IMX8M - MINI Monochrome Grey RAW 8 Sensor support

[saideepak_r]

Issue   

We are evaluating a Monochrome camera and added GREY8 format in the platform driver side. Can't get the GREY8 frames in the application side. The application waits exactly at the DEQUE_BUF v4l2-ctl ioctl call. In the platform driver side we have added debug prints in the mx6s_capture.c. The debug prints stops exactly at the end of streamon function in the platform driver. Later it is in waiting state with no  error messages and frame. And there is no call to this mx6s_csi_irq_handler function.  

Value of CR18 register in csi_enable function is 0xd44ad030. 

Value of CR1 register in csi_enable_int function is 0x11b0902.

Note   

We previously evaluated with a UYVY camera and we were able to get frames successfully.   

Request   

Our side we have added necessary changes in dtb and platform driver side. Don’t know whether we are missing anything related to GREY8 format or anything that need to be added for GREY8 format. Waiting for your quick and valuable response.  
 
We use the below setup for development: 
   

DART-MX8M-MINI : NXP i.MX8M Mini   

Linux kernel : 4.14.78 

***I have attached the DTS and Kernel Patch for your reference.   

[Bio_TICFSL]

Hello Saideepak,

Which sensor do you use？

Have you tried to capture raw8 by ov5640?

For capturing ov5640 RAW8, you could use below format which has included in mx6s_capture.c and no need to add "GREY8 (Y8)" support.

 263         }, {                                                
 264                 .name           = "RAWRGB8 (SBGGR8)",       
 265                 .fourcc         = V4L2_PIX_FMT_SBGGR8,      
 266                 .pixelformat    = V4L2_PIX_FMT_SBGGR8,      
 267                 .mbus_code      = MEDIA_BUS_FMT_SBGGR8_1X8, 
 268                 .bpp            = 1,                        
 269         }               

Regards

[Bio_TICFSL]

BTW, Here are additional comments:

We previously evaluated with a UYVY camera and we were able to get frames successfully.

I believe you have 2 different cameras one UYVY camera and another monochrome camera. Is this understanding correct? If yes, I suggest to first try with the supported format like RGB or YUV. This will ensure that the monochrome camera that you are using is working well, with no modifications in BSP and commonly supported format. Then we would suggest continuing with the GREY8 format.

Can't get the GREY8 frames in the application side. The application waits exactly at the DEQUE_BUF v4l2-ctl ioctl call. In the platform driver side we have added debug prints in the mx6s_capture.c. The debug prints stops exactly at the end of streamon function in the platform driver. Later it is in waiting state with no  error messages and frame. And there is no call to this mx6s_csi_irq_handler function.  

It seems that you are not receiving any frames. The possible reason could be

1. The device is not detected over I2C
2. The clock signal is not generated(good to validate this on an oscilloscope)
3. Everything is okay but the frame receive interrupt is not received.
4. You definitely would have verified that the camera sensor you are using is supporting the GREY8 format. In case not please verify it once. If it is supporting, then have you enabled or written the registers of camera over I2C for GREY8 format? Can you share the camera module that you are using?
   
   Can you please share the logs of application and driver to identify where exactly it is stuck at the end of streamon function? Are you using the GStreamer pipeline or any other command? Can please share that as well?

Our side we have added necessary changes in dtb and platform driver side. Don’t know whether we are missing anything related to GREY8 format or anything that need to be added for GREY8 format.

Just a suggestion in case it helps, let the camera send the GREY8 format frames, capture the frame from SoC using RAW format only from v4l2-ctl ioctl. See if the frames are received at the driver level or not.

Regards