path: root/drivers/media/v4l2-core/v4l2-async.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * V4L2 asynchronous subdevice registration API
 *
 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 */

#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <media/v4l2-async.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-subdev.h>

#include "v4l2-subdev-priv.h"

static int v4l2_async_nf_call_bound(struct v4l2_async_notifier *n,
				    struct v4l2_subdev *subdev,
				    struct v4l2_async_connection *asc)
{
	if (!n->ops || !n->ops->bound)
		return 0;

	return n->ops->bound(n, subdev, asc);
}

static void v4l2_async_nf_call_unbind(struct v4l2_async_notifier *n,
				      struct v4l2_subdev *subdev,
				      struct v4l2_async_connection *asc)
{
	if (!n->ops || !n->ops->unbind)
		return;

	n->ops->unbind(n, subdev, asc);
}

static int v4l2_async_nf_call_complete(struct v4l2_async_notifier *n)
{
	if (!n->ops || !n->ops->complete)
		return 0;

	return n->ops->complete(n);
}

static void v4l2_async_nf_call_destroy(struct v4l2_async_notifier *n,
				       struct v4l2_async_connection *asc)
{
	if (!n->ops || !n->ops->destroy)
		return;

	n->ops->destroy(asc);
}

static bool match_i2c(struct v4l2_async_notifier *notifier,
		      struct v4l2_subdev *sd,
		      struct v4l2_async_match_desc *match)
{
#if IS_ENABLED(CONFIG_I2C)
	struct i2c_client *client = i2c_verify_client(sd->dev);

	return client &&
		match->i2c.adapter_id == client->adapter->nr &&
		match->i2c.address == client->addr;
#else
	return false;
#endif
}

static struct device *notifier_dev(struct v4l2_async_notifier *notifier)
{
	if (notifier->sd)
		return notifier->sd->dev;

	if (notifier->v4l2_dev)
		return notifier->v4l2_dev->dev;

	return NULL;
}

static bool
match_fwnode_one(struct v4l2_async_notifier *notifier,
		 struct v4l2_subdev *sd, struct fwnode_handle *sd_fwnode,
		 struct v4l2_async_match_desc *match)
{
	struct fwnode_handle *asd_dev_fwnode;
	bool ret;

	dev_dbg(notifier_dev(notifier),
		"v4l2-async: fwnode match: need %pfw, trying %pfw\n",
		sd_fwnode, match->fwnode);

	if (sd_fwnode == match->fwnode) {
		dev_dbg(notifier_dev(notifier),
			"v4l2-async: direct match found\n");
		return true;
	}

	if (!fwnode_graph_is_endpoint(match->fwnode)) {
		dev_dbg(notifier_dev(notifier),
			"v4l2-async: direct match not found\n");
		return false;
	}

	asd_dev_fwnode = fwnode_graph_get_port_parent(match->fwnode);

	ret = sd_fwnode == asd_dev_fwnode;

	fwnode_handle_put(asd_dev_fwnode);

	dev_dbg(notifier_dev(notifier),
		"v4l2-async: device--endpoint match %sfound\n",
		ret ? "" : "not ");

	return ret;
}

static bool match_fwnode(struct v4l2_async_notifier *notifier,
			 struct v4l2_subdev *sd,
			 struct v4l2_async_match_desc *match)
{
	dev_dbg(notifier_dev(notifier),
		"v4l2-async: matching for notifier %pfw, sd fwnode %pfw\n",
		dev_fwnode(notifier_dev(notifier)), sd->fwnode);

	if (!list_empty(&sd->async_subdev_endpoint_list)) {
		struct v4l2_async_subdev_endpoint *ase;

		dev_dbg(sd->dev,
			"v4l2-async: endpoint fwnode list available, looking for %pfw\n",
			match->fwnode);

		list_for_each_entry(ase, &sd->async_subdev_endpoint_list,
				    async_subdev_endpoint_entry) {
			bool matched = ase->endpoint == match->fwnode;

			dev_dbg(sd->dev,
				"v4l2-async: endpoint-endpoint match %sfound with %pfw\n",
				matched ? "" : "not ", ase->endpoint);

			if (matched)
				return true;
		}

		dev_dbg(sd->dev, "async: no endpoint matched\n");

		return false;
	}

	if (match_fwnode_one(notifier, sd, sd->fwnode, match))
		return true;

	/* Also check the secondary fwnode. */
	if (IS_ERR_OR_NULL(sd->fwnode->secondary))
		return false;

	dev_dbg(notifier_dev(notifier),
		"v4l2-async: trying secondary fwnode match\n");

	return match_fwnode_one(notifier, sd, sd->fwnode->secondary, match);
}

static LIST_HEAD(subdev_list);
static LIST_HEAD(notifier_list);
static DEFINE_MUTEX(list_lock);

static struct v4l2_async_connection *
v4l2_async_find_match(struct v4l2_async_notifier *notifier,
		      struct v4l2_subdev *sd)
{
	bool (*match)(struct v4l2_async_notifier *notifier,
		      struct v4l2_subdev *sd,
		      struct v4l2_async_match_desc *match);
	struct v4l2_async_connection *asc;

	list_for_each_entry(asc, &notifier->waiting_list, asc_entry) {
		/* bus_type has been verified valid before */
		switch (asc->match.type) {
		case V4L2_ASYNC_MATCH_TYPE_I2C:
			match = match_i2c;
			break;
		case V4L2_ASYNC_MATCH_TYPE_FWNODE:
			match = match_fwnode;
			break;
		default:
			/* Cannot happen, unless someone breaks us */
			WARN_ON(true);
			return NULL;
		}

		/* match cannot be NULL here */
		if (match(notifier, sd, &asc->