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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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6e239399e5
Whenever a control changes value or state an event is sent to anyone that subscribed to it. This functionality is useful for control panels but also for applications that need to wait for (usually status) controls to change value. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
127 lines
3.1 KiB
C
127 lines
3.1 KiB
C
/*
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* v4l2-fh.c
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*
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* V4L2 file handles.
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*
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* Copyright (C) 2009--2010 Nokia Corporation.
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*
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* Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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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., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#include <linux/bitops.h>
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#include <linux/slab.h>
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#include <media/v4l2-dev.h>
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#include <media/v4l2-fh.h>
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#include <media/v4l2-event.h>
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#include <media/v4l2-ioctl.h>
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int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
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{
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fh->vdev = vdev;
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/* Inherit from video_device. May be overridden by the driver. */
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fh->ctrl_handler = vdev->ctrl_handler;
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INIT_LIST_HEAD(&fh->list);
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set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
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fh->prio = V4L2_PRIORITY_UNSET;
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/*
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* fh->events only needs to be initialized if the driver
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* supports the VIDIOC_SUBSCRIBE_EVENT ioctl.
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*/
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if (vdev->ioctl_ops && vdev->ioctl_ops->vidioc_subscribe_event)
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return v4l2_event_init(fh);
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fh->events = NULL;
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_init);
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void v4l2_fh_add(struct v4l2_fh *fh)
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{
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unsigned long flags;
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if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
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v4l2_prio_open(fh->vdev->prio, &fh->prio);
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spin_lock_irqsave(&fh->vdev->fh_lock, flags);
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list_add(&fh->list, &fh->vdev->fh_list);
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spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_add);
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int v4l2_fh_open(struct file *filp)
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{
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struct video_device *vdev = video_devdata(filp);
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struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
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filp->private_data = fh;
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if (fh == NULL)
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return -ENOMEM;
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v4l2_fh_init(fh, vdev);
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v4l2_fh_add(fh);
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_open);
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void v4l2_fh_del(struct v4l2_fh *fh)
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{
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unsigned long flags;
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spin_lock_irqsave(&fh->vdev->fh_lock, flags);
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list_del_init(&fh->list);
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spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
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if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
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v4l2_prio_close(fh->vdev->prio, fh->prio);
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_del);
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void v4l2_fh_exit(struct v4l2_fh *fh)
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{
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if (fh->vdev == NULL)
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return;
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v4l2_event_free(fh);
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fh->vdev = NULL;
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_exit);
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int v4l2_fh_release(struct file *filp)
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{
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struct v4l2_fh *fh = filp->private_data;
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if (fh) {
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v4l2_fh_del(fh);
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v4l2_fh_exit(fh);
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kfree(fh);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_release);
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int v4l2_fh_is_singular(struct v4l2_fh *fh)
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{
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unsigned long flags;
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int is_singular;
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if (fh == NULL || fh->vdev == NULL)
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return 0;
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spin_lock_irqsave(&fh->vdev->fh_lock, flags);
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is_singular = list_is_singular(&fh->list);
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spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
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return is_singular;
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}
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EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
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