ARK-OS/arkos/kernel/Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst

.. SPDX-License-Identifier: (GPL-2.0-only OR MIT)
.. c:namespace:: V4L

.. _v4l2-meta-fmt-c3isp-stats:
.. _v4l2-meta-fmt-c3isp-params:

***********************************************************************
V4L2_META_FMT_C3ISP_STATS ('C3ST'), V4L2_META_FMT_C3ISP_PARAMS ('C3PM')
***********************************************************************

.. c3_isp_stats_info

3A Statistics
=============

The C3 ISP can collect different statistics over an input Bayer frame.
Those statistics are obtained from the "c3-isp-stats" metadata capture video nodes,
using the :c:type:`v4l2_meta_format` interface.
They are formatted as described by the :c:type:`c3_isp_stats_info` structure.

The statistics collected are  Auto-white balance,
Auto-exposure and Auto-focus information.

.. c3_isp_params_cfg

Configuration Parameters
========================

The configuration parameters are passed to the c3-isp-params metadata output video node,
using the :c:type:`v4l2_meta_format` interface. Rather than a single struct containing
sub-structs for each configurable area of the ISP, parameters for the C3-ISP
are defined as distinct structs or "blocks" which may be added to the data
member of :c:type:`c3_isp_params_cfg`. Userspace is responsible for
populating the data member with the blocks that need to be configured by the driver, but
need not populate it with **all** the blocks, or indeed with any at all if there
are no configuration changes to make. Populated blocks **must** be consecutive
in the buffer. To assist both userspace and the driver in identifying the
blocks each block-specific struct embeds
:c:type:`c3_isp_params_block_header` as its first member and userspace
must populate the type member with a value from
:c:type:`c3_isp_params_block_type`. Once the blocks have been populated
into the data buffer, the combined size of all populated blocks shall be set in
the data_size member of :c:type:`c3_isp_params_cfg`. For example:

.. code-block:: c

	struct c3_isp_params_cfg *params =
		(struct c3_isp_params_cfg *)buffer;

	params->version = C3_ISP_PARAM_BUFFER_V0;
	params->data_size = 0;

	void *data = (void *)params->data;

	struct c3_isp_params_awb_gains *gains =
		(struct c3_isp_params_awb_gains *)data;

	gains->header.type = C3_ISP_PARAMS_BLOCK_AWB_GAINS;
	gains->header.flags = C3_ISP_PARAMS_BLOCK_FL_ENABLE;
	gains->header.size = sizeof(struct c3_isp_params_awb_gains);

	gains->gr_gain = 256;
	gains->r_gain = 256;
	gains->b_gain = 256;
	gains->gb_gain = 256;

	data += sizeof(struct c3_isp__params_awb_gains);
	params->data_size += sizeof(struct c3_isp_params_awb_gains);

	struct c3_isp_params_awb_config *awb_cfg =
		(struct c3_isp_params_awb_config *)data;

	awb_cfg->header.type = C3_ISP_PARAMS_BLOCK_AWB_CONFIG;
	awb_cfg->header.flags = C3_ISP_PARAMS_BLOCK_FL_ENABLE;
	awb_cfg->header.size = sizeof(struct c3_isp_params_awb_config);

	awb_cfg->tap_point = C3_ISP_AWB_STATS_TAP_BEFORE_WB;
	awb_cfg->satur = 1;
	awb_cfg->horiz_zones_num = 32;
	awb_cfg->vert_zones_num = 24;

	params->data_size += sizeof(struct c3_isp_params_awb_config);

Amlogic C3 ISP uAPI data types
===============================

.. kernel-doc:: include/uapi/linux/media/amlogic/c3-isp-config.h