Re: [PATCH v5 09/10] Documentation: media: add documentation file metafmt-c3-isp.rst

Jacopo Mondi
2025-01-23T09:59:18Z

Hi Keke

On Fri, Dec 27, 2024 at 03:09:18PM +0800, Keke Li via B4 Relay wrote:
> From: Keke Li <keke.li@amlogic.com>
>
> Add the file 'metafmt-c3-isp.rst' that documents
> the meta format of c3-isp.
>
> Signed-off-by: Keke Li <keke.li@amlogic.com>

Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Thanks
j

> ---
> .../userspace-api/media/v4l/meta-formats.rst | 1 +
> .../userspace-api/media/v4l/metafmt-c3-isp.rst | 86 ++++++++++++++++++++++
> MAINTAINERS | 1 +
> 3 files changed, 88 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/meta-formats.rst b/Documentation/userspace-api/media/v4l/meta-formats.rst
> index 86ffb3bc8ade..bb6876cfc271 100644
> --- a/Documentation/userspace-api/media/v4l/meta-formats.rst
> +++ b/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
>
> + metafmt-c3-isp
> metafmt-d4xx
> metafmt-generic
> metafmt-intel-ipu3
> diff --git a/Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst b/Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
> new file mode 100644
> index 000000000000..b15c40841266
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
> @@ -0,0 +1,86 @@
> +.. SPDX-License-Identifier: (GPL-2.0-only OR MIT)
> +
> +.. _v4l2-meta-fmt-c3isp-stats:
> +.. _v4l2-meta-fmt-c3isp-params:
> +
> +***********************************************************************
> +V4L2_META_FMT_C3ISP_STATS ('CSTS'), V4L2_META_FMT_C3ISP_PARAMS ('CPRM')
> +***********************************************************************
> +
> +.. 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
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d92427630bfa..b2626a370cc0 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1248,6 +1248,7 @@ M: Keke Li <keke.li@amlogic.com>
> L: linux-media@vger.kernel.org
> S: Maintained
> F: Documentation/devicetree/bindings/media/amlogic,c3-isp.yaml
> +F: Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
> F: drivers/media/platform/amlogic/c3/isp/
> F: include/uapi/linux/media/amlogic/
>
>
> --
> 2.47.1
>
>