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[media] media: Media device

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The media_device structure abstracts functions common to all kind of
media devices (v4l2, dvb, alsa, ...). It manages media entities and
offers a userspace API to discover and configure the media device
internal topology.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Laurent Pinchart
2009-12-09 08:39:58 -03:00
committed by Mauro Carvalho Chehab
parent cf4b9211b5
commit 176fb0d108
8 changed files with 304 additions and 1 deletions
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drivers/media/media-device.c Normal file
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/*
* Media device
*
* Copyright (C) 2010 Nokia Corporation
*
* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
* Sakari Ailus <sakari.ailus@iki.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 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 <media/media-device.h>
#include <media/media-devnode.h>
static const struct media_file_operations media_device_fops = {
.owner = THIS_MODULE,
};
/* -----------------------------------------------------------------------------
* sysfs
*/
static ssize_t show_model(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct media_device *mdev = to_media_device(to_media_devnode(cd));
return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
}
static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
/* -----------------------------------------------------------------------------
* Registration/unregistration
*/
static void media_device_release(struct media_devnode *mdev)
{
}
/**
* media_device_register - register a media device
* @mdev: The media device
*
* The caller is responsible for initializing the media device before
* registration. The following fields must be set:
*
* - dev must point to the parent device
* - model must be filled with the device model name
*/
int __must_check media_device_register(struct media_device *mdev)
{
int ret;
if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
return -EINVAL;
/* Register the device node. */
mdev->devnode.fops = &media_device_fops;
mdev->devnode.parent = mdev->dev;
mdev->devnode.release = media_device_release;
ret = media_devnode_register(&mdev->devnode);
if (ret < 0)
return ret;
ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
if (ret < 0) {
media_devnode_unregister(&mdev->devnode);
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(media_device_register);
/**
* media_device_unregister - unregister a media device
* @mdev: The media device
*
*/
void media_device_unregister(struct media_device *mdev)
{
device_remove_file(&mdev->devnode.dev, &dev_attr_model);
media_devnode_unregister(&mdev->devnode);
}
EXPORT_SYMBOL_GPL(media_device_unregister);