diff options
Diffstat (limited to 'include/media/media-devnode.h')
| -rw-r--r-- | include/media/media-devnode.h | 110 |
1 files changed, 90 insertions, 20 deletions
diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h index 3446af279fca..d27c1c646c28 100644 --- a/include/media/media-devnode.h +++ b/include/media/media-devnode.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * Media device node * @@ -6,19 +7,6 @@ * 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 - * * -- * * Common functions for media-related drivers to register and unregister media @@ -33,6 +21,8 @@ #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 @@ -40,11 +30,25 @@ */ #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 *); - unsigned int (*poll) (struct file *, struct poll_table_struct *); + __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 *); @@ -53,9 +57,15 @@ struct media_file_operations { /** * 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 + * @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. * @@ -63,6 +73,8 @@ struct media_file_operations { * before registering the node. */ struct media_devnode { + struct media_device *media_dev; + /* device ops */ const struct media_file_operations *fops; @@ -76,23 +88,81 @@ struct media_devnode { unsigned long flags; /* Use bitops to access flags */ /* callbacks */ - void (*release)(struct media_devnode *mdev); + void (*release)(struct media_devnode *devnode); }; /* dev to media_devnode */ #define to_media_devnode(cd) container_of(cd, struct media_devnode, dev) -int __must_check media_devnode_register(struct media_devnode *mdev); -void media_devnode_unregister(struct media_devnode *mdev); +/** + * 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; } -static inline int media_devnode_is_registered(struct media_devnode *mdev) +/** + * 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) { - return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags); + if (!devnode) + return false; + + return test_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); } #endif /* _MEDIA_DEVNODE_H */ |