1 files changed, 293 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
new file mode 100644
index 0000000000..d2e58ae91f
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+    V4L2 device support.
+
+    Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>
+
+ */
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/videodev2.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ctrls.h>
+
+int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
+{
+	if (v4l2_dev == NULL)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&v4l2_dev->subdevs);
+	spin_lock_init(&v4l2_dev->lock);
+	v4l2_prio_init(&v4l2_dev->prio);
+	kref_init(&v4l2_dev->ref);
+	get_device(dev);
+	v4l2_dev->dev = dev;
+	if (dev == NULL) {
+		/* If dev == NULL, then name must be filled in by the caller */
+		if (WARN_ON(!v4l2_dev->name[0]))
+			return -EINVAL;
+		return 0;
+	}
+
+	/* Set name to driver name + device name if it is empty. */
+	if (!v4l2_dev->name[0])
+		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
+			dev->driver->name, dev_name(dev));
+	if (!dev_get_drvdata(dev))
+		dev_set_drvdata(dev, v4l2_dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_register);
+
+static void v4l2_device_release(struct kref *ref)
+{
+	struct v4l2_device *v4l2_dev =
+		container_of(ref, struct v4l2_device, ref);
+
+	if (v4l2_dev->release)
+		v4l2_dev->release(v4l2_dev);
+}
+
+int v4l2_device_put(struct v4l2_device *v4l2_dev)
+{
+	return kref_put(&v4l2_dev->ref, v4l2_device_release);
+}
+EXPORT_SYMBOL_GPL(v4l2_device_put);
+
+int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
+						atomic_t *instance)
+{
+	int num = atomic_inc_return(instance) - 1;
+	int len = strlen(basename);
+
+	if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
+		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
+				"%s-%d", basename, num);
+	else
+		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
+				"%s%d", basename, num);
+	return num;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_set_name);
+
+void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
+{
+	if (v4l2_dev->dev == NULL)
+		return;
+
+	if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
+		dev_set_drvdata(v4l2_dev->dev, NULL);
+	put_device(v4l2_dev->dev);
+	v4l2_dev->dev = NULL;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
+
+void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
+{
+	struct v4l2_subdev *sd, *next;
+
+	/* Just return if v4l2_dev is NULL or if it was already
+	 * unregistered before. */
+	if (v4l2_dev == NULL || !v4l2_dev->name[0])
+		return;
+	v4l2_device_disconnect(v4l2_dev);
+
+	/* Unregister subdevs */
+	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
+		v4l2_device_unregister_subdev(sd);
+		if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)
+			v4l2_i2c_subdev_unregister(sd);
+		else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)
+			v4l2_spi_subdev_unregister(sd);
+	}
+	/* Mark as unregistered, thus preventing duplicate unregistrations */
+	v4l2_dev->name[0] = '\0';
+}
+EXPORT_SYMBOL_GPL(v4l2_device_unregister);
+
+int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
+				struct v4l2_subdev *sd)
+{
+	int err;
+
+	/* Check for valid input */
+	if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
+		return -EINVAL;
+
+	/*
+	 * The reason to acquire the module here is to avoid unloading
+	 * a module of sub-device which is registered to a media
+	 * device. To make it possible to unload modules for media
+	 * devices that also register sub-devices, do not
+	 * try_module_get() such sub-device owners.
