CSI-2 defines standard data transmission and control interfaces between transmitter and receiver.

• Data transmission interface (CSI-2)
• unidirectional differential serial interface with data and clock signals
• D-PHY for physical layer of CSI-2
• Control interface (CCI)
• bi-directional control interface compatible with I2C standard

• PHY layer (described in MIPI standard for D-PHY)
• Transmission medium
• Electrical parameters for signaling
• Timing relationship between clock and data lanes
• Protocol layer : The Protocol layer specifies how multiple data streams may be tagged and interleaved so each data stream can be properly reconstructed.
• Pixel/Byte packing/Unpacking layer : CSI-2 supports image applications with varying pixel formats from six to twenty-four bits per pixels. 8 bits per pixel data is transferred unchanged
• Transmitter : packs pixels from the Application layer into bytes before sending the data to the Low Level Protocol layer
• Receiver : unpacks bytes from the Low Level Protocol layer into pixels before sending the data to the Application layer
• Low level protocol : bit-level and byte-level synchronization for serial data transferred between SoT (Start of Transmission) and EoT (End of Transmission) events and for passing data to the next layer
• Transmitter : appends header and optional error-checking information on to data to be transmitted
• Receiver : header is stripped off and interpreted by corresponding logic in the receiver
• Lane management : CSI-2 is Lane-scalable for increased performance.
• Application layer : higher-level encoding and interpretation of data contained in the data stream. The CSI-2 specification describes the mapping of pixel values to bytes

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1. V4L2 community : linuxtv

http://www.linuxtv.org

2. V4L2 repository

http://linuxtv.org/hg/v4l-dvb/

GIT 이 아닌 mercurial 을 사용

3. Mailing list

- http://vger.kernel.org/vger-lists.html#linux-media : 2009년 1월 2일부로 kernel.org 로 통합

- http://www.redhat.com/mailman/listinfo/video4linux-list : old mailing list

4. New API changes work

The way new API changes work is:
1. You should do a proposal at linux-media ML. People will review it and comment.
2. You should also propose the changes for the V4L2 API documentation.

After all guys being happy with your proposal, the API changes will be merged
at the development tree (and later at upstream kernel) together with your driver.

5. Documents

- Official V4L2 API doc : http://www.linuxtv.org/downloads/video4linux/API/V4L2_API/

- Latest V4L2 API docs : http://linuxtv.org/hg/~hverkuil/v4l-dvb-spec/file/ffe42a65649f/v4l2-spec/ : Make 가필요

- For driver developer : http://www.linuxtv.org/downloads/video4linux/v4l2dwgNew.html

- V4lL2 articles : http://lwn.net/Articles/203924/

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Proposal for presentation on CELF

Hello.

My name is Dongsoo Kim. and may I propose for a presentation about “Framework for digital camera in Linux” ?

In these days we practically use devices with camera in general which is based on SoC camera subsystem.

And those camera devices have been definitely improved in functional and performance level.

Let me take a specific case of mobile phone. Many of our mobile phones have camera on them and even dual for 3G handsets.

In case of Linux based smartphones, we have to control camera devices with video4linux APIs and thats what I want to talk about.

We’ve got several video4linux APIs in Linux kernel already but thats not enough. Because they are mostly for USB PC cameras as known as “webcam”.

But as I mentioned above, camera devices have been improved these days and they are running like a real digital camera. They have shutter device, iris, and some devices support object detection and wide dynamic range functionality.

But video4linux APIs in kernel mainline cannot cover all of them because those APIs are just considering cameras of “webcam” level.

So we are defining new video4linux APIs for digital cameras and wanna explain how it works.

Our presentation covers several SoC camera drivers in linux and legacy video4linux APIs and new video4linux APIs for digital camera.

And we also want to talk about camera porting issues.

Thank you.

I’m also attaching presentation contents below. You can refer to them.

Camera platform (except for USB camera) called SoC based camera subsystem

• Various ways of preview (Live view) in SoC camera subsystems.
• SoC camera subsystem in Linux kernel aspect

Aggressive development in mobile camera module devices

• Legacy mobile camera modules are far behind latest ones in functional and performance level
• Latest mobile camera modules are very close to real cameras
• Needs of proper V4L2 APIs for real digital cameras

V4L2 and digital camera

• V4L2 and legacy camera modules
• Dual camera for 3G handset
• New V4L2 APIs for digital cameras

Issues of porting in SoC camera subsystem

• I2C issues
• Size negotiation issues
• color space negotiation issues
• Lens control issues
• JPEG data synchronization issues
• Gstreamer & OpenMax

See you at San Francisco, CA on April 6th - 8th, 2009

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