mirror of https://gitee.com/openkylin/linux.git
87 lines
2.5 KiB
C
87 lines
2.5 KiB
C
/*
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V4L2 device support.
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Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/types.h>
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#include <linux/ioctl.h>
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#include <linux/i2c.h>
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#include <linux/videodev2.h>
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#include <media/v4l2-device.h>
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int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
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{
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if (dev == NULL || v4l2_dev == NULL)
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return -EINVAL;
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/* Warn if we apparently re-register a device */
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WARN_ON(dev_get_drvdata(dev));
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INIT_LIST_HEAD(&v4l2_dev->subdevs);
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spin_lock_init(&v4l2_dev->lock);
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v4l2_dev->dev = dev;
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snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
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dev->driver->name, dev->bus_id);
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dev_set_drvdata(dev, v4l2_dev);
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_register);
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void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
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{
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struct v4l2_subdev *sd, *next;
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if (v4l2_dev == NULL || v4l2_dev->dev == NULL)
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return;
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dev_set_drvdata(v4l2_dev->dev, NULL);
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/* unregister subdevs */
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list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
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v4l2_device_unregister_subdev(sd);
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v4l2_dev->dev = NULL;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_unregister);
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int v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd)
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{
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/* Check for valid input */
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if (dev == NULL || sd == NULL || !sd->name[0])
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return -EINVAL;
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/* Warn if we apparently re-register a subdev */
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WARN_ON(sd->dev);
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if (!try_module_get(sd->owner))
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return -ENODEV;
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sd->dev = dev;
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spin_lock(&dev->lock);
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list_add_tail(&sd->list, &dev->subdevs);
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spin_unlock(&dev->lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
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void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
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{
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/* return if it isn't registered */
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if (sd == NULL || sd->dev == NULL)
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return;
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spin_lock(&sd->dev->lock);
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list_del(&sd->list);
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spin_unlock(&sd->dev->lock);
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sd->dev = NULL;
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module_put(sd->owner);
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}
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EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
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