1 /* 2 * Media device node 3 * 4 * Copyright (C) 2010 Nokia Corporation 5 * 6 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com> 7 * Sakari Ailus <sakari.ailus@iki.fi> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 * 22 * -- 23 * 24 * Common functions for media-related drivers to register and unregister media 25 * device nodes. 26 */ 27 28 #ifndef _MEDIA_DEVNODE_H 29 #define _MEDIA_DEVNODE_H 30 31 #include <linux/poll.h> 32 #include <linux/fs.h> 33 #include <linux/device.h> 34 #include <linux/cdev.h> 35 36 /* 37 * Flag to mark the media_devnode struct as registered. Drivers must not touch 38 * this flag directly, it will be set and cleared by media_devnode_register and 39 * media_devnode_unregister. 40 */ 41 #define MEDIA_FLAG_REGISTERED 0 42 43 struct media_file_operations { 44 struct module *owner; 45 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); 46 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); 47 unsigned int (*poll) (struct file *, struct poll_table_struct *); 48 long (*ioctl) (struct file *, unsigned int, unsigned long); 49 int (*open) (struct file *); 50 int (*release) (struct file *); 51 }; 52 53 /** 54 * struct media_devnode - Media device node 55 * @parent: parent device 56 * @minor: device node minor number 57 * @flags: flags, combination of the MEDIA_FLAG_* constants 58 * 59 * This structure represents a media-related device node. 60 * 61 * The @parent is a physical device. It must be set by core or device drivers 62 * before registering the node. 63 */ 64 struct media_devnode { 65 /* device ops */ 66 const struct media_file_operations *fops; 67 68 /* sysfs */ 69 struct device dev; /* media device */ 70 struct cdev cdev; /* character device */ 71 struct device *parent; /* device parent */ 72 73 /* device info */ 74 int minor; 75 unsigned long flags; /* Use bitops to access flags */ 76 77 /* callbacks */ 78 void (*release)(struct media_devnode *mdev); 79 }; 80 81 /* dev to media_devnode */ 82 #define to_media_devnode(cd) container_of(cd, struct media_devnode, dev) 83 84 int __must_check media_devnode_register(struct media_devnode *mdev); 85 void media_devnode_unregister(struct media_devnode *mdev); 86 87 static inline struct media_devnode *media_devnode_data(struct file *filp) 88 { 89 return filp->private_data; 90 } 91 92 static inline int media_devnode_is_registered(struct media_devnode *mdev) 93 { 94 return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags); 95 } 96 97 #endif /* _MEDIA_DEVNODE_H */ 98