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 v4l2_prio_init(&v4l2_dev->prio); 41 kref_init(&v4l2_dev->ref); 42 get_device(dev); 43 v4l2_dev->dev = dev; 44 if (dev == NULL) { 45 /* If dev == NULL, then name must be filled in by the caller */ 46 if (WARN_ON(!v4l2_dev->name[0])) 47 return -EINVAL; 48 return 0; 49 } 50 51 /* Set name to driver name + device name if it is empty. */ 52 if (!v4l2_dev->name[0]) 53 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s", 54 dev->driver->name, dev_name(dev)); 55 if (!dev_get_drvdata(dev)) 56 dev_set_drvdata(dev, v4l2_dev); 57 return 0; 58 } 59 EXPORT_SYMBOL_GPL(v4l2_device_register); 60 61 static void v4l2_device_release(struct kref *ref) 62 { 63 struct v4l2_device *v4l2_dev = 64 container_of(ref, struct v4l2_device, ref); 65 66 if (v4l2_dev->release) 67 v4l2_dev->release(v4l2_dev); 68 } 69 70 int v4l2_device_put(struct v4l2_device *v4l2_dev) 71 { 72 return kref_put(&v4l2_dev->ref, v4l2_device_release); 73 } 74 EXPORT_SYMBOL_GPL(v4l2_device_put); 75 76 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename, 77 atomic_t *instance) 78 { 79 int num = atomic_inc_return(instance) - 1; 80 int len = strlen(basename); 81 82 if (basename[len - 1] >= '0' && basename[len - 1] <= '9') 83 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), 84 "%s-%d", basename, num); 85 else 86 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), 87 "%s%d", basename, num); 88 return num; 89 } 90 EXPORT_SYMBOL_GPL(v4l2_device_set_name); 91 92 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev) 93 { 94 if (v4l2_dev->dev == NULL) 95 return; 96 97 if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev) 98 dev_set_drvdata(v4l2_dev->dev, NULL); 99 put_device(v4l2_dev->dev); 100 v4l2_dev->dev = NULL; 101 } 102 EXPORT_SYMBOL_GPL(v4l2_device_disconnect); 103 104 void v4l2_device_unregister(struct v4l2_device *v4l2_dev) 105 { 106 struct v4l2_subdev *sd, *next; 107 108 /* Just return if v4l2_dev is NULL or if it was already 109 * unregistered before. */ 110 if (v4l2_dev == NULL || !v4l2_dev->name[0]) 111 return; 112 v4l2_device_disconnect(v4l2_dev); 113 114 /* Unregister subdevs */ 115 list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) { 116 v4l2_device_unregister_subdev(sd); 117 #if IS_ENABLED(CONFIG_I2C) 118 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) { 119 struct i2c_client *client = v4l2_get_subdevdata(sd); 120 121 /* We need to unregister the i2c client explicitly. 122 We cannot rely on i2c_del_adapter to always 123 unregister clients for us, since if the i2c bus 124 is a platform bus, then it is never deleted. */ 125 if (client) 126 i2c_unregister_device(client); 127 continue; 128 } 129 #endif 130 #if defined(CONFIG_SPI) 131 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) { 132 struct spi_device *spi = v4l2_get_subdevdata(sd); 133 134 if (spi) 135 spi_unregister_device(spi); 136 continue; 137 } 138 #endif 139 } 140 /* Mark as unregistered, thus preventing duplicate unregistrations */ 141 v4l2_dev->name[0] = '\0'; 142 } 143 EXPORT_SYMBOL_GPL(v4l2_device_unregister); 144 145 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, 146 struct v4l2_subdev *sd) 147 { 148 #if defined(CONFIG_MEDIA_CONTROLLER) 149 struct media_entity *entity = &sd->entity; 150 #endif 151 int err; 152 153 /* Check for valid input */ 154 if (v4l2_dev == NULL || sd == NULL || !sd->name[0]) 155 return -EINVAL; 156 157 /* Warn if we apparently re-register a subdev */ 158 WARN_ON(sd->v4l2_dev != NULL); 159 160 /* 161 * The reason to acquire the module here is to avoid unloading 162 * a module of sub-device which is registered to a media 163 * device. To make it possible to unload modules for media 164 * devices that also register sub-devices, do not 165 * try_module_get() such sub-device owners. 