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
 33int 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}
 59EXPORT_SYMBOL_GPL(v4l2_device_register);
 60
 61static 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
 70int v4l2_device_put(struct v4l2_device *v4l2_dev)
 71{
 72	return kref_put(&v4l2_dev->ref, v4l2_device_release);
 73}
 74EXPORT_SYMBOL_GPL(v4l2_device_put);
 75
 76int 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}
 90EXPORT_SYMBOL_GPL(v4l2_device_set_name);
 91
 92void 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}
102EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
103
104void 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			/*
122			 * We need to unregister the i2c client
123			 * explicitly. We cannot rely on
124			 * i2c_del_adapter to always unregister
125			 * clients for us, since if the i2c bus is a
126			 * platform bus, then it is never deleted.
127			 *
128			 * Device tree or ACPI based devices must not
129			 * be unregistered as they have not been
130			 * registered by us, and would not be
131			 * re-created by just probing the V4L2 driver.
132			 */
133			if (client &&
134			    !client->dev.of_node && !client->dev.fwnode)
135				i2c_unregister_device(client);
136			continue;
137		}
138#endif
139#if defined(CONFIG_SPI)
140		if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
141			struct spi_device *spi = v4l2_get_subdevdata(sd);
142
143			if (spi && !spi->dev.of_node && !spi->dev.fwnode)
144				spi_unregister_device(spi);
145			continue;
146		}
147#endif
148	}
149	/* Mark as unregistered, thus preventing duplicate unregistrations */
150	v4l2_dev->name[0] = '\0';
151}
152EXPORT_SYMBOL_GPL(v4l2_device_unregister);
153
154int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
155				struct v4l2_subdev *sd)
156{
157#if defined(CONFIG_MEDIA_CONTROLLER)
158	struct media_entity *entity = &sd->entity;
159#endif
160	int err;
161
162	/* Check for valid input */
163	if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
164		return -EINVAL;
165
166	/* Warn if we apparently re-register a subdev */
167	WARN_ON(sd->v4l2_dev != NULL);
168
169	/*
170	 * The reason to acquire the module here is to avoid unloading
171	 * a module of sub-device which is registered to a media
172	 * device. To make it possible to unload modules for media
173	 * devices that also register sub-devices, do not
174	 * try_module_get() such sub-device owners.
175	 */
176	sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
177		sd->owner == v4l2_dev->dev->driver->owner;
178
179	if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
180		return -ENODEV;
181
182	sd->v4l2_dev = v4l2_dev;
183	/* This just returns 0 if either of the two args is NULL */
184	err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL);
185	if (err)
186		goto error_module;
187
188#if defined(CONFIG_MEDIA_CONTROLLER)
189	/* Register the entity. */
190	if (v4l2_dev->mdev) {
191		err = media_device_register_entity(v4l2_dev->mdev, entity);
192		if (err < 0)
193			goto error_module;
194	}
195#endif
196
197	if (sd->internal_ops && sd->internal_ops->registered) {
198		err = sd->internal_ops->registered(sd);
199		if (err)
200			goto error_unregister;
201	}
202
203	spin_lock(&v4l2_dev->lock);
204	list_add_tail(&sd->list, &v4l2_dev->subdevs);
205	spin_unlock(&v4l2_dev->lock);
206
207	return 0;
208
209error_unregister:
210#if defined(CONFIG_MEDIA_CONTROLLER)
211	media_device_unregister_entity(entity);
212#endif
213error_module:
214	if (!sd->owner_v4l2_dev)
215		module_put(sd->owner);
216	sd->v4l2_dev = NULL;
217	return err;
218}
219EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
220
221static void v4l2_device_release_subdev_node(struct video_device *vdev)
222{
223	struct v4l2_subdev *sd = video_get_drvdata(vdev);
224	sd->devnode = NULL;
225	kfree(vdev);
226}
227
228int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
229{
230	struct video_device *vdev;
231	struct v4l2_subdev *sd;
232	int err;
233
234	/* Register a device node for every subdev marked with the
235	 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
236	 */
237	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
238		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
239			continue;
240
241		vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
242		if (!vdev) {
243			err = -ENOMEM;
244			goto clean_up;
245		}
246
247		video_set_drvdata(vdev, sd);
248		strlcpy(vdev->name, sd->name, sizeof(vdev->name));
249		vdev->v4l2_dev = v4l2_dev;
250		vdev->fops = &v4l2_subdev_fops;
251		vdev->release = v4l2_device_release_subdev_node;
252		vdev->ctrl_handler = sd->ctrl_handler;
253		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
254					      sd->owner);
255		if (err < 0) {
256			kfree(vdev);
257			goto clean_up;
258		}
259#if defined(CONFIG_MEDIA_CONTROLLER)
260		sd->entity.info.dev.major = VIDEO_MAJOR;
261		sd->entity.info.dev.minor = vdev->minor;
262
263		/* Interface is created by __video_register_device() */
264		if (vdev->v4l2_dev->mdev) {
265			struct media_link *link;
266
267			link = media_create_intf_link(&sd->entity,
268						      &vdev->intf_devnode->intf,
269						      MEDIA_LNK_FL_ENABLED);
270			if (!link) {
271				err = -ENOMEM;
272				goto clean_up;
273			}
274		}
275#endif
276		sd->devnode = vdev;
277	}
278	return 0;
279
280clean_up:
281	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
282		if (!sd->devnode)
283			break;
284		video_unregister_device(sd->devnode);
285	}
286
287	return err;
288}
289EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
290
291void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
292{
293	struct v4l2_device *v4l2_dev;
294
295	/* return if it isn't registered */
296	if (sd == NULL || sd->v4l2_dev == NULL)
297		return;
298
299	v4l2_dev = sd->v4l2_dev;
300
301	spin_lock(&v4l2_dev->lock);
302	list_del(&sd->list);
303	spin_unlock(&v4l2_dev->lock);
304
305	if (sd->internal_ops && sd->internal_ops->unregistered)
306		sd->internal_ops->unregistered(sd);
307	sd->v4l2_dev = NULL;
308
309#if defined(CONFIG_MEDIA_CONTROLLER)
310	if (v4l2_dev->mdev) {
311		/*
312		 * No need to explicitly remove links, as both pads and
313		 * links are removed by the function below, in the right order
314		 */
315		media_device_unregister_entity(&sd->entity);
316	}
317#endif
318	video_unregister_device(sd->devnode);
319	if (!sd->owner_v4l2_dev)
320		module_put(sd->owner);
321}
322EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);