Based on kernel version 6.13. Page generated on 2025-01-21 08:20 EST.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 | .. SPDX-License-Identifier: GPL-2.0 ============================================ Raspberry Pi PiSP Camera Front End (rp1-cfe) ============================================ The PiSP Camera Front End ========================= The PiSP Camera Front End (CFE) is a module which combines a CSI-2 receiver with a simple ISP, called the Front End (FE). The CFE has four DMA engines and can write frames from four separate streams received from the CSI-2 to the memory. One of those streams can also be routed directly to the FE, which can do minimal image processing, write two versions (e.g. non-scaled and downscaled versions) of the received frames to memory and provide statistics of the received frames. The FE registers are documented in the `Raspberry Pi Image Signal Processor (ISP) Specification document <https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf>`_, and example code for FE can be found in `libpisp <https://github.com/raspberrypi/libpisp>`_. The rp1-cfe driver ================== The Raspberry Pi PiSP Camera Front End (rp1-cfe) driver is located under drivers/media/platform/raspberrypi/rp1-cfe. It uses the `V4L2 API` to register a number of video capture and output devices, the `V4L2 subdev API` to register subdevices for the CSI-2 received and the FE that connects the video devices in a single media graph realized using the `Media Controller (MC) API`. The media topology registered by the `rp1-cfe` driver, in this particular example connected to an imx219 sensor, is the following one: .. _rp1-cfe-topology: .. kernel-figure:: raspberrypi-rp1-cfe.dot :alt: Diagram of an example media pipeline topology :align: center The media graph contains the following video device nodes: - rp1-cfe-csi2-ch0: capture device for the first CSI-2 stream - rp1-cfe-csi2-ch1: capture device for the second CSI-2 stream - rp1-cfe-csi2-ch2: capture device for the third CSI-2 stream - rp1-cfe-csi2-ch3: capture device for the fourth CSI-2 stream - rp1-cfe-fe-image0: capture device for the first FE output - rp1-cfe-fe-image1: capture device for the second FE output - rp1-cfe-fe-stats: capture device for the FE statistics - rp1-cfe-fe-config: output device for FE configuration rp1-cfe-csi2-chX ---------------- The rp1-cfe-csi2-chX capture devices are normal V4L2 capture devices which can be used to capture video frames or metadata received from the CSI-2. rp1-cfe-fe-image0, rp1-cfe-fe-image1 ------------------------------------ The rp1-cfe-fe-image0 and rp1-cfe-fe-image1 capture devices are used to write the processed frames to memory. rp1-cfe-fe-stats ---------------- The format of the FE statistics buffer is defined by :c:type:`pisp_statistics` C structure and the meaning of each parameter is described in the `PiSP specification` document. rp1-cfe-fe-config ----------------- The format of the FE configuration buffer is defined by :c:type:`pisp_fe_config` C structure and the meaning of each parameter is described in the `PiSP specification` document. |
