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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 V4L2 device support.4 5 Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>6 7 */8 9#include <linux/types.h>10#include <linux/ioctl.h>11#include <linux/module.h>12#include <linux/slab.h>13#include <linux/videodev2.h>14#include <media/v4l2-device.h>15#include <media/v4l2-ctrls.h>16 17int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)18{19 if (v4l2_dev == NULL)20 return -EINVAL;21 22 INIT_LIST_HEAD(&v4l2_dev->subdevs);23 spin_lock_init(&v4l2_dev->lock);24 v4l2_prio_init(&v4l2_dev->prio);25 kref_init(&v4l2_dev->ref);26 get_device(dev);27 v4l2_dev->dev = dev;28 if (dev == NULL) {29 /* If dev == NULL, then name must be filled in by the caller */30 if (WARN_ON(!v4l2_dev->name[0]))31 return -EINVAL;32 return 0;33 }34 35 /* Set name to driver name + device name if it is empty. */36 if (!v4l2_dev->name[0])37 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",38 dev->driver->name, dev_name(dev));39 if (!dev_get_drvdata(dev))40 dev_set_drvdata(dev, v4l2_dev);41 return 0;42}43EXPORT_SYMBOL_GPL(v4l2_device_register);44 45static void v4l2_device_release(struct kref *ref)46{47 struct v4l2_device *v4l2_dev =48 container_of(ref, struct v4l2_device, ref);49 50 if (v4l2_dev->release)51 v4l2_dev->release(v4l2_dev);52}53 54int v4l2_device_put(struct v4l2_device *v4l2_dev)55{56 return kref_put(&v4l2_dev->ref, v4l2_device_release);57}58EXPORT_SYMBOL_GPL(v4l2_device_put);59 60int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,61 atomic_t *instance)62{63 int num = atomic_inc_return(instance) - 1;64 int len = strlen(basename);65 66 if (basename[len - 1] >= '0' && basename[len - 1] <= '9')67 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),68 "%s-%d", basename, num);69 else70 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),71 "%s%d", basename, num);72 return num;73}74EXPORT_SYMBOL_GPL(v4l2_device_set_name);75 76void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)77{78 if (v4l2_dev->dev == NULL)79 return;80 81 if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)82 dev_set_drvdata(v4l2_dev->dev, NULL);83 put_device(v4l2_dev->dev);84 v4l2_dev->dev = NULL;85}86EXPORT_SYMBOL_GPL(v4l2_device_disconnect);87 88void v4l2_device_unregister(struct v4l2_device *v4l2_dev)89{90 struct v4l2_subdev *sd, *next;91 92 /* Just return if v4l2_dev is NULL or if it was already93 * unregistered before. */94 if (v4l2_dev == NULL || !v4l2_dev->name[0])95 return;96 v4l2_device_disconnect(v4l2_dev);97 98 /* Unregister subdevs */99 list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {100 v4l2_device_unregister_subdev(sd);101 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)102 v4l2_i2c_subdev_unregister(sd);103 else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)104 v4l2_spi_subdev_unregister(sd);105 }106 /* Mark as unregistered, thus preventing duplicate unregistrations */107 v4l2_dev->name[0] = '\0';108}109EXPORT_SYMBOL_GPL(v4l2_device_unregister);110 111int __v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,112 struct v4l2_subdev *sd, struct module *module)113{114 int err;115 116 /* Check for valid input */117 if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])118 return -EINVAL;119 120 /*121 * The reason to acquire the module here is to avoid unloading122 * a module of sub-device which is registered to a media123 * device. To make it possible to unload modules for media124 * devices that also register sub-devices, do not125 * try_module_get() such sub-device owners.126 */127 sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&128 module == v4l2_dev->dev->driver->owner;129 130 if (!sd->owner_v4l2_dev && !try_module_get(module))131 return -ENODEV;132 133 sd->v4l2_dev = v4l2_dev;134 /* This just returns 0 if either of the two args is NULL */135 err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,136 NULL, true);137 if (err)138 goto