1 /* 2 V4L2 device support. 3 4 Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl> 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 */ 20 21 #include <linux/types.h> 22 #include <linux/ioctl.h> 23 #include <linux/module.h> 24 #include <linux/i2c.h> 25 #include <linux/slab.h> 26 #if defined(CONFIG_SPI) 27 #include <linux/spi/spi.h> 28 #endif 29 #include <linux/videodev2.h> 30 #include <media/v4l2-device.h> 31 #include <media/v4l2-ctrls.h> 32 33 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) 34 { 35 if (v4l2_dev == NULL) 36 return -EINVAL; 37 38 INIT_LIST_HEAD(&v4l2_dev->subdevs); 39 spin_lock_init(&v4l2_dev->lock); 40 mutex_init(&v4l2_dev->ioctl_lock); 41 v4l2_prio_init(&v4l2_dev->prio); 42 kref_init(&v4l2_dev->ref); 43 get_device(dev); 44 v4l2_dev->dev = dev; 45 if (dev == NULL) { 46 /* If dev == NULL, then name must be filled in by the caller */ 47 if (WARN_ON(!v4l2_dev->name[0])) 48 return -EINVAL; 49 return 0; 50 } 51 52 /* Set name to driver name + device name if it is empty. */ 53 if (!v4l2_dev->name[0]) 54 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s", 55 dev->driver->name, dev_name(dev)); 56 if (!dev_get_drvdata(dev)) 57 dev_set_drvdata(dev, v4l2_dev); 58 return 0; 59 } 60 EXPORT_SYMBOL_GPL(v4l2_device_register); 61 62 static void v4l2_device_release(struct kref *ref) 63 { 64 struct v4l2_device *v4l2_dev = 65 container_of(ref, struct v4l2_device, ref); 66 67 if (v4l2_dev->release) 68 v4l2_dev->release(v4l2_dev); 69 } 70 71 int v4l2_device_put(struct v4l2_device *v4l2_dev) 72 { 73 return kref_put(&v4l2_dev->ref, v4l2_device_release); 74 } 75 EXPORT_SYMBOL_GPL(v4l2_device_put); 76 77 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename, 78 atomic_t *instance) 79 { 80 int num = atomic_inc_return(instance) - 1; 81 int len = strlen(basename); 82 83 if (basename[len - 1] >= '0' && basename[len - 1] <= '9') 84 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), 85 "%s-%d", basename, num); 86 else 87 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), 88 "%s%d", basename, num); 89 return num; 90 } 91 EXPORT_SYMBOL_GPL(v4l2_device_set_name); 92 93 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev) 94 { 95 if (v4l2_dev->dev == NULL) 96 return; 97 98 if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev) 99 dev_set_drvdata(v4l2_dev->dev, NULL); 100 put_device(v4l2_dev->dev); 101 v4l2_dev->dev = NULL; 102 } 103 EXPORT_SYMBOL_GPL(v4l2_device_disconnect); 104 105 void v4l2_device_unregister(struct v4l2_device *v4l2_dev) 106 { 107 struct v4l2_subdev *sd, *next; 108 109 /* Just return if v4l2_dev is NULL or if it was already 110 * unregistered before. */ 111 if (v4l2_dev == NULL || !v4l2_dev->name[0]) 112 return; 113 v4l2_device_disconnect(v4l2_dev); 114 115 /* Unregister subdevs */ 116 list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) { 117 v4l2_device_unregister_subdev(sd); 118 #if IS_ENABLED(CONFIG_I2C) 119 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) { 120 struct i2c_client *client = v4l2_get_subdevdata(sd); 121 122 /* We need to unregister the i2c client explicitly. 123 We cannot rely on i2c_del_adapter to always 124 unregister clients for us, since if the i2c bus 125 is a platform bus, then it is never deleted. */ 126 if (client) 127 i2c_unregister_device(client); 128 continue; 129 } 130 #endif 131 #if defined(CONFIG_SPI) 132 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) { 133 struct spi_device *spi = v4l2_get_subdevdata(sd); 134 135 if (spi) 136 spi_unregister_device(spi); 137 continue; 138 } 139 #endif 140 } 141 /* Mark as unregistered, thus preventing duplicate unregistrations */ 142 v4l2_dev->name[0] = '\0'; 143 } 144 EXPORT_SYMBOL_GPL(v4l2_device_unregister); 145 146 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, 147 struct v4l2_subdev *sd) 148 { 149 #if defined(CONFIG_MEDIA_CONTROLLER) 150 struct media_entity *entity = &sd->entity; 151 #endif 152 int err; 153 154 /* Check for valid input */ 155 if (v4l2_dev == NULL || sd == NULL || !sd->name[0]) 156 return -EINVAL; 157 158 /* Warn if we apparently re-register a subdev */ 159 WARN_ON(sd->v4l2_dev != NULL); 160 161 /* 162 * The reason to acquire the module here is to avoid unloading 163 * a module of sub-device which is registered to a media 164 * device. To make it possible to unload modules for media 165 * devices that also register sub-devices, do not 166 * try_module_get() such sub-device owners. 