1.. SPDX-License-Identifier: GPL-2.0 2 3.. _v4l2-meta-fmt-rk-isp1-stat-3a: 4 5************************************************************************************************************************ 6V4L2_META_FMT_RK_ISP1_PARAMS ('rk1p'), V4L2_META_FMT_RK_ISP1_STAT_3A ('rk1s'), V4L2_META_FMT_RK_ISP1_EXT_PARAMS ('rk1e') 7************************************************************************************************************************ 8 9======================== 10Configuration parameters 11======================== 12 13The configuration of the RkISP1 ISP is performed by userspace by providing 14parameters for the ISP to the driver using the :c:type:`v4l2_meta_format` 15interface. 16 17There are two methods that allow to configure the ISP, the `fixed parameters` 18configuration format and the `extensible parameters` configuration 19format. 20 21.. _v4l2-meta-fmt-rk-isp1-params: 22 23Fixed parameters configuration format 24===================================== 25 26When using the fixed configuration format, parameters are passed to the 27:ref:`rkisp1_params <rkisp1_params>` metadata output video node, using 28the `V4L2_META_FMT_RK_ISP1_PARAMS` meta format. 29 30The buffer contains a single instance of the C structure 31:c:type:`rkisp1_params_cfg` defined in ``rkisp1-config.h``. So the structure can 32be obtained from the buffer by: 33 34.. code-block:: c 35 36 struct rkisp1_params_cfg *params = (struct rkisp1_params_cfg*) buffer; 37 38This method supports a subset of the ISP features only, new applications should 39use the extensible parameters method. 40 41.. _v4l2-meta-fmt-rk-isp1-ext-params: 42 43Extensible parameters configuration format 44========================================== 45 46When using the extensible configuration format, parameters are passed to the 47:ref:`rkisp1_params <rkisp1_params>` metadata output video node, using 48the `V4L2_META_FMT_RK_ISP1_EXT_PARAMS` meta format. 49 50The buffer contains a single instance of the C structure 51:c:type:`rkisp1_ext_params_cfg` defined in ``rkisp1-config.h``. The 52:c:type:`rkisp1_ext_params_cfg` structure is designed to allow userspace to 53populate the data buffer with only the configuration data for the ISP blocks it 54intends to configure. The extensible parameters format design allows developers 55to define new block types to support new configuration parameters, and defines a 56versioning scheme so that it can be extended and versioned without breaking 57compatibility with existing applications. 58 59For these reasons, this configuration method is preferred over the `fixed 60parameters` format alternative. 61 62.. rkisp1_stat_buffer 63 64=========================== 653A and histogram statistics 66=========================== 67 68The ISP1 device collects different statistics over an input Bayer frame. 69Those statistics are obtained from the :ref:`rkisp1_stats <rkisp1_stats>` 70metadata capture video node, 71using the :c:type:`v4l2_meta_format` interface. The buffer contains a single 72instance of the C structure :c:type:`rkisp1_stat_buffer` defined in 73``rkisp1-config.h``. So the structure can be obtained from the buffer by: 74 75.. code-block:: c 76 77 struct rkisp1_stat_buffer *stats = (struct rkisp1_stat_buffer*) buffer; 78 79The statistics collected are Exposure, AWB (Auto-white balance), Histogram and 80AF (Auto-focus). See :c:type:`rkisp1_stat_buffer` for details of the statistics. 81 82The 3A statistics and configuration parameters described here are usually 83consumed and produced by dedicated user space libraries that comprise the 84important tuning tools using software control loop. 85 86rkisp1 uAPI data types 87====================== 88 89.. kernel-doc:: include/uapi/linux/rkisp1-config.h 90