Implement video control framework

drivers/video/CMakeLists.txt

@@ -2,6 +2,7 @@
 
 zephyr_library()
 
+zephyr_library_sources(video_async.c)
 zephyr_library_sources(video_common.c)
 zephyr_library_sources(video_device.c)
 

drivers/video/video_async.c

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2024 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "video_async.h"
+#include "video_device.h"
+
+#include <zephyr/device.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/sys/slist.h>
+
+LOG_MODULE_REGISTER(video_async, CONFIG_VIDEO_LOG_LEVEL);
+
+static sys_slist_t notifiers_list;
+
+/* Find a registered notifier associated with this device */
+struct video_notifier *video_async_find_notifier(const struct device *dev)
+{
+	struct video_notifier *nf;
+
+	SYS_SLIST_FOR_EACH_CONTAINER(&notifiers_list, nf, node) {
+		if (nf->dev == dev) {
+			return nf;
+		}
+	}
+
+	return NULL;
+}
+
+/* Find the video device of the notifier tree that this notifier is part of */
+static struct video_device *video_async_find_vdev(struct video_notifier *notifier)
+{
+	if (!notifier) {
+		return NULL;
+	}
+
+	while (notifier->parent) {
+		notifier = notifier->parent;
+	}
+
+	return notifier->vdev;
+}
+
+void video_async_init(struct video_notifier *notifier, const struct device *dev,
+		      struct video_device *vdev, const struct device **children_devs,
+		      uint8_t children_num)
+{
+	if (!notifier) {
+		return;
+	}
+
+	notifier->dev = dev;
+	notifier->vdev = vdev;
+	notifier->children_devs = (const struct device **)children_devs;
+	notifier->children_num = children_num;
+}
+
+int video_async_register(struct video_notifier *notifier)
+{
+	uint8_t i = 0;
+	bool found_parent = false;
+	struct video_notifier *nf;
+	struct video_device *vdev = NULL;
+
+	if (!notifier) {
+		return -EINVAL;
+	}
+
+	if (sys_slist_find(&notifiers_list, &notifier->node, NULL)) {
+		LOG_ERR("Notifier of device %s is already registered", notifier->dev->name);
+		return -EALREADY;
+	}
+
+	SYS_SLIST_FOR_EACH_CONTAINER(&notifiers_list, nf, node) {
+		/* Find the parent notifier in the global notifiers registry */
+		if (!found_parent) {
+			for (i = 0; i < nf->children_num; ++i) {
+				if (nf->children_devs[i] == notifier->dev) {
+					notifier->parent = nf;
+
+					vdev = video_async_find_vdev(notifier);
+					if (vdev) {
+						notifier->vdev = vdev;
+					}
+
+					found_parent = true;
+					break;
+				}
+			}
+		}
+
+		/* Find all children notifiers in the notifiers registry */
+		for (i = 0; i < notifier->children_num; ++i) {
+			if (notifier->children_devs[i] == nf->dev) {
+				nf->parent = notifier;
+				break;
+			}
+		}
+	}
+
+	/* Add the notifier to the notifiers registry */
+	sys_slist_append(&notifiers_list, &notifier->node);
+
+	LOG_DBG("Notifier of device %s is registered", notifier->dev->name);
+
+	return 0;
+}
+
+void video_async_unregister(struct video_notifier *notifier)
+{
+	if (!notifier) {
+		return;
+	}
+
+	sys_slist_find_and_remove(&notifiers_list, &notifier->node);
+}

drivers/video/video_async.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2024 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_VIDEO_ASYNC_H_
+#define ZEPHYR_INCLUDE_VIDEO_ASYNC_H_
+
+#include <zephyr/device.h>
+#include <zephyr/sys/slist.h>
+
+struct video_device;
+
+struct video_notifier {
+	struct video_device *vdev;
+	const struct device *dev;
+	struct video_notifier *parent;
+	const struct device **children_devs;
+	uint8_t children_num;
+	sys_snode_t node;
+};
+
+void video_async_init(struct video_notifier *notifier, const struct device *dev,
+		      struct video_device *vdev, const struct device **children_devs,
+		      uint8_t children_num);
+
+int video_async_register(struct video_notifier *notifier);
+
+void video_async_unregister(struct video_notifier *notifier);
+
+struct video_notifier *video_async_find_notifier(const struct device *dev);
+
+#endif /* ZEPHYR_INCLUDE_VIDEO_ASYNC_H_ */