VIP V4L2 Sub Device

Annamalai Lakshmanan88

Other Parts Discussed in Thread: TVP5158

we are using Jacinto 6, In out platform there are multiple sources of video input (HDMI, TV Tuner etc...) however, the control path is not used ( we don't use i2C etcc.) the input source is connected via LVDS. the control path is routed not routed to Jacinto. In that case can we directly use the VIP driver ? do we need to define V4L2 sub device? or is it directly possible to the VIP driver available. without any modifications from TI.

over 8 years ago

0 Mariya Petkova over 8 years ago

TI__Expert 4885 points

Hi,

I forwarded your question to a VIP expert.

Regards,
Mariya

0 Annamalai Lakshmanan88 over 8 years ago in reply to Mariya Petkova

Mastermind 6285 points

ok thanks, for better clarity of our system, we have HDMI as Video Input source and there is NO I2C communication from hardware to J6. the Control information (resolution) is directly obtained from a different control path. Assuming the input format RGB888 and resolution eg:1080p is known and there no need for V4L2 sub device. what are the necessary changes required to enable this configuration in VIP driver in Linux kernel 4.4. we have 3 such input sources and there is no sub-device. what is the best possible approach.

0 Annamalai Lakshmanan88 over 8 years ago in reply to Annamalai Lakshmanan88

Mastermind 6285 points

is it possible to get an update?

0 Annamalai Lakshmanan88 over 8 years ago in reply to Annamalai Lakshmanan88

Mastermind 6285 points

hi, request to update this query as we require a solution for this problem,

0 David Huang over 8 years ago in reply to Annamalai Lakshmanan88

TI__Intellectual 2440 points

Hi,

The VIP driver relies on a V4L2 subdevice being defined. This includes functions such as start/stop streaming.

Thanks,

David

0 Annamalai Lakshmanan88 over 8 years ago in reply to David Huang

Mastermind 6285 points

hi david

thanks for your reply, in our case we dont have a subdevice like i2c/spi. so it is possible to create a dummy/stub sub-device with implementation of these functions.

can you just provide device tree sample code and sample driver (if possible) addressing this scenario. appreciate your help!!

(basic parameters like clk frequency, hsync, vsync will be available though), i also referred your wiki for integrating external decoder into VIP. but need specific example for the above scenario

regards

0 Annamalai Lakshmanan88 over 8 years ago in reply to Annamalai Lakshmanan88

Mastermind 6285 points

request some help and input on above scenario, sample implementation is helpful

0 Nikhil Devshatwar over 8 years ago in reply to Annamalai Lakshmanan88

TI__Genius 9905 points

Hello,

VIP driver is modelled to work with the V4L2 subdevice driver.

This makes the platform IP specific driver code different from the board specific camera/sensor/decoder chip specific code.

You can implement v4l2 subdevice as yet another platform device, it need not be i2c device.

Please refer to the ov1063x and tvp5158 driver as an example of how to implement the subdev driver.

You don't need to perform any i2c transactions if your HDMI chip is not configurable (or rather you are happy with fixed configuration)

So only worry is how to get the v4l2 subdev driver registered

- The answer to that is, register a platform device with a compatible string, Implement the V4L2 subdev driver with same comaptible string

- Preferrably have some check to detect the presence of the device and then register the V4L2 subdev

This way, the VIP code remains to be portable, and in future you have scope for adding support for configurable timings, etc.

Regards,

Nikhil D

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VIP V4L2 Sub Device