video: addition of video_transfer_buffer helper function

Addition of a helper function which takes care of dequeue
from a source video device and queue into a sink video device.

Signed-off-by: Alain Volmat <[email protected]>

Author: Alain Volmat

drivers/video/video_common.c

@@ -489,3 +489,20 @@ int video_set_compose_format(const struct device *dev, struct video_format *fmt)
 
 	return video_set_format(dev, fmt);
 }
+
+int video_transfer_buffer(const struct device *src, const struct device *sink,
+			  enum video_buf_type src_type, enum video_buf_type sink_type,
+			  k_timeout_t timeout)
+{
+	struct video_buffer *buf = &(struct video_buffer){.type = src_type};
+	int ret;
+
+	ret = video_dequeue(src, &buf, timeout);
+	if (ret < 0) {
+		return ret;
+	}
+
+	buf->type = sink_type;
+
+	return video_enqueue(sink, buf);
+}

include/zephyr/drivers/video.h

@@ -1003,6 +1003,24 @@ int video_estimate_fmt_size(struct video_format *fmt);
  */
 int video_set_compose_format(const struct device *dev, struct video_format *fmt);
 
+/**
+ * @brief Transfer a buffer between 2 video device
+ *
+ * Helper function which dequeues a buffer from a source device and enqueues it into a
+ * sink device, changing its buffer type between the two.
+ *
+ * @param src		Video device from where buffer is dequeued (source)
+ * @param sink		Video device into which the buffer is queued (sink)
+ * @param src_type	Video buffer type on the source device
+ * @param sink_type	Video buffer type on the sink device
+ * @param timeout	Timeout to be applied on dequeue
+ *
+ * @return 0 on success, otherwise a negative errno code
+ */
+int video_transfer_buffer(const struct device *src, const struct device *sink,
+			  enum video_buf_type src_type, enum video_buf_type sink_type,
+			  k_timeout_t timeout);
+
 /**
  * @defgroup video_pixel_formats Video pixel formats
  * The '|' characters separate the pixels or logical blocks, and spaces separate the bytes.