media: docs: v4l2-controls: rearrange control initialization sequence (e36160b8) · Commits · 戴 / test

Documentation/media/kapi/v4l2-controls.rst

+17 −23

Original line number	Diff line number	Diff line
		@@ -52,15 +52,29 @@ Basic usage for V4L2 and sub-device drivers

		1.1) Add the handler to your driver's top-level struct:

		For V4L2 drivers:

		.. code-block:: none

		struct foo_dev {
		...
		struct v4l2_device v4l2_dev;
		...
		struct v4l2_ctrl_handler ctrl_handler;
		...
		};

		struct foo_dev *foo;
		For sub-device drivers:

		.. code-block:: none

		struct foo_dev {
		...
		struct v4l2_subdev sd;
		...
		struct v4l2_ctrl_handler ctrl_handler;
		...
		};

		1.2) Initialize the handler:

		@@ -74,43 +88,23 @@ information. It is a hint only.

		1.3) Hook the control handler into the driver:

		1.3.1) For V4L2 drivers do this:
		For V4L2 drivers:

		.. code-block:: none

		struct foo_dev {
		...
		struct v4l2_device v4l2_dev;
		...
		struct v4l2_ctrl_handler ctrl_handler;
		...
		};

		foo->v4l2_dev.ctrl_handler = &foo->ctrl_handler;

		Where foo->v4l2_dev is of type struct v4l2_device.

		Finally, remove all control functions from your v4l2_ioctl_ops (if any):
		vidioc_queryctrl, vidioc_query_ext_ctrl, vidioc_querymenu, vidioc_g_ctrl,
		vidioc_s_ctrl, vidioc_g_ext_ctrls, vidioc_try_ext_ctrls and vidioc_s_ext_ctrls.
		Those are now no longer needed.

		1.3.2) For sub-device drivers do this:
		For sub-device drivers:

		.. code-block:: none

		struct foo_dev {
		...
		struct v4l2_subdev sd;
		...
		struct v4l2_ctrl_handler ctrl_handler;
		...
		};

		foo->sd.ctrl_handler = &foo->ctrl_handler;

		Where foo->sd is of type struct v4l2_subdev.

		1.4) Clean up the handler at the end:

		.. code-block:: none