[media] v4l: subdev: Add device node support (2096a5dc) · Commits · e / devices / android_kernel_teracube_2e

Documentation/video4linux/v4l2-framework.txt

+16 −0

Original line number	Diff line number	Diff line
		@@ -319,6 +319,22 @@ controlled through GPIO pins. This distinction is only relevant when setting
		up the device, but once the subdev is registered it is completely transparent.


		V4L2 sub-device userspace API
		-----------------------------

		Beside exposing a kernel API through the v4l2_subdev_ops structure, V4L2
		sub-devices can also be controlled directly by userspace applications.

		Device nodes named v4l-subdevX can be created in /dev to access sub-devices
		directly. If a sub-device supports direct userspace configuration it must set
		the V4L2_SUBDEV_FL_HAS_DEVNODE flag before being registered.

		After registering sub-devices, the v4l2_device driver can create device nodes
		for all registered sub-devices marked with V4L2_SUBDEV_FL_HAS_DEVNODE by calling
		v4l2_device_register_subdev_nodes(). Those device nodes will be automatically
		removed when sub-devices are unregistered.


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

drivers/media/video/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -11,7 +11,7 @@ stkwebcam-objs := stk-webcam.o stk-sensor.o
		omap2cam-objs := omap24xxcam.o omap24xxcam-dma.o

		videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
		v4l2-event.o v4l2-ctrls.o
		v4l2-event.o v4l2-ctrls.o v4l2-subdev.o

		# V4L2 core modules

drivers/media/video/v4l2-dev.c

+11 −16

Original line number	Diff line number	Diff line
		@@ -408,13 +408,14 @@ static int get_index(struct video_device *vdev)
		}

		/**
		* video_register_device - register video4linux devices
		* __video_register_device - register video4linux devices
		* @vdev: video device structure we want to register
		* @type: type of device to register
		* @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ...
		* -1 == first free)
		* @warn_if_nr_in_use: warn if the desired device node number
		* was already in use and another number was chosen instead.
		* @owner: module that owns the video device node
		*
		* The registration code assigns minor numbers and device node numbers
		* based on the requested type and registers the new device node with
		@@ -435,9 +436,11 @@ static int get_index(struct video_device *vdev)
		* %VFL_TYPE_VBI - Vertical blank data (undecoded)
		*
		* %VFL_TYPE_RADIO - A radio card
		*
		* %VFL_TYPE_SUBDEV - A subdevice
		*/
		static int __video_register_device(struct video_device *vdev, int type, int nr,
		int warn_if_nr_in_use)
		int __video_register_device(struct video_device *vdev, int type, int nr,
		int warn_if_nr_in_use, struct module *owner)
		{
		int i = 0;
		int ret;
		@@ -469,6 +472,9 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
		case VFL_TYPE_RADIO:
		name_base = "radio";
		break;
		case VFL_TYPE_SUBDEV:
		name_base = "v4l-subdev";
		break;
		default:
		printk(KERN_ERR "%s called with unknown type: %d\n",
		__func__, type);
		@@ -552,7 +558,7 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
		goto cleanup;
		}
		vdev->cdev->ops = &v4l2_fops;
		vdev->cdev->owner = vdev->fops->owner;
		vdev->cdev->owner = owner;
		ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
		if (ret < 0) {
		printk(KERN_ERR "%s: cdev_add failed\n", __func__);
		@@ -597,18 +603,7 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
		vdev->minor = -1;
		return ret;
		}

		int video_register_device(struct video_device *vdev, int type, int nr)
		{
		return __video_register_device(vdev, type, nr, 1);
		}
		EXPORT_SYMBOL(video_register_device);

		int video_register_device_no_warn(struct video_device *vdev, int type, int nr)
		{
		return __video_register_device(vdev, type, nr, 0);
		}
		EXPORT_SYMBOL(video_register_device_no_warn);
		EXPORT_SYMBOL(__video_register_device);

		/**
		* video_unregister_device - unregister a video4linux device

drivers/media/video/v4l2-device.c

+37 −0

Original line number	Diff line number	Diff line
		@@ -124,16 +124,20 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
		/* Check for valid input */
		if (v4l2_dev == NULL \|\| sd == NULL \|\| !sd->name[0])
		return -EINVAL;

		/* Warn if we apparently re-register a subdev */
		WARN_ON(sd->v4l2_dev != NULL);

		if (!try_module_get(sd->owner))
		return -ENODEV;

		sd->v4l2_dev = v4l2_dev;
		if (sd->internal_ops && sd->internal_ops->registered) {
		err = sd->internal_ops->registered(sd);
		if (err)
		return err;
		}

		/* This just returns 0 if either of the two args is NULL */
		err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
		if (err) {
		@@ -141,24 +145,57 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
		sd->internal_ops->unregistered(sd);
		return err;
		}

		spin_lock(&v4l2_dev->lock);
		list_add_tail(&sd->list, &v4l2_dev->subdevs);
		spin_unlock(&v4l2_dev->lock);

		return 0;
		}
		EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

		int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
		{
		struct video_device *vdev;
		struct v4l2_subdev *sd;
		int err;

		/* Register a device node for every subdev marked with the
		* V4L2_SUBDEV_FL_HAS_DEVNODE flag.
		*/
		list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
		continue;

		vdev = &sd->devnode;
		strlcpy(vdev->name, sd->name, sizeof(vdev->name));
		vdev->v4l2_dev = v4l2_dev;
		vdev->fops = &v4l2_subdev_fops;
		vdev->release = video_device_release_empty;
		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
		sd->owner);
		if (err < 0)
		return err;
		}

		return 0;
		}
		EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);

		void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
		{
		/* return if it isn't registered */
		if (sd == NULL \|\| sd->v4l2_dev == NULL)
		return;

		spin_lock(&sd->v4l2_dev->lock);
		list_del(&sd->list);
		spin_unlock(&sd->v4l2_dev->lock);
		if (sd->internal_ops && sd->internal_ops->unregistered)
		sd->internal_ops->unregistered(sd);
		sd->v4l2_dev = NULL;

		video_unregister_device(&sd->devnode);
		module_put(sd->owner);
		}
		EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);

drivers/media/video/v4l2-subdev.c

0 → 100644

+60 −0

Original line number	Diff line number	Diff line
		/*
		* V4L2 subdevice support.
		*
		* Copyright (C) 2010 Nokia Corporation
		*
		* Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		*/

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

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

		static int subdev_open(struct file *file)
		{
		return 0;
		}

		static int subdev_close(struct file *file)
		{
		return 0;
		}

		static long subdev_do_ioctl(struct file file, unsigned int cmd, void arg)
		{
		switch (cmd) {
		default:
		return -ENOIOCTLCMD;
		}

		return 0;
		}

		static long subdev_ioctl(struct file *file, unsigned int cmd,
		unsigned long arg)
		{
		return video_usercopy(file, cmd, arg, subdev_do_ioctl);
		}

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