ADV7535 support for imx8x Linux 5.10.72

[vasujoshi]

Hi,

I am using Linux 5.10.72 kernel for my project which contains adv7535 converter and HDMI display.

- i can communicate with the ADV7535 via I2C to retrieve chip ID as well as read/write registers (have not observed errors on register initialization)
-HPD interrupts are triggering as expected
- drm connector registering correctly and can read cable status from userspace (/sys/class/drm/card0-HDMI-A-1/status)

But, display is not working. I will get error "no signal" on display.

My dts settings are like shown below :

Attached the logs for your reference.

Can i get help here to resolve this issue.

Best Regards

Vasu Joshi

[Dhruvit]

Hi @vasujoshi,

I hope you are doing well

Please mention from two ports on which port you are connecting to MIPI-DSI(0 or 1).

Thanks & Regards

Dhruvit Vasavada

[vasujoshi]

MIPI-DSI 0

[Dhruvit]

Hi @vasujoshi,

I hope you are doing well

Each display has a Display init sequence and it is vendor specific.

Please check the Display init sequence for the display you are using.

Thanks & Regards,

Dhruvit Vasavada.

[vasujoshi]

Are you addressing to power up sequence of adv7535 (MIPI DSI to HDMI converter) or display ?

As per my knowledge, display will not have any power up sequence. I am using a LCD display through HDMI connector. 

[Dhruvit]

Hi @vasujoshi,

I hope you are doing well

Kindly mention the part number of the display you are using.  

Please share the datasheet of the display.

Kindly share the driver you are using for the display for further debugging.

Thanks & Regards,

Dhruvit Vasavada

[vasujoshi]

Hi Druvit,

The below diagram explains our setup which we are using and will give you the information which you asked :

Attached the kernel configuration which i used.

DTS settings already given in the first post.

[Dhruvit]

Hi @vasujoshi 

I hope you are doing well

Please try the below steps:

1. Flash fsl-imx8mq-evk-dcss-adv7535.dtb in your SD card's Boot partition.
2. In u-boot : setenv fdt_file fsl-imx8mq-evk-dcss-adv7535.dtb
3. saveenv
4. boot the board.

Please find this file for more information.

https://www.nxp.com/docs/en/application-note/AN12188.pdf 

If the issue is not related to this kindly share the datasheet of your display.

Thanks & Regards,

Dhruvit Vasavada

[vasujoshi]

Hi,

We cannot use fsl-imx8mq-evk-dcss-adv7535.dtb because we are using imx8x SoC.

[Dhruvit]

Hi @vasujoshi,

Please share the timing and resolution that is supported in HDMI.

Does the HDMI display support EDID? 

The BSP adv7535 driver needs to read EDID from the HDMI display side and then set it to DPU to generate the display timing. 

Please share the output of the below command.

cat /sys/class/graphics/fb0/modes

Thanks & Regards,
Dhruvit Vasavada

[vasujoshi]

Yes,

We are able to read EDID from display like shown in attachment. And we are able to read other status also properly. 

cat /sys/class/graphics/fb0/modes --> i hope this output will not be helpful here. because iMX8 will not support frame buffers.

[Dhruvit]

Hi @vasujoshi,

I hope you are doing well.

we tested this EDID on the iMX8QXP MEK board with the adv7535 adaptor, it works fine. Since it can't work on your side, maybe you need to check your hardware.

The tested BSP is L5.10.72_2.2.0. And I connected an HDMI TV as the display, it can show the current video mode on the screen.

Attached is the test patch and result on the HDMI screen.

Thanks & Regards,
Dhruvit Vasavada