error_module;139 140#if defined(CONFIG_MEDIA_CONTROLLER)141 /* Register the entity. */142 if (v4l2_dev->mdev) {143 err = media_device_register_entity(v4l2_dev->mdev, &sd->entity);144 if (err < 0)145 goto error_module;146 }147#endif148 149 if (sd->internal_ops && sd->internal_ops->registered) {150 err = sd->internal_ops->registered(sd);151 if (err)152 goto error_unregister;153 }154 155 sd->owner = module;156 157 spin_lock(&v4l2_dev->lock);158 list_add_tail(&sd->list, &v4l2_dev->subdevs);159 spin_unlock(&v4l2_dev->lock);160 161 return 0;162 163error_unregister:164#if defined(CONFIG_MEDIA_CONTROLLER)165 media_device_unregister_entity(&sd->entity);166#endif167error_module:168 if (!sd->owner_v4l2_dev)169 module_put(sd->owner);170 sd->v4l2_dev = NULL;171 return err;172}173EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev);174 175static void v4l2_subdev_release(struct v4l2_subdev *sd)176{177 struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;178 179 if (sd->internal_ops && sd->internal_ops->release)180 sd->internal_ops->release(sd);181 sd->devnode = NULL;182 module_put(owner);183}184 185static void v4l2_device_release_subdev_node(struct video_device *vdev)186{187 v4l2_subdev_release(video_get_drvdata(vdev));188 kfree(vdev);189}190 191int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,192 bool read_only)193{194 struct video_device *vdev;195 struct v4l2_subdev *sd;196 int err;197 198 /* Register a device node for every subdev marked with the199 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.200 */201 list_for_each_entry(sd, &v4l2_dev->subdevs, list) {202 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))203 continue;204 205 if (sd->devnode)206 continue;207 208 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);209 if (!vdev) {210 err = -ENOMEM;211 goto clean_up;212 }213 214 video_set_drvdata(vdev, sd);215 strscpy(vdev->name, sd->name, sizeof(vdev->name));216 vdev->dev_parent = sd->dev;217 vdev->v4l2_dev = v4l2_dev;218 vdev->fops = &v4l2_subdev_fops;219 vdev->release = v4l2_device_release_subdev_node;220 vdev->ctrl_handler = sd->ctrl_handler;221 if (read_only)222 set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);223 sd->devnode = vdev;224 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,225 sd->owner);226 if (err < 0) {227 sd->devnode = NULL;228 kfree(vdev);229 goto clean_up;230 }231#if defined(CONFIG_MEDIA_CONTROLLER)232 sd->entity.info.dev.major = VIDEO_MAJOR;233 sd->entity.info.dev.minor = vdev->minor;234 235 /* Interface is created by __video_register_device() */236 if (vdev->v4l2_dev->mdev) {237 struct media_link *link;238 239 link = media_create_intf_link(&sd->entity,240 &vdev->intf_devnode->intf,241 MEDIA_LNK_FL_ENABLED |242 MEDIA_LNK_FL_IMMUTABLE);243 if (!link) {244 err = -ENOMEM;245 goto clean_up;246 }247 }248#endif249 }250 return 0;251 252clean_up:253 list_for_each_entry(sd, &v4l2_dev->subdevs, list) {254 if (!sd->devnode)255 break;256 video_unregister_device(sd->devnode);257 }258 259 return err;260}261EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);262 263void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)264{265 struct v4l2_device *v4l2_dev;266 267 /* return if it isn't registered */268 if (sd == NULL || sd->v4l2_dev == NULL)269 return;270 271 v4l2_dev = sd->v4l2_dev;272 273 spin_lock(&v4l2_dev->lock);274 list_del(&sd->list);275 spin_unlock(&v4l2_dev->lock);276 277 if (sd->internal_ops && sd->internal_ops->unregistered)278 sd->internal_ops->unregistered(sd);279 sd->v4l2_dev = NULL;280 281#if defined(CONFIG_MEDIA_CONTROLLER)282 if (v4l2_dev->mdev) {283 /*284 * No need to explicitly remove links, as both pads and285 * links are removed by the function below, in the right order286 */287 media_device_unregister_entity(&sd->entity);288 }289#endif290 if (sd->devnode)291 video_unregister_device(sd->devnode);292 else293 v4l2_subdev_release(sd);294}295EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);296