166 */ 167 sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver && 168 sd->owner == v4l2_dev->dev->driver->owner; 169 170 if (!sd->owner_v4l2_dev && !try_module_get(sd->owner)) 171 return -ENODEV; 172 173 sd->v4l2_dev = v4l2_dev; 174 if (sd->internal_ops && sd->internal_ops->registered) { 175 err = sd->internal_ops->registered(sd); 176 if (err) 177 goto error_module; 178 } 179 180 /* This just returns 0 if either of the two args is NULL */ 181 err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL); 182 if (err) 183 goto error_unregister; 184 185 #if defined(CONFIG_MEDIA_CONTROLLER) 186 /* Register the entity. */ 187 if (v4l2_dev->mdev) { 188 err = media_device_register_entity(v4l2_dev->mdev, entity); 189 if (err < 0) 190 goto error_unregister; 191 } 192 #endif 193 194 spin_lock(&v4l2_dev->lock); 195 list_add_tail(&sd->list, &v4l2_dev->subdevs); 196 spin_unlock(&v4l2_dev->lock); 197 198 return 0; 199 200 error_unregister: 201 if (sd->internal_ops && sd->internal_ops->unregistered) 202 sd->internal_ops->unregistered(sd); 203 error_module: 204 if (!sd->owner_v4l2_dev) 205 module_put(sd->owner); 206 sd->v4l2_dev = NULL; 207 return err; 208 } 209 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev); 210 211 static void v4l2_device_release_subdev_node(struct video_device *vdev) 212 { 213 struct v4l2_subdev *sd = video_get_drvdata(vdev); 214 sd->devnode = NULL; 215 kfree(vdev); 216 } 217 218 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev) 219 { 220 struct video_device *vdev; 221 struct v4l2_subdev *sd; 222 int err; 223 224 /* Register a device node for every subdev marked with the 225 * V4L2_SUBDEV_FL_HAS_DEVNODE flag. 226 */ 227 list_for_each_entry(sd, &v4l2_dev->subdevs, list) { 228 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE)) 229 continue; 230 231 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL); 232 if (!vdev) { 233 err = -ENOMEM; 234 goto clean_up; 235 } 236 237 video_set_drvdata(vdev, sd); 238 strlcpy(vdev->name, sd->name, sizeof(vdev->name)); 239 vdev->v4l2_dev = v4l2_dev; 240 vdev->fops = &v4l2_subdev_fops; 241 vdev->release = v4l2_device_release_subdev_node; 242 vdev->ctrl_handler = sd->ctrl_handler; 243 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1, 244 sd->owner); 245 if (err < 0) { 246 kfree(vdev); 247 goto clean_up; 248 } 249 #if defined(CONFIG_MEDIA_CONTROLLER) 250 sd->entity.info.dev.major = VIDEO_MAJOR; 251 sd->entity.info.dev.minor = vdev->minor; 252 #endif 253 sd->devnode = vdev; 254 } 255 return 0; 256 257 clean_up: 258 list_for_each_entry(sd, &v4l2_dev->subdevs, list) { 259 if (!sd->devnode) 260 break; 261 video_unregister_device(sd->devnode); 262 } 263 264 return err; 265 } 266 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes); 267 268 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd) 269 { 270 struct v4l2_device *v4l2_dev; 271 272 /* return if it isn't registered */ 273 if (sd == NULL || sd->v4l2_dev == NULL) 274 return; 275 276 v4l2_dev = sd->v4l2_dev; 277 278 spin_lock(&v4l2_dev->lock); 279 list_del(&sd->list); 280 spin_unlock(&v4l2_dev->lock); 281 282 if (sd->internal_ops && sd->internal_ops->unregistered) 283 sd->internal_ops->unregistered(sd); 284 sd->v4l2_dev = NULL; 285 286 #if defined(CONFIG_MEDIA_CONTROLLER) 287 if (v4l2_dev->mdev) { 288 media_entity_remove_links(&sd->entity); 289 media_device_unregister_entity(&sd->entity); 290 } 291 #endif 292 video_unregister_device(sd->devnode); 293 if (!sd->owner_v4l2_dev) 294 module_put(sd->owner); 295 } 296 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev); 297