167 */ 168 sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver && 169 sd->owner == v4l2_dev->dev->driver->owner; 170 171 if (!sd->owner_v4l2_dev && !try_module_get(sd->owner)) 172 return -ENODEV; 173 174 sd->v4l2_dev = v4l2_dev; 175 if (sd->internal_ops && sd->internal_ops->registered) { 176 err = sd->internal_ops->registered(sd); 177 if (err) 178 goto error_module; 179 } 180 181 /* This just returns 0 if either of the two args is NULL */ 182 err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL); 183 if (err) 184 goto error_unregister; 185 186 #if defined(CONFIG_MEDIA_CONTROLLER) 187 /* Register the entity. */ 188 if (v4l2_dev->mdev) { 189 err = media_device_register_entity(v4l2_dev->mdev, entity); 190 if (err < 0) 191 goto error_unregister; 192 } 193 #endif 194 195 spin_lock(&v4l2_dev->lock); 196 list_add_tail(&sd->list, &v4l2_dev->subdevs); 197 spin_unlock(&v4l2_dev->lock); 198 199 return 0; 200 201 error_unregister: 202 if (sd->internal_ops && sd->internal_ops->unregistered) 203 sd->internal_ops->unregistered(sd); 204 error_module: 205 if (!sd->owner_v4l2_dev) 206 module_put(sd->owner); 207 sd->v4l2_dev = NULL; 208 return err; 209 } 210 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev); 211 212 static void v4l2_device_release_subdev_node(struct video_device *vdev) 213 { 214 struct v4l2_subdev *sd = video_get_drvdata(vdev); 215 sd->devnode = NULL; 216 kfree(vdev); 217 } 218 219 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev) 220 { 221 struct video_device *vdev; 222 struct v4l2_subdev *sd; 223 int err; 224 225 /* Register a device node for every subdev marked with the 226 * V4L2_SUBDEV_FL_HAS_DEVNODE flag. 227 */ 228 list_for_each_entry(sd, &v4l2_dev->subdevs, list) { 229 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE)) 230 continue; 231 232 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL); 233 if (!vdev) { 234 err = -ENOMEM; 235 goto clean_up; 236 } 237 238 video_set_drvdata(vdev, sd); 239 strlcpy(vdev->name, sd->name, sizeof(vdev->name)); 240 vdev->v4l2_dev = v4l2_dev; 241 vdev->fops = &v4l2_subdev_fops; 242 vdev->release = v4l2_device_release_subdev_node; 243 vdev->ctrl_handler = sd->ctrl_handler; 244 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1, 245 sd->owner); 246 if (err < 0) { 247 kfree(vdev); 248 goto clean_up; 249 } 250 #if defined(CONFIG_MEDIA_CONTROLLER) 251 sd->entity.info.dev.major = VIDEO_MAJOR; 252 sd->entity.info.dev.minor = vdev->minor; 253 #endif 254 sd->devnode = vdev; 255 } 256 return 0; 257 258 clean_up: 259 list_for_each_entry(sd, &v4l2_dev->subdevs, list) { 260 if (!sd->devnode) 261 break; 262 video_unregister_device(sd->devnode); 263 } 264 265 return err; 266 } 267 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes); 268 269 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd) 270 { 271 struct v4l2_device *v4l2_dev; 272 273 /* return if it isn't registered */ 274 if (sd == NULL || sd->v4l2_dev == NULL) 275 return; 276 277 v4l2_dev = sd->v4l2_dev; 278 279 spin_lock(&v4l2_dev->lock); 280 list_del(&sd->list); 281 spin_unlock(&v4l2_dev->lock); 282 283 if (sd->internal_ops && sd->internal_ops->unregistered) 284 sd->internal_ops->unregistered(sd); 285 sd->v4l2_dev = NULL; 286 287 #if defined(CONFIG_MEDIA_CONTROLLER) 288 if (v4l2_dev->mdev) { 289 media_entity_remove_links(&sd->entity); 290 media_device_unregister_entity(&sd->entity); 291 } 292 #endif 293 video_unregister_device(sd->devnode); 294 if (!sd->owner_v4l2_dev) 295 module_put(sd->owner); 296 } 297 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev); 298