From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Some drivers that implement a simple video pipeline may want to inherit
private controls from their subdevs and expose them through the video node.
That way there is no need to create v4l-subdev nodes to access the private
controls of the sub-devices.
Without this drivers are force to either hack the subdev driver to remove
the is_private setting, or manually add those controls to the bridge driver.
It's the bridge driver that determines whether or not the v4l-subdev nodes
are created, so the bridge driver should also be able to control this.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-device.c | 2 +-
include/media/v4l2-device.h | 10 +++++++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 7045cb2..bf1b047 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -170,7 +170,7 @@ 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,
- false, NULL);
+ v4l2_dev->inherit_private_ctrls, NULL);
if (err)
goto error_unregister;
diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
index c9b1593..8350ce5 100644
--- a/include/media/v4l2-device.h
+++ b/include/media/v4l2-device.h
@@ -56,6 +56,11 @@ struct v4l2_device {
unsigned int notification, void *arg);
/* The control handler. May be NULL. */
struct v4l2_ctrl_handler *ctrl_handler;
+ /*
+ * If true, then when adding controls from a sub-device also
+ * add the private controls. Used in v4l2_device_register_subdev().
+ */
+ bool inherit_private_ctrls;
/* Device's priority state */
struct v4l2_prio_state prio;
/* BKL replacement mutex. Temporary solution only. */
@@ -107,7 +112,10 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
/* Register a subdev with a v4l2 device. While registered the subdev module
is marked as in-use. An error is returned if the module is no longer
- loaded when you attempt to register it. */
+ loaded when you attempt to register it. The controls of the subdev are
+ automatically added to the control handler defined in v4l2_dev. Depending
+ on the inherit_private_ctrls field of v4l2_dev the private controls of
+ the subdev may also be added. */
int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
struct v4l2_subdev *sd);
/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
--
1.8.5.2
--
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