1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
new file mode 100644
index 000000000000..aae241730caa
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -0,0 +1,284 @@
+/*
+ * V4L2 asynchronous subdevice registration API
+ *
+ * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <media/v4l2-async.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-subdev.h>
+
+static bool match_i2c(struct device *dev, struct v4l2_async_subdev *asd)
+{
+#if IS_ENABLED(CONFIG_I2C)
+	struct i2c_client *client = i2c_verify_client(dev);
+	return client &&
+		asd->bus_type == V4L2_ASYNC_BUS_I2C &&
+		asd->match.i2c.adapter_id == client->adapter->nr &&
+		asd->match.i2c.address == client->addr;
+#else
+	return false;
+#endif
+}
+
+static bool match_platform(struct device *dev, struct v4l2_async_subdev *asd)
+{
+	return asd->bus_type == V4L2_ASYNC_BUS_PLATFORM &&
+		!strcmp(asd->match.platform.name, dev_name(dev));
+}
+
+static LIST_HEAD(subdev_list);
+static LIST_HEAD(notifier_list);
+static DEFINE_MUTEX(list_lock);
+
+static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *notifier,
+						    struct v4l2_async_subdev_list *asdl)
+{
+	struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl);
+	struct v4l2_async_subdev *asd;
+	bool (*match)(struct device *,
+		      struct v4l2_async_subdev *);
+
+	list_for_each_entry(asd, &notifier->waiting, list) {
+		/* bus_type has been verified valid before */
+		switch (asd->bus_type) {
+		case V4L2_ASYNC_BUS_CUSTOM:
+			match = asd->match.custom.match;
+			if (!match)
+				/* Match always */
+				return asd;
+			break;
+		case V4L2_ASYNC_BUS_PLATFORM:
+			match = match_platform;
+			break;
+		case V4L2_ASYNC_BUS_I2C:
+			match = match_i2c;
+			break;
+		default:
+			/* Cannot happen, unless someone breaks us */
+			WARN_ON(true);
+			return NULL;
+		}
+
+		/* match cannot be NULL here */
+		if (match(sd->dev, asd))
+			return asd;
+	}
+
+	return NULL;
+}
+
+static int v4l2_async_test_notify(struct v4l2_async_notifier *notifier,
+				  struct v4l2_async_subdev_list *asdl,
+				  struct v4l2_async_subdev *asd)
+{
+	struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl);
+	int ret;
+
+	/* Remove from the waiting list */
+	list_del(&asd->list);
+	asdl->asd = asd;
+	asdl->notifier = notifier;
+
+	if (notifier->bound) {
+		ret = notifier->bound(notifier, sd, asd);
+		if (ret < 0)
+			return ret;
+	}
+	/* Move from the global subdevice list to notifier's done */
+	list_move(&asdl->list, &notifier->done);
+
+	ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd);
+	if (ret < 0) {
+		if (notifier->unbind)
+			notifier->unbind(notifier, sd, asd);
+		return ret;
+	}
+
+	if (list_empty(&notifier->waiting) && notifier->complete)
+		return notifier->complete(notifier);
+
+	return 0;
+}
+
+static void v4l2_async_cleanup(struct v4l2_async_subdev_list *asdl)
+{
+	struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl);
+
+	v4l2_device_unregister_subdev(sd);
+	/* Subdevice driver will reprobe and put asdl back onto the list */
+	list_del_init(&asdl->list);
+	asdl->asd = NULL;
+	sd->dev = NULL;
+}
+
+int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
+				 struct v4l2_async_notifier *notifier)
+{
+	struct v4l2_async_subdev_list *asdl, *tmp;
+	struct v4l2_async_subdev *asd;
+	int i;
+
+	if (!notifier->num_subdevs || notifier->num_subdevs > V4L2_MAX_SUBDEVS)
+		return -EINVAL;
+
+	notifier->v4l2_dev = v4l2_dev;
+	INIT_LIST_HEAD(&notifier->waiting);
