503c3d829e
Due to the wide differences between drivers regarding power management needs, the media controller does not implement power management. However, the media_entity structure includes a use_count field that media drivers can use to track the number of users of every entity for power management needs. The use_count field is owned by media drivers and must not be touched by entity drivers. Access to the field must be protected by the media device graph_mutex lock. 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>
157 lines
4.1 KiB
C
157 lines
4.1 KiB
C
/*
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* Media device
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*
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* Copyright (C) 2010 Nokia Corporation
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*
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* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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* Sakari Ailus <sakari.ailus@iki.fi>
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*
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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 version 2 as
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* 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,
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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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*
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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 <media/media-device.h>
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#include <media/media-devnode.h>
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#include <media/media-entity.h>
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static const struct media_file_operations media_device_fops = {
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.owner = THIS_MODULE,
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};
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/* -----------------------------------------------------------------------------
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* sysfs
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*/
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static ssize_t show_model(struct device *cd,
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struct device_attribute *attr, char *buf)
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{
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struct media_device *mdev = to_media_device(to_media_devnode(cd));
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return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
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}
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static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
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/* -----------------------------------------------------------------------------
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* Registration/unregistration
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*/
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static void media_device_release(struct media_devnode *mdev)
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{
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}
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/**
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* media_device_register - register a media device
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* @mdev: The media device
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*
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* The caller is responsible for initializing the media device before
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* registration. The following fields must be set:
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*
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* - dev must point to the parent device
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* - model must be filled with the device model name
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*/
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int __must_check media_device_register(struct media_device *mdev)
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{
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int ret;
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if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
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return -EINVAL;
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mdev->entity_id = 1;
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INIT_LIST_HEAD(&mdev->entities);
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spin_lock_init(&mdev->lock);
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mutex_init(&mdev->graph_mutex);
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/* Register the device node. */
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mdev->devnode.fops = &media_device_fops;
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mdev->devnode.parent = mdev->dev;
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mdev->devnode.release = media_device_release;
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ret = media_devnode_register(&mdev->devnode);
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if (ret < 0)
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return ret;
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ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
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if (ret < 0) {
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media_devnode_unregister(&mdev->devnode);
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return ret;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(media_device_register);
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/**
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* media_device_unregister - unregister a media device
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* @mdev: The media device
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*
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*/
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void media_device_unregister(struct media_device *mdev)
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{
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struct media_entity *entity;
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struct media_entity *next;
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list_for_each_entry_safe(entity, next, &mdev->entities, list)
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media_device_unregister_entity(entity);
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device_remove_file(&mdev->devnode.dev, &dev_attr_model);
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media_devnode_unregister(&mdev->devnode);
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}
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EXPORT_SYMBOL_GPL(media_device_unregister);
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/**
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* media_device_register_entity - Register an entity with a media device
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* @mdev: The media device
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* @entity: The entity
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*/
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int __must_check media_device_register_entity(struct media_device *mdev,
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struct media_entity *entity)
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{
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/* Warn if we apparently re-register an entity */
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WARN_ON(entity->parent != NULL);
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entity->parent = mdev;
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spin_lock(&mdev->lock);
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if (entity->id == 0)
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entity->id = mdev->entity_id++;
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else
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mdev->entity_id = max(entity->id + 1, mdev->entity_id);
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list_add_tail(&entity->list, &mdev->entities);
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spin_unlock(&mdev->lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(media_device_register_entity);
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/**
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* media_device_unregister_entity - Unregister an entity
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* @entity: The entity
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*
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* If the entity has never been registered this function will return
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* immediately.
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*/
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void media_device_unregister_entity(struct media_entity *entity)
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{
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struct media_device *mdev = entity->parent;
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if (mdev == NULL)
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return;
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spin_lock(&mdev->lock);
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list_del(&entity->list);
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spin_unlock(&mdev->lock);
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entity->parent = NULL;
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}
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EXPORT_SYMBOL_GPL(media_device_unregister_entity);
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