+	 */
+	sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
+		sd->owner == v4l2_dev->dev->driver->owner;
+
+	if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
+		return -ENODEV;
+
+	sd->v4l2_dev = v4l2_dev;
+	/* This just returns 0 if either of the two args is NULL */
+	err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,
+				    NULL, true);
+	if (err)
+		goto error_module;
+
+#if defined(CONFIG_MEDIA_CONTROLLER)
+	/* Register the entity. */
+	if (v4l2_dev->mdev) {
+		err = media_device_register_entity(v4l2_dev->mdev, &sd->entity);
+		if (err < 0)
+			goto error_module;
+	}
+#endif
+
+	if (sd->internal_ops && sd->internal_ops->registered) {
+		err = sd->internal_ops->registered(sd);
+		if (err)
+			goto error_unregister;
+	}
+
+	spin_lock(&v4l2_dev->lock);
+	list_add_tail(&sd->list, &v4l2_dev->subdevs);
+	spin_unlock(&v4l2_dev->lock);
+
+	return 0;
+
+error_unregister:
+#if defined(CONFIG_MEDIA_CONTROLLER)
+	media_device_unregister_entity(&sd->entity);
+#endif
+error_module:
+	if (!sd->owner_v4l2_dev)
+		module_put(sd->owner);
+	sd->v4l2_dev = NULL;
+	return err;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
+
+static void v4l2_subdev_release(struct v4l2_subdev *sd)
+{
+	struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
+
+	if (sd->internal_ops && sd->internal_ops->release)
+		sd->internal_ops->release(sd);
+	sd->devnode = NULL;
+	module_put(owner);
+}
+
+static void v4l2_device_release_subdev_node(struct video_device *vdev)
+{
+	v4l2_subdev_release(video_get_drvdata(vdev));
+	kfree(vdev);
+}
+
+int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
+					bool read_only)
+{
+	struct video_device *vdev;
+	struct v4l2_subdev *sd;
+	int err;
+
+	/* Register a device node for every subdev marked with the
+	 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
+	 */
+	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
+		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
+			continue;
+
+		if (sd->devnode)
+			continue;
+
+		vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
+		if (!vdev) {
+			err = -ENOMEM;
+			goto clean_up;
+		}
+
+		video_set_drvdata(vdev, sd);
+		strscpy(vdev->name, sd->name, sizeof(vdev->name));
+		vdev->dev_parent = sd->dev;
+		vdev->v4l2_dev = v4l2_dev;
+		vdev->fops = &v4l2_subdev_fops;
+		vdev->release = v4l2_device_release_subdev_node;
+		vdev->ctrl_handler = sd->ctrl_handler;
+		if (read_only)
+			set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
+		sd->devnode = vdev;
+		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
+					      sd->owner);
+		if (err < 0) {
+			sd->devnode = NULL;
+			kfree(vdev);
+			goto clean_up;
+		}
+#if defined(CONFIG_MEDIA_CONTROLLER)
+		sd->entity.info.dev.major = VIDEO_MAJOR;
+		sd->entity.info.dev.minor = vdev->minor;
+
+		/* Interface is created by __video_register_device() */
+		if (vdev->v4l2_dev->mdev) {
+			struct media_link *link;
+
+			link = media_create_intf_link(&sd->entity,
+						      &vdev->intf_devnode->intf,
+						      MEDIA_LNK_FL_ENABLED |
+						      MEDIA_LNK_FL_IMMUTABLE);
+			if (!link) {
+				err = -ENOMEM;
+				goto clean_up;
+			}
+		}
+#endif
+	}
+	return 0;
+
+clean_up:
+	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
+		if (!sd->devnode)
+			break;
+		video_unregister_device(sd->devnode);
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);
+
+void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
+{
+	struct v4l2_device *v4l2_dev;
+
+	/* return if it isn't registered */
+	if (sd == NULL || sd->v4l2_dev == NULL)
+		return;
+
+	v4l2_dev = sd->v4l2_dev;
+
+	spin_lock(&v4l2_dev->lock);
+	list_del(&sd->list);
+	spin_unlock(&v4l2_dev->lock);
+
+	if (sd->internal_ops && sd->internal_ops->unregistered)
+		sd->internal_ops->unregistered(sd);
+	sd->v4l2_dev = NULL;
+
+#if defined(CONFIG_MEDIA_CONTROLLER)
+	if (v4l2_dev->mdev) {
+		/*
+		 * No need to explicitly remove links, as both pads and
+		 * links are removed by the function below, in the right order
+		 */
+		media_device_unregister_entity(&sd->entity);
+	}
+#endif
+	if (sd->devnode)
+		video_unregister_device(sd->devnode);
+	else
+		v4l2_subdev_release(sd);
+}
+EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);