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V4l2 subdev support - custom_board - 96Boards Forum

V4l2 subdev support

#1

Hi all,

I am controlling spi slave device with my spi-tool which uses linux,spidev in kernel. It is working fine.
I want to connect this slave device to CSI camera port. Basically i have to create a sub dev driver. Somehow i faked with v4l2_i2c_subdev registration and added slave under i2c node, so probe succeded. I am focusing on video part, control part is from spi-tool. I am testing with yavta. DQBUF is not receiving any buffers. Let me know the possible ways to debug the issue. I probed CSI lanes, I could see data traffic. Clock everything is fine.
what could be the reason for not receiving buffers?
@todortomov, @Loic any ideas?
I am sorry, i am working on mediatek platform now. I know this forum is for db820c.
Thanks,
Pradeep

#2

For all 96Boards.

I can not say much, you need to identify the MediaTek video interface driver (CSI, parallel…), and check that it’s correctly started on capture, also check that interrupts are triggered (e.g. on start of frame, dma done…).

#3

Hi @Loic,
Yes, i managed to get framedata from csi video node. I am getting csi irq’s, Vb2_buf_done is happening . I am able to dump frames to file but frames are black. When i open the file with text editor, all are zeros. It seems dummy bytes are written to file. My video format is RGB24. In Mediatek csi driver, only yuv support is there. I asked mediatek about RGB support.
Do you know how to do conversion from rgb_24 to yuyv_8 format on v4l2 buffer?

Thanks,
Pradeep