How to configure i.MX6Q to support camera parallel with greyscale 16-bit input data?

[liamtien]

• According to iMX6-IPU.pdf, camera parallel supports grayscale 16-bit data input, but why IPUx_CSI0_SENS_CONF register's bit 10–8 (CSI0_SENS_DATA_FORMAT) doesn't support grayscale 16-bit data input?

  Table 37-2. Data Formats Supported By The Camera Port

  Gray scale 8 bits  Yes

  Gray scale 16 bits  Written to the MSB of a 16-bit word

  Data format from the sensor. This field defines the data format for the input of the CSI sensor.

  Values:

  000 full RGB or YUV444

  001 YUV422 (YUYV...)

  010 YUV422 (UYVY...)

  011 Bayer or Generic data

  100 RGB565

  101 RGB555

  110 RGB444

  111 JPEG

  37.4.3.9 16 bit camera support

  16 bit RGB as generic data

  In this mode the CSI receives 3 components per cycle. If the external device is 24bit -

  the user can get connect a 16 bit sample of it (such as RGB565) The CSI is

  programmed to accept the data as 16 bit generic data.

  When the data is read back from the memory for further processing

  in the IPU it will be read as 16 bit RGB data. The IDMAC's mapping unit will be used

  to remap the 16 bit data to the internal 24bpp RGB format

    I follows above description to configure it to "16 bit RGB as generic data" mode. In hardware, our FPGA connects i.MX6Q with 8 data pins. FPGA sends 1-byte greyscale data twice,  i.e 16-bit per pixel.

• I am using Linux kernel v4.1.44, it is default to support YUYV format and can work.

• The attached p0.jpg is the captured picture. The left is FPGA's original input picture, the right is i.MX6Q captures and saved picture.

• The attached grey16.raw is the log file dumped from _ipu_ch_param_dump() which is called by ipu_init_channel_buffer() in ipu_common.c.

• How to modify my drivers? any patch I can reference?  Thank a lot in advcance!

[igorpadykov]

Hi liam

greyscale cameras are not supported in nxp bsps, 

however there are some posts covering some topics about raw capture:

IPU - bayer pattern conversion 
i.MX6Q MIPI CSI2: Capturing RAW12 generic data 
CSI -> IPU -> MEM retrieve 16 bits RAW DATA 
https://community.nxp.com/thread/319780 

Best regards
igor
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[liamtien]

Hi igor:

   Thanks for your quick answer.

We just want to get the imtact greyscale 16-bit data, i.e. the data is complete and in its original value, "what the data input is what the data output". Doesn't need to modify the data by i.MX6Q. 

  I  change to CSI -> IPU -> MEM to retrieve greyscale 16-bit data, but it stops at _ipu_dp_dc_disable, as follows. By the way, we don't use LCD to display it. Thansk!

   In _ipu_dp_dc_disable
   In _ipu_dp_dc_disable: irq=451
   imx-ipuv3 2800000.ipu: DC stop timeout - 1 * 10ms
   imx-ipuv3 2800000.ipu: ipu busfreq high release.