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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /include/media/media-devnode.h
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'include/media/media-devnode.h')
-rw-r--r--include/media/media-devnode.h168
1 files changed, 168 insertions, 0 deletions
diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Media device node
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ *
+ * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ * Sakari Ailus <sakari.ailus@iki.fi>
+ *
+ * --
+ *
+ * Common functions for media-related drivers to register and unregister media
+ * device nodes.
+ */
+
+#ifndef _MEDIA_DEVNODE_H
+#define _MEDIA_DEVNODE_H
+
+#include <linux/poll.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+
+struct media_device;
+
+/*
+ * Flag to mark the media_devnode struct as registered. Drivers must not touch
+ * this flag directly, it will be set and cleared by media_devnode_register and
+ * media_devnode_unregister.
+ */
+#define MEDIA_FLAG_REGISTERED 0
+
+/**
+ * struct media_file_operations - Media device file operations
+ *
+ * @owner: should be filled with %THIS_MODULE
+ * @read: pointer to the function that implements read() syscall
+ * @write: pointer to the function that implements write() syscall
+ * @poll: pointer to the function that implements poll() syscall
+ * @ioctl: pointer to the function that implements ioctl() syscall
+ * @compat_ioctl: pointer to the function that will handle 32 bits userspace
+ * calls to the ioctl() syscall on a Kernel compiled with 64 bits.
+ * @open: pointer to the function that implements open() syscall
+ * @release: pointer to the function that will release the resources allocated
+ * by the @open function.
+ */
+struct media_file_operations {
+ struct module *owner;
+ ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
+ ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
+ __poll_t (*poll) (struct file *, struct poll_table_struct *);
+ long (*ioctl) (struct file *, unsigned int, unsigned long);
+ long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
+ int (*open) (struct file *);
+ int (*release) (struct file *);
+};
+
+/**
+ * struct media_devnode - Media device node
+ * @media_dev: pointer to struct &media_device
+ * @fops: pointer to struct &media_file_operations with media device ops
+ * @dev: pointer to struct &device containing the media controller device
+ * @cdev: struct cdev pointer character device
+ * @parent: parent device
+ * @minor: device node minor number
+ * @flags: flags, combination of the ``MEDIA_FLAG_*`` constants
+ * @release: release callback called at the end of ``media_devnode_release()``
+ * routine at media-device.c.
+ *
+ * This structure represents a media-related device node.
+ *
+ * The @parent is a physical device. It must be set by core or device drivers
+ * before registering the node.
+ */
+struct media_devnode {
+ struct media_device *media_dev;
+
+ /* device ops */
+ const struct media_file_operations *fops;
+
+ /* sysfs */
+ struct device dev; /* media device */
+ struct cdev cdev; /* character device */
+ struct device *parent; /* device parent */
+
+ /* device info */
+ int minor;
+ unsigned long flags; /* Use bitops to access flags */
+
+ /* callbacks */
+ void (*release)(struct media_devnode *devnode);
+};
+
+/* dev to media_devnode */
+#define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)
+
+/**
+ * media_devnode_register - register a media device node
+ *
+ * @mdev: struct media_device we want to register a device node
+ * @devnode: media device node structure we want to register
+ * @owner: should be filled with %THIS_MODULE
+ *
+ * The registration code assigns minor numbers and registers the new device node
+ * with the kernel. An error is returned if no free minor number can be found,
+ * or if the registration of the device node fails.
+ *
+ * Zero is returned on success.
+ *
+ * Note that if the media_devnode_register call fails, the release() callback of
+ * the media_devnode structure is *not* called, so the caller is responsible for
+ * freeing any data.
+ */
+int __must_check media_devnode_register(struct media_device *mdev,
+ struct media_devnode *devnode,
+ struct module *owner);
+
+/**
+ * media_devnode_unregister_prepare - clear the media device node register bit
+ * @devnode: the device node to prepare for unregister
+ *
+ * This clears the passed device register bit. Future open calls will be met
+ * with errors. Should be called before media_devnode_unregister() to avoid
+ * races with unregister and device file open calls.
+ *
+ * This function can safely be called if the device node has never been
+ * registered or has already been unregistered.
+ */
+void media_devnode_unregister_prepare(struct media_devnode *devnode);
+
+/**
+ * media_devnode_unregister - unregister a media device node
+ * @devnode: the device node to unregister
+ *
+ * This unregisters the passed device. Future open calls will be met with
+ * errors.
+ *
+ * Should be called after media_devnode_unregister_prepare()
+ */
+void media_devnode_unregister(struct media_devnode *devnode);
+
+/**
+ * media_devnode_data - returns a pointer to the &media_devnode
+ *
+ * @filp: pointer to struct &file
+ */
+static inline struct media_devnode *media_devnode_data(struct file *filp)
+{
+ return filp->private_data;
+}
+
+/**
+ * media_devnode_is_registered - returns true if &media_devnode is registered;
+ * false otherwise.
+ *
+ * @devnode: pointer to struct &media_devnode.
+ *
+ * Note: If mdev is NULL, it also returns false.
+ */
+static inline int media_devnode_is_registered(struct media_devnode *devnode)
+{
+ if (!devnode)
+ return false;
+
+ return test_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
+}
+
+#endif /* _MEDIA_DEVNODE_H */