Commit fa88fbda authored by Rui Miguel Silva's avatar Rui Miguel Silva Committed by Mauro Carvalho Chehab
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media: imx7.rst: add documentation for i.MX7 media driver 



Add rst document to describe the i.MX7 media driver and also a working
example from the Warp7 board usage with a OV2680 sensor.

Signed-off-by: default avatarRui Miguel Silva <rui.silva@linaro.org>
Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 7807063b

Documentation/media/v4l-drivers/imx7.rst

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.. SPDX-License-Identifier: GPL-2.0



i.MX7 Video Capture Driver

==========================



Introduction

------------



The i.MX7 contrary to the i.MX5/6 family does not contain an Image Processing

Unit (IPU); because of that the capabilities to perform operations or

manipulation of the capture frames are less feature rich.



For image capture the i.MX7 has three units:

- CMOS Sensor Interface (CSI)

- Video Multiplexer

- MIPI CSI-2 Receiver



::

                                           |\

   MIPI Camera Input ---> MIPI CSI-2 --- > | \

                                           |  \

                                           | M |

                                           | U | ------>  CSI ---> Capture

                                           | X |

                                           |  /

   Parallel Camera Input ----------------> | /

                                           |/



For additional information, please refer to the latest versions of the i.MX7

reference manual [#f1]_.



Entities

--------



imx7-mipi-csi2

--------------



This is the MIPI CSI-2 receiver entity. It has one sink pad to receive the pixel

data from MIPI CSI-2 camera sensor. It has one source pad, corresponding to the

virtual channel 0. This module is compliant to previous version of Samsung

D-phy, and supports two D-PHY Rx Data lanes.



csi_mux

-------



This is the video multiplexer. It has two sink pads to select from either camera

sensor with a parallel interface or from MIPI CSI-2 virtual channel 0.  It has

a single source pad that routes to the CSI.



csi

---



The CSI enables the chip to connect directly to external CMOS image sensor. CSI

can interface directly with Parallel and MIPI CSI-2 buses. It has 256 x 64 FIFO

to store received image pixel data and embedded DMA controllers to transfer data

from the FIFO through AHB bus.



This entity has one sink pad that receives from the csi_mux entity and a single

source pad that routes video frames directly to memory buffers. This pad is

routed to a capture device node.



Usage Notes

-----------



To aid in configuration and for backward compatibility with V4L2 applications

that access controls only from video device nodes, the capture device interfaces

inherit controls from the active entities in the current pipeline, so controls

can be accessed either directly from the subdev or from the active capture

device interface. For example, the sensor controls are available either from the

sensor subdevs or from the active capture device.



Warp7 with OV2680

-----------------



On this platform an OV2680 MIPI CSI-2 module is connected to the internal MIPI

CSI-2 receiver. The following example configures a video capture pipeline with

an output of 800x600, and BGGR 10 bit bayer format:



.. code-block:: none

   # Setup links

   media-ctl -l "'ov2680 1-0036':0 -> 'imx7-mipi-csis.0':0[1]"

   media-ctl -l "'imx7-mipi-csis.0':1 -> 'csi_mux':1[1]"

   media-ctl -l "'csi_mux':2 -> 'csi':0[1]"

   media-ctl -l "'csi':1 -> 'csi capture':0[1]"



   # Configure pads for pipeline

   media-ctl -V "'ov2680 1-0036':0 [fmt:SBGGR10_1X10/800x600 field:none]"

   media-ctl -V "'csi_mux':1 [fmt:SBGGR10_1X10/800x600 field:none]"

   media-ctl -V "'csi_mux':2 [fmt:SBGGR10_1X10/800x600 field:none]"

   media-ctl -V "'imx7-mipi-csis.0':0 [fmt:SBGGR10_1X10/800x600 field:none]"

   media-ctl -V "'csi':0 [fmt:SBGGR10_1X10/800x600 field:none]"



After this streaming can start. The v4l2-ctl tool can be used to select any of

the resolutions supported by the sensor.



.. code-block:: none

    root@imx7s-warp:~# media-ctl -p

    Media controller API version 4.17.0



    Media device information

    ------------------------

    driver          imx-media

    model           imx-media

    serial

    bus info

    hw revision     0x0

    driver version  4.17.0



    Device topology

    - entity 1: csi (2 pads, 2 links)

		type V4L2 subdev subtype Unknown flags 0

		device node name /dev/v4l-subdev0

	    pad0: Sink

		    [fmt:SBGGR10_1X10/800x600 field:none]

		    <- "csi_mux":2 [ENABLED]

	    pad1: Source

		    [fmt:SBGGR10_1X10/800x600 field:none]

		    -> "csi capture":0 [ENABLED]



    - entity 4: csi capture (1 pad, 1 link)

		type Node subtype V4L flags 0

		device node name /dev/video0

	    pad0: Sink

		    <- "csi":1 [ENABLED]



    - entity 10: csi_mux (3 pads, 2 links)

		type V4L2 subdev subtype Unknown flags 0

		device node name /dev/v4l-subdev1

	    pad0: Sink

		    [fmt:unknown/0x0]

	    pad1: Sink

		    [fmt:unknown/800x600 field:none]

		    <- "imx7-mipi-csis.0":1 [ENABLED]

	    pad2: Source

		    [fmt:unknown/800x600 field:none]

		    -> "csi":0 [ENABLED]



    - entity 14: imx7-mipi-csis.0 (2 pads, 2 links)

		type V4L2 subdev subtype Unknown flags 0

		device node name /dev/v4l-subdev2

	    pad0: Sink

		    [fmt:SBGGR10_1X10/800x600 field:none]

		    <- "ov2680 1-0036":0 [ENABLED]

	    pad1: Source

		    [fmt:SBGGR10_1X10/800x600 field:none]

		    -> "csi_mux":1 [ENABLED]



    - entity 17: ov2680 1-0036 (1 pad, 1 link)

		type V4L2 subdev subtype Sensor flags 0

		device node name /dev/v4l-subdev3

	    pad0: Source

		    [fmt:SBGGR10_1X10/800x600 field:none]

		    -> "imx7-mipi-csis.0":0 [ENABLED]





References

----------



.. [#f1] https://www.nxp.com/docs/en/reference-manual/IMX7SRM.pdf

Documentation/media/v4l-drivers/index.rst

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@@ -44,6 +44,7 @@ For more details see the file COPYING in the source distribution of Linux. 
	davinci-vpbe

	fimc

	imx

	imx7

	ipu3

	ivtv

	max2175