(sd);
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 6890f5e11ad0..801adb466bd2 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -384,14 +384,28 @@ struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
   * @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.