[media] v4l: subdev: Events support (02adb1cc) · Commits · e / devices / android_kernel_teracube_2e

Documentation/video4linux/v4l2-framework.txt

+18 −0

Original line number	Diff line number	Diff line
		@@ -350,6 +350,24 @@ VIDIOC_TRY_EXT_CTRLS
		controls can be also be accessed through one (or several) V4L2 device
		nodes.

		VIDIOC_DQEVENT
		VIDIOC_SUBSCRIBE_EVENT
		VIDIOC_UNSUBSCRIBE_EVENT

		The events ioctls are identical to the ones defined in V4L2. They
		behave identically, with the only exception that they deal only with
		events generated by the sub-device. Depending on the driver, those
		events can also be reported by one (or several) V4L2 device nodes.

		Sub-device drivers that want to use events need to set the
		V4L2_SUBDEV_USES_EVENTS v4l2_subdev::flags and initialize
		v4l2_subdev::nevents to events queue depth before registering the
		sub-device. After registration events can be queued as usual on the
		v4l2_subdev::devnode device node.

		To properly support events, the poll() file operation is also
		implemented.


		I2C sub-device drivers
		----------------------

drivers/media/video/v4l2-subdev.c

+77 −1

Original line number	Diff line number	Diff line
		@@ -20,21 +20,66 @@
		* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		*/

		#include <linux/types.h>
		#include <linux/ioctl.h>
		#include <linux/slab.h>
		#include <linux/types.h>
		#include <linux/videodev2.h>

		#include <media/v4l2-ctrls.h>
		#include <media/v4l2-device.h>
		#include <media/v4l2-ioctl.h>
		#include <media/v4l2-fh.h>
		#include <media/v4l2-event.h>

		static int subdev_open(struct file *file)
		{
		struct video_device *vdev = video_devdata(file);
		struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
		struct v4l2_fh *vfh;
		int ret;

		if (sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS) {
		vfh = kzalloc(sizeof(*vfh), GFP_KERNEL);
		if (vfh == NULL)
		return -ENOMEM;

		ret = v4l2_fh_init(vfh, vdev);
		if (ret)
		goto err;

		ret = v4l2_event_init(vfh);
		if (ret)
		goto err;

		ret = v4l2_event_alloc(vfh, sd->nevents);
		if (ret)
		goto err;

		v4l2_fh_add(vfh);
		file->private_data = vfh;
		}

		return 0;

		err:
		if (vfh != NULL) {
		v4l2_fh_exit(vfh);
		kfree(vfh);
		}

		return ret;
		}

		static int subdev_close(struct file *file)
		{
		struct v4l2_fh *vfh = file->private_data;

		if (vfh != NULL) {
		v4l2_fh_del(vfh);
		v4l2_fh_exit(vfh);
		kfree(vfh);
		}

		return 0;
		}

		@@ -42,6 +87,7 @@ static long subdev_do_ioctl(struct file file, unsigned int cmd, void arg)
		{
		struct video_device *vdev = video_devdata(file);
		struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
		struct v4l2_fh *fh = file->private_data;

		switch (cmd) {
		case VIDIOC_QUERYCTRL:
		@@ -65,6 +111,18 @@ static long subdev_do_ioctl(struct file file, unsigned int cmd, void arg)
		case VIDIOC_TRY_EXT_CTRLS:
		return v4l2_subdev_try_ext_ctrls(sd, arg);

		case VIDIOC_DQEVENT:
		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
		return -ENOIOCTLCMD;

		return v4l2_event_dequeue(fh, arg, file->f_flags & O_NONBLOCK);

		case VIDIOC_SUBSCRIBE_EVENT:
		return v4l2_subdev_call(sd, core, subscribe_event, fh, arg);

		case VIDIOC_UNSUBSCRIBE_EVENT:
		return v4l2_subdev_call(sd, core, unsubscribe_event, fh, arg);

		default:
		return -ENOIOCTLCMD;
		}
		@@ -78,11 +136,29 @@ static long subdev_ioctl(struct file *file, unsigned int cmd,
		return video_usercopy(file, cmd, arg, subdev_do_ioctl);
		}

		static unsigned int subdev_poll(struct file file, poll_table wait)
		{
		struct video_device *vdev = video_devdata(file);
		struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
		struct v4l2_fh *fh = file->private_data;

		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
		return POLLERR;

		poll_wait(file, &fh->events->wait, wait);

		if (v4l2_event_pending(fh))
		return POLLPRI;

		return 0;
		}

		const struct v4l2_file_operations v4l2_subdev_fops = {
		.owner = THIS_MODULE,
		.open = subdev_open,
		.unlocked_ioctl = subdev_ioctl,
		.release = subdev_close,
		.poll = subdev_poll,
		};

		void v4l2_subdev_init(struct v4l2_subdev sd, const struct v4l2_subdev_ops ops)

include/media/v4l2-subdev.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,8 @@

		struct v4l2_device;
		struct v4l2_ctrl_handler;
		struct v4l2_event_subscription;
		struct v4l2_fh;
		struct v4l2_subdev;
		struct tuner_setup;

		@@ -161,6 +163,10 @@ struct v4l2_subdev_core_ops {
		int (s_power)(struct v4l2_subdev sd, int on);
		int (interrupt_service_routine)(struct v4l2_subdev sd,
		u32 status, bool *handled);
		int (subscribe_event)(struct v4l2_subdev sd, struct v4l2_fh *fh,
		struct v4l2_event_subscription *sub);
		int (unsubscribe_event)(struct v4l2_subdev sd, struct v4l2_fh *fh,
		struct v4l2_event_subscription *sub);
		};

		/* s_mode: switch the tuner to a specific tuner mode. Replacement of s_radio.
		@@ -437,6 +443,8 @@ struct v4l2_subdev_internal_ops {
		#define V4L2_SUBDEV_FL_IS_SPI (1U << 1)
		/* Set this flag if this subdev needs a device node. */
		#define V4L2_SUBDEV_FL_HAS_DEVNODE (1U << 2)
		/* Set this flag if this subdev generates events. */
		#define V4L2_SUBDEV_FL_HAS_EVENTS (1U << 3)

		/* Each instance of a subdev driver should create this struct, either
		stand-alone or embedded in a larger struct.
		@@ -460,6 +468,8 @@ struct v4l2_subdev {
		void *host_priv;
		/* subdev device node */
		struct video_device devnode;
		/* number of events to be allocated on open */
		unsigned int nevents;
		};

		#define vdev_to_v4l2_subdev(vdev) \