+	INIT_LIST_HEAD(&notifier->done);
+
+	for (i = 0; i < notifier->num_subdevs; i++) {
+		asd = notifier->subdev[i];
+
+		switch (asd->bus_type) {
+		case V4L2_ASYNC_BUS_CUSTOM:
+		case V4L2_ASYNC_BUS_PLATFORM:
+		case V4L2_ASYNC_BUS_I2C:
+			break;
+		default:
+			dev_err(notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL,
+				"Invalid bus-type %u on %p\n",
+				asd->bus_type, asd);
+			return -EINVAL;
+		}
+		list_add_tail(&asd->list, &notifier->waiting);
+	}
+
+	mutex_lock(&list_lock);
+
+	/* Keep also completed notifiers on the list */
+	list_add(&notifier->list, &notifier_list);
+
+	list_for_each_entry_safe(asdl, tmp, &subdev_list, list) {
+		int ret;
+
+		asd = v4l2_async_belongs(notifier, asdl);
+		if (!asd)
+			continue;
+
+		ret = v4l2_async_test_notify(notifier, asdl, asd);
+		if (ret < 0) {
+			mutex_unlock(&list_lock);
+			return ret;
+		}
+	}
+
+	mutex_unlock(&list_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(v4l2_async_notifier_register);
+
+void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
+{
+	struct v4l2_async_subdev_list *asdl, *tmp;
+	unsigned int notif_n_subdev = notifier->num_subdevs;
+	unsigned int n_subdev = min(notif_n_subdev, V4L2_MAX_SUBDEVS);
+	struct device *dev[n_subdev];
+	int i = 0;
+
+	mutex_lock(&list_lock);
+
+	list_del(&notifier->list);
+
+	list_for_each_entry_safe(asdl, tmp, &notifier->done, list) {
+		struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl);
+
+		dev[i] = get_device(sd->dev);
+
+		v4l2_async_cleanup(asdl);
+
+		/* If we handled USB devices, we'd have to lock the parent too */
+		device_release_driver(dev[i++]);
+
+		if (notifier->unbind)
+			notifier->unbind(notifier, sd, sd->asdl.asd);
+	}
+
+	mutex_unlock(&list_lock);
+
+	while (i--) {
+		struct device *d = dev[i];
+
+		if (d && device_attach(d) < 0) {
+			const char *name = "(none)";
+			int lock = device_trylock(d);
+
+			if (lock && d->driver)
+				name = d->driver->name;
+			dev_err(d, "Failed to re-probe to %s\n", name);
+			if (lock)
+				device_unlock(d);
+		}
+		put_device(d);
+	}
+	/*
+	 * Don't care about the waiting list, it is initialised and populated
+	 * upon notifier registration.
+	 */
+}
+EXPORT_SYMBOL(v4l2_async_notifier_unregister);
+
+int v4l2_async_register_subdev(struct v4l2_subdev *sd)
+{
+	struct v4l2_async_subdev_list *asdl = &sd->asdl;
+	struct v4l2_async_notifier *notifier;
+
+	mutex_lock(&list_lock);
+
+	INIT_LIST_HEAD(&asdl->list);
+
+	list_for_each_entry(notifier, &notifier_list, list) {
+		struct v4l2_async_subdev *asd = v4l2_async_belongs(notifier, asdl);
+		if (asd) {
+			int ret = v4l2_async_test_notify(notifier, asdl, asd);
+			mutex_unlock(&list_lock);
+			return ret;
+		}
+	}
+
+	/* None matched, wait for hot-plugging */
+	list_add(&asdl->list, &subdev_list);
+
+	mutex_unlock(&list_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(v4l2_async_register_subdev);
+
+void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
+{
+	struct v4l2_async_subdev_list *asdl = &sd->asdl;
+	struct v4l2_async_notifier *notifier = asdl->notifier;
+
+	if (!asdl->asd) {
+		if (!list_empty(&asdl->list))
+			v4l2_async_cleanup(asdl);
+		return;
+	}
+
+	mutex_lock(&list_lock);
+
+	list_add(&asdl->asd->list, &notifier->waiting);
+
+	v4l2_async_cleanup(asdl);
+
+	if (notifier->unbind)
+		notifier->unbind(notifier, sd, sd->asdl.asd);
+
+	mutex_unlock(&list_lock);
+}
+EXPORT_SYMBOL(v4l2_async_unregister_subdev);