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diff --git a/Documentation/admin-guide/media/rkisp1.rst b/Documentation/admin-guide/media/rkisp1.rst new file mode 100644 index 000000000..42e37ed25 --- /dev/null +++ b/Documentation/admin-guide/media/rkisp1.rst @@ -0,0 +1,181 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. include:: <isonum.txt> + +========================================= +Rockchip Image Signal Processor (rkisp1) +========================================= + +Introduction +============ + +This file documents the driver for the Rockchip ISP1 that is part of RK3288 +and RK3399 SoCs. The driver is located under drivers/staging/media/rkisp1 +and uses the Media-Controller API. + +Topology +======== +.. _rkisp1_topology_graph: + +.. kernel-figure:: rkisp1.dot + :alt: Diagram of the default media pipeline topology + :align: center + + +The driver has 4 video devices: + +- rkisp1_mainpath: capture device for retrieving images, usually in higher + resolution. +- rkisp1_selfpath: capture device for retrieving images. +- rkisp1_stats: a metadata capture device that sends statistics. +- rkisp1_params: a metadata output device that receives parameters + configurations from userspace. + +The driver has 3 subdevices: + +- rkisp1_resizer_mainpath: used to resize and downsample frames for the + mainpath capture device. +- rkisp1_resizer_selfpath: used to resize and downsample frames for the + selfpath capture device. +- rkisp1_isp: is connected to the sensor and is responsible for all the isp + operations. + + +rkisp1_mainpath, rkisp1_selfpath - Frames Capture Video Nodes +------------------------------------------------------------- +Those are the `mainpath` and `selfpath` capture devices to capture frames. +Those entities are the DMA engines that write the frames to memory. +The selfpath video device can capture YUV/RGB formats. Its input is YUV encoded +stream and it is able to convert it to RGB. The selfpath is not able to +capture bayer formats. +The mainpath can capture both bayer and YUV formats but it is not able to +capture RGB formats. +Both capture videos support +the ``V4L2_CAP_IO_MC`` :ref:`capability <device-capabilities>`. + + +rkisp1_resizer_mainpath, rkisp1_resizer_selfpath - Resizers Subdevices Nodes +---------------------------------------------------------------------------- +Those are resizer entities for the mainpath and the selfpath. Those entities +can scale the frames up and down and also change the YUV sampling (for example +YUV4:2:2 -> YUV4:2:0). They also have cropping capability on the sink pad. +The resizers entities can only operate on YUV:4:2:2 format +(MEDIA_BUS_FMT_YUYV8_2X8). +The mainpath capture device supports capturing video in bayer formats. In that +case the resizer of the mainpath is set to 'bypass' mode - it just forward the +frame without operating on it. + +rkisp1_isp - Image Signal Processing Subdevice Node +--------------------------------------------------- +This is the isp entity. It is connected to the sensor on sink pad 0 and +receives the frames using the CSI-2 protocol. It is responsible of configuring +the CSI-2 protocol. It has a cropping capability on sink pad 0 that is +connected to the sensor and on source pad 2 connected to the resizer entities. +Cropping on sink pad 0 defines the image region from the sensor. +Cropping on source pad 2 defines the region for the Image Stabilizer (IS). + +.. _rkisp1_stats: + +rkisp1_stats - Statistics Video Node +------------------------------------ +The statistics video node outputs the 3A (auto focus, auto exposure and auto +white balance) statistics, and also histogram statistics for the frames that +are being processed by the rkisp1 to userspace applications. +Using these data, applications can implement algorithms and re-parameterize +the driver through the rkisp_params node to improve image quality during a +video stream. +The buffer format is defined by struct :c:type:`rkisp1_stat_buffer`, and +userspace should set +:ref:`V4L2_META_FMT_RK_ISP1_STAT_3A <v4l2-meta-fmt-stat-rkisp1>` as the +dataformat. + +.. _rkisp1_params: + +rkisp1_params - Parameters Video Node +------------------------------------- +The