Re: [PATCH v3 13/14] media: imx7.rst: add documentation for i.MX7 media driver

[Rui Miguel Silva <rui.silva@linaro.org>]

Hi Randy,
On Tue 08 May 2018 at 17:24, Randy Dunlap wrote:
> Hi,
>
> I have a few editing suggestions below...

Thank you very much for this. I will incorporate this in the next 
version.

---
Cheers,
	Rui

>
> On 05/07/2018 09:21 AM, Rui Miguel Silva wrote:
>> 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: Rui Miguel Silva <rui.silva@linaro.org>
>> ---
>>  Documentation/media/v4l-drivers/imx7.rst  | 157 
>>  ++++++++++++++++++++++
>>  Documentation/media/v4l-drivers/index.rst |   1 +
>>  2 files changed, 158 insertions(+)
>>  create mode 100644 Documentation/media/v4l-drivers/imx7.rst
>> 
>> diff --git a/Documentation/media/v4l-drivers/imx7.rst 
>> b/Documentation/media/v4l-drivers/imx7.rst
>> new file mode 100644
>> index 000000000000..64b97b442277
>> --- /dev/null
>> +++ b/Documentation/media/v4l-drivers/imx7.rst
>> @@ -0,0 +1,157 @@
>> +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
>
> s/,/;/
>
>> +manipulation of the capture frames is less feature rich.
>
>                                       are less
>
>> +
>> +For image capture the i.MX7 have three units:
>
>                                has
>
>> +- 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 recevier entity. It has one sink pad to 
>> receive the pixel
>
>                           receiver
>
>> +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 support two D-PHY Rx Data lanes.
>
>               supports
>
>> +
>> +csi_mux
>> +-------
>> +
>> +This is the video multiplexer. It has two sink pads to select 
>> from either camera
>> +sensors with a parallel interface or from MIPI CSI-2 virtual 
>> channel 0.  It has
>
>    sensor
>
>> +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 interfaces directly with Parallel and MIPI CSI-2 buses. It 
>> has 256 x 64 FIFO
>
>        interface
>
>> +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 receive from the csi_mux 
>> entity and a single
>
>                                      receives
>
>> +source pad that route video frames directly to memory buffers, 
>> this pad is
>
>                    routes 
>                    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
>
>                         can start. The
>
>> +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
>
> thanks.