I2C control in Debian 17.06.1 for csi ov5640


#1

Hello all,

I am building a carrier board for apq8016e SOM, and I am updating from 16.06 to latest 17.06.1 Debian and getting some troubles detecting OV5640 camera.
Using Linaro debian 16.06 release from eInfochip, I get the camera to work and can take pictures (using I2C cci interface cam_i2c_sda and cam_i2c_scl). Then, in order to get better camera control, I updated the OS to the latest Linaro debian 17.06.1. And now the camera is no more detected; I suspect something is different regarding I2C bus controlling the camera between the 2 releases.
So here is my question: what pins from the processor are used for camera I2C control in the 17.06.1 release? If it is the dedicated cci lines, what could wrong then?

Thank you in advance for your help,

Victor


#2

Hi @Vix

I am not familiar with the eInfochips hardware. The APQ8016E contains 6 possible I2C controllers any one of which ‘could’ be connected to the camera. It is possible to use different controllers for each camera or to combine them and use a single controller for both cameras. The 17.06.1 kernel is set up for controller needed by the both the STMicro board, and the AiStarVision camera board (these both match the connections shown in the app note HERE. The D3 Engineering board uses a different connection, and the D3 Patches make the appropriate changes to the Device Tree to enable the correct controller.

It is very likely that eInfoChips made different choices and you will need to modify the device tree appropriately. Please check with eInfoChips for the appropriate settings for your board.

Full Disclosure: I am an employee of Qualcomm Canada, any opinions I may have expressed in this or any other post may not reflect the opinions of my employer.


#3

Thank you for your answer @ljking. The problem is solved.
For future reference, CCI was not working due to some conflict with the ADV HDMI chip; my custom board does not contain any hdmi chip, so I had to disable everything related to adv in the dtsi files, then camera control with CCI lines worked properly.