rkisp1_params video node receives a set of parameters from userspace +to be applied to the hardware during a video stream, allowing userspace +to dynamically modify values such as black level, cross talk corrections +and others. + +The buffer format is defined by struct :c:type:`rkisp1_params_cfg`, and +userspace should set +:ref:`V4L2_META_FMT_RK_ISP1_PARAMS <v4l2-meta-fmt-params-rkisp1>` as the +dataformat. + + +Capturing Video Frames Example +============================== + +In the following example, the sensor connected to pad 0 of 'rkisp1_isp' is +imx219. + +The following commands can be used to capture video from the selfpath video +node with dimension 900x800 planar format YUV 4:2:2. It uses all cropping +capabilities possible, (see explanation right below) + +.. code-block:: bash + + # set the links + "media-ctl" "-d" "platform:rkisp1" "-r" + "media-ctl" "-d" "platform:rkisp1" "-l" "'imx219 4-0010':0 -> 'rkisp1_isp':0 [1]" + "media-ctl" "-d" "platform:rkisp1" "-l" "'rkisp1_isp':2 -> 'rkisp1_resizer_selfpath':0 [1]" + "media-ctl" "-d" "platform:rkisp1" "-l" "'rkisp1_isp':2 -> 'rkisp1_resizer_mainpath':0 [0]" + + # set format for imx219 4-0010:0 + "media-ctl" "-d" "platform:rkisp1" "--set-v4l2" '"imx219 4-0010":0 [fmt:SRGGB10_1X10/1640x1232]' + + # set format for rkisp1_isp pads: + "media-ctl" "-d" "platform:rkisp1" "--set-v4l2" '"rkisp1_isp":0 [fmt:SRGGB10_1X10/1640x1232 crop: (0,0)/1600x1200]' + "media-ctl" "-d" "platform:rkisp1" "--set-v4l2" '"rkisp1_isp":2 [fmt:YUYV8_2X8/1600x1200 crop: (0,0)/1500x1100]' + + # set format for rkisp1_resizer_selfpath pads: + "media-ctl" "-d" "platform:rkisp1" "--set-v4l2" '"rkisp1_resizer_selfpath":0 [fmt:YUYV8_2X8/1500x1100 crop: (300,400)/1400x1000]' + "media-ctl" "-d" "platform:rkisp1" "--set-v4l2" '"rkisp1_resizer_selfpath":1 [fmt:YUYV8_2X8/900x800]' + + # set format for rkisp1_selfpath: + "v4l2-ctl" "-z" "platform:rkisp1" "-d" "rkisp1_selfpath" "-v" "width=900,height=800," + "v4l2-ctl" "-z" "platform:rkisp1" "-d" "rkisp1_selfpath" "-v" "pixelformat=422P" + + # start streaming: + v4l2-ctl "-z" "platform:rkisp1" "-d" "rkisp1_selfpath" "--stream-mmap" "--stream-count" "10" + + +In the above example the sensor is configured to bayer format: +`SRGGB10_1X10/1640x1232`. The rkisp1_isp:0 pad should be configured to the +same mbus format and dimensions as the sensor, otherwise streaming will fail +with 'EPIPE' error. So it is also configured to `SRGGB10_1X10/1640x1232`. +In addition, the rkisp1_isp:0 pad is configured to cropping `(0,0)/1600x1200`. + +The cropping dimensions are automatically propagated to be the format of the +isp source pad `rkisp1_isp:2`. Another cropping operation is configured on +the isp source pad: `(0,0)/1500x1100`. + +The resizer's sink pad `rkisp1_resizer_selfpath` should be configured to format +`YUYV8_2X8/1500x1100` in order to match the format on the other side of the +link. In addition a cropping `(300,400)/1400x1000` is configured on it. + +The source pad of the resizer, `rkisp1_resizer_selfpath:1` is configured to +format `YUYV8_2X8/900x800`. That means that the resizer first crop a window +of `(300,400)/1400x100` from the received frame and then scales this window +to dimension `900x800`. + +Note that the above example does not uses the stats-params control loop. +Therefore the capture frames will not go through the 3A algorithms and +probably won't have a good quality, and can even look dark and greenish. + +Configuring Quantization +======================== + +The driver supports limited and full range quantization on YUV formats, +where limited is the default. +To switch between one or the other, userspace should use the Colorspace +Conversion API (CSC) for subdevices on source pad 2 of the +isp (`rkisp1_isp:2`). The quantization configured on this pad is the +quantization of the captured video frames on the mainpath and selfpath +video nodes. +Note that the resizer and capture entities will always report +``V4L2_QUANTIZATION_DEFAULT`` even if the quantization is configured to full +range on `rkisp1_isp:2`. So in order to get the configured quantization, +application should get it from pad `rkisp1_isp:2`. + |