SK-AM62P-LP: MIPI DSI Display

Hello Wangpq

Thank you for the query.

Please add additional information on how you are testing, connecting the DSI and serdes including schematics or block diagram.

Is the DSI interface working OK during normal testing.

Regards,

Sreenivasa

When DSI was working normally, I simulated an abnormal power failure of Serdes (96755R PWDN short circuited to GND), and then re initialized Serdes by powering it on. Serdes could not receive the MIPI signal of the DSI interface of SOC normally.

Serdes technical support said that :  SOC should stop the MIPI signal of the DSI interface and then turn on the MIPI signal of the DSI interface, so that Serdes could receive the MIPI signal normally. 

so : 

    How to stop the output of MPI signal from DSI port on SOC?

    How to  start the output of MPI signal from DSI port on SOC? 

Hello Hello Wangpq

Thank you.

I am not sure on how the SOC understands the SERDES was powered cycled.

I suspect the current powering off method used could result in fail-safe operation.

Is the IO power supply for the attached device and the SOC sourced from same source.

Regards,

Sreenivasa

1. I use hardware line connections the serdes pin-pwdn to gnd, the serdes will stop work.

2. and then disConnection the pin-pwdn to gnd, the Serdes is work reset

3. initialized Serdes register, Serdes work normally.

this is not for SOC IO ctrl power supply.

Hello Hello Wangpq

Thank you.

Wangpq said:

3. initialized Serdes register, Serdes work normally.

Is the issue resolved?

Regards,

Sreenivasa

NO, Serdes cannot accept DSI MIPI signal.

 i ask serdes technical, erdes technical support said that : 

    1. SOC should stop the MIPI signal of the DSI interface.

    2. then turn on the MIPI signal of the DSI interface.

    so that Serdes could receive the MIPI signal normally. 

so : 

    How to stop the output of MPI signal from DSI port on SOC?

    How to  start the output of MPI signal from DSI port on SOC? 

 Hello Wangpq

Thank you.

Let me check with the experts and update you.

Regards,

Sreenivasa

 Hello Wangpq

 I checked with the design team and understood there is no way to reset the DSI interface when an error occurs. Only way to reset is unloading the drivers and following the initialization sequence in the driver to initialize the DSI 

Can you please check if this works.

I am continuing to check internally. 

Regards,

Sreenivasa 

Hi

  I rmmod the serdes.ko, the dsi mipi is not stop! 

  Can  dsi_j721e_enable and dsi_j721e_disable stop the DPHY to start/stop MIPI signal ?

&dphy_tx0 {
	compatible = "ti,j721e-dphy";
	status = "okay";
};

I change the j721e-dsi register：

    When starting up, the initialization value of the j721e-dsi register MCTL_MAIN_EN is 0x000040f9. 

    disable (0x000040f1) the dsi mipi signal (clk and data[1~4]) is stop.

    enable (0x000040f9) the dsi mipi clk is start, but data[1~4] is not start.

please help me resolve this issue:

    why  enable (0x000040f9) the dsi mipi clk is start, but data[1~4] is not start.?

How to Reset DSS Module and reInit DSS Module?

Hello Kallikuppa Sreenivasa

 the  j721e-dsi register VID_MODE_STS(val=0x00000403) have error, how to resolve?

Dear Pengqi.

Per discussed, it is not possible to pause MIPI output then resume as you tried.

and please check  below answer from Sreenivasa to your question.

"I checked with the design team and understood there is no way to reset the DSI interface when an error occurs. Only way to reset is unloading the drivers and following the initialization sequence in the driver to initialize the DSI "

Wangpq said:

How to Reset DSS Module and reInit DSS Module?

thanks a lot!

yong

Hello Wangpq

Thank you and good to hear the progress.

Would you mind adding a couple of sentences on the resolution that can help other users.

Regards,

Sreenivasa