media: uapi: v4l2-core: Add ISP statistics output V4L2 fourcc type

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

Add V4L2_META_FMT_BCM2835_ISP_STATS V4L2 format type.

This new format will be used by the BCM2835 ISP device to return
out ISP statistics for 3A.
Signed-off-by: NNaushir Patuck <naush@raspberrypi.com>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

Documentation/userspace-api/media/v4l/meta-formats.rst

@@ -12,6 +12,7 @@ These formats are used for the :ref:`metadata` interface only.
 .. toctree::
     :maxdepth: 1
 
+    pixfmt-meta-bcm2835-isp-stats
     pixfmt-meta-d4xx
     pixfmt-meta-intel-ipu3
     pixfmt-meta-rkisp1

Documentation/userspace-api/media/v4l/pixfmt-meta-bcm2835-isp-stats.rst

+.. Permission is granted to copy, distribute and/or modify this
+.. document under the terms of the GNU Free Documentation License,
+.. Version 1.1 or any later version published by the Free Software
+.. Foundation, with no Invariant Sections, no Front-Cover Texts
+.. and no Back-Cover Texts. A copy of the license is included at
+.. Documentation/media/uapi/fdl-appendix.rst.
+..
+.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
+
+.. _v4l2-meta-fmt-bcm2835-isp-stats:
+
+*****************************************
+V4L2_META_FMT_BCM2835_ISP_STATS  ('BSTA')
+*****************************************
+
+BCM2835 ISP Statistics
+
+Description
+===========
+
+The BCM2835 ISP hardware calculate image statistics for an input Bayer frame.
+These statistics are obtained from the "bcm2835-isp0-capture3" device node
+using the :c:type:`v4l2_meta_format` interface. They are formatted as described
+by the :c:type:`bcm2835_isp_stats` structure below.
+
+.. code-block:: c
+
+	#define DEFAULT_AWB_REGIONS_X 16
+	#define DEFAULT_AWB_REGIONS_Y 12
+
+	#define NUM_HISTOGRAMS 2
+	#define NUM_HISTOGRAM_BINS 128
+	#define AWB_REGIONS (DEFAULT_AWB_REGIONS_X * DEFAULT_AWB_REGIONS_Y)
+	#define FLOATING_REGIONS 16
+	#define AGC_REGIONS 16
+	#define FOCUS_REGIONS 12
+
+.. kernel-doc:: include/uapi/linux/bcm2835-isp.h
+   :functions: bcm2835_isp_stats_hist bcm2835_isp_stats_region
+	             bcm2835_isp_stats_focus bcm2835_isp_stats
+

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -1405,6 +1405,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 	case V4L2_META_FMT_D4XX:	descr = "Intel D4xx UVC Metadata"; break;
 	case V4L2_META_FMT_VIVID:       descr = "Vivid Metadata"; break;
 	case V4L2_META_FMT_SENSOR_DATA:	descr = "Sensor Ancillary Metadata"; break;
+	case V4L2_META_FMT_BCM2835_ISP_STATS: descr = "BCM2835 ISP Image Statistics"; break;
 
 	default:
 		/* Compressed formats */

include/uapi/linux/videodev2.h

@@ -779,6 +779,7 @@ struct v4l2_pix_format {
 #define V4L2_META_FMT_D4XX        v4l2_fourcc('D', '4', 'X', 'X') /* D4XX Payload Header metadata */
 #define V4L2_META_FMT_VIVID	  v4l2_fourcc('V', 'I', 'V', 'D') /* Vivid Metadata */
 #define V4L2_META_FMT_SENSOR_DATA v4l2_fourcc('S', 'E', 'N', 'S') /* Sensor Ancillary metadata */
+#define V4L2_META_FMT_BCM2835_ISP_STATS v4l2_fourcc('B', 'S', 'T', 'A') /* BCM2835 ISP image statistics output */
 
 /* priv field value to indicates that subsequent fields are valid. */
 #define V4L2_PIX_FMT_PRIV_MAGIC		0xfeedcafe